1#ifndef STRBUF_H 2#define STRBUF_H 3 4/* 5 * Strbuf's can be use in many ways: as a byte array, or to store arbitrary 6 * long, overflow safe strings. 7 * 8 * Strbufs has some invariants that are very important to keep in mind: 9 * 10 * 1. the ->buf member is always malloc-ed, hence strbuf's can be used to 11 * build complex strings/buffers whose final size isn't easily known. 12 * 13 * It is legal to copy the ->buf pointer away. Though if you want to reuse 14 * the strbuf after that, setting ->buf to NULL isn't legal. 15 * `strbuf_detach' is the operation that detachs a buffer from its shell 16 * while keeping the shell valid wrt its invariants. 17 * 18 * 2. the ->buf member is a byte array that has at least ->len + 1 bytes 19 * allocated. The extra byte is used to store a '\0', allowing the ->buf 20 * member to be a valid C-string. Every strbuf function ensure this 21 * invariant is preserved. 22 * 23 * Note that it is OK to "play" with the buffer directly if you work it 24 * that way: 25 * 26 * strbuf_grow(sb, SOME_SIZE); 27 * // ... here the memory areay starting at sb->buf, and of length 28 * // sb_avail(sb) is all yours, and you are sure that sb_avail(sb) is at 29 * // least SOME_SIZE 30 * strbuf_setlen(sb, sb->len + SOME_OTHER_SIZE); 31 * 32 * Of course, SOME_OTHER_SIZE must be smaller or equal to sb_avail(sb). 33 * 34 * Doing so is safe, though if it has to be done in many places, adding the 35 * missing API to the strbuf module is the way to go. 36 * 37 * XXX: do _not_ assume that the area that is yours is of size ->alloc - 1 38 * even if it's true in the current implementation. Alloc is somehow a 39 * "private" member that should not be messed with. 40 */ 41 42#include <assert.h> 43 44struct strbuf { 45 size_t alloc; 46 size_t len; 47 int eof; 48 char *buf; 49}; 50 51#define STRBUF_INIT { 0, 0, 0, NULL } 52 53/*----- strbuf life cycle -----*/ 54extern void strbuf_init(struct strbuf *); 55extern void strbuf_release(struct strbuf *); 56extern void strbuf_reset(struct strbuf *); 57extern char *strbuf_detach(struct strbuf *); 58 59/*----- strbuf size related -----*/ 60static inline size_t strbuf_avail(struct strbuf *sb) { 61 return sb->alloc ? sb->alloc - sb->len - 1 : 0; 62} 63static inline void strbuf_setlen(struct strbuf *sb, size_t len) { 64 assert (len < sb->alloc); 65 sb->len = len; 66 sb->buf[len] = '\0'; 67} 68 69extern void strbuf_grow(struct strbuf *, size_t); 70 71/*----- add data in your buffer -----*/ 72static inline void strbuf_addch(struct strbuf *sb, int c) { 73 strbuf_grow(sb, 1); 74 sb->buf[sb->len++] = c; 75 sb->buf[sb->len] = '\0'; 76} 77 78extern void strbuf_add(struct strbuf *, const void *, size_t); 79static inline void strbuf_addstr(struct strbuf *sb, const char *s) { 80 strbuf_add(sb, s, strlen(s)); 81} 82static inline void strbuf_addbuf(struct strbuf *sb, struct strbuf *sb2) { 83 strbuf_add(sb, sb2->buf, sb2->len); 84} 85 86__attribute__((format(printf,2,3))) 87extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...); 88 89extern size_t strbuf_fread(struct strbuf *, size_t, FILE *); 90/* XXX: if read fails, any partial read is undone */ 91extern ssize_t strbuf_read(struct strbuf *, int fd); 92 93extern void read_line(struct strbuf *, FILE *, int); 94 95#endif /* STRBUF_H */