about summary refs log tree commit diff
path: root/absl/strings/internal/str_format/extension.h
blob: 0a7640354fd4de2d12d3bf4e8efcd27c0eb88d24 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
//
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#ifndef ABSL_STRINGS_INTERNAL_STR_FORMAT_EXTENSION_H_
#define ABSL_STRINGS_INTERNAL_STR_FORMAT_EXTENSION_H_

#include <limits.h>

#include <cstddef>
#include <cstring>
#include <ostream>

#include "absl/base/config.h"
#include "absl/base/port.h"
#include "absl/strings/internal/str_format/output.h"
#include "absl/strings/string_view.h"

namespace absl {
ABSL_NAMESPACE_BEGIN
namespace str_format_internal {

class FormatRawSinkImpl {
 public:
  // Implicitly convert from any type that provides the hook function as
  // described above.
  template <typename T, decltype(str_format_internal::InvokeFlush(
                            std::declval<T*>(), string_view()))* = nullptr>
  FormatRawSinkImpl(T* raw)  // NOLINT
      : sink_(raw), write_(&FormatRawSinkImpl::Flush<T>) {}

  void Write(string_view s) { write_(sink_, s); }

  template <typename T>
  static FormatRawSinkImpl Extract(T s) {
    return s.sink_;
  }

 private:
  template <typename T>
  static void Flush(void* r, string_view s) {
    str_format_internal::InvokeFlush(static_cast<T*>(r), s);
  }

  void* sink_;
  void (*write_)(void*, string_view);
};

// An abstraction to which conversions write their string data.
class FormatSinkImpl {
 public:
  explicit FormatSinkImpl(FormatRawSinkImpl raw) : raw_(raw) {}

  ~FormatSinkImpl() { Flush(); }

  void Flush() {
    raw_.Write(string_view(buf_, pos_ - buf_));
    pos_ = buf_;
  }

  void Append(size_t n, char c) {
    if (n == 0) return;
    size_ += n;
    auto raw_append = [&](size_t count) {
      memset(pos_, c, count);
      pos_ += count;
    };
    while (n > Avail()) {
      n -= Avail();
      if (Avail() > 0) {
        raw_append(Avail());
      }
      Flush();
    }
    raw_append(n);
  }

  void Append(string_view v) {
    size_t n = v.size();
    if (n == 0) return;
    size_ += n;
    if (n >= Avail()) {
      Flush();
      raw_.Write(v);
      return;
    }
    memcpy(pos_, v.data(), n);
    pos_ += n;
  }

  size_t size() const { return size_; }

  // Put 'v' to 'sink' with specified width, precision, and left flag.
  bool PutPaddedString(string_view v, int w, int p, bool l);

  template <typename T>
  T Wrap() {
    return T(this);
  }

  template <typename T>
  static FormatSinkImpl* Extract(T* s) {
    return s->sink_;
  }

 private:
  size_t Avail() const { return buf_ + sizeof(buf_) - pos_; }

  FormatRawSinkImpl raw_;
  size_t size_ = 0;
  char* pos_ = buf_;
  char buf_[1024];
};

struct Flags {
  bool basic : 1;     // fastest conversion: no flags, width, or precision
  bool left : 1;      // "-"
  bool show_pos : 1;  // "+"
  bool sign_col : 1;  // " "
  bool alt : 1;       // "#"
  bool zero : 1;      // "0"
  std::string ToString() const;
  friend std::ostream& operator<<(std::ostream& os, const Flags& v) {
    return os << v.ToString();
  }
};

struct ABSL_DLL LengthMod {
 public:
  enum Id : uint8_t {
    h, hh, l, ll, L, j, z, t, q, none
  };
  static const size_t kNumValues = none + 1;

  LengthMod() : id_(none) {}

  // Index into the opaque array of LengthMod enums.
  // Requires: i < kNumValues
  static LengthMod FromIndex(size_t i) {
    return LengthMod(kSpecs[i].value);
  }

  static LengthMod FromId(Id id) { return LengthMod(id); }

  // The length modifier std::string associated with a specified LengthMod.
  string_view name() const {
    const Spec& spec = kSpecs[id_];
    return {spec.name, spec.name_length};
  }

  Id id() const { return id_; }

  friend bool operator==(const LengthMod& a, const LengthMod& b) {
    return a.id() == b.id();
  }
  friend bool operator!=(const LengthMod& a, const LengthMod& b) {
    return !(a == b);
  }
  friend std::ostream& operator<<(std::ostream& os, const LengthMod& v) {
    return os << v.name();
  }

 private:
  struct Spec {
    Id value;
    const char *name;
    size_t name_length;
  };
  static const Spec kSpecs[];

  explicit LengthMod(Id id) : id_(id) {}

  Id id_;
};

// clang-format off
#define ABSL_CONVERSION_CHARS_EXPAND_(X_VAL, X_SEP) \
  /* text */ \
  X_VAL(c) X_SEP X_VAL(C) X_SEP X_VAL(s) X_SEP X_VAL(S) X_SEP \
  /* ints */ \
  X_VAL(d) X_SEP X_VAL(i) X_SEP X_VAL(o) X_SEP \
  X_VAL(u) X_SEP X_VAL(x) X_SEP X_VAL(X) X_SEP \
  /* floats */ \
  X_VAL(f) X_SEP X_VAL(F) X_SEP X_VAL(e) X_SEP X_VAL(E) X_SEP \
  X_VAL(g) X_SEP X_VAL(G) X_SEP X_VAL(a) X_SEP X_VAL(A) X_SEP \
  /* misc */ \
  X_VAL(n) X_SEP X_VAL(p)
// clang-format on

struct ABSL_DLL ConversionChar {
 public:
  enum Id : uint8_t {
    c, C, s, S,              // text
    d, i, o, u, x, X,        // int
    f, F, e, E, g, G, a, A,  // float
    n, p,                    // misc
    none
  };
  static const size_t kNumValues = none + 1;

  ConversionChar() : id_(none) {}

 public:
  // Index into the opaque array of ConversionChar enums.
  // Requires: i < kNumValues
  static ConversionChar FromIndex(size_t i) {
    return ConversionChar(kSpecs[i].value);
  }

  static ConversionChar FromChar(char c) {
    ConversionChar::Id out_id = ConversionChar::none;
    switch (c) {
#define X_VAL(id)                \
  case #id[0]:                   \
    out_id = ConversionChar::id; \
    break;
      ABSL_CONVERSION_CHARS_EXPAND_(X_VAL, )
#undef X_VAL
      default:
        break;
    }
    return ConversionChar(out_id);
  }

  static ConversionChar FromId(Id id) { return ConversionChar(id); }
  Id id() const { return id_; }

  int radix() const {
    switch (id()) {
      case x: case X: case a: case A: case p: return 16;
      case o: return 8;
      default: return 10;
    }
  }

  bool upper() const {
    switch (id()) {
      case X: case F: case E: case G: case A: return true;
      default: return false;
    }
  }

  bool is_signed() const {
    switch (id()) {
      case d: case i: return true;
      default: return false;
    }
  }

  bool is_integral() const {
    switch (id()) {
      case d: case i: case u: case o: case x: case X:
        return true;
      default: return false;
    }
  }

  bool is_float() const {
    switch (id()) {
      case a: case e: case f: case g: case A: case E: case F: case G:
        return true;
      default: return false;
    }
  }

  bool IsValid() const { return id() != none; }

  // The associated char.
  char Char() const { return kSpecs[id_].name; }

  friend bool operator==(const ConversionChar& a, const ConversionChar& b) {
    return a.id() == b.id();
  }
  friend bool operator!=(const ConversionChar& a, const ConversionChar& b) {
    return !(a == b);
  }
  friend std::ostream& operator<<(std::ostream& os, const ConversionChar& v) {
    char c = v.Char();
    if (!c) c = '?';
    return os << c;
  }

 private:
  struct Spec {
    Id value;
    char name;
  };
  static const Spec kSpecs[];

  explicit ConversionChar(Id id) : id_(id) {}

  Id id_;
};

class ConversionSpec {
 public:
  Flags flags() const { return flags_; }
  LengthMod length_mod() const { return length_mod_; }
  ConversionChar conv() const {
    // Keep this field first in the struct . It generates better code when
    // accessing it when ConversionSpec is passed by value in registers.
    static_assert(offsetof(ConversionSpec, conv_) == 0, "");
    return conv_;
  }

  // Returns the specified width. If width is unspecfied, it returns a negative
  // value.
  int width() const { return width_; }
  // Returns the specified precision. If precision is unspecfied, it returns a
  // negative value.
  int precision() const { return precision_; }

  void set_flags(Flags f) { flags_ = f; }
  void set_length_mod(LengthMod lm) { length_mod_ = lm; }
  void set_conv(ConversionChar c) { conv_ = c; }
  void set_width(int w) { width_ = w; }
  void set_precision(int p) { precision_ = p; }
  void set_left(bool b) { flags_.left = b; }

 private:
  ConversionChar conv_;
  Flags flags_;
  LengthMod length_mod_;
  int width_;
  int precision_;
};

constexpr uint64_t ConversionCharToConvValue(char conv) {
  return
#define CONV_SET_CASE(c) \
  conv == #c[0] ? (uint64_t{1} << (1 + ConversionChar::Id::c)):
      ABSL_CONVERSION_CHARS_EXPAND_(CONV_SET_CASE, )
#undef CONV_SET_CASE
                  conv == '*'
          ? 1
          : 0;
}

enum class Conv : uint64_t {
#define CONV_SET_CASE(c) c = ConversionCharToConvValue(#c[0]),
  ABSL_CONVERSION_CHARS_EXPAND_(CONV_SET_CASE, )
#undef CONV_SET_CASE

  // Used for width/precision '*' specification.
  star = ConversionCharToConvValue('*'),

  // Some predefined values:
  integral = d | i | u | o | x | X,
  floating = a | e | f | g | A | E | F | G,
  numeric = integral | floating,
  string = s,
  pointer = p
};

// Type safe OR operator.
// We need this for two reasons:
//  1. operator| on enums makes them decay to integers and the result is an
//     integer. We need the result to stay as an enum.
//  2. We use "enum class" which would not work even if we accepted the decay.
constexpr Conv operator|(Conv a, Conv b) {
  return Conv(static_cast<uint64_t>(a) | static_cast<uint64_t>(b));
}

// Get a conversion with a single character in it.
constexpr Conv ConversionCharToConv(char c) {
  return Conv(ConversionCharToConvValue(c));
}

// Checks whether `c` exists in `set`.
constexpr bool Contains(Conv set, char c) {
  return (static_cast<uint64_t>(set) & ConversionCharToConvValue(c)) != 0;
}

// Checks whether all the characters in `c` are contained in `set`
constexpr bool Contains(Conv set, Conv c) {
  return (static_cast<uint64_t>(set) & static_cast<uint64_t>(c)) ==
         static_cast<uint64_t>(c);
}

// Return type of the AbslFormatConvert() functions.
// The Conv template parameter is used to inform the framework of what
// conversion characters are supported by that AbslFormatConvert routine.
template <Conv C>
struct ConvertResult {
  static constexpr Conv kConv = C;
  bool value;
};
template <Conv C>
constexpr Conv ConvertResult<C>::kConv;

// Return capacity - used, clipped to a minimum of 0.
inline size_t Excess(size_t used, size_t capacity) {
  return used < capacity ? capacity - used : 0;
}

}  // namespace str_format_internal

ABSL_NAMESPACE_END
}  // namespace absl

#endif  // ABSL_STRINGS_INTERNAL_STR_FORMAT_EXTENSION_H_