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1 /*
2  * Copyright 2014 Google Inc. All rights reserved.
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  *     http://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 
17 #ifndef FLATBUFFERS_UTIL_H_
18 #define FLATBUFFERS_UTIL_H_
19 
20 #include <ctype.h>
21 #include <errno.h>
22 
23 #include "flatbuffers/base.h"
24 #include "flatbuffers/stl_emulation.h"
25 
26 #ifndef FLATBUFFERS_PREFER_PRINTF
27 #  include <iomanip>
28 #  include <sstream>
29 #else  // FLATBUFFERS_PREFER_PRINTF
30 #  include <float.h>
31 #  include <stdio.h>
32 #endif  // FLATBUFFERS_PREFER_PRINTF
33 
34 #include <string>
35 
36 namespace flatbuffers {
37 
38 // @locale-independent functions for ASCII characters set.
39 
40 // Fast checking that character lies in closed range: [a <= x <= b]
41 // using one compare (conditional branch) operator.
check_ascii_range(char x,char a,char b)42 inline bool check_ascii_range(char x, char a, char b) {
43   FLATBUFFERS_ASSERT(a <= b);
44   // (Hacker's Delight): `a <= x <= b` <=> `(x-a) <={u} (b-a)`.
45   // The x, a, b will be promoted to int and subtracted without overflow.
46   return static_cast<unsigned int>(x - a) <= static_cast<unsigned int>(b - a);
47 }
48 
49 // Case-insensitive isalpha
is_alpha(char c)50 inline bool is_alpha(char c) {
51   // ASCII only: alpha to upper case => reset bit 0x20 (~0x20 = 0xDF).
52   return check_ascii_range(c & 0xDF, 'a' & 0xDF, 'z' & 0xDF);
53 }
54 
55 // Check for uppercase alpha
is_alpha_upper(char c)56 inline bool is_alpha_upper(char c) { return check_ascii_range(c, 'A', 'Z'); }
57 
58 // Check (case-insensitive) that `c` is equal to alpha.
is_alpha_char(char c,char alpha)59 inline bool is_alpha_char(char c, char alpha) {
60   FLATBUFFERS_ASSERT(is_alpha(alpha));
61   // ASCII only: alpha to upper case => reset bit 0x20 (~0x20 = 0xDF).
62   return ((c & 0xDF) == (alpha & 0xDF));
63 }
64 
65 // https://en.cppreference.com/w/cpp/string/byte/isxdigit
66 // isdigit and isxdigit are the only standard narrow character classification
67 // functions that are not affected by the currently installed C locale. although
68 // some implementations (e.g. Microsoft in 1252 codepage) may classify
69 // additional single-byte characters as digits.
is_digit(char c)70 inline bool is_digit(char c) { return check_ascii_range(c, '0', '9'); }
71 
is_xdigit(char c)72 inline bool is_xdigit(char c) {
73   // Replace by look-up table.
74   return is_digit(c) || check_ascii_range(c & 0xDF, 'a' & 0xDF, 'f' & 0xDF);
75 }
76 
77 // Case-insensitive isalnum
is_alnum(char c)78 inline bool is_alnum(char c) { return is_alpha(c) || is_digit(c); }
79 
CharToUpper(char c)80 inline char CharToUpper(char c) {
81   return static_cast<char>(::toupper(static_cast<unsigned char>(c)));
82 }
83 
CharToLower(char c)84 inline char CharToLower(char c) {
85   return static_cast<char>(::tolower(static_cast<unsigned char>(c)));
86 }
87 
88 // @end-locale-independent functions for ASCII character set
89 
90 #ifdef FLATBUFFERS_PREFER_PRINTF
IntToDigitCount(T t)91 template<typename T> size_t IntToDigitCount(T t) {
92   size_t digit_count = 0;
93   // Count the sign for negative numbers
94   if (t < 0) digit_count++;
95   // Count a single 0 left of the dot for fractional numbers
96   if (-1 < t && t < 1) digit_count++;
97   // Count digits until fractional part
98   T eps = std::numeric_limits<T>::epsilon();
99   while (t <= (-1 + eps) || (1 - eps) <= t) {
100     t /= 10;
101     digit_count++;
102   }
103   return digit_count;
104 }
105 
106 template<typename T> size_t NumToStringWidth(T t, int precision = 0) {
107   size_t string_width = IntToDigitCount(t);
108   // Count the dot for floating point numbers
109   if (precision) string_width += (precision + 1);
110   return string_width;
111 }
112 
113 template<typename T>
114 std::string NumToStringImplWrapper(T t, const char *fmt, int precision = 0) {
115   size_t string_width = NumToStringWidth(t, precision);
116   std::string s(string_width, 0x00);
117   // Allow snprintf to use std::string trailing null to detect buffer overflow
118   snprintf(const_cast<char *>(s.data()), (s.size() + 1), fmt, string_width, t);
119   return s;
120 }
121 #endif  // FLATBUFFERS_PREFER_PRINTF
122 
123 // Convert an integer or floating point value to a string.
124 // In contrast to std::stringstream, "char" values are
125 // converted to a string of digits, and we don't use scientific notation.
NumToString(T t)126 template<typename T> std::string NumToString(T t) {
127   // clang-format off
128 
129   #ifndef FLATBUFFERS_PREFER_PRINTF
130     std::stringstream ss;
131     ss << t;
132     return ss.str();
133   #else // FLATBUFFERS_PREFER_PRINTF
134     auto v = static_cast<long long>(t);
135     return NumToStringImplWrapper(v, "%.*lld");
136   #endif // FLATBUFFERS_PREFER_PRINTF
137   // clang-format on
138 }
139 // Avoid char types used as character data.
140 template<> inline std::string NumToString<signed char>(signed char t) {
141   return NumToString(static_cast<int>(t));
142 }
143 template<> inline std::string NumToString<unsigned char>(unsigned char t) {
144   return NumToString(static_cast<int>(t));
145 }
146 template<> inline std::string NumToString<char>(char t) {
147   return NumToString(static_cast<int>(t));
148 }
149 
150 // Special versions for floats/doubles.
FloatToString(T t,int precision)151 template<typename T> std::string FloatToString(T t, int precision) {
152   // clang-format off
153 
154   #ifndef FLATBUFFERS_PREFER_PRINTF
155     // to_string() prints different numbers of digits for floats depending on
156     // platform and isn't available on Android, so we use stringstream
157     std::stringstream ss;
158     // Use std::fixed to suppress scientific notation.
159     ss << std::fixed;
160     // Default precision is 6, we want that to be higher for doubles.
161     ss << std::setprecision(precision);
162     ss << t;
163     auto s = ss.str();
164   #else // FLATBUFFERS_PREFER_PRINTF
165     auto v = static_cast<double>(t);
166     auto s = NumToStringImplWrapper(v, "%0.*f", precision);
167   #endif // FLATBUFFERS_PREFER_PRINTF
168   // clang-format on
169   // Sadly, std::fixed turns "1" into "1.00000", so here we undo that.
170   auto p = s.find_last_not_of('0');
171   if (p != std::string::npos) {
172     // Strip trailing zeroes. If it is a whole number, keep one zero.
173     s.resize(p + (s[p] == '.' ? 2 : 1));
174   }
175   return s;
176 }
177 
178 template<> inline std::string NumToString<double>(double t) {
179   return FloatToString(t, 12);
180 }
181 template<> inline std::string NumToString<float>(float t) {
182   return FloatToString(t, 6);
183 }
184 
185 // Convert an integer value to a hexadecimal string.
186 // The returned string length is always xdigits long, prefixed by 0 digits.
187 // For example, IntToStringHex(0x23, 8) returns the string "00000023".
IntToStringHex(int i,int xdigits)188 inline std::string IntToStringHex(int i, int xdigits) {
189   FLATBUFFERS_ASSERT(i >= 0);
190   // clang-format off
191 
192   #ifndef FLATBUFFERS_PREFER_PRINTF
193     std::stringstream ss;
194     ss << std::setw(xdigits) << std::setfill('0') << std::hex << std::uppercase
195        << i;
196     return ss.str();
197   #else // FLATBUFFERS_PREFER_PRINTF
198     return NumToStringImplWrapper(i, "%.*X", xdigits);
199   #endif // FLATBUFFERS_PREFER_PRINTF
200   // clang-format on
201 }
202 
203 // clang-format off
204 // Use locale independent functions {strtod_l, strtof_l, strtoll_l, strtoull_l}.
205 #if defined(FLATBUFFERS_LOCALE_INDEPENDENT) && (FLATBUFFERS_LOCALE_INDEPENDENT > 0)
206   class ClassicLocale {
207     #ifdef _MSC_VER
208       typedef _locale_t locale_type;
209     #else
210       typedef locale_t locale_type;  // POSIX.1-2008 locale_t type
211     #endif
212     ClassicLocale();
213     ~ClassicLocale();
214     locale_type locale_;
215     static ClassicLocale instance_;
216   public:
Get()217     static locale_type Get() { return instance_.locale_; }
218   };
219 
220   #ifdef _MSC_VER
221     #define __strtoull_impl(s, pe, b) _strtoui64_l(s, pe, b, ClassicLocale::Get())
222     #define __strtoll_impl(s, pe, b) _strtoi64_l(s, pe, b, ClassicLocale::Get())
223     #define __strtod_impl(s, pe) _strtod_l(s, pe, ClassicLocale::Get())
224     #define __strtof_impl(s, pe) _strtof_l(s, pe, ClassicLocale::Get())
225   #else
226     #define __strtoull_impl(s, pe, b) strtoull_l(s, pe, b, ClassicLocale::Get())
227     #define __strtoll_impl(s, pe, b) strtoll_l(s, pe, b, ClassicLocale::Get())
228     #define __strtod_impl(s, pe) strtod_l(s, pe, ClassicLocale::Get())
229     #define __strtof_impl(s, pe) strtof_l(s, pe, ClassicLocale::Get())
230   #endif
231 #else
232   #define __strtod_impl(s, pe) strtod(s, pe)
233   #define __strtof_impl(s, pe) static_cast<float>(strtod(s, pe))
234   #ifdef _MSC_VER
235     #define __strtoull_impl(s, pe, b) _strtoui64(s, pe, b)
236     #define __strtoll_impl(s, pe, b) _strtoi64(s, pe, b)
237   #else
238     #define __strtoull_impl(s, pe, b) strtoull(s, pe, b)
239     #define __strtoll_impl(s, pe, b) strtoll(s, pe, b)
240   #endif
241 #endif
242 
strtoval_impl(int64_t * val,const char * str,char ** endptr,int base)243 inline void strtoval_impl(int64_t *val, const char *str, char **endptr,
244                                  int base) {
245     *val = __strtoll_impl(str, endptr, base);
246 }
247 
strtoval_impl(uint64_t * val,const char * str,char ** endptr,int base)248 inline void strtoval_impl(uint64_t *val, const char *str, char **endptr,
249                                  int base) {
250   *val = __strtoull_impl(str, endptr, base);
251 }
252 
strtoval_impl(double * val,const char * str,char ** endptr)253 inline void strtoval_impl(double *val, const char *str, char **endptr) {
254   *val = __strtod_impl(str, endptr);
255 }
256 
257 // UBSAN: double to float is safe if numeric_limits<float>::is_iec559 is true.
258 __supress_ubsan__("float-cast-overflow")
strtoval_impl(float * val,const char * str,char ** endptr)259 inline void strtoval_impl(float *val, const char *str, char **endptr) {
260   *val = __strtof_impl(str, endptr);
261 }
262 #undef __strtoull_impl
263 #undef __strtoll_impl
264 #undef __strtod_impl
265 #undef __strtof_impl
266 // clang-format on
267 
268 // Adaptor for strtoull()/strtoll().
269 // Flatbuffers accepts numbers with any count of leading zeros (-009 is -9),
270 // while strtoll with base=0 interprets first leading zero as octal prefix.
271 // In future, it is possible to add prefixed 0b0101.
272 // 1) Checks errno code for overflow condition (out of range).
273 // 2) If base <= 0, function try to detect base of number by prefix.
274 //
275 // Return value (like strtoull and strtoll, but reject partial result):
276 // - If successful, an integer value corresponding to the str is returned.
277 // - If full string conversion can't be performed, 0 is returned.
278 // - If the converted value falls out of range of corresponding return type, a
279 // range error occurs. In this case value MAX(T)/MIN(T) is returned.
280 template<typename T>
281 inline bool StringToIntegerImpl(T *val, const char *const str,
282                                 const int base = 0,
283                                 const bool check_errno = true) {
284   // T is int64_t or uint64_T
285   FLATBUFFERS_ASSERT(str);
286   if (base <= 0) {
287     auto s = str;
288     while (*s && !is_digit(*s)) s++;
289     if (s[0] == '0' && is_alpha_char(s[1], 'X'))
290       return StringToIntegerImpl(val, str, 16, check_errno);
291     // if a prefix not match, try base=10
292     return StringToIntegerImpl(val, str, 10, check_errno);
293   } else {
294     if (check_errno) errno = 0;  // clear thread-local errno
295     auto endptr = str;
296     strtoval_impl(val, str, const_cast<char **>(&endptr), base);
297     if ((*endptr != '\0') || (endptr == str)) {
298       *val = 0;      // erase partial result
299       return false;  // invalid string
300     }
301     // errno is out-of-range, return MAX/MIN
302     if (check_errno && errno) return false;
303     return true;
304   }
305 }
306 
307 template<typename T>
StringToFloatImpl(T * val,const char * const str)308 inline bool StringToFloatImpl(T *val, const char *const str) {
309   // Type T must be either float or double.
310   FLATBUFFERS_ASSERT(str && val);
311   auto end = str;
312   strtoval_impl(val, str, const_cast<char **>(&end));
313   auto done = (end != str) && (*end == '\0');
314   if (!done) *val = 0;  // erase partial result
315   return done;
316 }
317 
318 // Convert a string to an instance of T.
319 // Return value (matched with StringToInteger64Impl and strtod):
320 // - If successful, a numeric value corresponding to the str is returned.
321 // - If full string conversion can't be performed, 0 is returned.
322 // - If the converted value falls out of range of corresponding return type, a
323 // range error occurs. In this case value MAX(T)/MIN(T) is returned.
StringToNumber(const char * s,T * val)324 template<typename T> inline bool StringToNumber(const char *s, T *val) {
325   // Assert on `unsigned long` and `signed long` on LP64.
326   // If it is necessary, it could be solved with flatbuffers::enable_if<B,T>.
327   static_assert(sizeof(T) < sizeof(int64_t), "unexpected type T");
328   FLATBUFFERS_ASSERT(s && val);
329   int64_t i64;
330   // The errno check isn't needed, will return MAX/MIN on overflow.
331   if (StringToIntegerImpl(&i64, s, 0, false)) {
332     const int64_t max = (flatbuffers::numeric_limits<T>::max)();
333     const int64_t min = flatbuffers::numeric_limits<T>::lowest();
334     if (i64 > max) {
335       *val = static_cast<T>(max);
336       return false;
337     }
338     if (i64 < min) {
339       // For unsigned types return max to distinguish from
340       // "no conversion can be performed" when 0 is returned.
341       *val = static_cast<T>(flatbuffers::is_unsigned<T>::value ? max : min);
342       return false;
343     }
344     *val = static_cast<T>(i64);
345     return true;
346   }
347   *val = 0;
348   return false;
349 }
350 
351 template<> inline bool StringToNumber<int64_t>(const char *str, int64_t *val) {
352   return StringToIntegerImpl(val, str);
353 }
354 
355 template<>
356 inline bool StringToNumber<uint64_t>(const char *str, uint64_t *val) {
357   if (!StringToIntegerImpl(val, str)) return false;
358   // The strtoull accepts negative numbers:
359   // If the minus sign was part of the input sequence, the numeric value
360   // calculated from the sequence of digits is negated as if by unary minus
361   // in the result type, which applies unsigned integer wraparound rules.
362   // Fix this behaviour (except -0).
363   if (*val) {
364     auto s = str;
365     while (*s && !is_digit(*s)) s++;
366     s = (s > str) ? (s - 1) : s;  // step back to one symbol
367     if (*s == '-') {
368       // For unsigned types return the max to distinguish from
369       // "no conversion can be performed".
370       *val = (flatbuffers::numeric_limits<uint64_t>::max)();
371       return false;
372     }
373   }
374   return true;
375 }
376 
StringToNumber(const char * s,float * val)377 template<> inline bool StringToNumber(const char *s, float *val) {
378   return StringToFloatImpl(val, s);
379 }
380 
StringToNumber(const char * s,double * val)381 template<> inline bool StringToNumber(const char *s, double *val) {
382   return StringToFloatImpl(val, s);
383 }
384 
385 inline int64_t StringToInt(const char *s, int base = 10) {
386   int64_t val;
387   return StringToIntegerImpl(&val, s, base) ? val : 0;
388 }
389 
390 inline uint64_t StringToUInt(const char *s, int base = 10) {
391   uint64_t val;
392   return StringToIntegerImpl(&val, s, base) ? val : 0;
393 }
394 
395 typedef bool (*LoadFileFunction)(const char *filename, bool binary,
396                                  std::string *dest);
397 typedef bool (*FileExistsFunction)(const char *filename);
398 
399 LoadFileFunction SetLoadFileFunction(LoadFileFunction load_file_function);
400 
401 FileExistsFunction SetFileExistsFunction(
402     FileExistsFunction file_exists_function);
403 
404 // Check if file "name" exists.
405 bool FileExists(const char *name);
406 
407 // Check if "name" exists and it is also a directory.
408 bool DirExists(const char *name);
409 
410 // Load file "name" into "buf" returning true if successful
411 // false otherwise.  If "binary" is false data is read
412 // using ifstream's text mode, otherwise data is read with
413 // no transcoding.
414 bool LoadFile(const char *name, bool binary, std::string *buf);
415 
416 // Save data "buf" of length "len" bytes into a file
417 // "name" returning true if successful, false otherwise.
418 // If "binary" is false data is written using ifstream's
419 // text mode, otherwise data is written with no
420 // transcoding.
421 bool SaveFile(const char *name, const char *buf, size_t len, bool binary);
422 
423 // Save data "buf" into file "name" returning true if
424 // successful, false otherwise.  If "binary" is false
425 // data is written using ifstream's text mode, otherwise
426 // data is written with no transcoding.
SaveFile(const char * name,const std::string & buf,bool binary)427 inline bool SaveFile(const char *name, const std::string &buf, bool binary) {
428   return SaveFile(name, buf.c_str(), buf.size(), binary);
429 }
430 
431 // Functionality for minimalistic portable path handling.
432 
433 // The functions below behave correctly regardless of whether posix ('/') or
434 // Windows ('/' or '\\') separators are used.
435 
436 // Any new separators inserted are always posix.
437 FLATBUFFERS_CONSTEXPR char kPathSeparator = '/';
438 
439 // Returns the path with the extension, if any, removed.
440 std::string StripExtension(const std::string &filepath);
441 
442 // Returns the extension, if any.
443 std::string GetExtension(const std::string &filepath);
444 
445 // Return the last component of the path, after the last separator.
446 std::string StripPath(const std::string &filepath);
447 
448 // Strip the last component of the path + separator.
449 std::string StripFileName(const std::string &filepath);
450 
451 std::string StripPrefix(const std::string &filepath,
452                         const std::string &prefix_to_remove);
453 
454 // Concatenates a path with a filename, regardless of whether the path
455 // ends in a separator or not.
456 std::string ConCatPathFileName(const std::string &path,
457                                const std::string &filename);
458 
459 // Replaces any '\\' separators with '/'
460 std::string PosixPath(const char *path);
461 std::string PosixPath(const std::string &path);
462 
463 // This function ensure a directory exists, by recursively
464 // creating dirs for any parts of the path that don't exist yet.
465 void EnsureDirExists(const std::string &filepath);
466 
467 // Obtains the absolute path from any other path.
468 // Returns the input path if the absolute path couldn't be resolved.
469 std::string AbsolutePath(const std::string &filepath);
470 
471 // Returns files relative to the --project_root path, prefixed with `//`.
472 std::string RelativeToRootPath(const std::string &project,
473                                const std::string &filepath);
474 
475 // To and from UTF-8 unicode conversion functions
476 
477 // Convert a unicode code point into a UTF-8 representation by appending it
478 // to a string. Returns the number of bytes generated.
ToUTF8(uint32_t ucc,std::string * out)479 inline int ToUTF8(uint32_t ucc, std::string *out) {
480   FLATBUFFERS_ASSERT(!(ucc & 0x80000000));  // Top bit can't be set.
481   // 6 possible encodings: http://en.wikipedia.org/wiki/UTF-8
482   for (int i = 0; i < 6; i++) {
483     // Max bits this encoding can represent.
484     uint32_t max_bits = 6 + i * 5 + static_cast<int>(!i);
485     if (ucc < (1u << max_bits)) {  // does it fit?
486       // Remaining bits not encoded in the first byte, store 6 bits each
487       uint32_t remain_bits = i * 6;
488       // Store first byte:
489       (*out) += static_cast<char>((0xFE << (max_bits - remain_bits)) |
490                                   (ucc >> remain_bits));
491       // Store remaining bytes:
492       for (int j = i - 1; j >= 0; j--) {
493         (*out) += static_cast<char>(((ucc >> (j * 6)) & 0x3F) | 0x80);
494       }
495       return i + 1;  // Return the number of bytes added.
496     }
497   }
498   FLATBUFFERS_ASSERT(0);  // Impossible to arrive here.
499   return -1;
500 }
501 
502 // Converts whatever prefix of the incoming string corresponds to a valid
503 // UTF-8 sequence into a unicode code. The incoming pointer will have been
504 // advanced past all bytes parsed.
505 // returns -1 upon corrupt UTF-8 encoding (ignore the incoming pointer in
506 // this case).
FromUTF8(const char ** in)507 inline int FromUTF8(const char **in) {
508   int len = 0;
509   // Count leading 1 bits.
510   for (int mask = 0x80; mask >= 0x04; mask >>= 1) {
511     if (**in & mask) {
512       len++;
513     } else {
514       break;
515     }
516   }
517   if ((static_cast<unsigned char>(**in) << len) & 0x80)
518     return -1;  // Bit after leading 1's must be 0.
519   if (!len) return *(*in)++;
520   // UTF-8 encoded values with a length are between 2 and 4 bytes.
521   if (len < 2 || len > 4) { return -1; }
522   // Grab initial bits of the code.
523   int ucc = *(*in)++ & ((1 << (7 - len)) - 1);
524   for (int i = 0; i < len - 1; i++) {
525     if ((**in & 0xC0) != 0x80) return -1;  // Upper bits must 1 0.
526     ucc <<= 6;
527     ucc |= *(*in)++ & 0x3F;  // Grab 6 more bits of the code.
528   }
529   // UTF-8 cannot encode values between 0xD800 and 0xDFFF (reserved for
530   // UTF-16 surrogate pairs).
531   if (ucc >= 0xD800 && ucc <= 0xDFFF) { return -1; }
532   // UTF-8 must represent code points in their shortest possible encoding.
533   switch (len) {
534     case 2:
535       // Two bytes of UTF-8 can represent code points from U+0080 to U+07FF.
536       if (ucc < 0x0080 || ucc > 0x07FF) { return -1; }
537       break;
538     case 3:
539       // Three bytes of UTF-8 can represent code points from U+0800 to U+FFFF.
540       if (ucc < 0x0800 || ucc > 0xFFFF) { return -1; }
541       break;
542     case 4:
543       // Four bytes of UTF-8 can represent code points from U+10000 to U+10FFFF.
544       if (ucc < 0x10000 || ucc > 0x10FFFF) { return -1; }
545       break;
546   }
547   return ucc;
548 }
549 
550 #ifndef FLATBUFFERS_PREFER_PRINTF
551 // Wraps a string to a maximum length, inserting new lines where necessary. Any
552 // existing whitespace will be collapsed down to a single space. A prefix or
553 // suffix can be provided, which will be inserted before or after a wrapped
554 // line, respectively.
WordWrap(const std::string in,size_t max_length,const std::string wrapped_line_prefix,const std::string wrapped_line_suffix)555 inline std::string WordWrap(const std::string in, size_t max_length,
556                             const std::string wrapped_line_prefix,
557                             const std::string wrapped_line_suffix) {
558   std::istringstream in_stream(in);
559   std::string wrapped, line, word;
560 
561   in_stream >> word;
562   line = word;
563 
564   while (in_stream >> word) {
565     if ((line.length() + 1 + word.length() + wrapped_line_suffix.length()) <
566         max_length) {
567       line += " " + word;
568     } else {
569       wrapped += line + wrapped_line_suffix + "\n";
570       line = wrapped_line_prefix + word;
571     }
572   }
573   wrapped += line;
574 
575   return wrapped;
576 }
577 #endif  // !FLATBUFFERS_PREFER_PRINTF
578 
EscapeString(const char * s,size_t length,std::string * _text,bool allow_non_utf8,bool natural_utf8)579 inline bool EscapeString(const char *s, size_t length, std::string *_text,
580                          bool allow_non_utf8, bool natural_utf8) {
581   std::string &text = *_text;
582   text += "\"";
583   for (uoffset_t i = 0; i < length; i++) {
584     char c = s[i];
585     switch (c) {
586       case '\n': text += "\\n"; break;
587       case '\t': text += "\\t"; break;
588       case '\r': text += "\\r"; break;
589       case '\b': text += "\\b"; break;
590       case '\f': text += "\\f"; break;
591       case '\"': text += "\\\""; break;
592       case '\\': text += "\\\\"; break;
593       default:
594         if (c >= ' ' && c <= '~') {
595           text += c;
596         } else {
597           // Not printable ASCII data. Let's see if it's valid UTF-8 first:
598           const char *utf8 = s + i;
599           int ucc = FromUTF8(&utf8);
600           if (ucc < 0) {
601             if (allow_non_utf8) {
602               text += "\\x";
603               text += IntToStringHex(static_cast<uint8_t>(c), 2);
604             } else {
605               // There are two cases here:
606               //
607               // 1) We reached here by parsing an IDL file. In that case,
608               // we previously checked for non-UTF-8, so we shouldn't reach
609               // here.
610               //
611               // 2) We reached here by someone calling GenerateText()
612               // on a previously-serialized flatbuffer. The data might have
613               // non-UTF-8 Strings, or might be corrupt.
614               //
615               // In both cases, we have to give up and inform the caller
616               // they have no JSON.
617               return false;
618             }
619           } else {
620             if (natural_utf8) {
621               // utf8 points to past all utf-8 bytes parsed
622               text.append(s + i, static_cast<size_t>(utf8 - s - i));
623             } else if (ucc <= 0xFFFF) {
624               // Parses as Unicode within JSON's \uXXXX range, so use that.
625               text += "\\u";
626               text += IntToStringHex(ucc, 4);
627             } else if (ucc <= 0x10FFFF) {
628               // Encode Unicode SMP values to a surrogate pair using two \u
629               // escapes.
630               uint32_t base = ucc - 0x10000;
631               auto high_surrogate = (base >> 10) + 0xD800;
632               auto low_surrogate = (base & 0x03FF) + 0xDC00;
633               text += "\\u";
634               text += IntToStringHex(high_surrogate, 4);
635               text += "\\u";
636               text += IntToStringHex(low_surrogate, 4);
637             }
638             // Skip past characters recognized.
639             i = static_cast<uoffset_t>(utf8 - s - 1);
640           }
641         }
642         break;
643     }
644   }
645   text += "\"";
646   return true;
647 }
648 
BufferToHexText(const void * buffer,size_t buffer_size,size_t max_length,const std::string & wrapped_line_prefix,const std::string & wrapped_line_suffix)649 inline std::string BufferToHexText(const void *buffer, size_t buffer_size,
650                                    size_t max_length,
651                                    const std::string &wrapped_line_prefix,
652                                    const std::string &wrapped_line_suffix) {
653   std::string text = wrapped_line_prefix;
654   size_t start_offset = 0;
655   const char *s = reinterpret_cast<const char *>(buffer);
656   for (size_t i = 0; s && i < buffer_size; i++) {
657     // Last iteration or do we have more?
658     bool have_more = i + 1 < buffer_size;
659     text += "0x";
660     text += IntToStringHex(static_cast<uint8_t>(s[i]), 2);
661     if (have_more) { text += ','; }
662     // If we have more to process and we reached max_length
663     if (have_more &&
664         text.size() + wrapped_line_suffix.size() >= start_offset + max_length) {
665       text += wrapped_line_suffix;
666       text += '\n';
667       start_offset = text.size();
668       text += wrapped_line_prefix;
669     }
670   }
671   text += wrapped_line_suffix;
672   return text;
673 }
674 
675 // Remove paired quotes in a string: "text"|'text' -> text.
676 std::string RemoveStringQuotes(const std::string &s);
677 
678 // Change th global C-locale to locale with name <locale_name>.
679 // Returns an actual locale name in <_value>, useful if locale_name is "" or
680 // null.
681 bool SetGlobalTestLocale(const char *locale_name,
682                          std::string *_value = nullptr);
683 
684 // Read (or test) a value of environment variable.
685 bool ReadEnvironmentVariable(const char *var_name,
686                              std::string *_value = nullptr);
687 
688 // MSVC specific: Send all assert reports to STDOUT to prevent CI hangs.
689 void SetupDefaultCRTReportMode();
690 
691 enum class Case {
692   kUnknown = 0,
693   // TheQuickBrownFox
694   kUpperCamel = 1,
695   // theQuickBrownFox
696   kLowerCamel = 2,
697   // the_quick_brown_fox
698   kSnake = 3,
699   // THE_QUICK_BROWN_FOX
700   kScreamingSnake = 4,
701   // THEQUICKBROWNFOX
702   kAllUpper = 5,
703   // thequickbrownfox
704   kAllLower = 6,
705   // the-quick-brown-fox
706   kDasher = 7,
707   // THEQuiCKBr_ownFox (or whatever you want, we won't change it)
708   kKeep = 8,
709   // the_quick_brown_fox123 (as opposed to the_quick_brown_fox_123)
710   kSnake2 = 9,
711 };
712 
713 // Convert the `input` string of case `input_case` to the specified `output_case`.
714 std::string ConvertCase(const std::string &input, Case output_case,
715                     Case input_case = Case::kSnake);
716 
717 }  // namespace flatbuffers
718 
719 #endif  // FLATBUFFERS_UTIL_H_
720