extension.h
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1 //
2 // Copyright 2017 The Abseil Authors.
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 // https://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
11 // distributed under the License is distributed on an "AS IS" BASIS,
12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 // See the License for the specific language governing permissions and
14 // limitations under the License.
15 //
16 #ifndef ABSL_STRINGS_INTERNAL_STR_FORMAT_EXTENSION_H_
17 #define ABSL_STRINGS_INTERNAL_STR_FORMAT_EXTENSION_H_
18 
19 #include <limits.h>
20 #include <cstddef>
21 #include <cstring>
22 #include <ostream>
23 
24 #include "absl/base/port.h"
27 
28 class Cord;
29 
30 namespace absl {
31 
32 namespace str_format_internal {
33 
35  public:
36  // Implicitly convert from any type that provides the hook function as
37  // described above.
38  template <typename T, decltype(str_format_internal::InvokeFlush(
39  std::declval<T*>(), string_view()))* = nullptr>
40  FormatRawSinkImpl(T* raw) // NOLINT
41  : sink_(raw), write_(&FormatRawSinkImpl::Flush<T>) {}
42 
43  void Write(string_view s) { write_(sink_, s); }
44 
45  template <typename T>
46  static FormatRawSinkImpl Extract(T s) {
47  return s.sink_;
48  }
49 
50  private:
51  template <typename T>
52  static void Flush(void* r, string_view s) {
53  str_format_internal::InvokeFlush(static_cast<T*>(r), s);
54  }
55 
56  void* sink_;
57  void (*write_)(void*, string_view);
58 };
59 
60 // An abstraction to which conversions write their string data.
62  public:
63  explicit FormatSinkImpl(FormatRawSinkImpl raw) : raw_(raw) {}
64 
66 
67  void Flush() {
68  raw_.Write(string_view(buf_, pos_ - buf_));
69  pos_ = buf_;
70  }
71 
72  void Append(size_t n, char c) {
73  if (n == 0) return;
74  size_ += n;
75  auto raw_append = [&](size_t count) {
76  memset(pos_, c, count);
77  pos_ += count;
78  };
79  while (n > Avail()) {
80  n -= Avail();
81  if (Avail() > 0) {
82  raw_append(Avail());
83  }
84  Flush();
85  }
86  raw_append(n);
87  }
88 
90  size_t n = v.size();
91  if (n == 0) return;
92  size_ += n;
93  if (n >= Avail()) {
94  Flush();
95  raw_.Write(v);
96  return;
97  }
98  memcpy(pos_, v.data(), n);
99  pos_ += n;
100  }
101 
102  size_t size() const { return size_; }
103 
104  // Put 'v' to 'sink' with specified width, precision, and left flag.
105  bool PutPaddedString(string_view v, int w, int p, bool l);
106 
107  template <typename T>
108  T Wrap() {
109  return T(this);
110  }
111 
112  template <typename T>
113  static FormatSinkImpl* Extract(T* s) {
114  return s->sink_;
115  }
116 
117  private:
118  size_t Avail() const { return buf_ + sizeof(buf_) - pos_; }
119 
121  size_t size_ = 0;
122  char* pos_ = buf_;
123  char buf_[1024];
124 };
125 
126 struct Flags {
127  bool basic : 1; // fastest conversion: no flags, width, or precision
128  bool left : 1; // "-"
129  bool show_pos : 1; // "+"
130  bool sign_col : 1; // " "
131  bool alt : 1; // "#"
132  bool zero : 1; // "0"
133  std::string ToString() const;
134  friend std::ostream& operator<<(std::ostream& os, const Flags& v) {
135  return os << v.ToString();
136  }
137 };
138 
139 struct LengthMod {
140  public:
141  enum Id : uint8_t {
142  h, hh, l, ll, L, j, z, t, q, none
143  };
144  static const size_t kNumValues = none + 1;
145 
146  LengthMod() : id_(none) {}
147 
148  // Index into the opaque array of LengthMod enums.
149  // Requires: i < kNumValues
150  static LengthMod FromIndex(size_t i) {
151  return LengthMod(kSpecs[i].value);
152  }
153 
154  static LengthMod FromId(Id id) { return LengthMod(id); }
155 
156  // The length modifier std::string associated with a specified LengthMod.
157  string_view name() const {
158  const Spec& spec = kSpecs[id_];
159  return {spec.name, spec.name_length};
160  }
161 
162  Id id() const { return id_; }
163 
164  friend bool operator==(const LengthMod& a, const LengthMod& b) {
165  return a.id() == b.id();
166  }
167  friend bool operator!=(const LengthMod& a, const LengthMod& b) {
168  return !(a == b);
169  }
170  friend std::ostream& operator<<(std::ostream& os, const LengthMod& v) {
171  return os << v.name();
172  }
173 
174  private:
175  struct Spec {
177  const char *name;
178  size_t name_length;
179  };
180  static const Spec kSpecs[];
181 
182  explicit LengthMod(Id id) : id_(id) {}
183 
185 };
186 
187 // clang-format off
188 #define ABSL_CONVERSION_CHARS_EXPAND_(X_VAL, X_SEP) \
189  /* text */ \
190  X_VAL(c) X_SEP X_VAL(C) X_SEP X_VAL(s) X_SEP X_VAL(S) X_SEP \
191  /* ints */ \
192  X_VAL(d) X_SEP X_VAL(i) X_SEP X_VAL(o) X_SEP \
193  X_VAL(u) X_SEP X_VAL(x) X_SEP X_VAL(X) X_SEP \
194  /* floats */ \
195  X_VAL(f) X_SEP X_VAL(F) X_SEP X_VAL(e) X_SEP X_VAL(E) X_SEP \
196  X_VAL(g) X_SEP X_VAL(G) X_SEP X_VAL(a) X_SEP X_VAL(A) X_SEP \
197  /* misc */ \
198  X_VAL(n) X_SEP X_VAL(p)
199 // clang-format on
200 
202  public:
203  enum Id : uint8_t {
204  c, C, s, S, // text
205  d, i, o, u, x, X, // int
206  f, F, e, E, g, G, a, A, // float
207  n, p, // misc
208  none
209  };
210  static const size_t kNumValues = none + 1;
211 
212  ConversionChar() : id_(none) {}
213 
214  public:
215  // Index into the opaque array of ConversionChar enums.
216  // Requires: i < kNumValues
217  static ConversionChar FromIndex(size_t i) {
218  return ConversionChar(kSpecs[i].value);
219  }
220 
221  static ConversionChar FromChar(char c) {
223  switch (c) {
224 #define X_VAL(id) \
225  case #id[0]: \
226  out_id = ConversionChar::id; \
227  break;
229 #undef X_VAL
230  default:
231  break;
232  }
233  return ConversionChar(out_id);
234  }
235 
236  static ConversionChar FromId(Id id) { return ConversionChar(id); }
237  Id id() const { return id_; }
238 
239  int radix() const {
240  switch (id()) {
241  case x: case X: case a: case A: case p: return 16;
242  case o: return 8;
243  default: return 10;
244  }
245  }
246 
247  bool upper() const {
248  switch (id()) {
249  case X: case F: case E: case G: case A: return true;
250  default: return false;
251  }
252  }
253 
254  bool is_signed() const {
255  switch (id()) {
256  case d: case i: return true;
257  default: return false;
258  }
259  }
260 
261  bool is_integral() const {
262  switch (id()) {
263  case d: case i: case u: case o: case x: case X:
264  return true;
265  default: return false;
266  }
267  }
268 
269  bool is_float() const {
270  switch (id()) {
271  case a: case e: case f: case g: case A: case E: case F: case G:
272  return true;
273  default: return false;
274  }
275  }
276 
277  bool IsValid() const { return id() != none; }
278 
279  // The associated char.
280  char Char() const { return kSpecs[id_].name; }
281 
282  friend bool operator==(const ConversionChar& a, const ConversionChar& b) {
283  return a.id() == b.id();
284  }
285  friend bool operator!=(const ConversionChar& a, const ConversionChar& b) {
286  return !(a == b);
287  }
288  friend std::ostream& operator<<(std::ostream& os, const ConversionChar& v) {
289  char c = v.Char();
290  if (!c) c = '?';
291  return os << c;
292  }
293 
294  private:
295  struct Spec {
297  char name;
298  };
299  static const Spec kSpecs[];
300 
301  explicit ConversionChar(Id id) : id_(id) {}
302 
304 };
305 
307  public:
308  Flags flags() const { return flags_; }
309  LengthMod length_mod() const { return length_mod_; }
311  // Keep this field first in the struct . It generates better code when
312  // accessing it when ConversionSpec is passed by value in registers.
313  static_assert(offsetof(ConversionSpec, conv_) == 0, "");
314  return conv_;
315  }
316 
317  // Returns the specified width. If width is unspecfied, it returns a negative
318  // value.
319  int width() const { return width_; }
320  // Returns the specified precision. If precision is unspecfied, it returns a
321  // negative value.
322  int precision() const { return precision_; }
323 
324  void set_flags(Flags f) { flags_ = f; }
325  void set_length_mod(LengthMod lm) { length_mod_ = lm; }
326  void set_conv(ConversionChar c) { conv_ = c; }
327  void set_width(int w) { width_ = w; }
328  void set_precision(int p) { precision_ = p; }
329  void set_left(bool b) { flags_.left = b; }
330 
331  private:
335  int width_;
337 };
338 
339 constexpr uint64_t ConversionCharToConvValue(char conv) {
340  return
341 #define CONV_SET_CASE(c) \
342  conv == #c[0] ? (uint64_t{1} << (1 + ConversionChar::Id::c)):
344 #undef CONV_SET_CASE
345  conv == '*'
346  ? 1
347  : 0;
348 }
349 
350 enum class Conv : uint64_t {
351 #define CONV_SET_CASE(c) c = ConversionCharToConvValue(#c[0]),
353 #undef CONV_SET_CASE
354 
355  // Used for width/precision '*' specification.
357 
358  // Some predefined values:
359  integral = d | i | u | o | x | X,
360  floating = a | e | f | g | A | E | F | G,
362  string = s,
363  pointer = p
364 };
365 
366 // Type safe OR operator.
367 // We need this for two reasons:
368 // 1. operator| on enums makes them decay to integers and the result is an
369 // integer. We need the result to stay as an enum.
370 // 2. We use "enum class" which would not work even if we accepted the decay.
371 constexpr Conv operator|(Conv a, Conv b) {
372  return Conv(static_cast<uint64_t>(a) | static_cast<uint64_t>(b));
373 }
374 
375 // Get a conversion with a single character in it.
376 constexpr Conv ConversionCharToConv(char c) {
377  return Conv(ConversionCharToConvValue(c));
378 }
379 
380 // Checks whether `c` exists in `set`.
381 constexpr bool Contains(Conv set, char c) {
382  return (static_cast<uint64_t>(set) & ConversionCharToConvValue(c)) != 0;
383 }
384 
385 // Checks whether all the characters in `c` are contained in `set`
386 constexpr bool Contains(Conv set, Conv c) {
387  return (static_cast<uint64_t>(set) & static_cast<uint64_t>(c)) ==
388  static_cast<uint64_t>(c);
389 }
390 
391 // Return type of the AbslFormatConvert() functions.
392 // The Conv template parameter is used to inform the framework of what
393 // conversion characters are supported by that AbslFormatConvert routine.
394 template <Conv C>
396  static constexpr Conv kConv = C;
397  bool value;
398 };
399 template <Conv C>
400 constexpr Conv ConvertResult<C>::kConv;
401 
402 // Return capacity - used, clipped to a minimum of 0.
403 inline size_t Excess(size_t used, size_t capacity) {
404  return used < capacity ? capacity - used : 0;
405 }
406 
407 } // namespace str_format_internal
408 
409 } // namespace absl
410 
411 #endif // ABSL_STRINGS_INTERNAL_STR_FORMAT_EXTENSION_H_
int v
Definition: variant_test.cc:81
constexpr uint64_t ConversionCharToConvValue(char conv)
Definition: extension.h:339
static void Flush(void *r, string_view s)
Definition: extension.h:52
FormatSinkImpl(FormatRawSinkImpl raw)
Definition: extension.h:63
static LengthMod FromId(Id id)
Definition: extension.h:154
#define ABSL_CONVERSION_CHARS_EXPAND_(X_VAL, X_SEP)
Definition: extension.h:188
auto InvokeFlush(T *out, string_view s) -> decltype(str_format_internal::AbslFormatFlush(out, s))
Definition: output.h:93
static FormatRawSinkImpl Extract(T s)
Definition: extension.h:46
constexpr Conv operator|(Conv a, Conv b)
Definition: extension.h:371
friend bool operator!=(const LengthMod &a, const LengthMod &b)
Definition: extension.h:167
#define X_VAL(id)
#define X(c)
Definition: algorithm.h:29
constexpr size_type size() const noexcept
Definition: string_view.h:260
friend std::ostream & operator<<(std::ostream &os, const LengthMod &v)
Definition: extension.h:170
static FormatSinkImpl * Extract(T *s)
Definition: extension.h:113
size_t value
size_t Excess(size_t used, size_t capacity)
Definition: extension.h:403
friend bool operator!=(const ConversionChar &a, const ConversionChar &b)
Definition: extension.h:285
friend std::ostream & operator<<(std::ostream &os, const Flags &v)
Definition: extension.h:134
std::string ToString() const
Definition: extension.cc:56
UnboundConversion o
Definition: parser_test.cc:86
constexpr bool Contains(Conv set, char c)
Definition: extension.h:381
constexpr Conv ConversionCharToConv(char c)
Definition: extension.h:376
void(* write_)(void *, string_view)
Definition: extension.h:57
static ConversionChar FromIndex(size_t i)
Definition: extension.h:217
friend bool operator==(const ConversionChar &a, const ConversionChar &b)
Definition: extension.h:282
constexpr const_pointer data() const noexcept
Definition: string_view.h:302
int size_
Definition: arg.cc:107
static ConversionChar FromId(Id id)
Definition: extension.h:236
friend bool operator==(const LengthMod &a, const LengthMod &b)
Definition: extension.h:164
static ConversionChar FromChar(char c)
Definition: extension.h:221
uint64_t b
Definition: layout_test.cc:50
#define C(x)
Definition: city_test.cc:47
friend std::ostream & operator<<(std::ostream &os, const ConversionChar &v)
Definition: extension.h:288
static LengthMod FromIndex(size_t i)
Definition: extension.h:150


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autogenerated on Wed Jun 19 2019 19:19:56