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  1. #ifndef STRBUF_H
  2. #define STRBUF_H
  3. /**
  4. * strbuf's are meant to be used with all the usual C string and memory
  5. * APIs. Given that the length of the buffer is known, it's often better to
  6. * use the mem* functions than a str* one (memchr vs. strchr e.g.).
  7. * Though, one has to be careful about the fact that str* functions often
  8. * stop on NULs and that strbufs may have embedded NULs.
  9. *
  10. * A strbuf is NUL terminated for convenience, but no function in the
  11. * strbuf API actually relies on the string being free of NULs.
  12. *
  13. * strbufs have some invariants that are very important to keep in mind:
  14. *
  15. * - The `buf` member is never NULL, so it can be used in any usual C
  16. * string operations safely. strbuf's _have_ to be initialized either by
  17. * `strbuf_init()` or by `= STRBUF_INIT` before the invariants, though.
  18. *
  19. * Do *not* assume anything on what `buf` really is (e.g. if it is
  20. * allocated memory or not), use `strbuf_detach()` to unwrap a memory
  21. * buffer from its strbuf shell in a safe way. That is the sole supported
  22. * way. This will give you a malloced buffer that you can later `free()`.
  23. *
  24. * However, it is totally safe to modify anything in the string pointed by
  25. * the `buf` member, between the indices `0` and `len-1` (inclusive).
  26. *
  27. * - The `buf` member is a byte array that has at least `len + 1` bytes
  28. * allocated. The extra byte is used to store a `'\0'`, allowing the
  29. * `buf` member to be a valid C-string. Every strbuf function ensure this
  30. * invariant is preserved.
  31. *
  32. * NOTE: It is OK to "play" with the buffer directly if you work it this
  33. * way:
  34. *
  35. * strbuf_grow(sb, SOME_SIZE); <1>
  36. * strbuf_setlen(sb, sb->len + SOME_OTHER_SIZE);
  37. *
  38. * <1> Here, the memory array starting at `sb->buf`, and of length
  39. * `strbuf_avail(sb)` is all yours, and you can be sure that
  40. * `strbuf_avail(sb)` is at least `SOME_SIZE`.
  41. *
  42. * NOTE: `SOME_OTHER_SIZE` must be smaller or equal to `strbuf_avail(sb)`.
  43. *
  44. * Doing so is safe, though if it has to be done in many places, adding the
  45. * missing API to the strbuf module is the way to go.
  46. *
  47. * WARNING: Do _not_ assume that the area that is yours is of size `alloc
  48. * - 1` even if it's true in the current implementation. Alloc is somehow a
  49. * "private" member that should not be messed with. Use `strbuf_avail()`
  50. * instead.
  51. */
  52. /**
  53. * Data Structures
  54. * ---------------
  55. */
  56. /**
  57. * This is the string buffer structure. The `len` member can be used to
  58. * determine the current length of the string, and `buf` member provides
  59. * access to the string itself.
  60. */
  61. struct strbuf {
  62. size_t alloc;
  63. size_t len;
  64. char *buf;
  65. };
  66. extern char strbuf_slopbuf[];
  67. #define STRBUF_INIT { 0, 0, strbuf_slopbuf }
  68. /**
  69. * Life Cycle Functions
  70. * --------------------
  71. */
  72. /**
  73. * Initialize the structure. The second parameter can be zero or a bigger
  74. * number to allocate memory, in case you want to prevent further reallocs.
  75. */
  76. extern void strbuf_init(struct strbuf *, size_t);
  77. /**
  78. * Release a string buffer and the memory it used. You should not use the
  79. * string buffer after using this function, unless you initialize it again.
  80. */
  81. extern void strbuf_release(struct strbuf *);
  82. /**
  83. * Detach the string from the strbuf and returns it; you now own the
  84. * storage the string occupies and it is your responsibility from then on
  85. * to release it with `free(3)` when you are done with it.
  86. */
  87. extern char *strbuf_detach(struct strbuf *, size_t *);
  88. /**
  89. * Attach a string to a buffer. You should specify the string to attach,
  90. * the current length of the string and the amount of allocated memory.
  91. * The amount must be larger than the string length, because the string you
  92. * pass is supposed to be a NUL-terminated string. This string _must_ be
  93. * malloc()ed, and after attaching, the pointer cannot be relied upon
  94. * anymore, and neither be free()d directly.
  95. */
  96. extern void strbuf_attach(struct strbuf *, void *, size_t, size_t);
  97. /**
  98. * Swap the contents of two string buffers.
  99. */
  100. static inline void strbuf_swap(struct strbuf *a, struct strbuf *b)
  101. {
  102. struct strbuf tmp = *a;
  103. *a = *b;
  104. *b = tmp;
  105. }
  106. /**
  107. * Functions related to the size of the buffer
  108. * -------------------------------------------
  109. */
  110. /**
  111. * Determine the amount of allocated but unused memory.
  112. */
  113. static inline size_t strbuf_avail(const struct strbuf *sb)
  114. {
  115. return sb->alloc ? sb->alloc - sb->len - 1 : 0;
  116. }
  117. /**
  118. * Ensure that at least this amount of unused memory is available after
  119. * `len`. This is used when you know a typical size for what you will add
  120. * and want to avoid repetitive automatic resizing of the underlying buffer.
  121. * This is never a needed operation, but can be critical for performance in
  122. * some cases.
  123. */
  124. extern void strbuf_grow(struct strbuf *, size_t);
  125. /**
  126. * Set the length of the buffer to a given value. This function does *not*
  127. * allocate new memory, so you should not perform a `strbuf_setlen()` to a
  128. * length that is larger than `len + strbuf_avail()`. `strbuf_setlen()` is
  129. * just meant as a 'please fix invariants from this strbuf I just messed
  130. * with'.
  131. */
  132. static inline void strbuf_setlen(struct strbuf *sb, size_t len)
  133. {
  134. if (len > (sb->alloc ? sb->alloc - 1 : 0))
  135. die("BUG: strbuf_setlen() beyond buffer");
  136. sb->len = len;
  137. sb->buf[len] = '\0';
  138. }
  139. /**
  140. * Empty the buffer by setting the size of it to zero.
  141. */
  142. #define strbuf_reset(sb) strbuf_setlen(sb, 0)
  143. /**
  144. * Functions related to the contents of the buffer
  145. * -----------------------------------------------
  146. */
  147. /**
  148. * Strip whitespace from the beginning (`ltrim`), end (`rtrim`), or both side
  149. * (`trim`) of a string.
  150. */
  151. extern void strbuf_trim(struct strbuf *);
  152. extern void strbuf_rtrim(struct strbuf *);
  153. extern void strbuf_ltrim(struct strbuf *);
  154. /**
  155. * Replace the contents of the strbuf with a reencoded form. Returns -1
  156. * on error, 0 on success.
  157. */
  158. extern int strbuf_reencode(struct strbuf *sb, const char *from, const char *to);
  159. /**
  160. * Lowercase each character in the buffer using `tolower`.
  161. */
  162. extern void strbuf_tolower(struct strbuf *sb);
  163. /**
  164. * Compare two buffers. Returns an integer less than, equal to, or greater
  165. * than zero if the first buffer is found, respectively, to be less than,
  166. * to match, or be greater than the second buffer.
  167. */
  168. extern int strbuf_cmp(const struct strbuf *, const struct strbuf *);
  169. /**
  170. * Adding data to the buffer
  171. * -------------------------
  172. *
  173. * NOTE: All of the functions in this section will grow the buffer as
  174. * necessary. If they fail for some reason other than memory shortage and the
  175. * buffer hadn't been allocated before (i.e. the `struct strbuf` was set to
  176. * `STRBUF_INIT`), then they will free() it.
  177. */
  178. /**
  179. * Add a single character to the buffer.
  180. */
  181. static inline void strbuf_addch(struct strbuf *sb, int c)
  182. {
  183. if (!strbuf_avail(sb))
  184. strbuf_grow(sb, 1);
  185. sb->buf[sb->len++] = c;
  186. sb->buf[sb->len] = '\0';
  187. }
  188. /**
  189. * Add a character the specified number of times to the buffer.
  190. */
  191. extern void strbuf_addchars(struct strbuf *sb, int c, size_t n);
  192. /**
  193. * Insert data to the given position of the buffer. The remaining contents
  194. * will be shifted, not overwritten.
  195. */
  196. extern void strbuf_insert(struct strbuf *, size_t pos, const void *, size_t);
  197. /**
  198. * Remove given amount of data from a given position of the buffer.
  199. */
  200. extern void strbuf_remove(struct strbuf *, size_t pos, size_t len);
  201. /**
  202. * Remove the bytes between `pos..pos+len` and replace it with the given
  203. * data.
  204. */
  205. extern void strbuf_splice(struct strbuf *, size_t pos, size_t len,
  206. const void *, size_t);
  207. /**
  208. * Add a NUL-terminated string to the buffer. Each line will be prepended
  209. * by a comment character and a blank.
  210. */
  211. extern void strbuf_add_commented_lines(struct strbuf *out, const char *buf, size_t size);
  212. /**
  213. * Add data of given length to the buffer.
  214. */
  215. extern void strbuf_add(struct strbuf *, const void *, size_t);
  216. /**
  217. * Add a NUL-terminated string to the buffer.
  218. *
  219. * NOTE: This function will *always* be implemented as an inline or a macro
  220. * using strlen, meaning that this is efficient to write things like:
  221. *
  222. * strbuf_addstr(sb, "immediate string");
  223. *
  224. */
  225. static inline void strbuf_addstr(struct strbuf *sb, const char *s)
  226. {
  227. strbuf_add(sb, s, strlen(s));
  228. }
  229. /**
  230. * Copy the contents of another buffer at the end of the current one.
  231. */
  232. static inline void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2)
  233. {
  234. strbuf_grow(sb, sb2->len);
  235. strbuf_add(sb, sb2->buf, sb2->len);
  236. }
  237. /**
  238. * Copy part of the buffer from a given position till a given length to the
  239. * end of the buffer.
  240. */
  241. extern void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len);
  242. /**
  243. * This function can be used to expand a format string containing
  244. * placeholders. To that end, it parses the string and calls the specified
  245. * function for every percent sign found.
  246. *
  247. * The callback function is given a pointer to the character after the `%`
  248. * and a pointer to the struct strbuf. It is expected to add the expanded
  249. * version of the placeholder to the strbuf, e.g. to add a newline
  250. * character if the letter `n` appears after a `%`. The function returns
  251. * the length of the placeholder recognized and `strbuf_expand()` skips
  252. * over it.
  253. *
  254. * The format `%%` is automatically expanded to a single `%` as a quoting
  255. * mechanism; callers do not need to handle the `%` placeholder themselves,
  256. * and the callback function will not be invoked for this placeholder.
  257. *
  258. * All other characters (non-percent and not skipped ones) are copied
  259. * verbatim to the strbuf. If the callback returned zero, meaning that the
  260. * placeholder is unknown, then the percent sign is copied, too.
  261. *
  262. * In order to facilitate caching and to make it possible to give
  263. * parameters to the callback, `strbuf_expand()` passes a context pointer,
  264. * which can be used by the programmer of the callback as she sees fit.
  265. */
  266. typedef size_t (*expand_fn_t) (struct strbuf *sb, const char *placeholder, void *context);
  267. extern void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn, void *context);
  268. /**
  269. * Used as callback for `strbuf_expand()`, expects an array of
  270. * struct strbuf_expand_dict_entry as context, i.e. pairs of
  271. * placeholder and replacement string. The array needs to be
  272. * terminated by an entry with placeholder set to NULL.
  273. */
  274. struct strbuf_expand_dict_entry {
  275. const char *placeholder;
  276. const char *value;
  277. };
  278. extern size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder, void *context);
  279. /**
  280. * Append the contents of one strbuf to another, quoting any
  281. * percent signs ("%") into double-percents ("%%") in the
  282. * destination. This is useful for literal data to be fed to either
  283. * strbuf_expand or to the *printf family of functions.
  284. */
  285. extern void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src);
  286. /**
  287. * Append the given byte size as a human-readable string (i.e. 12.23 KiB,
  288. * 3.50 MiB).
  289. */
  290. extern void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes);
  291. /**
  292. * Add a formatted string to the buffer.
  293. */
  294. __attribute__((format (printf,2,3)))
  295. extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...);
  296. /**
  297. * Add a formatted string prepended by a comment character and a
  298. * blank to the buffer.
  299. */
  300. __attribute__((format (printf, 2, 3)))
  301. extern void strbuf_commented_addf(struct strbuf *sb, const char *fmt, ...);
  302. __attribute__((format (printf,2,0)))
  303. extern void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap);
  304. /**
  305. * Add the time specified by `tm`, as formatted by `strftime`.
  306. */
  307. extern void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm);
  308. /**
  309. * Read a given size of data from a FILE* pointer to the buffer.
  310. *
  311. * NOTE: The buffer is rewound if the read fails. If -1 is returned,
  312. * `errno` must be consulted, like you would do for `read(3)`.
  313. * `strbuf_read()`, `strbuf_read_file()` and `strbuf_getline_*()`
  314. * family of functions have the same behaviour as well.
  315. */
  316. extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
  317. /**
  318. * Read the contents of a given file descriptor. The third argument can be
  319. * used to give a hint about the file size, to avoid reallocs. If read fails,
  320. * any partial read is undone.
  321. */
  322. extern ssize_t strbuf_read(struct strbuf *, int fd, size_t hint);
  323. /**
  324. * Read the contents of a given file descriptor partially by using only one
  325. * attempt of xread. The third argument can be used to give a hint about the
  326. * file size, to avoid reallocs. Returns the number of new bytes appended to
  327. * the sb.
  328. */
  329. extern ssize_t strbuf_read_once(struct strbuf *, int fd, size_t hint);
  330. /**
  331. * Read the contents of a file, specified by its path. The third argument
  332. * can be used to give a hint about the file size, to avoid reallocs.
  333. */
  334. extern ssize_t strbuf_read_file(struct strbuf *sb, const char *path, size_t hint);
  335. /**
  336. * Read the target of a symbolic link, specified by its path. The third
  337. * argument can be used to give a hint about the size, to avoid reallocs.
  338. */
  339. extern int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint);
  340. /**
  341. * Read a line from a FILE *, overwriting the existing contents of
  342. * the strbuf. The strbuf_getline*() family of functions share
  343. * this signature, but have different line termination conventions.
  344. *
  345. * Reading stops after the terminator or at EOF. The terminator
  346. * is removed from the buffer before returning. Returns 0 unless
  347. * there was nothing left before EOF, in which case it returns `EOF`.
  348. */
  349. typedef int (*strbuf_getline_fn)(struct strbuf *, FILE *);
  350. /* Uses LF as the line terminator */
  351. extern int strbuf_getline_lf(struct strbuf *sb, FILE *fp);
  352. /* Uses NUL as the line terminator */
  353. extern int strbuf_getline_nul(struct strbuf *sb, FILE *fp);
  354. /*
  355. * Similar to strbuf_getline_lf(), but additionally treats a CR that
  356. * comes immediately before the LF as part of the terminator.
  357. * This is the most friendly version to be used to read "text" files
  358. * that can come from platforms whose native text format is CRLF
  359. * terminated.
  360. */
  361. extern int strbuf_getline(struct strbuf *, FILE *);
  362. /**
  363. * Like `strbuf_getline`, but keeps the trailing terminator (if
  364. * any) in the buffer.
  365. */
  366. extern int strbuf_getwholeline(struct strbuf *, FILE *, int);
  367. /**
  368. * Like `strbuf_getwholeline`, but operates on a file descriptor.
  369. * It reads one character at a time, so it is very slow. Do not
  370. * use it unless you need the correct position in the file
  371. * descriptor.
  372. */
  373. extern int strbuf_getwholeline_fd(struct strbuf *, int, int);
  374. /**
  375. * Set the buffer to the path of the current working directory.
  376. */
  377. extern int strbuf_getcwd(struct strbuf *sb);
  378. /**
  379. * Add a path to a buffer, converting a relative path to an
  380. * absolute one in the process. Symbolic links are not
  381. * resolved.
  382. */
  383. extern void strbuf_add_absolute_path(struct strbuf *sb, const char *path);
  384. /**
  385. * Strip whitespace from a buffer. The second parameter controls if
  386. * comments are considered contents to be removed or not.
  387. */
  388. extern void strbuf_stripspace(struct strbuf *buf, int skip_comments);
  389. /**
  390. * Temporary alias until all topic branches have switched to use
  391. * strbuf_stripspace directly.
  392. */
  393. static inline void stripspace(struct strbuf *buf, int skip_comments)
  394. {
  395. strbuf_stripspace(buf, skip_comments);
  396. }
  397. static inline int strbuf_strip_suffix(struct strbuf *sb, const char *suffix)
  398. {
  399. if (strip_suffix_mem(sb->buf, &sb->len, suffix)) {
  400. strbuf_setlen(sb, sb->len);
  401. return 1;
  402. } else
  403. return 0;
  404. }
  405. /**
  406. * Split str (of length slen) at the specified terminator character.
  407. * Return a null-terminated array of pointers to strbuf objects
  408. * holding the substrings. The substrings include the terminator,
  409. * except for the last substring, which might be unterminated if the
  410. * original string did not end with a terminator. If max is positive,
  411. * then split the string into at most max substrings (with the last
  412. * substring containing everything following the (max-1)th terminator
  413. * character).
  414. *
  415. * The most generic form is `strbuf_split_buf`, which takes an arbitrary
  416. * pointer/len buffer. The `_str` variant takes a NUL-terminated string,
  417. * the `_max` variant takes a strbuf, and just `strbuf_split` is a convenience
  418. * wrapper to drop the `max` parameter.
  419. *
  420. * For lighter-weight alternatives, see string_list_split() and
  421. * string_list_split_in_place().
  422. */
  423. extern struct strbuf **strbuf_split_buf(const char *, size_t,
  424. int terminator, int max);
  425. static inline struct strbuf **strbuf_split_str(const char *str,
  426. int terminator, int max)
  427. {
  428. return strbuf_split_buf(str, strlen(str), terminator, max);
  429. }
  430. static inline struct strbuf **strbuf_split_max(const struct strbuf *sb,
  431. int terminator, int max)
  432. {
  433. return strbuf_split_buf(sb->buf, sb->len, terminator, max);
  434. }
  435. static inline struct strbuf **strbuf_split(const struct strbuf *sb,
  436. int terminator)
  437. {
  438. return strbuf_split_max(sb, terminator, 0);
  439. }
  440. /**
  441. * Free a NULL-terminated list of strbufs (for example, the return
  442. * values of the strbuf_split*() functions).
  443. */
  444. extern void strbuf_list_free(struct strbuf **);
  445. /**
  446. * Add the abbreviation, as generated by find_unique_abbrev, of `sha1` to
  447. * the strbuf `sb`.
  448. */
  449. extern void strbuf_add_unique_abbrev(struct strbuf *sb,
  450. const unsigned char *sha1,
  451. int abbrev_len);
  452. /**
  453. * Launch the user preferred editor to edit a file and fill the buffer
  454. * with the file's contents upon the user completing their editing. The
  455. * third argument can be used to set the environment which the editor is
  456. * run in. If the buffer is NULL the editor is launched as usual but the
  457. * file's contents are not read into the buffer upon completion.
  458. */
  459. extern int launch_editor(const char *path, struct strbuf *buffer, const char *const *env);
  460. extern void strbuf_add_lines(struct strbuf *sb, const char *prefix, const char *buf, size_t size);
  461. /**
  462. * Append s to sb, with the characters '<', '>', '&' and '"' converted
  463. * into XML entities.
  464. */
  465. extern void strbuf_addstr_xml_quoted(struct strbuf *sb, const char *s);
  466. /**
  467. * "Complete" the contents of `sb` by ensuring that either it ends with the
  468. * character `term`, or it is empty. This can be used, for example,
  469. * to ensure that text ends with a newline, but without creating an empty
  470. * blank line if there is no content in the first place.
  471. */
  472. static inline void strbuf_complete(struct strbuf *sb, char term)
  473. {
  474. if (sb->len && sb->buf[sb->len - 1] != term)
  475. strbuf_addch(sb, term);
  476. }
  477. static inline void strbuf_complete_line(struct strbuf *sb)
  478. {
  479. strbuf_complete(sb, '\n');
  480. }
  481. extern int strbuf_branchname(struct strbuf *sb, const char *name);
  482. extern int strbuf_check_branch_ref(struct strbuf *sb, const char *name);
  483. extern void strbuf_addstr_urlencode(struct strbuf *, const char *,
  484. int reserved);
  485. __attribute__((format (printf,1,2)))
  486. extern int printf_ln(const char *fmt, ...);
  487. __attribute__((format (printf,2,3)))
  488. extern int fprintf_ln(FILE *fp, const char *fmt, ...);
  489. char *xstrdup_tolower(const char *);
  490. /**
  491. * Create a newly allocated string using printf format. You can do this easily
  492. * with a strbuf, but this provides a shortcut to save a few lines.
  493. */
  494. __attribute__((format (printf, 1, 0)))
  495. char *xstrvfmt(const char *fmt, va_list ap);
  496. __attribute__((format (printf, 1, 2)))
  497. char *xstrfmt(const char *fmt, ...);
  498. #endif /* STRBUF_H */