strbuf.h

   1 /*
   2  * From git 1.7.3.1
   3  * License: GPL-2
   4  *
   5  * Modifications (2010-10-19):
   6  *  - add license header.
   7  *  - remove unneeded functions.
   8  */
   9
  10 #ifndef STRBUF_H
  11 #define STRBUF_H
  12
  13 /*
  14  * Strbuf's can be use in many ways: as a byte array, or to store arbitrary
  15  * long, overflow safe strings.
  16  *
  17  * Strbufs has some invariants that are very important to keep in mind:
  18  *
  19  * 1. the ->buf member is always malloc-ed, hence strbuf's can be used to
  20  *    build complex strings/buffers whose final size isn't easily known.
  21  *
  22  *    It is NOT legal to copy the ->buf pointer away.
  23  *
  24  * 2. the ->buf member is a byte array that has at least ->len + 1 bytes
  25  *    allocated. The extra byte is used to store a '\0', allowing the ->buf
  26  *    member to be a valid C-string. Every strbuf function ensures this
  27  *    invariant is preserved.
  28  *
  29  *    Note that it is OK to "play" with the buffer directly if you work it
  30  *    that way:
  31  *
  32  *    strbuf_grow(sb, SOME_SIZE);
  33  *       ... Here, the memory array starting at sb->buf, and of length
  34  *       ... strbuf_avail(sb) is all yours, and you are sure that
  35  *       ... strbuf_avail(sb) is at least SOME_SIZE.
  36  *    strbuf_setlen(sb, sb->len + SOME_OTHER_SIZE);
  37  *
  38  *    Doing so is safe, though if it has to be done in many places, adding the
  39  *    missing API to the strbuf module is the way to go.
  40  *
  41  *    XXX: do _not_ assume that the area that is yours is of size ->alloc - 1
  42  *         even if it's true in the current implementation. Alloc is somehow a
  43  *         "private" member that should not be messed with.
  44  */
  45
  46 #include <assert.h>
  47
  48 extern char strbuf_slopbuf[];
  49 struct strbuf {
  50         size_t alloc;
  51         size_t len;
  52         char *buf;
  53 };
  54
  55 #define STRBUF_INIT  { 0, 0, strbuf_slopbuf }
  56
  57 /*----- strbuf life cycle -----*/
  58 extern void strbuf_init(struct strbuf *, size_t);
  59 extern void strbuf_release(struct strbuf *);
  60
  61 /*----- strbuf size related -----*/
  62 extern void strbuf_grow(struct strbuf *, size_t);
  63
  64 static inline void strbuf_setlen(struct strbuf *sb, size_t len) {
  65         if (!sb->alloc)
  66                 strbuf_grow(sb, 0);
  67         assert(len < sb->alloc);
  68         sb->len = len;
  69         sb->buf[len] = '\0';
  70 }
  71 #define strbuf_reset(sb)  strbuf_setlen(sb, 0)
  72
  73 /*----- add data in your buffer -----*/
  74 static inline void strbuf_addch(struct strbuf *sb, int c) {
  75         strbuf_grow(sb, 1);
  76         sb->buf[sb->len++] = c;
  77         sb->buf[sb->len] = '\0';
  78 }
  79
  80 extern void strbuf_add(struct strbuf *, const void *, size_t);
  81
  82 extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
  83
  84 #endif /* STRBUF_H */