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-rw-r--r--src/linenoise/linenoise.cpp3457
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diff --git a/src/linenoise/linenoise.cpp b/src/linenoise/linenoise.cpp
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+/* linenoise.c -- guerrilla line editing library against the idea that a
+ * line editing lib needs to be 20,000 lines of C code.
+ *
+ * Copyright (c) 2010, Salvatore Sanfilippo <antirez at gmail dot com>
+ * Copyright (c) 2010, Pieter Noordhuis <pcnoordhuis at gmail dot com>
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Redis nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * line editing lib needs to be 20,000 lines of C code.
+ *
+ * You can find the latest source code at:
+ *
+ *   http://github.com/antirez/linenoise
+ *
+ * Does a number of crazy assumptions that happen to be true in 99.9999% of
+ * the 2010 UNIX computers around.
+ *
+ * References:
+ * - http://invisible-island.net/xterm/ctlseqs/ctlseqs.html
+ * - http://www.3waylabs.com/nw/WWW/products/wizcon/vt220.html
+ *
+ * Todo list:
+ * - Switch to gets() if $TERM is something we can't support.
+ * - Filter bogus Ctrl+<char> combinations.
+ * - Win32 support
+ *
+ * Bloat:
+ * - Completion?
+ * - History search like Ctrl+r in readline?
+ *
+ * List of escape sequences used by this program, we do everything just
+ * with three sequences. In order to be so cheap we may have some
+ * flickering effect with some slow terminal, but the lesser sequences
+ * the more compatible.
+ *
+ * CHA (Cursor Horizontal Absolute)
+ *    Sequence: ESC [ n G
+ *    Effect: moves cursor to column n (1 based)
+ *
+ * EL (Erase Line)
+ *    Sequence: ESC [ n K
+ *    Effect: if n is 0 or missing, clear from cursor to end of line
+ *    Effect: if n is 1, clear from beginning of line to cursor
+ *    Effect: if n is 2, clear entire line
+ *
+ * CUF (Cursor Forward)
+ *    Sequence: ESC [ n C
+ *    Effect: moves cursor forward of n chars
+ *
+ * The following are used to clear the screen: ESC [ H ESC [ 2 J
+ * This is actually composed of two sequences:
+ *
+ * cursorhome
+ *    Sequence: ESC [ H
+ *    Effect: moves the cursor to upper left corner
+ *
+ * ED2 (Clear entire screen)
+ *    Sequence: ESC [ 2 J
+ *    Effect: clear the whole screen
+ *
+ */
+
+#ifdef _WIN32
+
+#include <conio.h>
+#include <windows.h>
+#include <io.h>
+
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#define snprintf _snprintf  // Microsoft headers use underscores in some names
+#endif
+
+#if !defined GNUC
+#define strcasecmp _stricmp
+#endif
+
+#define strdup _strdup
+#define isatty _isatty
+#define write _write
+#define STDIN_FILENO 0
+
+#else /* _WIN32 */
+
+#include <signal.h>
+#include <termios.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <cctype>
+#include <wctype.h>
+
+#endif /* _WIN32 */
+
+#include <stdio.h>
+#include <errno.h>
+#include <fcntl.h>
+
+#include "linenoise.h"
+#include "ConvertUTF.h"
+
+#include <string>
+#include <vector>
+#include <memory>
+
+using std::string;
+using std::vector;
+using std::unique_ptr;
+using namespace linenoise_ng;
+
+typedef unsigned char char8_t;
+
+static ConversionResult copyString8to32(char32_t* dst, size_t dstSize,
+                                        size_t& dstCount, const char* src) {
+  const UTF8* sourceStart = reinterpret_cast<const UTF8*>(src);
+  const UTF8* sourceEnd = sourceStart + strlen(src);
+  UTF32* targetStart = reinterpret_cast<UTF32*>(dst);
+  UTF32* targetEnd = targetStart + dstSize;
+
+  ConversionResult res = ConvertUTF8toUTF32(
+      &sourceStart, sourceEnd, &targetStart, targetEnd, lenientConversion);
+
+  if (res == conversionOK) {
+    dstCount = targetStart - reinterpret_cast<UTF32*>(dst);
+
+    if (dstCount < dstSize) {
+      *targetStart = 0;
+    }
+  }
+
+  return res;
+}
+
+static ConversionResult copyString8to32(char32_t* dst, size_t dstSize,
+                                        size_t& dstCount, const char8_t* src) {
+  return copyString8to32(dst, dstSize, dstCount,
+                         reinterpret_cast<const char*>(src));
+}
+
+static size_t strlen32(const char32_t* str) {
+  const char32_t* ptr = str;
+
+  while (*ptr) {
+    ++ptr;
+  }
+
+  return ptr - str;
+}
+
+static size_t strlen8(const char8_t* str) {
+  return strlen(reinterpret_cast<const char*>(str));
+}
+
+static char8_t* strdup8(const char* src) {
+  return reinterpret_cast<char8_t*>(strdup(src));
+}
+
+#ifdef _WIN32
+static const int FOREGROUND_WHITE =
+    FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE;
+static const int BACKGROUND_WHITE =
+    BACKGROUND_RED | BACKGROUND_GREEN | BACKGROUND_BLUE;
+static const int INTENSITY = FOREGROUND_INTENSITY | BACKGROUND_INTENSITY;
+
+class WinAttributes {
+ public:
+  WinAttributes() {
+    CONSOLE_SCREEN_BUFFER_INFO info;
+    GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &info);
+    _defaultAttribute = info.wAttributes & INTENSITY;
+    _defaultColor = info.wAttributes & FOREGROUND_WHITE;
+    _defaultBackground = info.wAttributes & BACKGROUND_WHITE;
+
+    _consoleAttribute = _defaultAttribute;
+    _consoleColor = _defaultColor | _defaultBackground;
+  }
+
+ public:
+  int _defaultAttribute;
+  int _defaultColor;
+  int _defaultBackground;
+
+  int _consoleAttribute;
+  int _consoleColor;
+};
+
+static WinAttributes WIN_ATTR;
+
+static void copyString32to16(char16_t* dst, size_t dstSize, size_t* dstCount,
+                             const char32_t* src, size_t srcSize) {
+  const UTF32* sourceStart = reinterpret_cast<const UTF32*>(src);
+  const UTF32* sourceEnd = sourceStart + srcSize;
+  char16_t* targetStart = reinterpret_cast<char16_t*>(dst);
+  char16_t* targetEnd = targetStart + dstSize;
+
+  ConversionResult res = ConvertUTF32toUTF16(
+      &sourceStart, sourceEnd, &targetStart, targetEnd, lenientConversion);
+
+  if (res == conversionOK) {
+    *dstCount = targetStart - reinterpret_cast<char16_t*>(dst);
+
+    if (*dstCount < dstSize) {
+      *targetStart = 0;
+    }
+  }
+}
+#endif
+
+static void copyString32to8(char* dst, size_t dstSize, size_t* dstCount,
+                            const char32_t* src, size_t srcSize) {
+  const UTF32* sourceStart = reinterpret_cast<const UTF32*>(src);
+  const UTF32* sourceEnd = sourceStart + srcSize;
+  UTF8* targetStart = reinterpret_cast<UTF8*>(dst);
+  UTF8* targetEnd = targetStart + dstSize;
+
+  ConversionResult res = ConvertUTF32toUTF8(
+      &sourceStart, sourceEnd, &targetStart, targetEnd, lenientConversion);
+
+  if (res == conversionOK) {
+    *dstCount = targetStart - reinterpret_cast<UTF8*>(dst);
+
+    if (*dstCount < dstSize) {
+      *targetStart = 0;
+    }
+  }
+}
+
+static void copyString32to8(char* dst, size_t dstLen, const char32_t* src) {
+  size_t dstCount = 0;
+  copyString32to8(dst, dstLen, &dstCount, src, strlen32(src));
+}
+
+static void copyString32(char32_t* dst, const char32_t* src, size_t len) {
+  while (0 < len && *src) {
+    *dst++ = *src++;
+    --len;
+  }
+
+  *dst = 0;
+}
+
+static int strncmp32(const char32_t* left, const char32_t* right, size_t len) {
+  while (0 < len && *left) {
+    if (*left != *right) {
+      return *left - *right;
+    }
+
+    ++left;
+    ++right;
+    --len;
+  }
+
+  return 0;
+}
+
+#ifdef _WIN32
+#include <iostream>
+
+static size_t OutputWin(char16_t* text16, char32_t* text32, size_t len32) {
+  size_t count16 = 0;
+
+  copyString32to16(text16, len32, &count16, text32, len32);
+  WriteConsoleW(GetStdHandle(STD_OUTPUT_HANDLE), text16,
+                static_cast<DWORD>(count16), nullptr, nullptr);
+
+  return count16;
+}
+
+static char32_t* HandleEsc(char32_t* p, char32_t* end) {
+  if (*p == '[') {
+    int code = 0;
+
+    for (++p; p < end; ++p) {
+      char32_t c = *p;
+
+      if ('0' <= c && c <= '9') {
+        code = code * 10 + (c - '0');
+      } else if (c == 'm' || c == ';') {
+        switch (code) {
+          case 0:
+            WIN_ATTR._consoleAttribute = WIN_ATTR._defaultAttribute;
+            WIN_ATTR._consoleColor =
+                WIN_ATTR._defaultColor | WIN_ATTR._defaultBackground;
+            break;
+
+          case 1:  // BOLD
+          case 5:  // BLINK
+            WIN_ATTR._consoleAttribute =
+                (WIN_ATTR._defaultAttribute ^ FOREGROUND_INTENSITY) & INTENSITY;
+            break;
+
+          case 30:
+            WIN_ATTR._consoleColor = BACKGROUND_WHITE;
+            break;
+
+          case 31:
+            WIN_ATTR._consoleColor =
+                FOREGROUND_RED | WIN_ATTR._defaultBackground;
+            break;
+
+          case 32:
+            WIN_ATTR._consoleColor =
+                FOREGROUND_GREEN | WIN_ATTR._defaultBackground;
+            break;
+
+          case 33:
+            WIN_ATTR._consoleColor =
+                FOREGROUND_RED | FOREGROUND_GREEN | WIN_ATTR._defaultBackground;
+            break;
+
+          case 34:
+            WIN_ATTR._consoleColor =
+                FOREGROUND_BLUE | WIN_ATTR._defaultBackground;
+            break;
+
+          case 35:
+            WIN_ATTR._consoleColor =
+                FOREGROUND_BLUE | FOREGROUND_RED | WIN_ATTR._defaultBackground;
+            break;
+
+          case 36:
+            WIN_ATTR._consoleColor = FOREGROUND_BLUE | FOREGROUND_GREEN |
+                                     WIN_ATTR._defaultBackground;
+            break;
+
+          case 37:
+            WIN_ATTR._consoleColor = FOREGROUND_GREEN | FOREGROUND_RED |
+                                     FOREGROUND_BLUE |
+                                     WIN_ATTR._defaultBackground;
+            break;
+        }
+
+        code = 0;
+      }
+
+      if (*p == 'm') {
+        ++p;
+        break;
+      }
+    }
+  } else {
+    ++p;
+  }
+
+  auto handle = GetStdHandle(STD_OUTPUT_HANDLE);
+  SetConsoleTextAttribute(handle,
+                          WIN_ATTR._consoleAttribute | WIN_ATTR._consoleColor);
+
+  return p;
+}
+
+static size_t WinWrite32(char16_t* text16, char32_t* text32, size_t len32) {
+  char32_t* p = text32;
+  char32_t* q = p;
+  char32_t* e = text32 + len32;
+  size_t count16 = 0;
+
+  while (p < e) {
+    if (*p == 27) {
+      if (q < p) {
+        count16 += OutputWin(text16, q, p - q);
+      }
+
+      q = p = HandleEsc(p + 1, e);
+    } else {
+      ++p;
+    }
+  }
+
+  if (q < p) {
+    count16 += OutputWin(text16, q, p - q);
+  }
+
+  return count16;
+}
+#endif
+
+static int write32(int fd, char32_t* text32, int len32) {
+#ifdef _WIN32
+  if (isatty(fd)) {
+    size_t len16 = 2 * len32 + 1;
+    unique_ptr<char16_t[]> text16(new char16_t[len16]);
+    size_t count16 = WinWrite32(text16.get(), text32, len32);
+
+    return static_cast<int>(count16);
+  } else {
+    size_t len8 = 4 * len32 + 1;
+    unique_ptr<char[]> text8(new char[len8]);
+    size_t count8 = 0;
+
+    copyString32to8(text8.get(), len8, &count8, text32, len32);
+
+    return write(fd, text8.get(), static_cast<unsigned int>(count8));
+  }
+#else
+  size_t len8 = 4 * len32 + 1;
+  unique_ptr<char[]> text8(new char[len8]);
+  size_t count8 = 0;
+
+  copyString32to8(text8.get(), len8, &count8, text32, len32);
+
+  return write(fd, text8.get(), count8);
+#endif
+}
+
+class Utf32String {
+ public:
+  Utf32String() : _length(0), _data(nullptr) { 
+    // note: parens intentional, _data must be properly initialized
+    _data = new char32_t[1](); 
+  }
+
+  explicit Utf32String(const char* src) : _length(0), _data(nullptr) {
+    size_t len = strlen(src);
+    // note: parens intentional, _data must be properly initialized
+    _data = new char32_t[len + 1]();
+    copyString8to32(_data, len + 1, _length, src);
+  }
+
+  explicit Utf32String(const char8_t* src) : _length(0), _data(nullptr) {
+    size_t len = strlen(reinterpret_cast<const char*>(src));
+    // note: parens intentional, _data must be properly initialized
+    _data = new char32_t[len + 1]();
+    copyString8to32(_data, len + 1, _length, src);
+  }
+
+  explicit Utf32String(const char32_t* src) : _length(0), _data(nullptr) {
+    for (_length = 0; src[_length] != 0; ++_length) {
+    }
+
+    // note: parens intentional, _data must be properly initialized
+    _data = new char32_t[_length + 1]();
+    memcpy(_data, src, _length * sizeof(char32_t));
+  }
+
+  explicit Utf32String(const char32_t* src, int len) : _length(len), _data(nullptr) {
+    // note: parens intentional, _data must be properly initialized
+    _data = new char32_t[len + 1]();
+    memcpy(_data, src, len * sizeof(char32_t));
+  }
+
+  explicit Utf32String(int len) : _length(0), _data(nullptr) { 
+    // note: parens intentional, _data must be properly initialized
+    _data = new char32_t[len](); 
+  }
+
+  explicit Utf32String(const Utf32String& that) : _length(that._length), _data(nullptr) {
+    // note: parens intentional, _data must be properly initialized
+    _data = new char32_t[_length + 1]();
+    memcpy(_data, that._data, sizeof(char32_t) * _length);
+  }
+
+  Utf32String& operator=(const Utf32String& that) {
+    if (this != &that) {
+      delete[] _data;
+      _data = new char32_t[that._length]();
+      _length = that._length;
+      memcpy(_data, that._data, sizeof(char32_t) * _length);
+    }
+
+    return *this;
+  }
+
+  ~Utf32String() { delete[] _data; }
+
+ public:
+  char32_t* get() const { return _data; }
+
+  size_t length() const { return _length; }
+
+  size_t chars() const { return _length; }
+
+  void initFromBuffer() {
+    for (_length = 0; _data[_length] != 0; ++_length) {
+    }
+  }
+
+  const char32_t& operator[](size_t pos) const { return _data[pos]; }
+
+  char32_t& operator[](size_t pos) { return _data[pos]; }
+
+ private:
+  size_t _length;
+  char32_t* _data;
+};
+
+class Utf8String {
+  Utf8String(const Utf8String&) = delete;
+  Utf8String& operator=(const Utf8String&) = delete;
+
+ public:
+  explicit Utf8String(const Utf32String& src) {
+    size_t len = src.length() * 4 + 1;
+    _data = new char[len];
+    copyString32to8(_data, len, src.get());
+  }
+
+  ~Utf8String() { delete[] _data; }
+
+ public:
+  char* get() const { return _data; }
+
+ private:
+  char* _data;
+};
+
+struct linenoiseCompletions {
+  vector<Utf32String> completionStrings;
+};
+
+#define LINENOISE_DEFAULT_HISTORY_MAX_LEN 100
+#define LINENOISE_MAX_LINE 4096
+
+// make control-characters more readable
+#define ctrlChar(upperCaseASCII) (upperCaseASCII - 0x40)
+
+/**
+ * Recompute widths of all characters in a char32_t buffer
+ * @param text          input buffer of Unicode characters
+ * @param widths        output buffer of character widths
+ * @param charCount     number of characters in buffer
+ */
+namespace linenoise_ng {
+int mk_wcwidth(char32_t ucs);
+}
+
+static void recomputeCharacterWidths(const char32_t* text, char* widths,
+                                     int charCount) {
+  for (int i = 0; i < charCount; ++i) {
+    widths[i] = mk_wcwidth(text[i]);
+  }
+}
+
+/**
+ * Calculate a new screen position given a starting position, screen width and
+ * character count
+ * @param x             initial x position (zero-based)
+ * @param y             initial y position (zero-based)
+ * @param screenColumns screen column count
+ * @param charCount     character positions to advance
+ * @param xOut          returned x position (zero-based)
+ * @param yOut          returned y position (zero-based)
+ */
+static void calculateScreenPosition(int x, int y, int screenColumns,
+                                    int charCount, int& xOut, int& yOut) {
+  xOut = x;
+  yOut = y;
+  int charsRemaining = charCount;
+  while (charsRemaining > 0) {
+    int charsThisRow = (x + charsRemaining < screenColumns) ? charsRemaining
+                                                            : screenColumns - x;
+    xOut = x + charsThisRow;
+    yOut = y;
+    charsRemaining -= charsThisRow;
+    x = 0;
+    ++y;
+  }
+  if (xOut == screenColumns) {  // we have to special-case line wrap
+    xOut = 0;
+    ++yOut;
+  }
+}
+
+/**
+ * Calculate a column width using mk_wcswidth()
+ * @param buf32  text to calculate
+ * @param len    length of text to calculate
+ */
+namespace linenoise_ng {
+int mk_wcswidth(const char32_t* pwcs, size_t n);
+}
+
+static int calculateColumnPosition(char32_t* buf32, int len) {
+  int width = mk_wcswidth(reinterpret_cast<const char32_t*>(buf32), len);
+  if (width == -1)
+    return len;
+  else
+    return width;
+}
+
+static bool isControlChar(char32_t testChar) {
+  return (testChar < ' ') ||                      // C0 controls
+         (testChar >= 0x7F && testChar <= 0x9F);  // DEL and C1 controls
+}
+
+struct PromptBase {            // a convenience struct for grouping prompt info
+  Utf32String promptText;      // our copy of the prompt text, edited
+  char* promptCharWidths;      // character widths from mk_wcwidth()
+  int promptChars;             // chars in promptText
+  int promptBytes;             // bytes in promptText
+  int promptExtraLines;        // extra lines (beyond 1) occupied by prompt
+  int promptIndentation;       // column offset to end of prompt
+  int promptLastLinePosition;  // index into promptText where last line begins
+  int promptPreviousInputLen;  // promptChars of previous input line, for
+                               // clearing
+  int promptCursorRowOffset;   // where the cursor is relative to the start of
+                               // the prompt
+  int promptScreenColumns;     // width of screen in columns
+  int promptPreviousLen;       // help erasing
+  int promptErrorCode;         // error code (invalid UTF-8) or zero
+
+  PromptBase() : promptPreviousInputLen(0) {}
+
+  bool write() {
+    if (write32(1, promptText.get(), promptBytes) == -1) return false;
+
+    return true;
+  }
+};
+
+struct PromptInfo : public PromptBase {
+  PromptInfo(const char* textPtr, int columns) {
+    promptExtraLines = 0;
+    promptLastLinePosition = 0;
+    promptPreviousLen = 0;
+    promptScreenColumns = columns;
+    Utf32String tempUnicode(textPtr);
+
+    // strip control characters from the prompt -- we do allow newline
+    char32_t* pIn = tempUnicode.get();
+    char32_t* pOut = pIn;
+
+    int len = 0;
+    int x = 0;
+
+    bool const strip = (isatty(1) == 0);
+
+    while (*pIn) {
+      char32_t c = *pIn;
+      if ('\n' == c || !isControlChar(c)) {
+        *pOut = c;
+        ++pOut;
+        ++pIn;
+        ++len;
+        if ('\n' == c || ++x >= promptScreenColumns) {
+          x = 0;
+          ++promptExtraLines;
+          promptLastLinePosition = len;
+        }
+      } else if (c == '\x1b') {
+        if (strip) {
+          // jump over control chars
+          ++pIn;
+          if (*pIn == '[') {
+            ++pIn;
+            while (*pIn && ((*pIn == ';') || ((*pIn >= '0' && *pIn <= '9')))) {
+              ++pIn;
+            }
+            if (*pIn == 'm') {
+              ++pIn;
+            }
+          }
+        } else {
+          // copy control chars
+          *pOut = *pIn;
+          ++pOut;
+          ++pIn;
+          if (*pIn == '[') {
+            *pOut = *pIn;
+            ++pOut;
+            ++pIn;
+            while (*pIn && ((*pIn == ';') || ((*pIn >= '0' && *pIn <= '9')))) {
+              *pOut = *pIn;
+              ++pOut;
+              ++pIn;
+            }
+            if (*pIn == 'm') {
+              *pOut = *pIn;
+              ++pOut;
+              ++pIn;
+            }
+          }
+        }
+      } else {
+        ++pIn;
+      }
+    }
+    *pOut = 0;
+    promptChars = len;
+    promptBytes = static_cast<int>(pOut - tempUnicode.get());
+    promptText = tempUnicode;
+
+    promptIndentation = len - promptLastLinePosition;
+    promptCursorRowOffset = promptExtraLines;
+  }
+};
+
+// Used with DynamicPrompt (history search)
+//
+static const Utf32String forwardSearchBasePrompt("(i-search)`");
+static const Utf32String reverseSearchBasePrompt("(reverse-i-search)`");
+static const Utf32String endSearchBasePrompt("': ");
+static Utf32String
+    previousSearchText;  // remembered across invocations of linenoise()
+
+// changing prompt for "(reverse-i-search)`text':" etc.
+//
+struct DynamicPrompt : public PromptBase {
+  Utf32String searchText;  // text we are searching for
+  char* searchCharWidths;  // character widths from mk_wcwidth()
+  int searchTextLen;       // chars in searchText
+  int direction;           // current search direction, 1=forward, -1=reverse
+
+  DynamicPrompt(PromptBase& pi, int initialDirection)
+      : searchTextLen(0), direction(initialDirection) {
+    promptScreenColumns = pi.promptScreenColumns;
+    promptCursorRowOffset = 0;
+    Utf32String emptyString(1);
+    searchText = emptyString;
+    const Utf32String* basePrompt =
+        (direction > 0) ? &forwardSearchBasePrompt : &reverseSearchBasePrompt;
+    size_t promptStartLength = basePrompt->length();
+    promptChars =
+        static_cast<int>(promptStartLength + endSearchBasePrompt.length());
+    promptBytes = promptChars;
+    promptLastLinePosition = promptChars;  // TODO fix this, we are asssuming
+                                           // that the history prompt won't wrap
+                                           // (!)
+    promptPreviousLen = promptChars;
+    Utf32String tempUnicode(promptChars + 1);
+    memcpy(tempUnicode.get(), basePrompt->get(),
+           sizeof(char32_t) * promptStartLength);
+    memcpy(&tempUnicode[promptStartLength], endSearchBasePrompt.get(),
+           sizeof(char32_t) * (endSearchBasePrompt.length() + 1));
+    tempUnicode.initFromBuffer();
+    promptText = tempUnicode;
+    calculateScreenPosition(0, 0, pi.promptScreenColumns, promptChars,
+                            promptIndentation, promptExtraLines);
+  }
+
+  void updateSearchPrompt(void) {
+    const Utf32String* basePrompt =
+        (direction > 0) ? &forwardSearchBasePrompt : &reverseSearchBasePrompt;
+    size_t promptStartLength = basePrompt->length();
+    promptChars = static_cast<int>(promptStartLength + searchTextLen +
+                                   endSearchBasePrompt.length());
+    promptBytes = promptChars;
+    Utf32String tempUnicode(promptChars + 1);
+    memcpy(tempUnicode.get(), basePrompt->get(),
+           sizeof(char32_t) * promptStartLength);
+    memcpy(&tempUnicode[promptStartLength], searchText.get(),
+           sizeof(char32_t) * searchTextLen);
+    size_t endIndex = promptStartLength + searchTextLen;
+    memcpy(&tempUnicode[endIndex], endSearchBasePrompt.get(),
+           sizeof(char32_t) * (endSearchBasePrompt.length() + 1));
+    tempUnicode.initFromBuffer();
+    promptText = tempUnicode;
+  }
+
+  void updateSearchText(const char32_t* textPtr) {
+    Utf32String tempUnicode(textPtr);
+    searchTextLen = static_cast<int>(tempUnicode.chars());
+    searchText = tempUnicode;
+    updateSearchPrompt();
+  }
+};
+
+class KillRing {
+  static const int capacity = 10;
+  int size;
+  int index;
+  char indexToSlot[10];
+  vector<Utf32String> theRing;
+
+ public:
+  enum action { actionOther, actionKill, actionYank };
+  action lastAction;
+  size_t lastYankSize;
+
+  KillRing() : size(0), index(0), lastAction(actionOther) {
+    theRing.reserve(capacity);
+  }
+
+  void kill(const char32_t* text, int textLen, bool forward) {
+    if (textLen == 0) {
+      return;
+    }
+    Utf32String killedText(text, textLen);
+    if (lastAction == actionKill && size > 0) {
+      int slot = indexToSlot[0];
+      int currentLen = static_cast<int>(theRing[slot].length());
+      int resultLen = currentLen + textLen;
+      Utf32String temp(resultLen + 1);
+      if (forward) {
+        memcpy(temp.get(), theRing[slot].get(), currentLen * sizeof(char32_t));
+        memcpy(&temp[currentLen], killedText.get(), textLen * sizeof(char32_t));
+      } else {
+        memcpy(temp.get(), killedText.get(), textLen * sizeof(char32_t));
+        memcpy(&temp[textLen], theRing[slot].get(),
+               currentLen * sizeof(char32_t));
+      }
+      temp[resultLen] = 0;
+      temp.initFromBuffer();
+      theRing[slot] = temp;
+    } else {
+      if (size < capacity) {
+        if (size > 0) {
+          memmove(&indexToSlot[1], &indexToSlot[0], size);
+        }
+        indexToSlot[0] = size;
+        size++;
+        theRing.push_back(killedText);
+      } else {
+        int slot = indexToSlot[capacity - 1];
+        theRing[slot] = killedText;
+        memmove(&indexToSlot[1], &indexToSlot[0], capacity - 1);
+        indexToSlot[0] = slot;
+      }
+      index = 0;
+    }
+  }
+
+  Utf32String* yank() { return (size > 0) ? &theRing[indexToSlot[index]] : 0; }
+
+  Utf32String* yankPop() {
+    if (size == 0) {
+      return 0;
+    }
+    ++index;
+    if (index == size) {
+      index = 0;
+    }
+    return &theRing[indexToSlot[index]];
+  }
+};
+
+class InputBuffer {
+  char32_t* buf32;   // input buffer
+  char* charWidths;  // character widths from mk_wcwidth()
+  int buflen;        // buffer size in characters
+  int len;           // length of text in input buffer
+  int pos;           // character position in buffer ( 0 <= pos <= len )
+
+  void clearScreen(PromptBase& pi);
+  int incrementalHistorySearch(PromptBase& pi, int startChar);
+  int completeLine(PromptBase& pi);
+  void refreshLine(PromptBase& pi);
+
+ public:
+  InputBuffer(char32_t* buffer, char* widthArray, int bufferLen)
+      : buf32(buffer),
+        charWidths(widthArray),
+        buflen(bufferLen - 1),
+        len(0),
+        pos(0) {
+    buf32[0] = 0;
+  }
+  void preloadBuffer(const char* preloadText) {
+    size_t ucharCount = 0;
+    copyString8to32(buf32, buflen + 1, ucharCount, preloadText);
+    recomputeCharacterWidths(buf32, charWidths, static_cast<int>(ucharCount));
+    len = static_cast<int>(ucharCount);
+    pos = static_cast<int>(ucharCount);
+  }
+  int getInputLine(PromptBase& pi);
+  int length(void) const { return len; }
+};
+
+// Special codes for keyboard input:
+//
+// Between Windows and the various Linux "terminal" programs, there is some
+// pretty diverse behavior in the "scan codes" and escape sequences we are
+// presented with.  So ... we'll translate them all into our own pidgin
+// pseudocode, trying to stay out of the way of UTF-8 and international
+// characters.  Here's the general plan.
+//
+// "User input keystrokes" (key chords, whatever) will be encoded as a single
+// value.
+// The low 21 bits are reserved for Unicode characters.  Popular function-type
+// keys
+// get their own codes in the range 0x10200000 to (if needed) 0x1FE00000,
+// currently
+// just arrow keys, Home, End and Delete.  Keypresses with Ctrl get ORed with
+// 0x20000000, with Alt get ORed with 0x40000000.  So, Ctrl+Alt+Home is encoded
+// as 0x20000000 + 0x40000000 + 0x10A00000 == 0x70A00000.  To keep things
+// complicated,
+// the Alt key is equivalent to prefixing the keystroke with ESC, so ESC
+// followed by
+// D is treated the same as Alt + D ... we'll just use Emacs terminology and
+// call
+// this "Meta".  So, we will encode both ESC followed by D and Alt held down
+// while D
+// is pressed the same, as Meta-D, encoded as 0x40000064.
+//
+// Here are the definitions of our component constants:
+//
+// Maximum unsigned 32-bit value    = 0xFFFFFFFF;   // For reference, max 32-bit
+// value
+// Highest allocated Unicode char   = 0x001FFFFF;   // For reference, max
+// Unicode value
+static const int META = 0x40000000;  // Meta key combination
+static const int CTRL = 0x20000000;  // Ctrl key combination
+// static const int SPECIAL_KEY = 0x10000000;   // Common bit for all special
+// keys
+static const int UP_ARROW_KEY = 0x10200000;  // Special keys
+static const int DOWN_ARROW_KEY = 0x10400000;
+static const int RIGHT_ARROW_KEY = 0x10600000;
+static const int LEFT_ARROW_KEY = 0x10800000;
+static const int HOME_KEY = 0x10A00000;
+static const int END_KEY = 0x10C00000;
+static const int DELETE_KEY = 0x10E00000;
+static const int PAGE_UP_KEY = 0x11000000;
+static const int PAGE_DOWN_KEY = 0x11200000;
+
+static const char* unsupported_term[] = {"dumb", "cons25", "emacs", NULL};
+static linenoiseCompletionCallback* completionCallback = NULL;
+
+#ifdef _WIN32
+static HANDLE console_in, console_out;
+static DWORD oldMode;
+static WORD oldDisplayAttribute;
+#else
+static struct termios orig_termios; /* in order to restore at exit */
+#endif
+
+static KillRing killRing;
+
+static int rawmode = 0; /* for atexit() function to check if restore is needed*/
+static int atexit_registered = 0; /* register atexit just 1 time */
+static int historyMaxLen = LINENOISE_DEFAULT_HISTORY_MAX_LEN;
+static int historyLen = 0;
+static int historyIndex = 0;
+static char8_t** history = NULL;
+
+// used to emulate Windows command prompt on down-arrow after a recall
+// we use -2 as our "not set" value because we add 1 to the previous index on
+// down-arrow,
+// and zero is a valid index (so -1 is a valid "previous index")
+static int historyPreviousIndex = -2;
+static bool historyRecallMostRecent = false;
+
+static void linenoiseAtExit(void);
+
+static bool isUnsupportedTerm(void) {
+  char* term = getenv("TERM");
+  if (term == NULL) return false;
+  for (int j = 0; unsupported_term[j]; ++j)
+    if (!strcasecmp(term, unsupported_term[j])) {
+      return true;
+    }
+  return false;
+}
+
+static void beep() {
+  fprintf(stderr, "\x7");  // ctrl-G == bell/beep
+  fflush(stderr);
+}
+
+void linenoiseHistoryFree(void) {
+  if (history) {
+    for (int j = 0; j < historyLen; ++j) free(history[j]);
+    historyLen = 0;
+    free(history);
+    history = 0;
+  }
+}
+
+static int enableRawMode(void) {
+#ifdef _WIN32
+  if (!console_in) {
+    console_in = GetStdHandle(STD_INPUT_HANDLE);
+    console_out = GetStdHandle(STD_OUTPUT_HANDLE);
+
+    GetConsoleMode(console_in, &oldMode);
+    SetConsoleMode(console_in, oldMode &
+                                   ~(ENABLE_LINE_INPUT | ENABLE_ECHO_INPUT |
+                                     ENABLE_PROCESSED_INPUT));
+  }
+  return 0;
+#else
+  struct termios raw;
+
+  if (!isatty(STDIN_FILENO)) goto fatal;
+  if (!atexit_registered) {
+    atexit(linenoiseAtExit);
+    atexit_registered = 1;
+  }
+  if (tcgetattr(0, &orig_termios) == -1) goto fatal;
+
+  raw = orig_termios; /* modify the original mode */
+  /* input modes: no break, no CR to NL, no parity check, no strip char,
+   * no start/stop output control. */
+  raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
+  /* output modes - disable post processing */
+  // this is wrong, we don't want raw output, it turns newlines into straight
+  // linefeeds
+  // raw.c_oflag &= ~(OPOST);
+  /* control modes - set 8 bit chars */
+  raw.c_cflag |= (CS8);
+  /* local modes - echoing off, canonical off, no extended functions,
+   * no signal chars (^Z,^C) */
+  raw.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
+  /* control chars - set return condition: min number of bytes and timer.
+   * We want read to return every single byte, without timeout. */
+  raw.c_cc[VMIN] = 1;
+  raw.c_cc[VTIME] = 0; /* 1 byte, no timer */
+
+  /* put terminal in raw mode after flushing */
+  if (tcsetattr(0, TCSADRAIN, &raw) < 0) goto fatal;
+  rawmode = 1;
+  return 0;
+
+fatal:
+  errno = ENOTTY;
+  return -1;
+#endif
+}
+
+static void disableRawMode(void) {
+#ifdef _WIN32
+  SetConsoleMode(console_in, oldMode);
+  console_in = 0;
+  console_out = 0;
+#else
+  if (rawmode && tcsetattr(0, TCSADRAIN, &orig_termios) != -1) rawmode = 0;
+#endif
+}
+
+// At exit we'll try to fix the terminal to the initial conditions
+static void linenoiseAtExit(void) { disableRawMode(); }
+
+static int getScreenColumns(void) {
+  int cols;
+#ifdef _WIN32
+  CONSOLE_SCREEN_BUFFER_INFO inf;
+  GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &inf);
+  cols = inf.dwSize.X;
+#else
+  struct winsize ws;
+  cols = (ioctl(1, TIOCGWINSZ, &ws) == -1) ? 80 : ws.ws_col;
+#endif
+  // cols is 0 in certain circumstances like inside debugger, which creates
+  // further issues
+  return (cols > 0) ? cols : 80;
+}
+
+static int getScreenRows(void) {
+  int rows;
+#ifdef _WIN32
+  CONSOLE_SCREEN_BUFFER_INFO inf;
+  GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &inf);
+  rows = 1 + inf.srWindow.Bottom - inf.srWindow.Top;
+#else
+  struct winsize ws;
+  rows = (ioctl(1, TIOCGWINSZ, &ws) == -1) ? 24 : ws.ws_row;
+#endif
+  return (rows > 0) ? rows : 24;
+}
+
+static void setDisplayAttribute(bool enhancedDisplay, bool error) {
+#ifdef _WIN32
+  if (enhancedDisplay) {
+    CONSOLE_SCREEN_BUFFER_INFO inf;
+    GetConsoleScreenBufferInfo(console_out, &inf);
+    oldDisplayAttribute = inf.wAttributes;
+    BYTE oldLowByte = oldDisplayAttribute & 0xFF;
+    BYTE newLowByte;
+    switch (oldLowByte) {
+      case 0x07:
+        // newLowByte = FOREGROUND_BLUE | FOREGROUND_INTENSITY;  // too dim
+        // newLowByte = FOREGROUND_BLUE;                         // even dimmer
+        newLowByte = FOREGROUND_BLUE |
+                     FOREGROUND_GREEN;  // most similar to xterm appearance
+        break;
+      case 0x70:
+        newLowByte = BACKGROUND_BLUE | BACKGROUND_INTENSITY;
+        break;
+      default:
+        newLowByte = oldLowByte ^ 0xFF;  // default to inverse video
+        break;
+    }
+    inf.wAttributes = (inf.wAttributes & 0xFF00) | newLowByte;
+    SetConsoleTextAttribute(console_out, inf.wAttributes);
+  } else {
+    SetConsoleTextAttribute(console_out, oldDisplayAttribute);
+  }
+#else
+  if (enhancedDisplay) {
+    char const* p = (error ? "\x1b[1;31m" : "\x1b[1;34m");
+    if (write(1, p, 7) == -1)
+      return; /* bright blue (visible with both B&W bg) */
+  } else {
+    if (write(1, "\x1b[0m", 4) == -1) return; /* reset */
+  }
+#endif
+}
+
+/**
+ * Display the dynamic incremental search prompt and the current user input
+ * line.
+ * @param pi   PromptBase struct holding information about the prompt and our
+ * screen position
+ * @param buf32  input buffer to be displayed
+ * @param len  count of characters in the buffer
+ * @param pos  current cursor position within the buffer (0 <= pos <= len)
+ */
+static void dynamicRefresh(PromptBase& pi, char32_t* buf32, int len, int pos) {
+  // calculate the position of the end of the prompt
+  int xEndOfPrompt, yEndOfPrompt;
+  calculateScreenPosition(0, 0, pi.promptScreenColumns, pi.promptChars,
+                          xEndOfPrompt, yEndOfPrompt);
+  pi.promptIndentation = xEndOfPrompt;
+
+  // calculate the position of the end of the input line
+  int xEndOfInput, yEndOfInput;
+  calculateScreenPosition(xEndOfPrompt, yEndOfPrompt, pi.promptScreenColumns,
+                          calculateColumnPosition(buf32, len), xEndOfInput,
+                          yEndOfInput);
+
+  // calculate the desired position of the cursor
+  int xCursorPos, yCursorPos;
+  calculateScreenPosition(xEndOfPrompt, yEndOfPrompt, pi.promptScreenColumns,
+                          calculateColumnPosition(buf32, pos), xCursorPos,
+                          yCursorPos);
+
+#ifdef _WIN32
+  // position at the start of the prompt, clear to end of previous input
+  CONSOLE_SCREEN_BUFFER_INFO inf;
+  GetConsoleScreenBufferInfo(console_out, &inf);
+  inf.dwCursorPosition.X = 0;
+  inf.dwCursorPosition.Y -= pi.promptCursorRowOffset /*- pi.promptExtraLines*/;
+  SetConsoleCursorPosition(console_out, inf.dwCursorPosition);
+  DWORD count;
+  FillConsoleOutputCharacterA(console_out, ' ',
+                              pi.promptPreviousLen + pi.promptPreviousInputLen,
+                              inf.dwCursorPosition, &count);
+  pi.promptPreviousLen = pi.promptIndentation;
+  pi.promptPreviousInputLen = len;
+
+  // display the prompt
+  if (!pi.write()) return;
+
+  // display the input line
+  if (write32(1, buf32, len) == -1) return;
+
+  // position the cursor
+  GetConsoleScreenBufferInfo(console_out, &inf);
+  inf.dwCursorPosition.X = xCursorPos;  // 0-based on Win32
+  inf.dwCursorPosition.Y -= yEndOfInput - yCursorPos;
+  SetConsoleCursorPosition(console_out, inf.dwCursorPosition);
+#else  // _WIN32
+  char seq[64];
+  int cursorRowMovement = pi.promptCursorRowOffset - pi.promptExtraLines;
+  if (cursorRowMovement > 0) {  // move the cursor up as required
+    snprintf(seq, sizeof seq, "\x1b[%dA", cursorRowMovement);
+    if (write(1, seq, strlen(seq)) == -1) return;
+  }
+  // position at the start of the prompt, clear to end of screen
+  snprintf(seq, sizeof seq, "\x1b[1G\x1b[J");  // 1-based on VT100
+  if (write(1, seq, strlen(seq)) == -1) return;
+
+  // display the prompt
+  if (!pi.write()) return;
+
+  // display the input line
+  if (write32(1, buf32, len) == -1) return;
+
+  // we have to generate our own newline on line wrap
+  if (xEndOfInput == 0 && yEndOfInput > 0)
+    if (write(1, "\n", 1) == -1) return;
+
+  // position the cursor
+  cursorRowMovement = yEndOfInput - yCursorPos;
+  if (cursorRowMovement > 0) {  // move the cursor up as required
+    snprintf(seq, sizeof seq, "\x1b[%dA", cursorRowMovement);
+    if (write(1, seq, strlen(seq)) == -1) return;
+  }
+  // position the cursor within the line
+  snprintf(seq, sizeof seq, "\x1b[%dG", xCursorPos + 1);  // 1-based on VT100
+  if (write(1, seq, strlen(seq)) == -1) return;
+#endif
+
+  pi.promptCursorRowOffset =
+      pi.promptExtraLines + yCursorPos;  // remember row for next pass
+}
+
+/**
+ * Refresh the user's input line: the prompt is already onscreen and is not
+ * redrawn here
+ * @param pi   PromptBase struct holding information about the prompt and our
+ * screen position
+ */
+void InputBuffer::refreshLine(PromptBase& pi) {
+  // check for a matching brace/bracket/paren, remember its position if found
+  int highlight = -1;
+  bool indicateError = false;
+  if (pos < len) {
+    /* this scans for a brace matching buf32[pos] to highlight */
+    unsigned char part1, part2;
+    int scanDirection = 0;
+    if (strchr("}])", buf32[pos])) {
+      scanDirection = -1; /* backwards */
+      if (buf32[pos] == '}') {
+        part1 = '}'; part2 = '{';
+      } else if (buf32[pos] == ']') {
+        part1 = ']'; part2 = '[';
+      } else {
+        part1 = ')'; part2 = '(';
+      }
+    }
+    else if (strchr("{[(", buf32[pos])) {
+      scanDirection = 1; /* forwards */
+      if (buf32[pos] == '{') {
+        //part1 = '{'; part2 = '}';
+        part1 = '}'; part2 = '{';
+      } else if (buf32[pos] == '[') {
+        //part1 = '['; part2 = ']';
+        part1 = ']'; part2 = '[';
+      } else {
+        //part1 = '('; part2 = ')';
+        part1 = ')'; part2 = '(';
+      }
+    }
+
+    if (scanDirection) {
+      int unmatched = scanDirection;
+      int unmatchedOther = 0;
+      for (int i = pos + scanDirection; i >= 0 && i < len; i += scanDirection) {
+        /* TODO: the right thing when inside a string */
+        if (strchr("}])", buf32[i])) {
+          if (buf32[i] == part1) {
+            --unmatched;
+          } else {
+            --unmatchedOther;
+          }
+        } else if (strchr("{[(", buf32[i])) {
+          if (buf32[i] == part2) {
+            ++unmatched;
+          } else {
+            ++unmatchedOther;
+          }
+        }
+/*
+        if (strchr("}])", buf32[i]))
+          --unmatched;
+        else if (strchr("{[(", buf32[i]))
+          ++unmatched;
+*/
+        if (unmatched == 0) {
+          highlight = i;
+          indicateError = (unmatchedOther != 0);
+          break;
+        }
+      }
+    }
+  }
+
+  // calculate the position of the end of the input line
+  int xEndOfInput, yEndOfInput;
+  calculateScreenPosition(pi.promptIndentation, 0, pi.promptScreenColumns,
+                          calculateColumnPosition(buf32, len), xEndOfInput,
+                          yEndOfInput);
+
+  // calculate the desired position of the cursor
+  int xCursorPos, yCursorPos;
+  calculateScreenPosition(pi.promptIndentation, 0, pi.promptScreenColumns,
+                          calculateColumnPosition(buf32, pos), xCursorPos,
+                          yCursorPos);
+
+#ifdef _WIN32
+  // position at the end of the prompt, clear to end of previous input
+  CONSOLE_SCREEN_BUFFER_INFO inf;
+  GetConsoleScreenBufferInfo(console_out, &inf);
+  inf.dwCursorPosition.X = pi.promptIndentation;  // 0-based on Win32
+  inf.dwCursorPosition.Y -= pi.promptCursorRowOffset - pi.promptExtraLines;
+  SetConsoleCursorPosition(console_out, inf.dwCursorPosition);
+  DWORD count;
+  if (len < pi.promptPreviousInputLen)
+    FillConsoleOutputCharacterA(console_out, ' ', pi.promptPreviousInputLen,
+                                inf.dwCursorPosition, &count);
+  pi.promptPreviousInputLen = len;
+
+  // display the input line
+  if (highlight == -1) {
+    if (write32(1, buf32, len) == -1) return;
+  } else {
+    if (write32(1, buf32, highlight) == -1) return;
+    setDisplayAttribute(true, indicateError); /* bright blue (visible with both B&W bg) */
+    if (write32(1, &buf32[highlight], 1) == -1) return;
+    setDisplayAttribute(false, indicateError);
+    if (write32(1, buf32 + highlight + 1, len - highlight - 1) == -1) return;
+  }
+
+  // position the cursor
+  GetConsoleScreenBufferInfo(console_out, &inf);
+  inf.dwCursorPosition.X = xCursorPos;  // 0-based on Win32
+  inf.dwCursorPosition.Y -= yEndOfInput - yCursorPos;
+  SetConsoleCursorPosition(console_out, inf.dwCursorPosition);
+#else  // _WIN32
+  char seq[64];
+  int cursorRowMovement = pi.promptCursorRowOffset - pi.promptExtraLines;
+  if (cursorRowMovement > 0) {  // move the cursor up as required
+    snprintf(seq, sizeof seq, "\x1b[%dA", cursorRowMovement);
+    if (write(1, seq, strlen(seq)) == -1) return;
+  }
+  // position at the end of the prompt, clear to end of screen
+  snprintf(seq, sizeof seq, "\x1b[%dG\x1b[J",
+           pi.promptIndentation + 1);  // 1-based on VT100
+  if (write(1, seq, strlen(seq)) == -1) return;
+
+  if (highlight == -1) {  // write unhighlighted text
+    if (write32(1, buf32, len) == -1) return;
+  } else {  // highlight the matching brace/bracket/parenthesis
+    if (write32(1, buf32, highlight) == -1) return;
+    setDisplayAttribute(true, indicateError);
+    if (write32(1, &buf32[highlight], 1) == -1) return;
+    setDisplayAttribute(false, indicateError);
+    if (write32(1, buf32 + highlight + 1, len - highlight - 1) == -1) return;
+  }
+
+  // we have to generate our own newline on line wrap
+  if (xEndOfInput == 0 && yEndOfInput > 0)
+    if (write(1, "\n", 1) == -1) return;
+
+  // position the cursor
+  cursorRowMovement = yEndOfInput - yCursorPos;
+  if (cursorRowMovement > 0) {  // move the cursor up as required
+    snprintf(seq, sizeof seq, "\x1b[%dA", cursorRowMovement);
+    if (write(1, seq, strlen(seq)) == -1) return;
+  }
+  // position the cursor within the line
+  snprintf(seq, sizeof seq, "\x1b[%dG", xCursorPos + 1);  // 1-based on VT100
+  if (write(1, seq, strlen(seq)) == -1) return;
+#endif
+
+  pi.promptCursorRowOffset =
+      pi.promptExtraLines + yCursorPos;  // remember row for next pass
+}
+
+#ifndef _WIN32
+
+/**
+ * Read a UTF-8 sequence from the non-Windows keyboard and return the Unicode
+ * (char32_t) character it
+ * encodes
+ *
+ * @return  char32_t Unicode character
+ */
+static char32_t readUnicodeCharacter(void) {
+  static char8_t utf8String[5];
+  static size_t utf8Count = 0;
+  while (true) {
+    char8_t c;
+
+    /* Continue reading if interrupted by signal. */
+    ssize_t nread;
+    do {
+      nread = read(0, &c, 1);
+    } while ((nread == -1) && (errno == EINTR));
+
+    if (nread <= 0) return 0;
+    if (c <= 0x7F) {  // short circuit ASCII
+      utf8Count = 0;
+      return c;
+    } else if (utf8Count < sizeof(utf8String) - 1) {
+      utf8String[utf8Count++] = c;
+      utf8String[utf8Count] = 0;
+      char32_t unicodeChar[2];
+      size_t ucharCount;
+      ConversionResult res =
+          copyString8to32(unicodeChar, 2, ucharCount, utf8String);
+      if (res == conversionOK && ucharCount) {
+        utf8Count = 0;
+        return unicodeChar[0];
+      }
+    } else {
+      utf8Count =
+          0;  // this shouldn't happen: got four bytes but no UTF-8 character
+    }
+  }
+}
+
+namespace EscapeSequenceProcessing {  // move these out of global namespace
+
+// This chunk of code does parsing of the escape sequences sent by various Linux
+// terminals.
+//
+// It handles arrow keys, Home, End and Delete keys by interpreting the
+// sequences sent by
+// gnome terminal, xterm, rxvt, konsole, aterm and yakuake including the Alt and
+// Ctrl key
+// combinations that are understood by linenoise.
+//
+// The parsing uses tables, a bunch of intermediate dispatch routines and a
+// doDispatch
+// loop that reads the tables and sends control to "deeper" routines to continue
+// the
+// parsing.  The starting call to doDispatch( c, initialDispatch ) will
+// eventually return
+// either a character (with optional CTRL and META bits set), or -1 if parsing
+// fails, or
+// zero if an attempt to read from the keyboard fails.
+//
+// This is rather sloppy escape sequence processing, since we're not paying
+// attention to what the
+// actual TERM is set to and are processing all key sequences for all terminals,
+// but it works with
+// the most common keystrokes on the most common terminals.  It's intricate, but
+// the nested 'if'
+// statements required to do it directly would be worse.  This way has the
+// advantage of allowing
+// changes and extensions without having to touch a lot of code.
+
+// This is a typedef for the routine called by doDispatch().  It takes the
+// current character
+// as input, does any required processing including reading more characters and
+// calling other
+// dispatch routines, then eventually returns the final (possibly extended or
+// special) character.
+//
+typedef char32_t (*CharacterDispatchRoutine)(char32_t);
+
+// This structure is used by doDispatch() to hold a list of characters to test
+// for and
+// a list of routines to call if the character matches.  The dispatch routine
+// list is one
+// longer than the character list; the final entry is used if no character
+// matches.
+//
+struct CharacterDispatch {
+  unsigned int len;                    // length of the chars list
+  const char* chars;                   // chars to test
+  CharacterDispatchRoutine* dispatch;  // array of routines to call
+};
+
+// This dispatch routine is given a dispatch table and then farms work out to
+// routines
+// listed in the table based on the character it is called with.  The dispatch
+// routines can
+// read more input characters to decide what should eventually be returned.
+// Eventually,
+// a called routine returns either a character or -1 to indicate parsing
+// failure.
+//
+static char32_t doDispatch(char32_t c, CharacterDispatch& dispatchTable) {
+  for (unsigned int i = 0; i < dispatchTable.len; ++i) {
+    if (static_cast<unsigned char>(dispatchTable.chars[i]) == c) {
+      return dispatchTable.dispatch[i](c);
+    }
+  }
+  return dispatchTable.dispatch[dispatchTable.len](c);
+}
+
+static char32_t thisKeyMetaCtrl =
+    0;  // holds pre-set Meta and/or Ctrl modifiers
+
+// Final dispatch routines -- return something
+//
+static char32_t normalKeyRoutine(char32_t c) { return thisKeyMetaCtrl | c; }
+static char32_t upArrowKeyRoutine(char32_t) {
+  return thisKeyMetaCtrl | UP_ARROW_KEY;
+}
+static char32_t downArrowKeyRoutine(char32_t) {
+  return thisKeyMetaCtrl | DOWN_ARROW_KEY;
+}
+static char32_t rightArrowKeyRoutine(char32_t) {
+  return thisKeyMetaCtrl | RIGHT_ARROW_KEY;
+}
+static char32_t leftArrowKeyRoutine(char32_t) {
+  return thisKeyMetaCtrl | LEFT_ARROW_KEY;
+}
+static char32_t homeKeyRoutine(char32_t) { return thisKeyMetaCtrl | HOME_KEY; }
+static char32_t endKeyRoutine(char32_t) { return thisKeyMetaCtrl | END_KEY; }
+static char32_t pageUpKeyRoutine(char32_t) {
+  return thisKeyMetaCtrl | PAGE_UP_KEY;
+}
+static char32_t pageDownKeyRoutine(char32_t) {
+  return thisKeyMetaCtrl | PAGE_DOWN_KEY;
+}
+static char32_t deleteCharRoutine(char32_t) {
+  return thisKeyMetaCtrl | ctrlChar('H');
+}  // key labeled Backspace
+static char32_t deleteKeyRoutine(char32_t) {
+  return thisKeyMetaCtrl | DELETE_KEY;
+}  // key labeled Delete
+static char32_t ctrlUpArrowKeyRoutine(char32_t) {
+  return thisKeyMetaCtrl | CTRL | UP_ARROW_KEY;
+}
+static char32_t ctrlDownArrowKeyRoutine(char32_t) {
+  return thisKeyMetaCtrl | CTRL | DOWN_ARROW_KEY;
+}
+static char32_t ctrlRightArrowKeyRoutine(char32_t) {
+  return thisKeyMetaCtrl | CTRL | RIGHT_ARROW_KEY;
+}
+static char32_t ctrlLeftArrowKeyRoutine(char32_t) {
+  return thisKeyMetaCtrl | CTRL | LEFT_ARROW_KEY;
+}
+static char32_t escFailureRoutine(char32_t) {
+  beep();
+  return -1;
+}
+
+// Handle ESC [ 1 ; 3 (or 5) <more stuff> escape sequences
+//
+static CharacterDispatchRoutine escLeftBracket1Semicolon3or5Routines[] = {
+    upArrowKeyRoutine, downArrowKeyRoutine, rightArrowKeyRoutine,
+    leftArrowKeyRoutine, escFailureRoutine};
+static CharacterDispatch escLeftBracket1Semicolon3or5Dispatch = {
+    4, "ABCD", escLeftBracket1Semicolon3or5Routines};
+
+// Handle ESC [ 1 ; <more stuff> escape sequences
+//
+static char32_t escLeftBracket1Semicolon3Routine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  thisKeyMetaCtrl |= META;
+  return doDispatch(c, escLeftBracket1Semicolon3or5Dispatch);
+}
+static char32_t escLeftBracket1Semicolon5Routine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  thisKeyMetaCtrl |= CTRL;
+  return doDispatch(c, escLeftBracket1Semicolon3or5Dispatch);
+}
+static CharacterDispatchRoutine escLeftBracket1SemicolonRoutines[] = {
+    escLeftBracket1Semicolon3Routine, escLeftBracket1Semicolon5Routine,
+    escFailureRoutine};
+static CharacterDispatch escLeftBracket1SemicolonDispatch = {
+    2, "35", escLeftBracket1SemicolonRoutines};
+
+// Handle ESC [ 1 <more stuff> escape sequences
+//
+static char32_t escLeftBracket1SemicolonRoutine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  return doDispatch(c, escLeftBracket1SemicolonDispatch);
+}
+static CharacterDispatchRoutine escLeftBracket1Routines[] = {
+    homeKeyRoutine, escLeftBracket1SemicolonRoutine, escFailureRoutine};
+static CharacterDispatch escLeftBracket1Dispatch = {2, "~;",
+                                                    escLeftBracket1Routines};
+
+// Handle ESC [ 3 <more stuff> escape sequences
+//
+static CharacterDispatchRoutine escLeftBracket3Routines[] = {deleteKeyRoutine,
+                                                             escFailureRoutine};
+static CharacterDispatch escLeftBracket3Dispatch = {1, "~",
+                                                    escLeftBracket3Routines};
+
+// Handle ESC [ 4 <more stuff> escape sequences
+//
+static CharacterDispatchRoutine escLeftBracket4Routines[] = {endKeyRoutine,
+                                                             escFailureRoutine};
+static CharacterDispatch escLeftBracket4Dispatch = {1, "~",
+                                                    escLeftBracket4Routines};
+
+// Handle ESC [ 5 <more stuff> escape sequences
+//
+static CharacterDispatchRoutine escLeftBracket5Routines[] = {pageUpKeyRoutine,
+                                                             escFailureRoutine};
+static CharacterDispatch escLeftBracket5Dispatch = {1, "~",
+                                                    escLeftBracket5Routines};
+
+// Handle ESC [ 6 <more stuff> escape sequences
+//
+static CharacterDispatchRoutine escLeftBracket6Routines[] = {pageDownKeyRoutine,
+                                                             escFailureRoutine};
+static CharacterDispatch escLeftBracket6Dispatch = {1, "~",
+                                                    escLeftBracket6Routines};
+
+// Handle ESC [ 7 <more stuff> escape sequences
+//
+static CharacterDispatchRoutine escLeftBracket7Routines[] = {homeKeyRoutine,
+                                                             escFailureRoutine};
+static CharacterDispatch escLeftBracket7Dispatch = {1, "~",
+                                                    escLeftBracket7Routines};
+
+// Handle ESC [ 8 <more stuff> escape sequences
+//
+static CharacterDispatchRoutine escLeftBracket8Routines[] = {endKeyRoutine,
+                                                             escFailureRoutine};
+static CharacterDispatch escLeftBracket8Dispatch = {1, "~",
+                                                    escLeftBracket8Routines};
+
+// Handle ESC [ <digit> escape sequences
+//
+static char32_t escLeftBracket0Routine(char32_t c) {
+  return escFailureRoutine(c);
+}
+static char32_t escLeftBracket1Routine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  return doDispatch(c, escLeftBracket1Dispatch);
+}
+static char32_t escLeftBracket2Routine(char32_t c) {
+  return escFailureRoutine(c);  // Insert key, unused
+}
+static char32_t escLeftBracket3Routine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  return doDispatch(c, escLeftBracket3Dispatch);
+}
+static char32_t escLeftBracket4Routine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  return doDispatch(c, escLeftBracket4Dispatch);
+}
+static char32_t escLeftBracket5Routine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  return doDispatch(c, escLeftBracket5Dispatch);
+}
+static char32_t escLeftBracket6Routine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  return doDispatch(c, escLeftBracket6Dispatch);
+}
+static char32_t escLeftBracket7Routine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  return doDispatch(c, escLeftBracket7Dispatch);
+}
+static char32_t escLeftBracket8Routine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  return doDispatch(c, escLeftBracket8Dispatch);
+}
+static char32_t escLeftBracket9Routine(char32_t c) {
+  return escFailureRoutine(c);
+}
+
+// Handle ESC [ <more stuff> escape sequences
+//
+static CharacterDispatchRoutine escLeftBracketRoutines[] = {
+    upArrowKeyRoutine,      downArrowKeyRoutine,    rightArrowKeyRoutine,
+    leftArrowKeyRoutine,    homeKeyRoutine,         endKeyRoutine,
+    escLeftBracket0Routine, escLeftBracket1Routine, escLeftBracket2Routine,
+    escLeftBracket3Routine, escLeftBracket4Routine, escLeftBracket5Routine,
+    escLeftBracket6Routine, escLeftBracket7Routine, escLeftBracket8Routine,
+    escLeftBracket9Routine, escFailureRoutine};
+static CharacterDispatch escLeftBracketDispatch = {16, "ABCDHF0123456789",
+                                                   escLeftBracketRoutines};
+
+// Handle ESC O <char> escape sequences
+//
+static CharacterDispatchRoutine escORoutines[] = {
+    upArrowKeyRoutine,       downArrowKeyRoutine,     rightArrowKeyRoutine,
+    leftArrowKeyRoutine,     homeKeyRoutine,          endKeyRoutine,
+    ctrlUpArrowKeyRoutine,   ctrlDownArrowKeyRoutine, ctrlRightArrowKeyRoutine,
+    ctrlLeftArrowKeyRoutine, escFailureRoutine};
+static CharacterDispatch escODispatch = {10, "ABCDHFabcd", escORoutines};
+
+// Initial ESC dispatch -- could be a Meta prefix or the start of an escape
+// sequence
+//
+static char32_t escLeftBracketRoutine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  return doDispatch(c, escLeftBracketDispatch);
+}
+static char32_t escORoutine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  return doDispatch(c, escODispatch);
+}
+static char32_t setMetaRoutine(char32_t c);  // need forward reference
+static CharacterDispatchRoutine escRoutines[] = {escLeftBracketRoutine,
+                                                 escORoutine, setMetaRoutine};
+static CharacterDispatch escDispatch = {2, "[O", escRoutines};
+
+// Initial dispatch -- we are not in the middle of anything yet
+//
+static char32_t escRoutine(char32_t c) {
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+  return doDispatch(c, escDispatch);
+}
+static CharacterDispatchRoutine initialRoutines[] = {
+    escRoutine, deleteCharRoutine, normalKeyRoutine};
+static CharacterDispatch initialDispatch = {2, "\x1B\x7F", initialRoutines};
+
+// Special handling for the ESC key because it does double duty
+//
+static char32_t setMetaRoutine(char32_t c) {
+  thisKeyMetaCtrl = META;
+  if (c == 0x1B) {  // another ESC, stay in ESC processing mode
+    c = readUnicodeCharacter();
+    if (c == 0) return 0;
+    return doDispatch(c, escDispatch);
+  }
+  return doDispatch(c, initialDispatch);
+}
+
+}  // namespace EscapeSequenceProcessing // move these out of global namespace
+
+#endif  // #ifndef _WIN32
+
+// linenoiseReadChar -- read a keystroke or keychord from the keyboard, and
+// translate it
+// into an encoded "keystroke".  When convenient, extended keys are translated
+// into their
+// simpler Emacs keystrokes, so an unmodified "left arrow" becomes Ctrl-B.
+//
+// A return value of zero means "no input available", and a return value of -1
+// means "invalid key".
+//
+static char32_t linenoiseReadChar(void) {
+#ifdef _WIN32
+
+  INPUT_RECORD rec;
+  DWORD count;
+  int modifierKeys = 0;
+  bool escSeen = false;
+  while (true) {
+    ReadConsoleInputW(console_in, &rec, 1, &count);
+#if 0  // helper for debugging keystrokes, display info in the debug "Output"
+       // window in the debugger
+        {
+            if ( rec.EventType == KEY_EVENT ) {
+                //if ( rec.Event.KeyEvent.uChar.UnicodeChar ) {
+                    char buf[1024];
+                    sprintf(
+                            buf,
+                            "Unicode character 0x%04X, repeat count %d, virtual keycode 0x%04X, "
+                            "virtual scancode 0x%04X, key %s%s%s%s%s\n",
+                            rec.Event.KeyEvent.uChar.UnicodeChar,
+                            rec.Event.KeyEvent.wRepeatCount,
+                            rec.Event.KeyEvent.wVirtualKeyCode,
+                            rec.Event.KeyEvent.wVirtualScanCode,
+                            rec.Event.KeyEvent.bKeyDown ? "down" : "up",
+                                (rec.Event.KeyEvent.dwControlKeyState & LEFT_CTRL_PRESSED)  ?
+                                    " L-Ctrl" : "",
+                                (rec.Event.KeyEvent.dwControlKeyState & RIGHT_CTRL_PRESSED) ?
+                                    " R-Ctrl" : "",
+                                (rec.Event.KeyEvent.dwControlKeyState & LEFT_ALT_PRESSED)   ?
+                                    " L-Alt"  : "",
+                                (rec.Event.KeyEvent.dwControlKeyState & RIGHT_ALT_PRESSED)  ?
+                                    " R-Alt"  : ""
+                           );
+                    OutputDebugStringA( buf );
+                //}
+            }
+        }
+#endif
+    if (rec.EventType != KEY_EVENT) {
+      continue;
+    }
+    // Windows provides for entry of characters that are not on your keyboard by
+    // sending the
+    // Unicode characters as a "key up" with virtual keycode 0x12 (VK_MENU ==
+    // Alt key) ...
+    // accept these characters, otherwise only process characters on "key down"
+    if (!rec.Event.KeyEvent.bKeyDown &&
+        rec.Event.KeyEvent.wVirtualKeyCode != VK_MENU) {
+      continue;
+    }
+    modifierKeys = 0;
+    // AltGr is encoded as ( LEFT_CTRL_PRESSED | RIGHT_ALT_PRESSED ), so don't
+    // treat this
+    // combination as either CTRL or META we just turn off those two bits, so it
+    // is still
+    // possible to combine CTRL and/or META with an AltGr key by using
+    // right-Ctrl and/or
+    // left-Alt
+    if ((rec.Event.KeyEvent.dwControlKeyState &
+         (LEFT_CTRL_PRESSED | RIGHT_ALT_PRESSED)) ==
+        (LEFT_CTRL_PRESSED | RIGHT_ALT_PRESSED)) {
+      rec.Event.KeyEvent.dwControlKeyState &=
+          ~(LEFT_CTRL_PRESSED | RIGHT_ALT_PRESSED);
+    }
+    if (rec.Event.KeyEvent.dwControlKeyState &
+        (RIGHT_CTRL_PRESSED | LEFT_CTRL_PRESSED)) {
+      modifierKeys |= CTRL;
+    }
+    if (rec.Event.KeyEvent.dwControlKeyState &
+        (RIGHT_ALT_PRESSED | LEFT_ALT_PRESSED)) {
+      modifierKeys |= META;
+    }
+    if (escSeen) {
+      modifierKeys |= META;
+    }
+    if (rec.Event.KeyEvent.uChar.UnicodeChar == 0) {
+      switch (rec.Event.KeyEvent.wVirtualKeyCode) {
+        case VK_LEFT:
+          return modifierKeys | LEFT_ARROW_KEY;
+        case VK_RIGHT:
+          return modifierKeys | RIGHT_ARROW_KEY;
+        case VK_UP:
+          return modifierKeys | UP_ARROW_KEY;
+        case VK_DOWN:
+          return modifierKeys | DOWN_ARROW_KEY;
+        case VK_DELETE:
+          return modifierKeys | DELETE_KEY;
+        case VK_HOME:
+          return modifierKeys | HOME_KEY;
+        case VK_END:
+          return modifierKeys | END_KEY;
+        case VK_PRIOR:
+          return modifierKeys | PAGE_UP_KEY;
+        case VK_NEXT:
+          return modifierKeys | PAGE_DOWN_KEY;
+        default:
+          continue;  // in raw mode, ReadConsoleInput shows shift, ctrl ...
+      }              //  ... ignore them
+    } else if (rec.Event.KeyEvent.uChar.UnicodeChar ==
+               ctrlChar('[')) {  // ESC, set flag for later
+      escSeen = true;
+      continue;
+    } else {
+      // we got a real character, return it
+      return modifierKeys | rec.Event.KeyEvent.uChar.UnicodeChar;
+    }
+  }
+
+#else
+  char32_t c;
+  c = readUnicodeCharacter();
+  if (c == 0) return 0;
+
+// If _DEBUG_LINUX_KEYBOARD is set, then ctrl-^ puts us into a keyboard
+// debugging mode
+// where we print out decimal and decoded values for whatever the "terminal"
+// program
+// gives us on different keystrokes.  Hit ctrl-C to exit this mode.
+//
+#define _DEBUG_LINUX_KEYBOARD
+#if defined(_DEBUG_LINUX_KEYBOARD)
+  if (c == ctrlChar('^')) {  // ctrl-^, special debug mode, prints all keys hit,
+                             // ctrl-C to get out
+    printf(
+        "\nEntering keyboard debugging mode (on ctrl-^), press ctrl-C to exit "
+        "this mode\n");
+    while (true) {
+      unsigned char keys[10];
+      int ret = read(0, keys, 10);
+
+      if (ret <= 0) {
+        printf("\nret: %d\n", ret);
+      }
+      for (int i = 0; i < ret; ++i) {
+        char32_t key = static_cast<char32_t>(keys[i]);
+        char* friendlyTextPtr;
+        char friendlyTextBuf[10];
+        const char* prefixText = (key < 0x80) ? "" : "0x80+";
+        char32_t keyCopy = (key < 0x80) ? key : key - 0x80;
+        if (keyCopy >= '!' && keyCopy <= '~') {  // printable
+          friendlyTextBuf[0] = '\'';
+          friendlyTextBuf[1] = keyCopy;
+          friendlyTextBuf[2] = '\'';
+          friendlyTextBuf[3] = 0;
+          friendlyTextPtr = friendlyTextBuf;
+        } else if (keyCopy == ' ') {
+          friendlyTextPtr = const_cast<char*>("space");
+        } else if (keyCopy == 27) {
+          friendlyTextPtr = const_cast<char*>("ESC");
+        } else if (keyCopy == 0) {
+          friendlyTextPtr = const_cast<char*>("NUL");
+        } else if (keyCopy == 127) {
+          friendlyTextPtr = const_cast<char*>("DEL");
+        } else {
+          friendlyTextBuf[0] = '^';
+          friendlyTextBuf[1] = keyCopy + 0x40;
+          friendlyTextBuf[2] = 0;
+          friendlyTextPtr = friendlyTextBuf;
+        }
+        printf("%d x%02X (%s%s)  ", key, key, prefixText, friendlyTextPtr);
+      }
+      printf("\x1b[1G\n");  // go to first column of new line
+
+      // drop out of this loop on ctrl-C
+      if (keys[0] == ctrlChar('C')) {
+        printf("Leaving keyboard debugging mode (on ctrl-C)\n");
+        fflush(stdout);
+        return -2;
+      }
+    }
+  }
+#endif  // _DEBUG_LINUX_KEYBOARD
+
+  EscapeSequenceProcessing::thisKeyMetaCtrl =
+      0;  // no modifiers yet at initialDispatch
+  return EscapeSequenceProcessing::doDispatch(
+      c, EscapeSequenceProcessing::initialDispatch);
+#endif  // #_WIN32
+}
+
+/**
+ * Free memory used in a recent command completion session
+ *
+ * @param lc pointer to a linenoiseCompletions struct
+ */
+static void freeCompletions(linenoiseCompletions* lc) {
+  lc->completionStrings.clear();
+}
+
+/**
+ * convert {CTRL + 'A'}, {CTRL + 'a'} and {CTRL + ctrlChar( 'A' )} into
+ * ctrlChar( 'A' )
+ * leave META alone
+ *
+ * @param c character to clean up
+ * @return cleaned-up character
+ */
+static int cleanupCtrl(int c) {
+  if (c & CTRL) {
+    int d = c & 0x1FF;
+    if (d >= 'a' && d <= 'z') {
+      c = (c + ('a' - ctrlChar('A'))) & ~CTRL;
+    }
+    if (d >= 'A' && d <= 'Z') {
+      c = (c + ('A' - ctrlChar('A'))) & ~CTRL;
+    }
+    if (d >= ctrlChar('A') && d <= ctrlChar('Z')) {
+      c = c & ~CTRL;
+    }
+  }
+  return c;
+}
+
+// break characters that may precede items to be completed
+static const char breakChars[] = " =+-/\\*?\"'`&<>;|@{([])}";
+
+// maximum number of completions to display without asking
+static const size_t completionCountCutoff = 100;
+
+/**
+ * Handle command completion, using a completionCallback() routine to provide
+ * possible substitutions
+ * This routine handles the mechanics of updating the user's input buffer with
+ * possible replacement
+ * of text as the user selects a proposed completion string, or cancels the
+ * completion attempt.
+ * @param pi     PromptBase struct holding information about the prompt and our
+ * screen position
+ */
+int InputBuffer::completeLine(PromptBase& pi) {
+  linenoiseCompletions lc;
+  char32_t c = 0;
+
+  // completionCallback() expects a parsable entity, so find the previous break
+  // character and
+  // extract a copy to parse.  we also handle the case where tab is hit while
+  // not at end-of-line.
+  int startIndex = pos;
+  while (--startIndex >= 0) {
+    if (strchr(breakChars, buf32[startIndex])) {
+      break;
+    }
+  }
+  ++startIndex;
+  int itemLength = pos - startIndex;
+  Utf32String unicodeCopy(&buf32[startIndex], itemLength);
+  Utf8String parseItem(unicodeCopy);
+
+  // get a list of completions
+  completionCallback(parseItem.get(), &lc);
+
+  // if no completions, we are done
+  if (lc.completionStrings.size() == 0) {
+    beep();
+    freeCompletions(&lc);
+    return 0;
+  }
+
+  // at least one completion
+  int longestCommonPrefix = 0;
+  int displayLength = 0;
+  if (lc.completionStrings.size() == 1) {
+    longestCommonPrefix = static_cast<int>(lc.completionStrings[0].length());
+  } else {
+    bool keepGoing = true;
+    while (keepGoing) {
+      for (size_t j = 0; j < lc.completionStrings.size() - 1; ++j) {
+        char32_t c1 = lc.completionStrings[j][longestCommonPrefix];
+        char32_t c2 = lc.completionStrings[j + 1][longestCommonPrefix];
+        if ((0 == c1) || (0 == c2) || (c1 != c2)) {
+          keepGoing = false;
+          break;
+        }
+      }
+      if (keepGoing) {
+        ++longestCommonPrefix;
+      }
+    }
+  }
+  if (lc.completionStrings.size() != 1) {  // beep if ambiguous
+    beep();
+  }
+
+  // if we can extend the item, extend it and return to main loop
+  if (longestCommonPrefix > itemLength) {
+    displayLength = len + longestCommonPrefix - itemLength;
+    if (displayLength > buflen) {
+      longestCommonPrefix -= displayLength - buflen;  // don't overflow buffer
+      displayLength = buflen;                         // truncate the insertion
+      beep();                                         // and make a noise
+    }
+    Utf32String displayText(displayLength + 1);
+    memcpy(displayText.get(), buf32, sizeof(char32_t) * startIndex);
+    memcpy(&displayText[startIndex], &lc.completionStrings[0][0],
+           sizeof(char32_t) * longestCommonPrefix);
+    int tailIndex = startIndex + longestCommonPrefix;
+    memcpy(&displayText[tailIndex], &buf32[pos],
+           sizeof(char32_t) * (displayLength - tailIndex + 1));
+    copyString32(buf32, displayText.get(), displayLength);
+    pos = startIndex + longestCommonPrefix;
+    len = displayLength;
+    refreshLine(pi);
+    return 0;
+  }
+
+  // we can't complete any further, wait for second tab
+  do {
+    c = linenoiseReadChar();
+    c = cleanupCtrl(c);
+  } while (c == static_cast<char32_t>(-1));
+
+  // if any character other than tab, pass it to the main loop
+  if (c != ctrlChar('I')) {
+    freeCompletions(&lc);
+    return c;
+  }
+
+  // we got a second tab, maybe show list of possible completions
+  bool showCompletions = true;
+  bool onNewLine = false;
+  if (lc.completionStrings.size() > completionCountCutoff) {
+    int savePos =
+        pos;  // move cursor to EOL to avoid overwriting the command line
+    pos = len;
+    refreshLine(pi);
+    pos = savePos;
+    printf("\nDisplay all %u possibilities? (y or n)",
+           static_cast<unsigned int>(lc.completionStrings.size()));
+    fflush(stdout);
+    onNewLine = true;
+    while (c != 'y' && c != 'Y' && c != 'n' && c != 'N' && c != ctrlChar('C')) {
+      do {
+        c = linenoiseReadChar();
+        c = cleanupCtrl(c);
+      } while (c == static_cast<char32_t>(-1));
+    }
+    switch (c) {
+      case 'n':
+      case 'N':
+        showCompletions = false;
+        freeCompletions(&lc);
+        break;
+      case ctrlChar('C'):
+        showCompletions = false;
+        freeCompletions(&lc);
+        if (write(1, "^C", 2) == -1) return -1;  // Display the ^C we got
+        c = 0;
+        break;
+    }
+  }
+
+  // if showing the list, do it the way readline does it
+  bool stopList = false;
+  if (showCompletions) {
+    int longestCompletion = 0;
+    for (size_t j = 0; j < lc.completionStrings.size(); ++j) {
+      itemLength = static_cast<int>(lc.completionStrings[j].length());
+      if (itemLength > longestCompletion) {
+        longestCompletion = itemLength;
+      }
+    }
+    longestCompletion += 2;
+    int columnCount = pi.promptScreenColumns / longestCompletion;
+    if (columnCount < 1) {
+      columnCount = 1;
+    }
+    if (!onNewLine) {  // skip this if we showed "Display all %d possibilities?"
+      int savePos =
+          pos;  // move cursor to EOL to avoid overwriting the command line
+      pos = len;
+      refreshLine(pi);
+      pos = savePos;
+    }
+    size_t pauseRow = getScreenRows() - 1;
+    size_t rowCount =
+        (lc.completionStrings.size() + columnCount - 1) / columnCount;
+    for (size_t row = 0; row < rowCount; ++row) {
+      if (row == pauseRow) {
+        printf("\n--More--");
+        fflush(stdout);
+        c = 0;
+        bool doBeep = false;
+        while (c != ' ' && c != '\r' && c != '\n' && c != 'y' && c != 'Y' &&
+               c != 'n' && c != 'N' && c != 'q' && c != 'Q' &&
+               c != ctrlChar('C')) {
+          if (doBeep) {
+            beep();
+          }
+          doBeep = true;
+          do {
+            c = linenoiseReadChar();
+            c = cleanupCtrl(c);
+          } while (c == static_cast<char32_t>(-1));
+        }
+        switch (c) {
+          case ' ':
+          case 'y':
+          case 'Y':
+            printf("\r        \r");
+            pauseRow += getScreenRows() - 1;
+            break;
+          case '\r':
+          case '\n':
+            printf("\r        \r");
+            ++pauseRow;
+            break;
+          case 'n':
+          case 'N':
+          case 'q':
+          case 'Q':
+            printf("\r        \r");
+            stopList = true;
+            break;
+          case ctrlChar('C'):
+            if (write(1, "^C", 2) == -1) return -1;  // Display the ^C we got
+            stopList = true;
+            break;
+        }
+      } else {
+        printf("\n");
+      }
+      if (stopList) {
+        break;
+      }
+      for (int column = 0; column < columnCount; ++column) {
+        size_t index = (column * rowCount) + row;
+        if (index < lc.completionStrings.size()) {
+          itemLength = static_cast<int>(lc.completionStrings[index].length());
+          fflush(stdout);
+          if (write32(1, lc.completionStrings[index].get(), itemLength) == -1)
+            return -1;
+          if (((column + 1) * rowCount) + row < lc.completionStrings.size()) {
+            for (int k = itemLength; k < longestCompletion; ++k) {
+              printf(" ");
+            }
+          }
+        }
+      }
+    }
+    fflush(stdout);
+    freeCompletions(&lc);
+  }
+
+  // display the prompt on a new line, then redisplay the input buffer
+  if (!stopList || c == ctrlChar('C')) {
+    if (write(1, "\n", 1) == -1) return 0;
+  }
+  if (!pi.write()) return 0;
+#ifndef _WIN32
+  // we have to generate our own newline on line wrap on Linux
+  if (pi.promptIndentation == 0 && pi.promptExtraLines > 0)
+    if (write(1, "\n", 1) == -1) return 0;
+#endif
+  pi.promptCursorRowOffset = pi.promptExtraLines;
+  refreshLine(pi);
+  return 0;
+}
+
+/**
+ * Clear the screen ONLY (no redisplay of anything)
+ */
+void linenoiseClearScreen(void) {
+#ifdef _WIN32
+  COORD coord = {0, 0};
+  CONSOLE_SCREEN_BUFFER_INFO inf;
+  HANDLE screenHandle = GetStdHandle(STD_OUTPUT_HANDLE);
+  GetConsoleScreenBufferInfo(screenHandle, &inf);
+  SetConsoleCursorPosition(screenHandle, coord);
+  DWORD count;
+  FillConsoleOutputCharacterA(screenHandle, ' ', inf.dwSize.X * inf.dwSize.Y,
+                              coord, &count);
+#else
+  if (write(1, "\x1b[H\x1b[2J", 7) <= 0) return;
+#endif
+}
+
+void InputBuffer::clearScreen(PromptBase& pi) {
+  linenoiseClearScreen();
+  if (!pi.write()) return;
+#ifndef _WIN32
+  // we have to generate our own newline on line wrap on Linux
+  if (pi.promptIndentation == 0 && pi.promptExtraLines > 0)
+    if (write(1, "\n", 1) == -1) return;
+#endif
+  pi.promptCursorRowOffset = pi.promptExtraLines;
+  refreshLine(pi);
+}
+
+/**
+ * Incremental history search -- take over the prompt and keyboard as the user
+ * types a search
+ * string, deletes characters from it, changes direction, and either accepts the
+ * found line (for
+ * execution orediting) or cancels.
+ * @param pi        PromptBase struct holding information about the (old,
+ * static) prompt and our
+ *                  screen position
+ * @param startChar the character that began the search, used to set the initial
+ * direction
+ */
+int InputBuffer::incrementalHistorySearch(PromptBase& pi, int startChar) {
+  size_t bufferSize;
+  size_t ucharCount = 0;
+
+  // if not already recalling, add the current line to the history list so we
+  // don't have to
+  // special case it
+  if (historyIndex == historyLen - 1) {
+    free(history[historyLen - 1]);
+    bufferSize = sizeof(char32_t) * len + 1;
+    unique_ptr<char[]> tempBuffer(new char[bufferSize]);
+    copyString32to8(tempBuffer.get(), bufferSize, buf32);
+    history[historyLen - 1] = strdup8(tempBuffer.get());
+  }
+  int historyLineLength = len;
+  int historyLinePosition = pos;
+  char32_t emptyBuffer[1];
+  char emptyWidths[1];
+  InputBuffer empty(emptyBuffer, emptyWidths, 1);
+  empty.refreshLine(pi);  // erase the old input first
+  DynamicPrompt dp(pi, (startChar == ctrlChar('R')) ? -1 : 1);
+
+  dp.promptPreviousLen = pi.promptPreviousLen;
+  dp.promptPreviousInputLen = pi.promptPreviousInputLen;
+  dynamicRefresh(dp, buf32, historyLineLength,
+                 historyLinePosition);  // draw user's text with our prompt
+
+  // loop until we get an exit character
+  int c = 0;
+  bool keepLooping = true;
+  bool useSearchedLine = true;
+  bool searchAgain = false;
+  char32_t* activeHistoryLine = 0;
+  while (keepLooping) {
+    c = linenoiseReadChar();
+    c = cleanupCtrl(c);  // convert CTRL + <char> into normal ctrl
+
+    switch (c) {
+      // these characters keep the selected text but do not execute it
+      case ctrlChar('A'):  // ctrl-A, move cursor to start of line
+      case HOME_KEY:
+      case ctrlChar('B'):  // ctrl-B, move cursor left by one character
+      case LEFT_ARROW_KEY:
+      case META + 'b':  // meta-B, move cursor left by one word
+      case META + 'B':
+      case CTRL + LEFT_ARROW_KEY:
+      case META + LEFT_ARROW_KEY:  // Emacs allows Meta, bash & readline don't
+      case ctrlChar('D'):
+      case META + 'd':  // meta-D, kill word to right of cursor
+      case META + 'D':
+      case ctrlChar('E'):  // ctrl-E, move cursor to end of line
+      case END_KEY:
+      case ctrlChar('F'):  // ctrl-F, move cursor right by one character
+      case RIGHT_ARROW_KEY:
+      case META + 'f':  // meta-F, move cursor right by one word
+      case META + 'F':
+      case CTRL + RIGHT_ARROW_KEY:
+      case META + RIGHT_ARROW_KEY:  // Emacs allows Meta, bash & readline don't
+      case META + ctrlChar('H'):
+      case ctrlChar('J'):
+      case ctrlChar('K'):  // ctrl-K, kill from cursor to end of line
+      case ctrlChar('M'):
+      case ctrlChar('N'):  // ctrl-N, recall next line in history
+      case ctrlChar('P'):  // ctrl-P, recall previous line in history
+      case DOWN_ARROW_KEY:
+      case UP_ARROW_KEY:
+      case ctrlChar('T'):  // ctrl-T, transpose characters
+      case ctrlChar(
+          'U'):  // ctrl-U, kill all characters to the left of the cursor
+      case ctrlChar('W'):
+      case META + 'y':  // meta-Y, "yank-pop", rotate popped text
+      case META + 'Y':
+      case 127:
+      case DELETE_KEY:
+      case META + '<':  // start of history
+      case PAGE_UP_KEY:
+      case META + '>':  // end of history
+      case PAGE_DOWN_KEY:
+        keepLooping = false;
+        break;
+
+      // these characters revert the input line to its previous state
+      case ctrlChar('C'):  // ctrl-C, abort this line
+      case ctrlChar('G'):
+      case ctrlChar('L'):  // ctrl-L, clear screen and redisplay line
+        keepLooping = false;
+        useSearchedLine = false;
+        if (c != ctrlChar('L')) {
+          c = -1;  // ctrl-C and ctrl-G just abort the search and do nothing
+                   // else
+        }
+        break;
+
+      // these characters stay in search mode and update the display
+      case ctrlChar('S'):
+      case ctrlChar('R'):
+        if (dp.searchTextLen ==
+            0) {  // if no current search text, recall previous text
+          if (previousSearchText.length()) {
+            dp.updateSearchText(previousSearchText.get());
+          }
+        }
+        if ((dp.direction == 1 && c == ctrlChar('R')) ||
+            (dp.direction == -1 && c == ctrlChar('S'))) {
+          dp.direction = 0 - dp.direction;  // reverse direction
+          dp.updateSearchPrompt();          // change the prompt
+        } else {
+          searchAgain = true;  // same direction, search again
+        }
+        break;
+
+// job control is its own thing
+#ifndef _WIN32
+      case ctrlChar('Z'):  // ctrl-Z, job control
+        disableRawMode();  // Returning to Linux (whatever) shell, leave raw
+                           // mode
+        raise(SIGSTOP);    // Break out in mid-line
+        enableRawMode();   // Back from Linux shell, re-enter raw mode
+        {
+          bufferSize = historyLineLength + 1;
+          unique_ptr<char32_t[]> tempUnicode(new char32_t[bufferSize]);
+          copyString8to32(tempUnicode.get(), bufferSize, ucharCount,
+                          history[historyIndex]);
+          dynamicRefresh(dp, tempUnicode.get(), historyLineLength,
+                         historyLinePosition);
+        }
+        continue;
+        break;
+#endif
+
+      // these characters update the search string, and hence the selected input
+      // line
+      case ctrlChar('H'):  // backspace/ctrl-H, delete char to left of cursor
+        if (dp.searchTextLen > 0) {
+          unique_ptr<char32_t[]> tempUnicode(new char32_t[dp.searchTextLen]);
+          --dp.searchTextLen;
+          dp.searchText[dp.searchTextLen] = 0;
+          copyString32(tempUnicode.get(), dp.searchText.get(),
+                       dp.searchTextLen);
+          dp.updateSearchText(tempUnicode.get());
+        } else {
+          beep();
+        }
+        break;
+
+      case ctrlChar('Y'):  // ctrl-Y, yank killed text
+        break;
+
+      default:
+        if (!isControlChar(c) && c <= 0x0010FFFF) {  // not an action character
+          unique_ptr<char32_t[]> tempUnicode(
+              new char32_t[dp.searchTextLen + 2]);
+          copyString32(tempUnicode.get(), dp.searchText.get(),
+                       dp.searchTextLen);
+          tempUnicode[dp.searchTextLen] = c;
+          tempUnicode[dp.searchTextLen + 1] = 0;
+          dp.updateSearchText(tempUnicode.get());
+        } else {
+          beep();
+        }
+    }  // switch
+
+    // if we are staying in search mode, search now
+    if (keepLooping) {
+      bufferSize = historyLineLength + 1;
+      if (activeHistoryLine) {
+        delete[] activeHistoryLine;
+        activeHistoryLine = nullptr;
+      }
+      activeHistoryLine = new char32_t[bufferSize];
+      copyString8to32(activeHistoryLine, bufferSize, ucharCount,
+                      history[historyIndex]);
+      if (dp.searchTextLen > 0) {
+        bool found = false;
+        int historySearchIndex = historyIndex;
+        int lineLength = static_cast<int>(ucharCount);
+        int lineSearchPos = historyLinePosition;
+        if (searchAgain) {
+          lineSearchPos += dp.direction;
+        }
+        searchAgain = false;
+        while (true) {
+          while ((dp.direction > 0) ? (lineSearchPos < lineLength)
+                                    : (lineSearchPos >= 0)) {
+            if (strncmp32(dp.searchText.get(),
+                          &activeHistoryLine[lineSearchPos],
+                          dp.searchTextLen) == 0) {
+              found = true;
+              break;
+            }
+            lineSearchPos += dp.direction;
+          }
+          if (found) {
+            historyIndex = historySearchIndex;
+            historyLineLength = lineLength;
+            historyLinePosition = lineSearchPos;
+            break;
+          } else if ((dp.direction > 0) ? (historySearchIndex < historyLen - 1)
+                                        : (historySearchIndex > 0)) {
+            historySearchIndex += dp.direction;
+            bufferSize = strlen8(history[historySearchIndex]) + 1;
+            delete[] activeHistoryLine;
+            activeHistoryLine = nullptr;
+            activeHistoryLine = new char32_t[bufferSize];
+            copyString8to32(activeHistoryLine, bufferSize, ucharCount,
+                            history[historySearchIndex]);
+            lineLength = static_cast<int>(ucharCount);
+            lineSearchPos =
+                (dp.direction > 0) ? 0 : (lineLength - dp.searchTextLen);
+          } else {
+            beep();
+            break;
+          }
+        };  // while
+      }
+      if (activeHistoryLine) {
+        delete[] activeHistoryLine;
+        activeHistoryLine = nullptr;
+      }
+      bufferSize = historyLineLength + 1;
+      activeHistoryLine = new char32_t[bufferSize];
+      copyString8to32(activeHistoryLine, bufferSize, ucharCount,
+                      history[historyIndex]);
+      dynamicRefresh(dp, activeHistoryLine, historyLineLength,
+                     historyLinePosition);  // draw user's text with our prompt
+    }
+  }  // while
+
+  // leaving history search, restore previous prompt, maybe make searched line
+  // current
+  PromptBase pb;
+  pb.promptChars = pi.promptIndentation;
+  pb.promptBytes = pi.promptBytes;
+  Utf32String tempUnicode(pb.promptBytes + 1);
+
+  copyString32(tempUnicode.get(), &pi.promptText[pi.promptLastLinePosition],
+               pb.promptBytes - pi.promptLastLinePosition);
+  tempUnicode.initFromBuffer();
+  pb.promptText = tempUnicode;
+  pb.promptExtraLines = 0;
+  pb.promptIndentation = pi.promptIndentation;
+  pb.promptLastLinePosition = 0;
+  pb.promptPreviousInputLen = historyLineLength;
+  pb.promptCursorRowOffset = dp.promptCursorRowOffset;
+  pb.promptScreenColumns = pi.promptScreenColumns;
+  pb.promptPreviousLen = dp.promptChars;
+  if (useSearchedLine && activeHistoryLine) {
+    historyRecallMostRecent = true;
+    copyString32(buf32, activeHistoryLine, buflen + 1);
+    len = historyLineLength;
+    pos = historyLinePosition;
+  }
+  if (activeHistoryLine) {
+    delete[] activeHistoryLine;
+    activeHistoryLine = nullptr;
+  }
+  dynamicRefresh(pb, buf32, len,
+                 pos);  // redraw the original prompt with current input
+  pi.promptPreviousInputLen = len;
+  pi.promptCursorRowOffset = pi.promptExtraLines + pb.promptCursorRowOffset;
+  previousSearchText =
+      dp.searchText;  // save search text for possible reuse on ctrl-R ctrl-R
+  return c;           // pass a character or -1 back to main loop
+}
+
+static bool isCharacterAlphanumeric(char32_t testChar) {
+#ifdef _WIN32
+  return (iswalnum((wint_t)testChar) != 0 ? true : false);
+#else
+  return (iswalnum(testChar) != 0 ? true : false);
+#endif
+}
+
+#ifndef _WIN32
+static bool gotResize = false;
+#endif
+static int keyType = 0;
+
+int InputBuffer::getInputLine(PromptBase& pi) {
+  keyType = 0;
+
+  // The latest history entry is always our current buffer
+  if (len > 0) {
+    size_t bufferSize = sizeof(char32_t) * len + 1;
+    unique_ptr<char[]> tempBuffer(new char[bufferSize]);
+    copyString32to8(tempBuffer.get(), bufferSize, buf32);
+    linenoiseHistoryAdd(tempBuffer.get());
+  } else {
+    linenoiseHistoryAdd("");
+  }
+  historyIndex = historyLen - 1;
+  historyRecallMostRecent = false;
+
+  // display the prompt
+  if (!pi.write()) return -1;
+
+#ifndef _WIN32
+  // we have to generate our own newline on line wrap on Linux
+  if (pi.promptIndentation == 0 && pi.promptExtraLines > 0)
+    if (write(1, "\n", 1) == -1) return -1;
+#endif
+
+  // the cursor starts out at the end of the prompt
+  pi.promptCursorRowOffset = pi.promptExtraLines;
+
+  // kill and yank start in "other" mode
+  killRing.lastAction = KillRing::actionOther;
+
+  // when history search returns control to us, we execute its terminating
+  // keystroke
+  int terminatingKeystroke = -1;
+
+  // if there is already text in the buffer, display it first
+  if (len > 0) {
+    refreshLine(pi);
+  }
+
+  // loop collecting characters, respond to line editing characters
+  while (true) {
+    int c;
+    if (terminatingKeystroke == -1) {
+      c = linenoiseReadChar();  // get a new keystroke
+
+      keyType = 0; 
+      if (c != 0) {
+        // set flag that we got some input
+        if (c == ctrlChar('C')) {
+          keyType = 1;
+        } else if (c == ctrlChar('D')) {
+          keyType = 2;
+        }
+      }
+
+#ifndef _WIN32
+      if (c == 0 && gotResize) {
+        // caught a window resize event
+        // now redraw the prompt and line
+        gotResize = false;
+        pi.promptScreenColumns = getScreenColumns();
+        dynamicRefresh(pi, buf32, len,
+                       pos);  // redraw the original prompt with current input
+        continue;
+      }
+#endif
+    } else {
+      c = terminatingKeystroke;   // use the terminating keystroke from search
+      terminatingKeystroke = -1;  // clear it once we've used it
+    }
+
+    c = cleanupCtrl(c);  // convert CTRL + <char> into normal ctrl
+
+    if (c == 0) {
+      return len;
+    }
+
+    if (c == -1) {
+      refreshLine(pi);
+      continue;
+    }
+
+    if (c == -2) {
+      if (!pi.write()) return -1;
+      refreshLine(pi);
+      continue;
+    }
+
+    // ctrl-I/tab, command completion, needs to be before switch statement
+    if (c == ctrlChar('I') && completionCallback) {
+      if (pos == 0)  // SERVER-4967 -- in earlier versions, you could paste
+                     // previous output
+        continue;    //  back into the shell ... this output may have leading
+                     //  tabs.
+      // This hack (i.e. what the old code did) prevents command completion
+      //  on an empty line but lets users paste text with leading tabs.
+
+      killRing.lastAction = KillRing::actionOther;
+      historyRecallMostRecent = false;
+
+      // completeLine does the actual completion and replacement
+      c = completeLine(pi);
+
+      if (c < 0)  // return on error
+        return len;
+
+      if (c == 0)  // read next character when 0
+        continue;
+
+      // deliberate fall-through here, so we use the terminating character
+    }
+
+    switch (c) {
+      case ctrlChar('A'):  // ctrl-A, move cursor to start of line
+      case HOME_KEY:
+        killRing.lastAction = KillRing::actionOther;
+        pos = 0;
+        refreshLine(pi);
+        break;
+
+      case ctrlChar('B'):  // ctrl-B, move cursor left by one character
+      case LEFT_ARROW_KEY:
+        killRing.lastAction = KillRing::actionOther;
+        if (pos > 0) {
+          --pos;
+          refreshLine(pi);
+        }
+        break;
+
+      case META + 'b':  // meta-B, move cursor left by one word
+      case META + 'B':
+      case CTRL + LEFT_ARROW_KEY:
+      case META + LEFT_ARROW_KEY:  // Emacs allows Meta, bash & readline don't
+        killRing.lastAction = KillRing::actionOther;
+        if (pos > 0) {
+          while (pos > 0 && !isCharacterAlphanumeric(buf32[pos - 1])) {
+            --pos;
+          }
+          while (pos > 0 && isCharacterAlphanumeric(buf32[pos - 1])) {
+            --pos;
+          }
+          refreshLine(pi);
+        }
+        break;
+
+      case ctrlChar('C'):  // ctrl-C, abort this line
+        killRing.lastAction = KillRing::actionOther;
+        historyRecallMostRecent = false;
+        errno = EAGAIN;
+        --historyLen;
+        free(history[historyLen]);
+        // we need one last refresh with the cursor at the end of the line
+        // so we don't display the next prompt over the previous input line
+        pos = len;  // pass len as pos for EOL
+        refreshLine(pi);
+        if (write(1, "^C", 2) == -1) return -1;  // Display the ^C we got
+        return -1;
+
+      case META + 'c':  // meta-C, give word initial Cap
+      case META + 'C':
+        killRing.lastAction = KillRing::actionOther;
+        historyRecallMostRecent = false;
+        if (pos < len) {
+          while (pos < len && !isCharacterAlphanumeric(buf32[pos])) {
+            ++pos;
+          }
+          if (pos < len && isCharacterAlphanumeric(buf32[pos])) {
+            if (buf32[pos] >= 'a' && buf32[pos] <= 'z') {
+              buf32[pos] += 'A' - 'a';
+            }
+            ++pos;
+          }
+          while (pos < len && isCharacterAlphanumeric(buf32[pos])) {
+            if (buf32[pos] >= 'A' && buf32[pos] <= 'Z') {
+              buf32[pos] += 'a' - 'A';
+            }
+            ++pos;
+          }
+          refreshLine(pi);
+        }
+        break;
+
+      // ctrl-D, delete the character under the cursor
+      // on an empty line, exit the shell
+      case ctrlChar('D'):
+        killRing.lastAction = KillRing::actionOther;
+        if (len > 0 && pos < len) {
+          historyRecallMostRecent = false;
+          memmove(buf32 + pos, buf32 + pos + 1, sizeof(char32_t) * (len - pos));
+          --len;
+          refreshLine(pi);
+        } else if (len == 0) {
+          --historyLen;
+          free(history[historyLen]);
+          return -1;
+        }
+        break;
+
+      case META + 'd':  // meta-D, kill word to right of cursor
+      case META + 'D':
+        if (pos < len) {
+          historyRecallMostRecent = false;
+          int endingPos = pos;
+          while (endingPos < len &&
+                 !isCharacterAlphanumeric(buf32[endingPos])) {
+            ++endingPos;
+          }
+          while (endingPos < len && isCharacterAlphanumeric(buf32[endingPos])) {
+            ++endingPos;
+          }
+          killRing.kill(&buf32[pos], endingPos - pos, true);
+          memmove(buf32 + pos, buf32 + endingPos,
+                  sizeof(char32_t) * (len - endingPos + 1));
+          len -= endingPos - pos;
+          refreshLine(pi);
+        }
+        killRing.lastAction = KillRing::actionKill;
+        break;
+
+      case ctrlChar('E'):  // ctrl-E, move cursor to end of line
+      case END_KEY:
+        killRing.lastAction = KillRing::actionOther;
+        pos = len;
+        refreshLine(pi);
+        break;
+
+      case ctrlChar('F'):  // ctrl-F, move cursor right by one character
+      case RIGHT_ARROW_KEY:
+        killRing.lastAction = KillRing::actionOther;
+        if (pos < len) {
+          ++pos;
+          refreshLine(pi);
+        }
+        break;
+
+      case META + 'f':  // meta-F, move cursor right by one word
+      case META + 'F':
+      case CTRL + RIGHT_ARROW_KEY:
+      case META + RIGHT_ARROW_KEY:  // Emacs allows Meta, bash & readline don't
+        killRing.lastAction = KillRing::actionOther;
+        if (pos < len) {
+          while (pos < len && !isCharacterAlphanumeric(buf32[pos])) {
+            ++pos;
+          }
+          while (pos < len && isCharacterAlphanumeric(buf32[pos])) {
+            ++pos;
+          }
+          refreshLine(pi);
+        }
+        break;
+
+      case ctrlChar('H'):  // backspace/ctrl-H, delete char to left of cursor
+        killRing.lastAction = KillRing::actionOther;
+        if (pos > 0) {
+          historyRecallMostRecent = false;
+          memmove(buf32 + pos - 1, buf32 + pos,
+                  sizeof(char32_t) * (1 + len - pos));
+          --pos;
+          --len;
+          refreshLine(pi);
+        }
+        break;
+
+      // meta-Backspace, kill word to left of cursor
+      case META + ctrlChar('H'):
+        if (pos > 0) {
+          historyRecallMostRecent = false;
+          int startingPos = pos;
+          while (pos > 0 && !isCharacterAlphanumeric(buf32[pos - 1])) {
+            --pos;
+          }
+          while (pos > 0 && isCharacterAlphanumeric(buf32[pos - 1])) {
+            --pos;
+          }
+          killRing.kill(&buf32[pos], startingPos - pos, false);
+          memmove(buf32 + pos, buf32 + startingPos,
+                  sizeof(char32_t) * (len - startingPos + 1));
+          len -= startingPos - pos;
+          refreshLine(pi);
+        }
+        killRing.lastAction = KillRing::actionKill;
+        break;
+
+      case ctrlChar('J'):  // ctrl-J/linefeed/newline, accept line
+      case ctrlChar('M'):  // ctrl-M/return/enter
+        killRing.lastAction = KillRing::actionOther;
+        // we need one last refresh with the cursor at the end of the line
+        // so we don't display the next prompt over the previous input line
+        pos = len;  // pass len as pos for EOL
+        refreshLine(pi);
+        historyPreviousIndex = historyRecallMostRecent ? historyIndex : -2;
+        --historyLen;
+        free(history[historyLen]);
+        return len;
+
+      case ctrlChar('K'):  // ctrl-K, kill from cursor to end of line
+        killRing.kill(&buf32[pos], len - pos, true);
+        buf32[pos] = '\0';
+        len = pos;
+        refreshLine(pi);
+        killRing.lastAction = KillRing::actionKill;
+        historyRecallMostRecent = false;
+        break;
+
+      case ctrlChar('L'):  // ctrl-L, clear screen and redisplay line
+        clearScreen(pi);
+        break;
+
+      case META + 'l':  // meta-L, lowercase word
+      case META + 'L':
+        killRing.lastAction = KillRing::actionOther;
+        if (pos < len) {
+          historyRecallMostRecent = false;
+          while (pos < len && !isCharacterAlphanumeric(buf32[pos])) {
+            ++pos;
+          }
+          while (pos < len && isCharacterAlphanumeric(buf32[pos])) {
+            if (buf32[pos] >= 'A' && buf32[pos] <= 'Z') {
+              buf32[pos] += 'a' - 'A';
+            }
+            ++pos;
+          }
+          refreshLine(pi);
+        }
+        break;
+
+      case ctrlChar('N'):  // ctrl-N, recall next line in history
+      case ctrlChar('P'):  // ctrl-P, recall previous line in history
+      case DOWN_ARROW_KEY:
+      case UP_ARROW_KEY:
+        killRing.lastAction = KillRing::actionOther;
+        // if not already recalling, add the current line to the history list so
+        // we don't
+        // have to special case it
+        if (historyIndex == historyLen - 1) {
+          free(history[historyLen - 1]);
+          size_t tempBufferSize = sizeof(char32_t) * len + 1;
+          unique_ptr<char[]> tempBuffer(new char[tempBufferSize]);
+          copyString32to8(tempBuffer.get(), tempBufferSize, buf32);
+          history[historyLen - 1] = strdup8(tempBuffer.get());
+        }
+        if (historyLen > 1) {
+          if (c == UP_ARROW_KEY) {
+            c = ctrlChar('P');
+          }
+          if (historyPreviousIndex != -2 && c != ctrlChar('P')) {
+            historyIndex =
+                1 + historyPreviousIndex;  // emulate Windows down-arrow
+          } else {
+            historyIndex += (c == ctrlChar('P')) ? -1 : 1;
+          }
+          historyPreviousIndex = -2;
+          if (historyIndex < 0) {
+            historyIndex = 0;
+            break;
+          } else if (historyIndex >= historyLen) {
+            historyIndex = historyLen - 1;
+            break;
+          }
+          historyRecallMostRecent = true;
+          size_t ucharCount = 0;
+          copyString8to32(buf32, buflen, ucharCount, history[historyIndex]);
+          len = pos = static_cast<int>(ucharCount);
+          refreshLine(pi);
+        }
+        break;
+
+      case ctrlChar('R'):  // ctrl-R, reverse history search
+      case ctrlChar('S'):  // ctrl-S, forward history search
+        terminatingKeystroke = incrementalHistorySearch(pi, c);
+        break;
+
+      case ctrlChar('T'):  // ctrl-T, transpose characters
+        killRing.lastAction = KillRing::actionOther;
+        if (pos > 0 && len > 1) {
+          historyRecallMostRecent = false;
+          size_t leftCharPos = (pos == len) ? pos - 2 : pos - 1;
+          char32_t aux = buf32[leftCharPos];
+          buf32[leftCharPos] = buf32[leftCharPos + 1];
+          buf32[leftCharPos + 1] = aux;
+          if (pos != len) ++pos;
+          refreshLine(pi);
+        }
+        break;
+
+      case ctrlChar(
+          'U'):  // ctrl-U, kill all characters to the left of the cursor
+        if (pos > 0) {
+          historyRecallMostRecent = false;
+          killRing.kill(&buf32[0], pos, false);
+          len -= pos;
+          memmove(buf32, buf32 + pos, sizeof(char32_t) * (len + 1));
+          pos = 0;
+          refreshLine(pi);
+        }
+        killRing.lastAction = KillRing::actionKill;
+        break;
+
+      case META + 'u':  // meta-U, uppercase word
+      case META + 'U':
+        killRing.lastAction = KillRing::actionOther;
+        if (pos < len) {
+          historyRecallMostRecent = false;
+          while (pos < len && !isCharacterAlphanumeric(buf32[pos])) {
+            ++pos;
+          }
+          while (pos < len && isCharacterAlphanumeric(buf32[pos])) {
+            if (buf32[pos] >= 'a' && buf32[pos] <= 'z') {
+              buf32[pos] += 'A' - 'a';
+            }
+            ++pos;
+          }
+          refreshLine(pi);
+        }
+        break;
+
+      // ctrl-W, kill to whitespace (not word) to left of cursor
+      case ctrlChar('W'):
+        if (pos > 0) {
+          historyRecallMostRecent = false;
+          int startingPos = pos;
+          while (pos > 0 && buf32[pos - 1] == ' ') {
+            --pos;
+          }
+          while (pos > 0 && buf32[pos - 1] != ' ') {
+            --pos;
+          }
+          killRing.kill(&buf32[pos], startingPos - pos, false);
+          memmove(buf32 + pos, buf32 + startingPos,
+                  sizeof(char32_t) * (len - startingPos + 1));
+          len -= startingPos - pos;
+          refreshLine(pi);
+        }
+        killRing.lastAction = KillRing::actionKill;
+        break;
+
+      case ctrlChar('Y'):  // ctrl-Y, yank killed text
+        historyRecallMostRecent = false;
+        {
+          Utf32String* restoredText = killRing.yank();
+          if (restoredText) {
+            bool truncated = false;
+            size_t ucharCount = restoredText->length();
+            if (ucharCount > static_cast<size_t>(buflen - len)) {
+              ucharCount = buflen - len;
+              truncated = true;
+            }
+            memmove(buf32 + pos + ucharCount, buf32 + pos,
+                    sizeof(char32_t) * (len - pos + 1));
+            memmove(buf32 + pos, restoredText->get(),
+                    sizeof(char32_t) * ucharCount);
+            pos += static_cast<int>(ucharCount);
+            len += static_cast<int>(ucharCount);
+            refreshLine(pi);
+            killRing.lastAction = KillRing::actionYank;
+            killRing.lastYankSize = ucharCount;
+            if (truncated) {
+              beep();
+            }
+          } else {
+            beep();
+          }
+        }
+        break;
+
+      case META + 'y':  // meta-Y, "yank-pop", rotate popped text
+      case META + 'Y':
+        if (killRing.lastAction == KillRing::actionYank) {
+          historyRecallMostRecent = false;
+          Utf32String* restoredText = killRing.yankPop();
+          if (restoredText) {
+            bool truncated = false;
+            size_t ucharCount = restoredText->length();
+            if (ucharCount >
+                static_cast<size_t>(killRing.lastYankSize + buflen - len)) {
+              ucharCount = killRing.lastYankSize + buflen - len;
+              truncated = true;
+            }
+            if (ucharCount > killRing.lastYankSize) {
+              memmove(buf32 + pos + ucharCount - killRing.lastYankSize,
+                      buf32 + pos, sizeof(char32_t) * (len - pos + 1));
+              memmove(buf32 + pos - killRing.lastYankSize, restoredText->get(),
+                      sizeof(char32_t) * ucharCount);
+            } else {
+              memmove(buf32 + pos - killRing.lastYankSize, restoredText->get(),
+                      sizeof(char32_t) * ucharCount);
+              memmove(buf32 + pos + ucharCount - killRing.lastYankSize,
+                      buf32 + pos, sizeof(char32_t) * (len - pos + 1));
+            }
+            pos += static_cast<int>(ucharCount - killRing.lastYankSize);
+            len += static_cast<int>(ucharCount - killRing.lastYankSize);
+            killRing.lastYankSize = ucharCount;
+            refreshLine(pi);
+            if (truncated) {
+              beep();
+            }
+            break;
+          }
+        }
+        beep();
+        break;
+
+#ifndef _WIN32
+      case ctrlChar('Z'):  // ctrl-Z, job control
+        disableRawMode();  // Returning to Linux (whatever) shell, leave raw
+                           // mode
+        raise(SIGSTOP);    // Break out in mid-line
+        enableRawMode();   // Back from Linux shell, re-enter raw mode
+        if (!pi.write()) break;  // Redraw prompt
+        refreshLine(pi);         // Refresh the line
+        break;
+#endif
+
+      // DEL, delete the character under the cursor
+      case 127:
+      case DELETE_KEY:
+        killRing.lastAction = KillRing::actionOther;
+        if (len > 0 && pos < len) {
+          historyRecallMostRecent = false;
+          memmove(buf32 + pos, buf32 + pos + 1, sizeof(char32_t) * (len - pos));
+          --len;
+          refreshLine(pi);
+        }
+        break;
+
+      case META + '<':     // meta-<, beginning of history
+      case PAGE_UP_KEY:    // Page Up, beginning of history
+      case META + '>':     // meta->, end of history
+      case PAGE_DOWN_KEY:  // Page Down, end of history
+        killRing.lastAction = KillRing::actionOther;
+        // if not already recalling, add the current line to the history list so
+        // we don't
+        // have to special case it
+        if (historyIndex == historyLen - 1) {
+          free(history[historyLen - 1]);
+          size_t tempBufferSize = sizeof(char32_t) * len + 1;
+          unique_ptr<char[]> tempBuffer(new char[tempBufferSize]);
+          copyString32to8(tempBuffer.get(), tempBufferSize, buf32);
+          history[historyLen - 1] = strdup8(tempBuffer.get());
+        }
+        if (historyLen > 1) {
+          historyIndex =
+              (c == META + '<' || c == PAGE_UP_KEY) ? 0 : historyLen - 1;
+          historyPreviousIndex = -2;
+          historyRecallMostRecent = true;
+          size_t ucharCount = 0;
+          copyString8to32(buf32, buflen, ucharCount, history[historyIndex]);
+          len = pos = static_cast<int>(ucharCount);
+          refreshLine(pi);
+        }
+        break;
+
+      // not one of our special characters, maybe insert it in the buffer
+      default:
+        killRing.lastAction = KillRing::actionOther;
+        historyRecallMostRecent = false;
+        if (c & (META | CTRL)) {  // beep on unknown Ctrl and/or Meta keys
+          beep();
+          break;
+        }
+        if (len < buflen) {
+          if (isControlChar(c)) {  // don't insert control characters
+            beep();
+            break;
+          }
+          if (len == pos) {  // at end of buffer
+            buf32[pos] = c;
+            ++pos;
+            ++len;
+            buf32[len] = '\0';
+            int inputLen = calculateColumnPosition(buf32, len);
+            if (pi.promptIndentation + inputLen < pi.promptScreenColumns) {
+              if (inputLen > pi.promptPreviousInputLen)
+                pi.promptPreviousInputLen = inputLen;
+              /* Avoid a full update of the line in the
+               * trivial case. */
+              if (write32(1, reinterpret_cast<char32_t*>(&c), 1) == -1)
+                return -1;
+            } else {
+              refreshLine(pi);
+            }
+          } else {  // not at end of buffer, have to move characters to our
+                    // right
+            memmove(buf32 + pos + 1, buf32 + pos,
+                    sizeof(char32_t) * (len - pos));
+            buf32[pos] = c;
+            ++len;
+            ++pos;
+            buf32[len] = '\0';
+            refreshLine(pi);
+          }
+        } else {
+          beep();  // buffer is full, beep on new characters
+        }
+        break;
+    }
+  }
+  return len;
+}
+
+static string preloadedBufferContents;  // used with linenoisePreloadBuffer
+static string preloadErrorMessage;
+
+/**
+ * linenoisePreloadBuffer provides text to be inserted into the command buffer
+ *
+ * the provided text will be processed to be usable and will be used to preload
+ * the input buffer on the next call to linenoise()
+ *
+ * @param preloadText text to begin with on the next call to linenoise()
+ */
+void linenoisePreloadBuffer(const char* preloadText) {
+  if (!preloadText) {
+    return;
+  }
+  int bufferSize = static_cast<int>(strlen(preloadText) + 1);
+  unique_ptr<char[]> tempBuffer(new char[bufferSize]);
+  strncpy(&tempBuffer[0], preloadText, bufferSize);
+
+  // remove characters that won't display correctly
+  char* pIn = &tempBuffer[0];
+  char* pOut = pIn;
+  bool controlsStripped = false;
+  bool whitespaceSeen = false;
+  while (*pIn) {
+    unsigned char c =
+        *pIn++;       // we need unsigned so chars 0x80 and above are allowed
+    if ('\r' == c) {  // silently skip CR
+      continue;
+    }
+    if ('\n' == c || '\t' == c) {  // note newline or tab
+      whitespaceSeen = true;
+      continue;
+    }
+    if (isControlChar(
+            c)) {  // remove other control characters, flag for message
+      controlsStripped = true;
+      *pOut++ = ' ';
+      continue;
+    }
+    if (whitespaceSeen) {  // convert whitespace to a single space
+      *pOut++ = ' ';
+      whitespaceSeen = false;
+    }
+    *pOut++ = c;
+  }
+  *pOut = 0;
+  int processedLength = static_cast<int>(pOut - tempBuffer.get());
+  bool lineTruncated = false;
+  if (processedLength > (LINENOISE_MAX_LINE - 1)) {
+    lineTruncated = true;
+    tempBuffer[LINENOISE_MAX_LINE - 1] = 0;
+  }
+  preloadedBufferContents = tempBuffer.get();
+  if (controlsStripped) {
+    preloadErrorMessage +=
+        " [Edited line: control characters were converted to spaces]\n";
+  }
+  if (lineTruncated) {
+    preloadErrorMessage += " [Edited line: the line length was reduced from ";
+    char buf[128];
+    snprintf(buf, sizeof(buf), "%d to %d]\n", processedLength,
+             (LINENOISE_MAX_LINE - 1));
+    preloadErrorMessage += buf;
+  }
+}
+
+/**
+ * linenoise is a readline replacement.
+ *
+ * call it with a prompt to display and it will return a line of input from the
+ * user
+ *
+ * @param prompt text of prompt to display to the user
+ * @return       the returned string belongs to the caller on return and must be
+ * freed to prevent
+ *               memory leaks
+ */
+char* linenoise(const char* prompt) {
+#ifndef _WIN32
+  gotResize = false;
+#endif
+  if (isatty(STDIN_FILENO)) {  // input is from a terminal
+    char32_t buf32[LINENOISE_MAX_LINE];
+    char charWidths[LINENOISE_MAX_LINE];
+    if (!preloadErrorMessage.empty()) {
+      printf("%s", preloadErrorMessage.c_str());
+      fflush(stdout);
+      preloadErrorMessage.clear();
+    }
+    PromptInfo pi(prompt, getScreenColumns());
+    if (isUnsupportedTerm()) {
+      if (!pi.write()) return 0;
+      fflush(stdout);
+      if (preloadedBufferContents.empty()) {
+        unique_ptr<char[]> buf8(new char[LINENOISE_MAX_LINE]);
+        if (fgets(buf8.get(), LINENOISE_MAX_LINE, stdin) == NULL) {
+          return NULL;
+        }
+        size_t len = strlen(buf8.get());
+        while (len && (buf8[len - 1] == '\n' || buf8[len - 1] == '\r')) {
+          --len;
+          buf8[len] = '\0';
+        }
+        return strdup(buf8.get());  // caller must free buffer
+      } else {
+        char* buf8 = strdup(preloadedBufferContents.c_str());
+        preloadedBufferContents.clear();
+        return buf8;  // caller must free buffer
+      }
+    } else {
+      if (enableRawMode() == -1) {
+        return NULL;
+      }
+      InputBuffer ib(buf32, charWidths, LINENOISE_MAX_LINE);
+      if (!preloadedBufferContents.empty()) {
+        ib.preloadBuffer(preloadedBufferContents.c_str());
+        preloadedBufferContents.clear();
+      }
+      int count = ib.getInputLine(pi);
+      disableRawMode();
+      printf("\n");
+      if (count == -1) {
+        return NULL;
+      }
+      size_t bufferSize = sizeof(char32_t) * ib.length() + 1;
+      unique_ptr<char[]> buf8(new char[bufferSize]);
+      copyString32to8(buf8.get(), bufferSize, buf32);
+      return strdup(buf8.get());  // caller must free buffer
+    }
+  } else {  // input not from a terminal, we should work with piped input, i.e.
+            // redirected stdin
+    unique_ptr<char[]> buf8(new char[LINENOISE_MAX_LINE]);
+    if (fgets(buf8.get(), LINENOISE_MAX_LINE, stdin) == NULL) {
+      return NULL;
+    }
+
+    // if fgets() gave us the newline, remove it
+    int count = static_cast<int>(strlen(buf8.get()));
+    if (count > 0 && buf8[count - 1] == '\n') {
+      --count;
+      buf8[count] = '\0';
+    }
+    return strdup(buf8.get());  // caller must free buffer
+  }
+}
+
+/* Register a callback function to be called for tab-completion. */
+void linenoiseSetCompletionCallback(linenoiseCompletionCallback* fn) {
+  completionCallback = fn;
+}
+
+void linenoiseAddCompletion(linenoiseCompletions* lc, const char* str) {
+  lc->completionStrings.push_back(Utf32String(str));
+}
+
+int linenoiseHistoryAdd(const char* line) {
+  if (historyMaxLen == 0) {
+    return 0;
+  }
+  if (history == NULL) {
+    history =
+        reinterpret_cast<char8_t**>(malloc(sizeof(char8_t*) * historyMaxLen));
+    if (history == NULL) {
+      return 0;
+    }
+    memset(history, 0, (sizeof(char*) * historyMaxLen));
+  }
+  char8_t* linecopy = strdup8(line);
+  if (!linecopy) {
+    return 0;
+  }
+
+  // convert newlines in multi-line code to spaces before storing
+  char8_t* p = linecopy;
+  while (*p) {
+    if (*p == '\n') {
+      *p = ' ';
+    }
+    ++p;
+  }
+
+  // prevent duplicate history entries
+  if (historyLen > 0 && history[historyLen - 1] != nullptr &&
+      strcmp(reinterpret_cast<char const*>(history[historyLen - 1]),
+             reinterpret_cast<char const*>(linecopy)) == 0) {
+    free(linecopy);
+    return 0;
+  }
+
+  if (historyLen == historyMaxLen) {
+    free(history[0]);
+    memmove(history, history + 1, sizeof(char*) * (historyMaxLen - 1));
+    --historyLen;
+    if (--historyPreviousIndex < -1) {
+      historyPreviousIndex = -2;
+    }
+  }
+
+  history[historyLen] = linecopy;
+  ++historyLen;
+  return 1;
+}
+
+int linenoiseHistorySetMaxLen(int len) {
+  if (len < 1) {
+    return 0;
+  }
+  if (history) {
+    int tocopy = historyLen;
+    char8_t** newHistory =
+        reinterpret_cast<char8_t**>(malloc(sizeof(char8_t*) * len));
+    if (newHistory == NULL) {
+      return 0;
+    }
+    if (len < tocopy) {
+      tocopy = len;
+    }
+    memcpy(newHistory, history + historyMaxLen - tocopy,
+           sizeof(char8_t*) * tocopy);
+    free(history);
+    history = newHistory;
+  }
+  historyMaxLen = len;
+  if (historyLen > historyMaxLen) {
+    historyLen = historyMaxLen;
+  }
+  return 1;
+}
+
+/* Fetch a line of the history by (zero-based) index.  If the requested
+ * line does not exist, NULL is returned.  The return value is a heap-allocated
+ * copy of the line, and the caller is responsible for de-allocating it. */
+char* linenoiseHistoryLine(int index) {
+  if (index < 0 || index >= historyLen) return NULL;
+
+  return strdup(reinterpret_cast<char const*>(history[index]));
+}
+
+/* Save the history in the specified file. On success 0 is returned
+ * otherwise -1 is returned. */
+int linenoiseHistorySave(const char* filename) {
+#if _WIN32
+  FILE* fp = fopen(filename, "wt");
+#else
+  int fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, S_IRUSR | S_IWUSR);
+
+  if (fd < 0) {
+    return -1;
+  }
+
+  FILE* fp = fdopen(fd, "wt");
+#endif
+
+  if (fp == NULL) {
+    return -1;
+  }
+
+  for (int j = 0; j < historyLen; ++j) {
+    if (history[j][0] != '\0') {
+      fprintf(fp, "%s\n", history[j]);
+    }
+  }
+
+  fclose(fp);
+
+  return 0;
+}
+
+/* Load the history from the specified file. If the file does not exist
+ * zero is returned and no operation is performed.
+ *
+ * If the file exists and the operation succeeded 0 is returned, otherwise
+ * on error -1 is returned. */
+int linenoiseHistoryLoad(const char* filename) {
+  FILE* fp = fopen(filename, "rt");
+  if (fp == NULL) {
+    return -1;
+  }
+
+  char buf[LINENOISE_MAX_LINE];
+  while (fgets(buf, LINENOISE_MAX_LINE, fp) != NULL) {
+    char* p = strchr(buf, '\r');
+    if (!p) {
+      p = strchr(buf, '\n');
+    }
+    if (p) {
+      *p = '\0';
+    }
+    if (p != buf) {
+      linenoiseHistoryAdd(buf);
+    }
+  }
+  fclose(fp);
+  return 0;
+}
+
+/* Set if to use or not the multi line mode. */
+/* note that this is a stub only, as linenoise-ng always multi-line */
+void linenoiseSetMultiLine(int) {}
+
+/* This special mode is used by linenoise in order to print scan codes
+ * on screen for debugging / development purposes. It is implemented
+ * by the linenoise_example program using the --keycodes option. */
+void linenoisePrintKeyCodes(void) {
+  char quit[4];
+
+  printf(
+      "Linenoise key codes debugging mode.\n"
+      "Press keys to see scan codes. Type 'quit' at any time to exit.\n");
+  if (enableRawMode() == -1) return;
+  memset(quit, ' ', 4);
+  while (1) {
+    char c;
+    int nread;
+
+#if _WIN32
+    nread = _read(STDIN_FILENO, &c, 1);
+#else
+    nread = read(STDIN_FILENO, &c, 1);
+#endif
+    if (nread <= 0) continue;
+    memmove(quit, quit + 1, sizeof(quit) - 1); /* shift string to left. */
+    quit[sizeof(quit) - 1] = c; /* Insert current char on the right. */
+    if (memcmp(quit, "quit", sizeof(quit)) == 0) break;
+
+    printf("'%c' %02x (%d) (type quit to exit)\n", isprint(c) ? c : '?', (int)c,
+           (int)c);
+    printf("\r"); /* Go left edge manually, we are in raw mode. */
+    fflush(stdout);
+  }
+  disableRawMode();
+}
+
+#ifndef _WIN32
+static void WindowSizeChanged(int) {
+  // do nothing here but setting this flag
+  gotResize = true;
+}
+#endif
+
+int linenoiseInstallWindowChangeHandler(void) {
+#ifndef _WIN32
+  struct sigaction sa;
+  sigemptyset(&sa.sa_mask);
+  sa.sa_flags = 0;
+  sa.sa_handler = &WindowSizeChanged;
+
+  if (sigaction(SIGWINCH, &sa, nullptr) == -1) {
+    return errno;
+  }
+#endif
+  return 0;
+}
+
+int linenoiseKeyType(void) {
+  return keyType;
+}