diff options
Diffstat (limited to 'strbuf.h')
| -rw-r--r-- | strbuf.h | 467 |
1 files changed, 399 insertions, 68 deletions
@@ -1,22 +1,112 @@ #ifndef STRBUF_H #define STRBUF_H -/* See Documentation/technical/api-strbuf.txt */ +/** + * strbuf's are meant to be used with all the usual C string and memory + * APIs. Given that the length of the buffer is known, it's often better to + * use the mem* functions than a str* one (memchr vs. strchr e.g.). + * Though, one has to be careful about the fact that str* functions often + * stop on NULs and that strbufs may have embedded NULs. + * + * A strbuf is NUL terminated for convenience, but no function in the + * strbuf API actually relies on the string being free of NULs. + * + * strbufs have some invariants that are very important to keep in mind: + * + * - The `buf` member is never NULL, so it can be used in any usual C + * string operations safely. strbuf's _have_ to be initialized either by + * `strbuf_init()` or by `= STRBUF_INIT` before the invariants, though. + * + * Do *not* assume anything on what `buf` really is (e.g. if it is + * allocated memory or not), use `strbuf_detach()` to unwrap a memory + * buffer from its strbuf shell in a safe way. That is the sole supported + * way. This will give you a malloced buffer that you can later `free()`. + * + * However, it is totally safe to modify anything in the string pointed by + * the `buf` member, between the indices `0` and `len-1` (inclusive). + * + * - The `buf` member is a byte array that has at least `len + 1` bytes + * allocated. The extra byte is used to store a `'\0'`, allowing the + * `buf` member to be a valid C-string. Every strbuf function ensure this + * invariant is preserved. + * + * NOTE: It is OK to "play" with the buffer directly if you work it this + * way: + * + * strbuf_grow(sb, SOME_SIZE); <1> + * strbuf_setlen(sb, sb->len + SOME_OTHER_SIZE); + * + * <1> Here, the memory array starting at `sb->buf`, and of length + * `strbuf_avail(sb)` is all yours, and you can be sure that + * `strbuf_avail(sb)` is at least `SOME_SIZE`. + * + * NOTE: `SOME_OTHER_SIZE` must be smaller or equal to `strbuf_avail(sb)`. + * + * Doing so is safe, though if it has to be done in many places, adding the + * missing API to the strbuf module is the way to go. + * + * WARNING: Do _not_ assume that the area that is yours is of size `alloc + * - 1` even if it's true in the current implementation. Alloc is somehow a + * "private" member that should not be messed with. Use `strbuf_avail()` + * instead. +*/ -extern char strbuf_slopbuf[]; +/** + * Data Structures + * --------------- + */ + +/** + * This is the string buffer structure. The `len` member can be used to + * determine the current length of the string, and `buf` member provides + * access to the string itself. + */ struct strbuf { size_t alloc; size_t len; char *buf; }; +extern char strbuf_slopbuf[]; #define STRBUF_INIT { 0, 0, strbuf_slopbuf } -/*----- strbuf life cycle -----*/ +/** + * Life Cycle Functions + * -------------------- + */ + +/** + * Initialize the structure. The second parameter can be zero or a bigger + * number to allocate memory, in case you want to prevent further reallocs. + */ extern void strbuf_init(struct strbuf *, size_t); + +/** + * Release a string buffer and the memory it used. You should not use the + * string buffer after using this function, unless you initialize it again. + */ extern void strbuf_release(struct strbuf *); + +/** + * Detach the string from the strbuf and returns it; you now own the + * storage the string occupies and it is your responsibility from then on + * to release it with `free(3)` when you are done with it. + */ extern char *strbuf_detach(struct strbuf *, size_t *); + +/** + * Attach a string to a buffer. You should specify the string to attach, + * the current length of the string and the amount of allocated memory. + * The amount must be larger than the string length, because the string you + * pass is supposed to be a NUL-terminated string. This string _must_ be + * malloc()ed, and after attaching, the pointer cannot be relied upon + * anymore, and neither be free()d directly. + */ extern void strbuf_attach(struct strbuf *, void *, size_t, size_t); + +/** + * Swap the contents of two string buffers. + */ static inline void strbuf_swap(struct strbuf *a, struct strbuf *b) { struct strbuf tmp = *a; @@ -24,14 +114,36 @@ static inline void strbuf_swap(struct strbuf *a, struct strbuf *b) *b = tmp; } -/*----- strbuf size related -----*/ + +/** + * Functions related to the size of the buffer + * ------------------------------------------- + */ + +/** + * Determine the amount of allocated but unused memory. + */ static inline size_t strbuf_avail(const struct strbuf *sb) { return sb->alloc ? sb->alloc - sb->len - 1 : 0; } +/** + * Ensure that at least this amount of unused memory is available after + * `len`. This is used when you know a typical size for what you will add + * and want to avoid repetitive automatic resizing of the underlying buffer. + * This is never a needed operation, but can be critical for performance in + * some cases. + */ extern void strbuf_grow(struct strbuf *, size_t); +/** + * Set the length of the buffer to a given value. This function does *not* + * allocate new memory, so you should not perform a `strbuf_setlen()` to a + * length that is larger than `len + strbuf_avail()`. `strbuf_setlen()` is + * just meant as a 'please fix invariants from this strbuf I just messed + * with'. + */ static inline void strbuf_setlen(struct strbuf *sb, size_t len) { if (len > (sb->alloc ? sb->alloc - 1 : 0)) @@ -39,114 +151,336 @@ static inline void strbuf_setlen(struct strbuf *sb, size_t len) sb->len = len; sb->buf[len] = '\0'; } + +/** + * Empty the buffer by setting the size of it to zero. + */ #define strbuf_reset(sb) strbuf_setlen(sb, 0) -/*----- content related -----*/ + +/** + * Functions related to the contents of the buffer + * ----------------------------------------------- + */ + +/** + * Strip whitespace from the beginning (`ltrim`), end (`rtrim`), or both side + * (`trim`) of a string. + */ extern void strbuf_trim(struct strbuf *); extern void strbuf_rtrim(struct strbuf *); extern void strbuf_ltrim(struct strbuf *); -extern int strbuf_cmp(const struct strbuf *, const struct strbuf *); -/* - * Split str (of length slen) at the specified terminator character. - * Return a null-terminated array of pointers to strbuf objects - * holding the substrings. The substrings include the terminator, - * except for the last substring, which might be unterminated if the - * original string did not end with a terminator. If max is positive, - * then split the string into at most max substrings (with the last - * substring containing everything following the (max-1)th terminator - * character). - * - * For lighter-weight alternatives, see string_list_split() and - * string_list_split_in_place(). +/** + * Replace the contents of the strbuf with a reencoded form. Returns -1 + * on error, 0 on success. */ -extern struct strbuf **strbuf_split_buf(const char *, size_t, - int terminator, int max); +extern int strbuf_reencode(struct strbuf *sb, const char *from, const char *to); -/* - * Split a NUL-terminated string at the specified terminator - * character. See strbuf_split_buf() for more information. +/** + * Lowercase each character in the buffer using `tolower`. */ -static inline struct strbuf **strbuf_split_str(const char *str, - int terminator, int max) -{ - return strbuf_split_buf(str, strlen(str), terminator, max); -} +extern void strbuf_tolower(struct strbuf *sb); -/* - * Split a strbuf at the specified terminator character. See - * strbuf_split_buf() for more information. +/** + * Compare two buffers. Returns an integer less than, equal to, or greater + * than zero if the first buffer is found, respectively, to be less than, + * to match, or be greater than the second buffer. */ -static inline struct strbuf **strbuf_split_max(const struct strbuf *sb, - int terminator, int max) -{ - return strbuf_split_buf(sb->buf, sb->len, terminator, max); -} +extern int strbuf_cmp(const struct strbuf *, const struct strbuf *); -/* - * Split a strbuf at the specified terminator character. See - * strbuf_split_buf() for more information. - */ -static inline struct strbuf **strbuf_split(const struct strbuf *sb, - int terminator) -{ - return strbuf_split_max(sb, terminator, 0); -} -/* - * Free a NULL-terminated list of strbufs (for example, the return - * values of the strbuf_split*() functions). +/** + * Adding data to the buffer + * ------------------------- + * + * NOTE: All of the functions in this section will grow the buffer as + * necessary. If they fail for some reason other than memory shortage and the + * buffer hadn't been allocated before (i.e. the `struct strbuf` was set to + * `STRBUF_INIT`), then they will free() it. */ -extern void strbuf_list_free(struct strbuf **); -/*----- add data in your buffer -----*/ +/** + * Add a single character to the buffer. + */ static inline void strbuf_addch(struct strbuf *sb, int c) { - strbuf_grow(sb, 1); + if (!strbuf_avail(sb)) + strbuf_grow(sb, 1); sb->buf[sb->len++] = c; sb->buf[sb->len] = '\0'; } +/** + * Add a character the specified number of times to the buffer. + */ +extern void strbuf_addchars(struct strbuf *sb, int c, size_t n); + +/** + * Insert data to the given position of the buffer. The remaining contents + * will be shifted, not overwritten. + */ extern void strbuf_insert(struct strbuf *, size_t pos, const void *, size_t); + +/** + * Remove given amount of data from a given position of the buffer. + */ extern void strbuf_remove(struct strbuf *, size_t pos, size_t len); -/* splice pos..pos+len with given data */ +/** + * Remove the bytes between `pos..pos+len` and replace it with the given + * data. + */ extern void strbuf_splice(struct strbuf *, size_t pos, size_t len, - const void *, size_t); + const void *, size_t); +/** + * Add a NUL-terminated string to the buffer. Each line will be prepended + * by a comment character and a blank. + */ extern void strbuf_add_commented_lines(struct strbuf *out, const char *buf, size_t size); + +/** + * Add data of given length to the buffer. + */ extern void strbuf_add(struct strbuf *, const void *, size_t); + +/** + * Add a NUL-terminated string to the buffer. + * + * NOTE: This function will *always* be implemented as an inline or a macro + * using strlen, meaning that this is efficient to write things like: + * + * strbuf_addstr(sb, "immediate string"); + * + */ static inline void strbuf_addstr(struct strbuf *sb, const char *s) { strbuf_add(sb, s, strlen(s)); } + +/** + * Copy the contents of another buffer at the end of the current one. + */ static inline void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2) { strbuf_grow(sb, sb2->len); strbuf_add(sb, sb2->buf, sb2->len); } + +/** + * Copy part of the buffer from a given position till a given length to the + * end of the buffer. + */ extern void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len); +/** + * This function can be used to expand a format string containing + * placeholders. To that end, it parses the string and calls the specified + * function for every percent sign found. + * + * The callback function is given a pointer to the character after the `%` + * and a pointer to the struct strbuf. It is expected to add the expanded + * version of the placeholder to the strbuf, e.g. to add a newline + * character if the letter `n` appears after a `%`. The function returns + * the length of the placeholder recognized and `strbuf_expand()` skips + * over it. + * + * The format `%%` is automatically expanded to a single `%` as a quoting + * mechanism; callers do not need to handle the `%` placeholder themselves, + * and the callback function will not be invoked for this placeholder. + * + * All other characters (non-percent and not skipped ones) are copied + * verbatim to the strbuf. If the callback returned zero, meaning that the + * placeholder is unknown, then the percent sign is copied, too. + * + * In order to facilitate caching and to make it possible to give + * parameters to the callback, `strbuf_expand()` passes a context pointer, + * which can be used by the programmer of the callback as she sees fit. + */ typedef size_t (*expand_fn_t) (struct strbuf *sb, const char *placeholder, void *context); extern void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn, void *context); + +/** + * Used as callback for `strbuf_expand()`, expects an array of + * struct strbuf_expand_dict_entry as context, i.e. pairs of + * placeholder and replacement string. The array needs to be + * terminated by an entry with placeholder set to NULL. + */ struct strbuf_expand_dict_entry { const char *placeholder; const char *value; }; extern size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder, void *context); + +/** + * Append the contents of one strbuf to another, quoting any + * percent signs ("%") into double-percents ("%%") in the + * destination. This is useful for literal data to be fed to either + * strbuf_expand or to the *printf family of functions. + */ extern void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src); +/** + * Append the given byte size as a human-readable string (i.e. 12.23 KiB, + * 3.50 MiB). + */ +extern void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes); + +/** + * Add a formatted string to the buffer. + */ __attribute__((format (printf,2,3))) extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...); + +/** + * Add a formatted string prepended by a comment character and a + * blank to the buffer. + */ __attribute__((format (printf, 2, 3))) extern void strbuf_commented_addf(struct strbuf *sb, const char *fmt, ...); + __attribute__((format (printf,2,0))) extern void strbuf_vaddf(struct strbuf *sb, const char *fmt, va_list ap); +/** + * Read a given size of data from a FILE* pointer to the buffer. + * + * NOTE: The buffer is rewound if the read fails. If -1 is returned, + * `errno` must be consulted, like you would do for `read(3)`. + * `strbuf_read()`, `strbuf_read_file()` and `strbuf_getline()` has the + * same behaviour as well. + */ +extern size_t strbuf_fread(struct strbuf *, size_t, FILE *); + +/** + * Read the contents of a given file descriptor. The third argument can be + * used to give a hint about the file size, to avoid reallocs. If read fails, + * any partial read is undone. + */ +extern ssize_t strbuf_read(struct strbuf *, int fd, size_t hint); + +/** + * Read the contents of a file, specified by its path. The third argument + * can be used to give a hint about the file size, to avoid reallocs. + */ +extern int strbuf_read_file(struct strbuf *sb, const char *path, size_t hint); + +/** + * Read the target of a symbolic link, specified by its path. The third + * argument can be used to give a hint about the size, to avoid reallocs. + */ +extern int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint); + +/** + * Read a line from a FILE *, overwriting the existing contents + * of the strbuf. The second argument specifies the line + * terminator character, typically `'\n'`. + * Reading stops after the terminator or at EOF. The terminator + * is removed from the buffer before returning. Returns 0 unless + * there was nothing left before EOF, in which case it returns `EOF`. + */ +extern int strbuf_getline(struct strbuf *, FILE *, int); + +/** + * Like `strbuf_getline`, but keeps the trailing terminator (if + * any) in the buffer. + */ +extern int strbuf_getwholeline(struct strbuf *, FILE *, int); + +/** + * Like `strbuf_getwholeline`, but operates on a file descriptor. + * It reads one character at a time, so it is very slow. Do not + * use it unless you need the correct position in the file + * descriptor. + */ +extern int strbuf_getwholeline_fd(struct strbuf *, int, int); + +/** + * Set the buffer to the path of the current working directory. + */ +extern int strbuf_getcwd(struct strbuf *sb); + +/** + * Add a path to a buffer, converting a relative path to an + * absolute one in the process. Symbolic links are not + * resolved. + */ +extern void strbuf_add_absolute_path(struct strbuf *sb, const char *path); + +/** + * Strip whitespace from a buffer. The second parameter controls if + * comments are considered contents to be removed or not. + */ +extern void stripspace(struct strbuf *buf, int skip_comments); + +static inline int strbuf_strip_suffix(struct strbuf *sb, const char *suffix) +{ + if (strip_suffix_mem(sb->buf, &sb->len, suffix)) { + strbuf_setlen(sb, sb->len); + return 1; + } else + return 0; +} + +/** + * Split str (of length slen) at the specified terminator character. + * Return a null-terminated array of pointers to strbuf objects + * holding the substrings. The substrings include the terminator, + * except for the last substring, which might be unterminated if the + * original string did not end with a terminator. If max is positive, + * then split the string into at most max substrings (with the last + * substring containing everything following the (max-1)th terminator + * character). + * + * The most generic form is `strbuf_split_buf`, which takes an arbitrary + * pointer/len buffer. The `_str` variant takes a NUL-terminated string, + * the `_max` variant takes a strbuf, and just `strbuf_split` is a convenience + * wrapper to drop the `max` parameter. + * + * For lighter-weight alternatives, see string_list_split() and + * string_list_split_in_place(). + */ +extern struct strbuf **strbuf_split_buf(const char *, size_t, + int terminator, int max); + +static inline struct strbuf **strbuf_split_str(const char *str, + int terminator, int max) +{ + return strbuf_split_buf(str, strlen(str), terminator, max); +} + +static inline struct strbuf **strbuf_split_max(const struct strbuf *sb, + int terminator, int max) +{ + return strbuf_split_buf(sb->buf, sb->len, terminator, max); +} + +static inline struct strbuf **strbuf_split(const struct strbuf *sb, + int terminator) +{ + return strbuf_split_max(sb, terminator, 0); +} + +/** + * Free a NULL-terminated list of strbufs (for example, the return + * values of the strbuf_split*() functions). + */ +extern void strbuf_list_free(struct strbuf **); + +/** + * Launch the user preferred editor to edit a file and fill the buffer + * with the file's contents upon the user completing their editing. The + * third argument can be used to set the environment which the editor is + * run in. If the buffer is NULL the editor is launched as usual but the + * file's contents are not read into the buffer upon completion. + */ +extern int launch_editor(const char *path, struct strbuf *buffer, const char *const *env); + extern void strbuf_add_lines(struct strbuf *sb, const char *prefix, const char *buf, size_t size); -/* +/** * Append s to sb, with the characters '<', '>', '&' and '"' converted * into XML entities. */ @@ -158,29 +492,26 @@ static inline void strbuf_complete_line(struct strbuf *sb) strbuf_addch(sb, '\n'); } -extern size_t strbuf_fread(struct strbuf *, size_t, FILE *); -/* XXX: if read fails, any partial read is undone */ -extern ssize_t strbuf_read(struct strbuf *, int fd, size_t hint); -extern int strbuf_read_file(struct strbuf *sb, const char *path, size_t hint); -extern int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint); - -extern int strbuf_getwholeline(struct strbuf *, FILE *, int); -extern int strbuf_getline(struct strbuf *, FILE *, int); -extern int strbuf_getwholeline_fd(struct strbuf *, int, int); - -extern void stripspace(struct strbuf *buf, int skip_comments); -extern int launch_editor(const char *path, struct strbuf *buffer, const char *const *env); - extern int strbuf_branchname(struct strbuf *sb, const char *name); extern int strbuf_check_branch_ref(struct strbuf *sb, const char *name); extern void strbuf_addstr_urlencode(struct strbuf *, const char *, int reserved); -extern void strbuf_humanise_bytes(struct strbuf *buf, off_t bytes); __attribute__((format (printf,1,2))) extern int printf_ln(const char *fmt, ...); __attribute__((format (printf,2,3))) extern int fprintf_ln(FILE *fp, const char *fmt, ...); +char *xstrdup_tolower(const char *); + +/** + * Create a newly allocated string using printf format. You can do this easily + * with a strbuf, but this provides a shortcut to save a few lines. + */ +__attribute__((format (printf, 1, 0))) +char *xstrvfmt(const char *fmt, va_list ap); +__attribute__((format (printf, 1, 2))) +char *xstrfmt(const char *fmt, ...); + #endif /* STRBUF_H */ |