about summary refs log tree commit diff
path: root/absl/strings/internal/str_format/arg.cc
blob: b567a5c5bcf0780f32c3e694dcfad37f800f0256 (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
//
// POSIX spec:
//   http://pubs.opengroup.org/onlinepubs/009695399/functions/fprintf.html
//
#include "absl/strings/internal/str_format/arg.h"

#include <cassert>
#include <cerrno>
#include <cstdlib>
#include <string>
#include <type_traits>

#include "absl/base/port.h"
#include "absl/strings/internal/str_format/float_conversion.h"

namespace absl {
namespace str_format_internal {
namespace {

const char kDigit[2][32] = { "0123456789abcdef", "0123456789ABCDEF" };

// Reduce *capacity by s.size(), clipped to a 0 minimum.
void ReducePadding(string_view s, size_t *capacity) {
  *capacity = Excess(s.size(), *capacity);
}

// Reduce *capacity by n, clipped to a 0 minimum.
void ReducePadding(size_t n, size_t *capacity) {
  *capacity = Excess(n, *capacity);
}

template <typename T>
struct MakeUnsigned : std::make_unsigned<T> {};
template <>
struct MakeUnsigned<absl::int128> {
  using type = absl::uint128;
};
template <>
struct MakeUnsigned<absl::uint128> {
  using type = absl::uint128;
};

template <typename T>
struct IsSigned : std::is_signed<T> {};
template <>
struct IsSigned<absl::int128> : std::true_type {};
template <>
struct IsSigned<absl::uint128> : std::false_type {};

class ConvertedIntInfo {
 public:
  template <typename T>
  ConvertedIntInfo(T v, ConversionChar conv) {
    using Unsigned = typename MakeUnsigned<T>::type;
    auto u = static_cast<Unsigned>(v);
    if (IsNeg(v)) {
      is_neg_ = true;
      u = Unsigned{} - u;
    } else {
      is_neg_ = false;
    }
    UnsignedToStringRight(u, conv);
  }

  string_view digits() const {
    return {end() - size_, static_cast<size_t>(size_)};
  }
  bool is_neg() const { return is_neg_; }

 private:
  template <typename T, bool IsSigned>
  struct IsNegImpl {
    static bool Eval(T v) { return v < 0; }
  };
  template <typename T>
  struct IsNegImpl<T, false> {
    static bool Eval(T) {
      return false;
    }
  };

  template <typename T>
  bool IsNeg(T v) {
    return IsNegImpl<T, IsSigned<T>::value>::Eval(v);
  }

  template <typename T>
  void UnsignedToStringRight(T u, ConversionChar conv) {
    char *p = end();
    switch (conv.radix()) {
      default:
      case 10:
        for (; u; u /= 10)
          *--p = static_cast<char>('0' + static_cast<size_t>(u % 10));
        break;
      case 8:
        for (; u; u /= 8)
          *--p = static_cast<char>('0' + static_cast<size_t>(u % 8));
        break;
      case 16: {
        const char *digits = kDigit[conv.upper() ? 1 : 0];
        for (; u; u /= 16) *--p = digits[static_cast<size_t>(u % 16)];
        break;
      }
    }
    size_ = static_cast<int>(end() - p);
  }

  const char *end() const { return storage_ + sizeof(storage_); }
  char *end() { return storage_ + sizeof(storage_); }

  bool is_neg_;
  int size_;
  // Max size: 128 bit value as octal -> 43 digits
  char storage_[128 / 3 + 1];
};

// Note: 'o' conversions do not have a base indicator, it's just that
// the '#' flag is specified to modify the precision for 'o' conversions.
string_view BaseIndicator(const ConvertedIntInfo &info,
                          const ConversionSpec conv) {
  bool alt = conv.flags().alt;
  int radix = conv.conv().radix();
  if (conv.conv().id() == ConversionChar::p)
    alt = true;  // always show 0x for %p.
  // From the POSIX description of '#' flag:
  //   "For x or X conversion specifiers, a non-zero result shall have
  //   0x (or 0X) prefixed to it."
  if (alt && radix == 16 && !info.digits().empty()) {
    if (conv.conv().upper()) return "0X";
    return "0x";
  }
  return {};
}

string_view SignColumn(bool neg, const ConversionSpec conv) {
  if (conv.conv().is_signed()) {
    if (neg) return "-";
    if (conv.flags().show_pos) return "+";
    if (conv.flags().sign_col) return " ";
  }
  return {};
}

bool ConvertCharImpl(unsigned char v, const ConversionSpec conv,
                     FormatSinkImpl *sink) {
  size_t fill = 0;
  if (conv.width() >= 0) fill = conv.width();
  ReducePadding(1, &fill);
  if (!conv.flags().left) sink->Append(fill, ' ');
  sink->Append(1, v);
  if (conv.flags().left) sink->Append(fill, ' ');
  return true;
}

bool ConvertIntImplInner(const ConvertedIntInfo &info,
                         const ConversionSpec conv, FormatSinkImpl *sink) {
  // Print as a sequence of Substrings:
  //   [left_spaces][sign][base_indicator][zeroes][formatted][right_spaces]
  size_t fill = 0;
  if (conv.width() >= 0) fill = conv.width();

  string_view formatted = info.digits();
  ReducePadding(formatted, &fill);

  string_view sign = SignColumn(info.is_neg(), conv);
  ReducePadding(sign, &fill);

  string_view base_indicator = BaseIndicator(info, conv);
  ReducePadding(base_indicator, &fill);

  int precision = conv.precision();
  bool precision_specified = precision >= 0;
  if (!precision_specified)
    precision = 1;

  if (conv.flags().alt && conv.conv().id() == ConversionChar::o) {
    // From POSIX description of the '#' (alt) flag:
    //   "For o conversion, it increases the precision (if necessary) to
    //   force the first digit of the result to be zero."
    if (formatted.empty() || *formatted.begin() != '0') {
      int needed = static_cast<int>(formatted.size()) + 1;
      precision = std::max(precision, needed);
    }
  }

  size_t num_zeroes = Excess(formatted.size(), precision);
  ReducePadding(num_zeroes, &fill);

  size_t num_left_spaces = !conv.flags().left ? fill : 0;
  size_t num_right_spaces = conv.flags().left ? fill : 0;

  // From POSIX description of the '0' (zero) flag:
  //   "For d, i, o, u, x, and X conversion specifiers, if a precision
  //   is specified, the '0' flag is ignored."
  if (!precision_specified && conv.flags().zero) {
    num_zeroes += num_left_spaces;
    num_left_spaces = 0;
  }

  sink->Append(num_left_spaces, ' ');
  sink->Append(sign);
  sink->Append(base_indicator);
  sink->Append(num_zeroes, '0');
  sink->Append(formatted);
  sink->Append(num_right_spaces, ' ');
  return true;
}

template <typename T>
bool ConvertIntImplInner(T v, const ConversionSpec conv, FormatSinkImpl *sink) {
  ConvertedIntInfo info(v, conv.conv());
  if (conv.flags().basic && conv.conv().id() != ConversionChar::p) {
    if (info.is_neg()) sink->Append(1, '-');
    if (info.digits().empty()) {
      sink->Append(1, '0');
    } else {
      sink->Append(info.digits());
    }
    return true;
  }
  return ConvertIntImplInner(info, conv, sink);
}

template <typename T>
bool ConvertIntArg(T v, const ConversionSpec conv, FormatSinkImpl *sink) {
  if (conv.conv().is_float()) {
    return FormatConvertImpl(static_cast<double>(v), conv, sink).value;
  }
  if (conv.conv().id() == ConversionChar::c)
    return ConvertCharImpl(static_cast<unsigned char>(v), conv, sink);
  if (!conv.conv().is_integral())
    return false;
  if (!conv.conv().is_signed() && IsSigned<T>::value) {
    using U = typename MakeUnsigned<T>::type;
    return FormatConvertImpl(static_cast<U>(v), conv, sink).value;
  }
  return ConvertIntImplInner(v, conv, sink);
}

template <typename T>
bool ConvertFloatArg(T v, const ConversionSpec conv, FormatSinkImpl *sink) {
  return conv.conv().is_float() && ConvertFloatImpl(v, conv, sink);
}

inline bool ConvertStringArg(string_view v, const ConversionSpec conv,
                             FormatSinkImpl *sink) {
  if (conv.conv().id() != ConversionChar::s)
    return false;
  if (conv.flags().basic) {
    sink->Append(v);
    return true;
  }
  return sink->PutPaddedString(v, conv.width(), conv.precision(),
                               conv.flags().left);
}

}  // namespace

// ==================== Strings ====================
ConvertResult<Conv::s> FormatConvertImpl(const std::string &v,
                                         const ConversionSpec conv,
                                         FormatSinkImpl *sink) {
  return {ConvertStringArg(v, conv, sink)};
}

ConvertResult<Conv::s> FormatConvertImpl(string_view v,
                                         const ConversionSpec conv,
                                         FormatSinkImpl *sink) {
  return {ConvertStringArg(v, conv, sink)};
}

ConvertResult<Conv::s | Conv::p> FormatConvertImpl(const char *v,
                                                   const ConversionSpec conv,
                                                   FormatSinkImpl *sink) {
  if (conv.conv().id() == ConversionChar::p)
    return {FormatConvertImpl(VoidPtr(v), conv, sink).value};
  size_t len;
  if (v == nullptr) {
    len = 0;
  } else if (conv.precision() < 0) {
    len = std::strlen(v);
  } else {
    // If precision is set, we look for the null terminator on the valid range.
    len = std::find(v, v + conv.precision(), '\0') - v;
  }
  return {ConvertStringArg(string_view(v, len), conv, sink)};
}

// ==================== Raw pointers ====================
ConvertResult<Conv::p> FormatConvertImpl(VoidPtr v, const ConversionSpec conv,
                                         FormatSinkImpl *sink) {
  if (conv.conv().id() != ConversionChar::p)
    return {false};
  if (!v.value) {
    sink->Append("(nil)");
    return {true};
  }
  return {ConvertIntImplInner(v.value, conv, sink)};
}

// ==================== Floats ====================
FloatingConvertResult FormatConvertImpl(float v, const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertFloatArg(v, conv, sink)};
}
FloatingConvertResult FormatConvertImpl(double v, const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertFloatArg(v, conv, sink)};
}
FloatingConvertResult FormatConvertImpl(long double v,
                                        const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertFloatArg(v, conv, sink)};
}

// ==================== Chars ====================
IntegralConvertResult FormatConvertImpl(char v, const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}
IntegralConvertResult FormatConvertImpl(signed char v,
                                        const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}
IntegralConvertResult FormatConvertImpl(unsigned char v,
                                        const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}

// ==================== Ints ====================
IntegralConvertResult FormatConvertImpl(short v,  // NOLINT
                                        const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}
IntegralConvertResult FormatConvertImpl(unsigned short v,  // NOLINT
                                        const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}
IntegralConvertResult FormatConvertImpl(int v, const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}
IntegralConvertResult FormatConvertImpl(unsigned v, const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}
IntegralConvertResult FormatConvertImpl(long v,  // NOLINT
                                        const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}
IntegralConvertResult FormatConvertImpl(unsigned long v,  // NOLINT
                                        const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}
IntegralConvertResult FormatConvertImpl(long long v,  // NOLINT
                                        const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}
IntegralConvertResult FormatConvertImpl(unsigned long long v,  // NOLINT
                                        const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}
IntegralConvertResult FormatConvertImpl(absl::int128 v,
                                        const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}
IntegralConvertResult FormatConvertImpl(absl::uint128 v,
                                        const ConversionSpec conv,
                                        FormatSinkImpl *sink) {
  return {ConvertIntArg(v, conv, sink)};
}

ABSL_INTERNAL_FORMAT_DISPATCH_OVERLOADS_EXPAND_();



}  // namespace str_format_internal

}  // namespace absl