Andrew's git - gitweb.git/blob

   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        char *buf;
  48};
  49
  50#define STRBUF_INIT  { 0, 0, NULL }
  51
  52/*----- strbuf life cycle -----*/
  53extern void strbuf_init(struct strbuf *, size_t);
  54extern void strbuf_release(struct strbuf *);
  55extern void strbuf_reset(struct strbuf *);
  56extern char *strbuf_detach(struct strbuf *);
  57extern void strbuf_attach(struct strbuf *, void *, size_t, size_t);
  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/*----- content related -----*/
  72extern void strbuf_rtrim(struct strbuf *);
  73
  74/*----- add data in your buffer -----*/
  75static inline void strbuf_addch(struct strbuf *sb, int c) {
  76        strbuf_grow(sb, 1);
  77        sb->buf[sb->len++] = c;
  78        sb->buf[sb->len] = '\0';
  79}
  80
  81/* inserts after pos, or appends if pos >= sb->len */
  82extern void strbuf_insert(struct strbuf *, size_t pos, const void *, size_t);
  83
  84/* splice pos..pos+len with given data */
  85extern void strbuf_splice(struct strbuf *, size_t pos, size_t len,
  86                                                  const void *, size_t);
  87
  88extern void strbuf_add(struct strbuf *, const void *, size_t);
  89static inline void strbuf_addstr(struct strbuf *sb, const char *s) {
  90        strbuf_add(sb, s, strlen(s));
  91}
  92static inline void strbuf_addbuf(struct strbuf *sb, struct strbuf *sb2) {
  93        strbuf_add(sb, sb2->buf, sb2->len);
  94}
  95
  96__attribute__((format(printf,2,3)))
  97extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...);
  98
  99extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
 100/* XXX: if read fails, any partial read is undone */
 101extern ssize_t strbuf_read(struct strbuf *, int fd, size_t hint);
 102
 103extern int strbuf_getline(struct strbuf *, FILE *, int);
 104
 105#endif /* STRBUF_H */