strbuf.h: drop asciidoc list formatting from API docs
[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 *
36 * ----
37 * strbuf_grow(sb, SOME_SIZE); <1>
38 * strbuf_setlen(sb, sb->len + SOME_OTHER_SIZE);
39 * ----
40 * <1> Here, the memory array starting at `sb->buf`, and of length
41 * `strbuf_avail(sb)` is all yours, and you can be sure that
42 * `strbuf_avail(sb)` is at least `SOME_SIZE`.
43 *
44 * NOTE: `SOME_OTHER_SIZE` must be smaller or equal to `strbuf_avail(sb)`.
45 *
46 * Doing so is safe, though if it has to be done in many places, adding the
47 * missing API to the strbuf module is the way to go.
48 *
49 * WARNING: Do _not_ assume that the area that is yours is of size `alloc
50 * - 1` even if it's true in the current implementation. Alloc is somehow a
51 * "private" member that should not be messed with. Use `strbuf_avail()`
52 * instead.
53*/
b449f4cf 54
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55/**
56 * Data Structures
57 * ---------------
58 */
59
60/**
61 * This is the string buffer structure. The `len` member can be used to
62 * determine the current length of the string, and `buf` member provides
63 * access to the string itself.
64 */
d1df5743 65struct strbuf {
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66 size_t alloc;
67 size_t len;
bf0f910d 68 char *buf;
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69};
70
bdfdaa49 71extern char strbuf_slopbuf[];
b315c5c0 72#define STRBUF_INIT { 0, 0, strbuf_slopbuf }
b449f4cf 73
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74/**
75 * Functions
76 * ---------
77 */
78
79/**
80 * * Life Cycle
81 */
82
83/**
84 * Initialize the structure. The second parameter can be zero or a bigger
85 * number to allocate memory, in case you want to prevent further reallocs.
86 */
f1696ee3 87extern void strbuf_init(struct strbuf *, size_t);
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88
89/**
90 * Release a string buffer and the memory it used. You should not use the
91 * string buffer after using this function, unless you initialize it again.
92 */
b449f4cf 93extern void strbuf_release(struct strbuf *);
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94
95/**
96 * Detach the string from the strbuf and returns it; you now own the
97 * storage the string occupies and it is your responsibility from then on
98 * to release it with `free(3)` when you are done with it.
99 */
b315c5c0 100extern char *strbuf_detach(struct strbuf *, size_t *);
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101
102/**
103 * Attach a string to a buffer. You should specify the string to attach,
104 * the current length of the string and the amount of allocated memory.
105 * The amount must be larger than the string length, because the string you
106 * pass is supposed to be a NUL-terminated string. This string _must_ be
107 * malloc()ed, and after attaching, the pointer cannot be relied upon
108 * anymore, and neither be free()d directly.
109 */
917c9a71 110extern void strbuf_attach(struct strbuf *, void *, size_t, size_t);
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111
112/**
113 * Swap the contents of two string buffers.
114 */
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115static inline void strbuf_swap(struct strbuf *a, struct strbuf *b)
116{
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117 struct strbuf tmp = *a;
118 *a = *b;
119 *b = tmp;
120}
b449f4cf 121
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122
123/**
124 * * Related to the size of the buffer
125 */
126
127/**
128 * Determine the amount of allocated but unused memory.
129 */
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130static inline size_t strbuf_avail(const struct strbuf *sb)
131{
c76689df 132 return sb->alloc ? sb->alloc - sb->len - 1 : 0;
b449f4cf 133}
a8f3e221 134
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135/**
136 * Ensure that at least this amount of unused memory is available after
137 * `len`. This is used when you know a typical size for what you will add
138 * and want to avoid repetitive automatic resizing of the underlying buffer.
139 * This is never a needed operation, but can be critical for performance in
140 * some cases.
141 */
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142extern void strbuf_grow(struct strbuf *, size_t);
143
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144/**
145 * Set the length of the buffer to a given value. This function does *not*
146 * allocate new memory, so you should not perform a `strbuf_setlen()` to a
147 * length that is larger than `len + strbuf_avail()`. `strbuf_setlen()` is
148 * just meant as a 'please fix invariants from this strbuf I just messed
149 * with'.
150 */
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151static inline void strbuf_setlen(struct strbuf *sb, size_t len)
152{
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153 if (len > (sb->alloc ? sb->alloc - 1 : 0))
154 die("BUG: strbuf_setlen() beyond buffer");
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155 sb->len = len;
156 sb->buf[len] = '\0';
b449f4cf 157}
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158
159/**
160 * Empty the buffer by setting the size of it to zero.
161 */
b315c5c0 162#define strbuf_reset(sb) strbuf_setlen(sb, 0)
b449f4cf 163
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164
165/**
166 * * Related to the contents of the buffer
167 */
168
169/**
170 * Strip whitespace from the beginning and end of a string.
171 * Equivalent to performing `strbuf_rtrim()` followed by `strbuf_ltrim()`.
172 */
eacd6dc5 173extern void strbuf_trim(struct strbuf *);
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174
175/**
176 * Strip whitespace from the end of a string.
177 */
f1696ee3 178extern void strbuf_rtrim(struct strbuf *);
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179
180/**
181 * Strip whitespace from the beginning of a string.
182 */
eacd6dc5 183extern void strbuf_ltrim(struct strbuf *);
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184
185/**
186 * Replace the contents of the strbuf with a reencoded form. Returns -1
187 * on error, 0 on success.
188 */
d4241f52 189extern int strbuf_reencode(struct strbuf *sb, const char *from, const char *to);
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190
191/**
192 * Lowercase each character in the buffer using `tolower`.
193 */
ffb20ce1 194extern void strbuf_tolower(struct strbuf *sb);
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195
196/**
197 * Compare two buffers. Returns an integer less than, equal to, or greater
198 * than zero if the first buffer is found, respectively, to be less than,
199 * to match, or be greater than the second buffer.
200 */
9b200fd6 201extern int strbuf_cmp(const struct strbuf *, const struct strbuf *);
eacd6dc5 202
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203
204/**
205 * * Adding data to the buffer
206 *
207 * NOTE: All of the functions in this section will grow the buffer as
208 * necessary. If they fail for some reason other than memory shortage and the
209 * buffer hadn't been allocated before (i.e. the `struct strbuf` was set to
210 * `STRBUF_INIT`), then they will free() it.
211 */
212
213/**
214 * Add a single character to the buffer.
215 */
216static inline void strbuf_addch(struct strbuf *sb, int c)
217{
218 strbuf_grow(sb, 1);
219 sb->buf[sb->len++] = c;
220 sb->buf[sb->len] = '\0';
221}
222
223/**
224 * Add a character the specified number of times to the buffer.
225 */
226extern void strbuf_addchars(struct strbuf *sb, int c, size_t n);
227
228/**
229 * Insert data to the given position of the buffer. The remaining contents
230 * will be shifted, not overwritten.
231 */
232extern void strbuf_insert(struct strbuf *, size_t pos, const void *, size_t);
233
234/**
235 * Remove given amount of data from a given position of the buffer.
236 */
237extern void strbuf_remove(struct strbuf *, size_t pos, size_t len);
238
239/**
240 * Remove the bytes between `pos..pos+len` and replace it with the given
241 * data.
242 */
243extern void strbuf_splice(struct strbuf *, size_t pos, size_t len,
244 const void *, size_t);
245
246/**
247 * Add a NUL-terminated string to the buffer. Each line will be prepended
248 * by a comment character and a blank.
249 */
250extern void strbuf_add_commented_lines(struct strbuf *out, const char *buf, size_t size);
251
252
253/**
254 * Add data of given length to the buffer.
255 */
256extern void strbuf_add(struct strbuf *, const void *, size_t);
257
258/**
259 * Add a NUL-terminated string to the buffer.
260 *
261 * NOTE: This function will *always* be implemented as an inline or a macro
262 * using strlen, meaning that this is efficient to write things like:
263 *
264 * ----
265 * strbuf_addstr(sb, "immediate string");
266 * ----
267 *
268 */
269static inline void strbuf_addstr(struct strbuf *sb, const char *s)
270{
271 strbuf_add(sb, s, strlen(s));
272}
273
274/**
275 * Copy the contents of another buffer at the end of the current one.
276 */
277static inline void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2)
278{
279 strbuf_grow(sb, sb2->len);
280 strbuf_add(sb, sb2->buf, sb2->len);
281}
282
283/**
284 * Copy part of the buffer from a given position till a given length to the
285 * end of the buffer.
286 */
287extern void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len);
288
289/**
290 * This function can be used to expand a format string containing
291 * placeholders. To that end, it parses the string and calls the specified
292 * function for every percent sign found.
293 *
294 * The callback function is given a pointer to the character after the `%`
295 * and a pointer to the struct strbuf. It is expected to add the expanded
296 * version of the placeholder to the strbuf, e.g. to add a newline
297 * character if the letter `n` appears after a `%`. The function returns
298 * the length of the placeholder recognized and `strbuf_expand()` skips
299 * over it.
300 *
301 * The format `%%` is automatically expanded to a single `%` as a quoting
302 * mechanism; callers do not need to handle the `%` placeholder themselves,
303 * and the callback function will not be invoked for this placeholder.
304 *
305 * All other characters (non-percent and not skipped ones) are copied
306 * verbatim to the strbuf. If the callback returned zero, meaning that the
307 * placeholder is unknown, then the percent sign is copied, too.
308 *
309 * In order to facilitate caching and to make it possible to give
310 * parameters to the callback, `strbuf_expand()` passes a context pointer,
311 * which can be used by the programmer of the callback as she sees fit.
312 */
313typedef size_t (*expand_fn_t) (struct strbuf *sb, const char *placeholder, void *context);
314extern void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn, void *context);
315
316/**
317 * Used as callback for `strbuf_expand()`, expects an array of
318 * struct strbuf_expand_dict_entry as context, i.e. pairs of
319 * placeholder and replacement string. The array needs to be
320 * terminated by an entry with placeholder set to NULL.
321 */
322struct strbuf_expand_dict_entry {
323 const char *placeholder;
324 const char *value;
325};
326extern size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder, void *context);
327
328/**
329 * Append the contents of one strbuf to another, quoting any
330 * percent signs ("%") into double-percents ("%%") in the
331 * destination. This is useful for literal data to be fed to either
332 * strbuf_expand or to the *printf family of functions.
333 */
334extern void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src);
335
336/**
337 * Append the given byte size as a human-readable string (i.e. 12.23 KiB,
338 * 3.50 MiB).
339 */
340extern void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes);
341
342/**
343 * Add a formatted string to the buffer.
344 */
345__attribute__((format (printf,2,3)))
346extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...);
347
348/**
349 * Add a formatted string prepended by a comment character and a
350 * blank to the buffer.
351 */
352__attribute__((format (printf, 2, 3)))
353extern void strbuf_commented_addf(struct strbuf *sb, const char *fmt, ...);
354
355__attribute__((format (printf,2,0)))
356extern void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap);
357
358/**
359 * Read a given size of data from a FILE* pointer to the buffer.
360 *
361 * NOTE: The buffer is rewound if the read fails. If -1 is returned,
362 * `errno` must be consulted, like you would do for `read(3)`.
363 * `strbuf_read()`, `strbuf_read_file()` and `strbuf_getline()` has the
364 * same behaviour as well.
365 */
366extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
367
368/**
369 * Read the contents of a given file descriptor. The third argument can be
370 * used to give a hint about the file size, to avoid reallocs. If read fails,
371 * any partial read is undone.
372 */
373extern ssize_t strbuf_read(struct strbuf *, int fd, size_t hint);
374
375/**
376 * Read the contents of a file, specified by its path. The third argument
377 * can be used to give a hint about the file size, to avoid reallocs.
378 */
379extern int strbuf_read_file(struct strbuf *sb, const char *path, size_t hint);
380
381/**
382 * Read the target of a symbolic link, specified by its path. The third
383 * argument can be used to give a hint about the size, to avoid reallocs.
384 */
385extern int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint);
386
387/**
388 * Read a line from a FILE *, overwriting the existing contents
389 * of the strbuf. The second argument specifies the line
390 * terminator character, typically `'\n'`.
391 * Reading stops after the terminator or at EOF. The terminator
392 * is removed from the buffer before returning. Returns 0 unless
393 * there was nothing left before EOF, in which case it returns `EOF`.
394 */
395extern int strbuf_getline(struct strbuf *, FILE *, int);
396
397/**
398 * Like `strbuf_getline`, but keeps the trailing terminator (if
399 * any) in the buffer.
400 */
401extern int strbuf_getwholeline(struct strbuf *, FILE *, int);
402
403/**
404 * Like `strbuf_getwholeline`, but operates on a file descriptor.
405 * It reads one character at a time, so it is very slow. Do not
406 * use it unless you need the correct position in the file
407 * descriptor.
408 */
409extern int strbuf_getwholeline_fd(struct strbuf *, int, int);
410
411/**
412 * Set the buffer to the path of the current working directory.
413 */
414extern int strbuf_getcwd(struct strbuf *sb);
415
416/**
417 * Add a path to a buffer, converting a relative path to an
418 * absolute one in the process. Symbolic links are not
419 * resolved.
420 */
421extern void strbuf_add_absolute_path(struct strbuf *sb, const char *path);
422
423/**
424 * Strip whitespace from a buffer. The second parameter controls if
425 * comments are considered contents to be removed or not.
426 */
427extern void stripspace(struct strbuf *buf, int skip_comments);
428
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429static inline int strbuf_strip_suffix(struct strbuf *sb, const char *suffix)
430{
431 if (strip_suffix_mem(sb->buf, &sb->len, suffix)) {
432 strbuf_setlen(sb, sb->len);
433 return 1;
434 } else
435 return 0;
436}
437
6afbbdda 438/**
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439 * Split str (of length slen) at the specified terminator character.
440 * Return a null-terminated array of pointers to strbuf objects
441 * holding the substrings. The substrings include the terminator,
442 * except for the last substring, which might be unterminated if the
443 * original string did not end with a terminator. If max is positive,
444 * then split the string into at most max substrings (with the last
445 * substring containing everything following the (max-1)th terminator
446 * character).
447 *
448 * For lighter-weight alternatives, see string_list_split() and
449 * string_list_split_in_place().
450 */
2f1d9e2b 451extern struct strbuf **strbuf_split_buf(const char *, size_t,
17b73dc6 452 int terminator, int max);
06379a65 453
6afbbdda 454/**
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455 * Split a NUL-terminated string at the specified terminator
456 * character. See strbuf_split_buf() for more information.
457 */
2f1d9e2b 458static inline struct strbuf **strbuf_split_str(const char *str,
17b73dc6 459 int terminator, int max)
2f1d9e2b 460{
17b73dc6 461 return strbuf_split_buf(str, strlen(str), terminator, max);
2f1d9e2b 462}
06379a65 463
6afbbdda 464/**
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465 * Split a strbuf at the specified terminator character. See
466 * strbuf_split_buf() for more information.
467 */
2f1d9e2b 468static inline struct strbuf **strbuf_split_max(const struct strbuf *sb,
17b73dc6 469 int terminator, int max)
2f1d9e2b 470{
17b73dc6 471 return strbuf_split_buf(sb->buf, sb->len, terminator, max);
2f1d9e2b 472}
06379a65 473
6afbbdda 474/**
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475 * Split a strbuf at the specified terminator character. See
476 * strbuf_split_buf() for more information.
477 */
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478static inline struct strbuf **strbuf_split(const struct strbuf *sb,
479 int terminator)
28fc3a68 480{
17b73dc6 481 return strbuf_split_max(sb, terminator, 0);
28fc3a68 482}
06379a65 483
6afbbdda 484/**
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485 * Free a NULL-terminated list of strbufs (for example, the return
486 * values of the strbuf_split*() functions).
487 */
eacd6dc5 488extern void strbuf_list_free(struct strbuf **);
f1696ee3 489
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490/**
491 * Launch the user preferred editor to edit a file and fill the buffer
492 * with the file's contents upon the user completing their editing. The
493 * third argument can be used to set the environment which the editor is
494 * run in. If the buffer is NULL the editor is launched as usual but the
495 * file's contents are not read into the buffer upon completion.
496 */
497extern int launch_editor(const char *path, struct strbuf *buffer, const char *const *env);
b449f4cf 498
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499extern void strbuf_add_lines(struct strbuf *sb, const char *prefix, const char *buf, size_t size);
500
6afbbdda 501/**
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502 * Append s to sb, with the characters '<', '>', '&' and '"' converted
503 * into XML entities.
504 */
505extern void strbuf_addstr_xml_quoted(struct strbuf *sb, const char *s);
506
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507static inline void strbuf_complete_line(struct strbuf *sb)
508{
509 if (sb->len && sb->buf[sb->len - 1] != '\n')
510 strbuf_addch(sb, '\n');
511}
512
a552de75 513extern int strbuf_branchname(struct strbuf *sb, const char *name);
a2fab531 514extern int strbuf_check_branch_ref(struct strbuf *sb, const char *name);
a552de75 515
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516extern void strbuf_addstr_urlencode(struct strbuf *, const char *,
517 int reserved);
679eebe2 518
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519__attribute__((format (printf,1,2)))
520extern int printf_ln(const char *fmt, ...);
521__attribute__((format (printf,2,3)))
522extern int fprintf_ln(FILE *fp, const char *fmt, ...);
523
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524char *xstrdup_tolower(const char *);
525
6afbbdda 526/**
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527 * Create a newly allocated string using printf format. You can do this easily
528 * with a strbuf, but this provides a shortcut to save a few lines.
529 */
530__attribute__((format (printf, 1, 0)))
531char *xstrvfmt(const char *fmt, va_list ap);
532__attribute__((format (printf, 1, 2)))
533char *xstrfmt(const char *fmt, ...);
534
d1df5743 535#endif /* STRBUF_H */