strbuf.h: format asciidoc code blocks as 4-space indent
[git/git.git] / strbuf.h
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1#ifndef STRBUF_H
2#define STRBUF_H
b449f4cf 3
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4/**
5 * strbuf's are meant to be used with all the usual C string and memory
6 * APIs. Given that the length of the buffer is known, it's often better to
7 * use the mem* functions than a str* one (memchr vs. strchr e.g.).
8 * Though, one has to be careful about the fact that str* functions often
9 * stop on NULs and that strbufs may have embedded NULs.
10 *
11 * A strbuf is NUL terminated for convenience, but no function in the
12 * strbuf API actually relies on the string being free of NULs.
13 *
14 * strbufs have some invariants that are very important to keep in mind:
15 *
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16 * - The `buf` member is never NULL, so it can be used in any usual C
17 * string operations safely. strbuf's _have_ to be initialized either by
18 * `strbuf_init()` or by `= STRBUF_INIT` before the invariants, though.
bdfdaa49 19 *
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20 * Do *not* assume anything on what `buf` really is (e.g. if it is
21 * allocated memory or not), use `strbuf_detach()` to unwrap a memory
22 * buffer from its strbuf shell in a safe way. That is the sole supported
23 * way. This will give you a malloced buffer that you can later `free()`.
24 *
25 * However, it is totally safe to modify anything in the string pointed by
26 * the `buf` member, between the indices `0` and `len-1` (inclusive).
27 *
28 * - The `buf` member is a byte array that has at least `len + 1` bytes
29 * allocated. The extra byte is used to store a `'\0'`, allowing the
30 * `buf` member to be a valid C-string. Every strbuf function ensure this
31 * invariant is preserved.
32 *
33 * NOTE: It is OK to "play" with the buffer directly if you work it this
34 * way:
35 *
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36 * strbuf_grow(sb, SOME_SIZE); <1>
37 * strbuf_setlen(sb, sb->len + SOME_OTHER_SIZE);
38 *
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39 * <1> Here, the memory array starting at `sb->buf`, and of length
40 * `strbuf_avail(sb)` is all yours, and you can be sure that
41 * `strbuf_avail(sb)` is at least `SOME_SIZE`.
42 *
43 * NOTE: `SOME_OTHER_SIZE` must be smaller or equal to `strbuf_avail(sb)`.
44 *
45 * Doing so is safe, though if it has to be done in many places, adding the
46 * missing API to the strbuf module is the way to go.
47 *
48 * WARNING: Do _not_ assume that the area that is yours is of size `alloc
49 * - 1` even if it's true in the current implementation. Alloc is somehow a
50 * "private" member that should not be messed with. Use `strbuf_avail()`
51 * instead.
52*/
b449f4cf 53
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54/**
55 * Data Structures
56 * ---------------
57 */
58
59/**
60 * This is the string buffer structure. The `len` member can be used to
61 * determine the current length of the string, and `buf` member provides
62 * access to the string itself.
63 */
d1df5743 64struct strbuf {
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65 size_t alloc;
66 size_t len;
bf0f910d 67 char *buf;
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68};
69
bdfdaa49 70extern char strbuf_slopbuf[];
b315c5c0 71#define STRBUF_INIT { 0, 0, strbuf_slopbuf }
b449f4cf 72
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73/**
74 * Functions
75 * ---------
76 */
77
78/**
79 * * Life Cycle
80 */
81
82/**
83 * Initialize the structure. The second parameter can be zero or a bigger
84 * number to allocate memory, in case you want to prevent further reallocs.
85 */
f1696ee3 86extern void strbuf_init(struct strbuf *, size_t);
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87
88/**
89 * Release a string buffer and the memory it used. You should not use the
90 * string buffer after using this function, unless you initialize it again.
91 */
b449f4cf 92extern void strbuf_release(struct strbuf *);
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93
94/**
95 * Detach the string from the strbuf and returns it; you now own the
96 * storage the string occupies and it is your responsibility from then on
97 * to release it with `free(3)` when you are done with it.
98 */
b315c5c0 99extern char *strbuf_detach(struct strbuf *, size_t *);
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100
101/**
102 * Attach a string to a buffer. You should specify the string to attach,
103 * the current length of the string and the amount of allocated memory.
104 * The amount must be larger than the string length, because the string you
105 * pass is supposed to be a NUL-terminated string. This string _must_ be
106 * malloc()ed, and after attaching, the pointer cannot be relied upon
107 * anymore, and neither be free()d directly.
108 */
917c9a71 109extern void strbuf_attach(struct strbuf *, void *, size_t, size_t);
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110
111/**
112 * Swap the contents of two string buffers.
113 */
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114static inline void strbuf_swap(struct strbuf *a, struct strbuf *b)
115{
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116 struct strbuf tmp = *a;
117 *a = *b;
118 *b = tmp;
119}
b449f4cf 120
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121
122/**
123 * * Related to the size of the buffer
124 */
125
126/**
127 * Determine the amount of allocated but unused memory.
128 */
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129static inline size_t strbuf_avail(const struct strbuf *sb)
130{
c76689df 131 return sb->alloc ? sb->alloc - sb->len - 1 : 0;
b449f4cf 132}
a8f3e221 133
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134/**
135 * Ensure that at least this amount of unused memory is available after
136 * `len`. This is used when you know a typical size for what you will add
137 * and want to avoid repetitive automatic resizing of the underlying buffer.
138 * This is never a needed operation, but can be critical for performance in
139 * some cases.
140 */
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141extern void strbuf_grow(struct strbuf *, size_t);
142
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143/**
144 * Set the length of the buffer to a given value. This function does *not*
145 * allocate new memory, so you should not perform a `strbuf_setlen()` to a
146 * length that is larger than `len + strbuf_avail()`. `strbuf_setlen()` is
147 * just meant as a 'please fix invariants from this strbuf I just messed
148 * with'.
149 */
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150static inline void strbuf_setlen(struct strbuf *sb, size_t len)
151{
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152 if (len > (sb->alloc ? sb->alloc - 1 : 0))
153 die("BUG: strbuf_setlen() beyond buffer");
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154 sb->len = len;
155 sb->buf[len] = '\0';
b449f4cf 156}
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157
158/**
159 * Empty the buffer by setting the size of it to zero.
160 */
b315c5c0 161#define strbuf_reset(sb) strbuf_setlen(sb, 0)
b449f4cf 162
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163
164/**
165 * * Related to the contents of the buffer
166 */
167
168/**
169 * Strip whitespace from the beginning and end of a string.
170 * Equivalent to performing `strbuf_rtrim()` followed by `strbuf_ltrim()`.
171 */
eacd6dc5 172extern void strbuf_trim(struct strbuf *);
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173
174/**
175 * Strip whitespace from the end of a string.
176 */
f1696ee3 177extern void strbuf_rtrim(struct strbuf *);
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178
179/**
180 * Strip whitespace from the beginning of a string.
181 */
eacd6dc5 182extern void strbuf_ltrim(struct strbuf *);
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183
184/**
185 * Replace the contents of the strbuf with a reencoded form. Returns -1
186 * on error, 0 on success.
187 */
d4241f52 188extern int strbuf_reencode(struct strbuf *sb, const char *from, const char *to);
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189
190/**
191 * Lowercase each character in the buffer using `tolower`.
192 */
ffb20ce1 193extern void strbuf_tolower(struct strbuf *sb);
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194
195/**
196 * Compare two buffers. Returns an integer less than, equal to, or greater
197 * than zero if the first buffer is found, respectively, to be less than,
198 * to match, or be greater than the second buffer.
199 */
9b200fd6 200extern int strbuf_cmp(const struct strbuf *, const struct strbuf *);
eacd6dc5 201
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202
203/**
204 * * Adding data to the buffer
205 *
206 * NOTE: All of the functions in this section will grow the buffer as
207 * necessary. If they fail for some reason other than memory shortage and the
208 * buffer hadn't been allocated before (i.e. the `struct strbuf` was set to
209 * `STRBUF_INIT`), then they will free() it.
210 */
211
212/**
213 * Add a single character to the buffer.
214 */
215static inline void strbuf_addch(struct strbuf *sb, int c)
216{
217 strbuf_grow(sb, 1);
218 sb->buf[sb->len++] = c;
219 sb->buf[sb->len] = '\0';
220}
221
222/**
223 * Add a character the specified number of times to the buffer.
224 */
225extern void strbuf_addchars(struct strbuf *sb, int c, size_t n);
226
227/**
228 * Insert data to the given position of the buffer. The remaining contents
229 * will be shifted, not overwritten.
230 */
231extern void strbuf_insert(struct strbuf *, size_t pos, const void *, size_t);
232
233/**
234 * Remove given amount of data from a given position of the buffer.
235 */
236extern void strbuf_remove(struct strbuf *, size_t pos, size_t len);
237
238/**
239 * Remove the bytes between `pos..pos+len` and replace it with the given
240 * data.
241 */
242extern void strbuf_splice(struct strbuf *, size_t pos, size_t len,
243 const void *, size_t);
244
245/**
246 * Add a NUL-terminated string to the buffer. Each line will be prepended
247 * by a comment character and a blank.
248 */
249extern void strbuf_add_commented_lines(struct strbuf *out, const char *buf, size_t size);
250
251
252/**
253 * Add data of given length to the buffer.
254 */
255extern void strbuf_add(struct strbuf *, const void *, size_t);
256
257/**
258 * Add a NUL-terminated string to the buffer.
259 *
260 * NOTE: This function will *always* be implemented as an inline or a macro
261 * using strlen, meaning that this is efficient to write things like:
262 *
088c9a86 263 * strbuf_addstr(sb, "immediate string");
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264 *
265 */
266static inline void strbuf_addstr(struct strbuf *sb, const char *s)
267{
268 strbuf_add(sb, s, strlen(s));
269}
270
271/**
272 * Copy the contents of another buffer at the end of the current one.
273 */
274static inline void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2)
275{
276 strbuf_grow(sb, sb2->len);
277 strbuf_add(sb, sb2->buf, sb2->len);
278}
279
280/**
281 * Copy part of the buffer from a given position till a given length to the
282 * end of the buffer.
283 */
284extern void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len);
285
286/**
287 * This function can be used to expand a format string containing
288 * placeholders. To that end, it parses the string and calls the specified
289 * function for every percent sign found.
290 *
291 * The callback function is given a pointer to the character after the `%`
292 * and a pointer to the struct strbuf. It is expected to add the expanded
293 * version of the placeholder to the strbuf, e.g. to add a newline
294 * character if the letter `n` appears after a `%`. The function returns
295 * the length of the placeholder recognized and `strbuf_expand()` skips
296 * over it.
297 *
298 * The format `%%` is automatically expanded to a single `%` as a quoting
299 * mechanism; callers do not need to handle the `%` placeholder themselves,
300 * and the callback function will not be invoked for this placeholder.
301 *
302 * All other characters (non-percent and not skipped ones) are copied
303 * verbatim to the strbuf. If the callback returned zero, meaning that the
304 * placeholder is unknown, then the percent sign is copied, too.
305 *
306 * In order to facilitate caching and to make it possible to give
307 * parameters to the callback, `strbuf_expand()` passes a context pointer,
308 * which can be used by the programmer of the callback as she sees fit.
309 */
310typedef size_t (*expand_fn_t) (struct strbuf *sb, const char *placeholder, void *context);
311extern void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn, void *context);
312
313/**
314 * Used as callback for `strbuf_expand()`, expects an array of
315 * struct strbuf_expand_dict_entry as context, i.e. pairs of
316 * placeholder and replacement string. The array needs to be
317 * terminated by an entry with placeholder set to NULL.
318 */
319struct strbuf_expand_dict_entry {
320 const char *placeholder;
321 const char *value;
322};
323extern size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder, void *context);
324
325/**
326 * Append the contents of one strbuf to another, quoting any
327 * percent signs ("%") into double-percents ("%%") in the
328 * destination. This is useful for literal data to be fed to either
329 * strbuf_expand or to the *printf family of functions.
330 */
331extern void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src);
332
333/**
334 * Append the given byte size as a human-readable string (i.e. 12.23 KiB,
335 * 3.50 MiB).
336 */
337extern void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes);
338
339/**
340 * Add a formatted string to the buffer.
341 */
342__attribute__((format (printf,2,3)))
343extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...);
344
345/**
346 * Add a formatted string prepended by a comment character and a
347 * blank to the buffer.
348 */
349__attribute__((format (printf, 2, 3)))
350extern void strbuf_commented_addf(struct strbuf *sb, const char *fmt, ...);
351
352__attribute__((format (printf,2,0)))
353extern void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap);
354
355/**
356 * Read a given size of data from a FILE* pointer to the buffer.
357 *
358 * NOTE: The buffer is rewound if the read fails. If -1 is returned,
359 * `errno` must be consulted, like you would do for `read(3)`.
360 * `strbuf_read()`, `strbuf_read_file()` and `strbuf_getline()` has the
361 * same behaviour as well.
362 */
363extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
364
365/**
366 * Read the contents of a given file descriptor. The third argument can be
367 * used to give a hint about the file size, to avoid reallocs. If read fails,
368 * any partial read is undone.
369 */
370extern ssize_t strbuf_read(struct strbuf *, int fd, size_t hint);
371
372/**
373 * Read the contents of a file, specified by its path. The third argument
374 * can be used to give a hint about the file size, to avoid reallocs.
375 */
376extern int strbuf_read_file(struct strbuf *sb, const char *path, size_t hint);
377
378/**
379 * Read the target of a symbolic link, specified by its path. The third
380 * argument can be used to give a hint about the size, to avoid reallocs.
381 */
382extern int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint);
383
384/**
385 * Read a line from a FILE *, overwriting the existing contents
386 * of the strbuf. The second argument specifies the line
387 * terminator character, typically `'\n'`.
388 * Reading stops after the terminator or at EOF. The terminator
389 * is removed from the buffer before returning. Returns 0 unless
390 * there was nothing left before EOF, in which case it returns `EOF`.
391 */
392extern int strbuf_getline(struct strbuf *, FILE *, int);
393
394/**
395 * Like `strbuf_getline`, but keeps the trailing terminator (if
396 * any) in the buffer.
397 */
398extern int strbuf_getwholeline(struct strbuf *, FILE *, int);
399
400/**
401 * Like `strbuf_getwholeline`, but operates on a file descriptor.
402 * It reads one character at a time, so it is very slow. Do not
403 * use it unless you need the correct position in the file
404 * descriptor.
405 */
406extern int strbuf_getwholeline_fd(struct strbuf *, int, int);
407
408/**
409 * Set the buffer to the path of the current working directory.
410 */
411extern int strbuf_getcwd(struct strbuf *sb);
412
413/**
414 * Add a path to a buffer, converting a relative path to an
415 * absolute one in the process. Symbolic links are not
416 * resolved.
417 */
418extern void strbuf_add_absolute_path(struct strbuf *sb, const char *path);
419
420/**
421 * Strip whitespace from a buffer. The second parameter controls if
422 * comments are considered contents to be removed or not.
423 */
424extern void stripspace(struct strbuf *buf, int skip_comments);
425
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426static inline int strbuf_strip_suffix(struct strbuf *sb, const char *suffix)
427{
428 if (strip_suffix_mem(sb->buf, &sb->len, suffix)) {
429 strbuf_setlen(sb, sb->len);
430 return 1;
431 } else
432 return 0;
433}
434
6afbbdda 435/**
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436 * Split str (of length slen) at the specified terminator character.
437 * Return a null-terminated array of pointers to strbuf objects
438 * holding the substrings. The substrings include the terminator,
439 * except for the last substring, which might be unterminated if the
440 * original string did not end with a terminator. If max is positive,
441 * then split the string into at most max substrings (with the last
442 * substring containing everything following the (max-1)th terminator
443 * character).
444 *
445 * For lighter-weight alternatives, see string_list_split() and
446 * string_list_split_in_place().
447 */
2f1d9e2b 448extern struct strbuf **strbuf_split_buf(const char *, size_t,
17b73dc6 449 int terminator, int max);
06379a65 450
6afbbdda 451/**
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452 * Split a NUL-terminated string at the specified terminator
453 * character. See strbuf_split_buf() for more information.
454 */
2f1d9e2b 455static inline struct strbuf **strbuf_split_str(const char *str,
17b73dc6 456 int terminator, int max)
2f1d9e2b 457{
17b73dc6 458 return strbuf_split_buf(str, strlen(str), terminator, max);
2f1d9e2b 459}
06379a65 460
6afbbdda 461/**
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462 * Split a strbuf at the specified terminator character. See
463 * strbuf_split_buf() for more information.
464 */
2f1d9e2b 465static inline struct strbuf **strbuf_split_max(const struct strbuf *sb,
17b73dc6 466 int terminator, int max)
2f1d9e2b 467{
17b73dc6 468 return strbuf_split_buf(sb->buf, sb->len, terminator, max);
2f1d9e2b 469}
06379a65 470
6afbbdda 471/**
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472 * Split a strbuf at the specified terminator character. See
473 * strbuf_split_buf() for more information.
474 */
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475static inline struct strbuf **strbuf_split(const struct strbuf *sb,
476 int terminator)
28fc3a68 477{
17b73dc6 478 return strbuf_split_max(sb, terminator, 0);
28fc3a68 479}
06379a65 480
6afbbdda 481/**
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482 * Free a NULL-terminated list of strbufs (for example, the return
483 * values of the strbuf_split*() functions).
484 */
eacd6dc5 485extern void strbuf_list_free(struct strbuf **);
f1696ee3 486
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487/**
488 * Launch the user preferred editor to edit a file and fill the buffer
489 * with the file's contents upon the user completing their editing. The
490 * third argument can be used to set the environment which the editor is
491 * run in. If the buffer is NULL the editor is launched as usual but the
492 * file's contents are not read into the buffer upon completion.
493 */
494extern int launch_editor(const char *path, struct strbuf *buffer, const char *const *env);
b449f4cf 495
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496extern void strbuf_add_lines(struct strbuf *sb, const char *prefix, const char *buf, size_t size);
497
6afbbdda 498/**
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499 * Append s to sb, with the characters '<', '>', '&' and '"' converted
500 * into XML entities.
501 */
502extern void strbuf_addstr_xml_quoted(struct strbuf *sb, const char *s);
503
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504static inline void strbuf_complete_line(struct strbuf *sb)
505{
506 if (sb->len && sb->buf[sb->len - 1] != '\n')
507 strbuf_addch(sb, '\n');
508}
509
a552de75 510extern int strbuf_branchname(struct strbuf *sb, const char *name);
a2fab531 511extern int strbuf_check_branch_ref(struct strbuf *sb, const char *name);
a552de75 512
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513extern void strbuf_addstr_urlencode(struct strbuf *, const char *,
514 int reserved);
679eebe2 515
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516__attribute__((format (printf,1,2)))
517extern int printf_ln(const char *fmt, ...);
518__attribute__((format (printf,2,3)))
519extern int fprintf_ln(FILE *fp, const char *fmt, ...);
520
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521char *xstrdup_tolower(const char *);
522
6afbbdda 523/**
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524 * Create a newly allocated string using printf format. You can do this easily
525 * with a strbuf, but this provides a shortcut to save a few lines.
526 */
527__attribute__((format (printf, 1, 0)))
528char *xstrvfmt(const char *fmt, va_list ap);
529__attribute__((format (printf, 1, 2)))
530char *xstrfmt(const char *fmt, ...);
531
d1df5743 532#endif /* STRBUF_H */