compat/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  * Modifications (2012-05-18):
   9  *  - restore functions needed for downstream changes.
  10  */
  11
  12 #ifndef STRBUF_H
  13 #define STRBUF_H
  14
  15 /*
  16  * Strbuf's can be use in many ways: as a byte array, or to store arbitrary
  17  * long, overflow safe strings.
  18  *
  19  * Strbufs has some invariants that are very important to keep in mind:
  20  *
  21  * 1. the ->buf member is always malloc-ed, hence strbuf's can be used to
  22  *    build complex strings/buffers whose final size isn't easily known.
  23  *
  24  *    It is NOT legal to copy the ->buf pointer away.
  25  *
  26  * 2. the ->buf member is a byte array that has at least ->len + 1 bytes
  27  *    allocated. The extra byte is used to store a '\0', allowing the ->buf
  28  *    member to be a valid C-string. Every strbuf function ensures this
  29  *    invariant is preserved.
  30  *
  31  *    Note that it is OK to "play" with the buffer directly if you work it
  32  *    that way:
  33  *
  34  *    strbuf_grow(sb, SOME_SIZE);
  35  *       ... Here, the memory array starting at sb->buf, and of length
  36  *       ... strbuf_avail(sb) is all yours, and you are sure that
  37  *       ... strbuf_avail(sb) is at least SOME_SIZE.
  38  *    strbuf_setlen(sb, sb->len + SOME_OTHER_SIZE);
  39  *
  40  *    Doing so is safe, though if it has to be done in many places, adding the
  41  *    missing API to the strbuf module is the way to go.
  42  *
  43  *    XXX: do _not_ assume that the area that is yours is of size ->alloc - 1
  44  *         even if it's true in the current implementation. Alloc is somehow a
  45  *         "private" member that should not be messed with.
  46  */
  47
  48 #include <assert.h>
  49
  50 extern char strbuf_slopbuf[];
  51 struct strbuf {
  52         size_t alloc;
  53         size_t len;
  54         char *buf;
  55 };
  56
  57 #define STRBUF_INIT  { 0, 0, strbuf_slopbuf }
  58
  59 /*----- strbuf life cycle -----*/
  60 extern void strbuf_init(struct strbuf *, size_t);
  61 extern void strbuf_release(struct strbuf *);
  62 static inline void strbuf_swap(struct strbuf *a, struct strbuf *b) {
  63         struct strbuf tmp = *a;
  64         *a = *b;
  65         *b = tmp;
  66 }
  67
  68 /*----- strbuf size related -----*/
  69 extern void strbuf_grow(struct strbuf *, size_t);
  70
  71 static inline void strbuf_setlen(struct strbuf *sb, size_t len) {
  72         if (!sb->alloc)
  73                 strbuf_grow(sb, 0);
  74         assert(len < sb->alloc);
  75         assert(sb->buf);
  76         sb->len = len;
  77         sb->buf[len] = '\0';
  78 }
  79 #define strbuf_reset(sb)  strbuf_setlen(sb, 0)
  80
  81 /*----- add data in your buffer -----*/
  82 static inline void strbuf_addch(struct strbuf *sb, int c) {
  83         strbuf_grow(sb, 1);
  84         sb->buf[sb->len++] = c;
  85         sb->buf[sb->len] = '\0';
  86 }
  87
  88 extern void strbuf_add(struct strbuf *, const void *, size_t);
  89 static inline void strbuf_addstr(struct strbuf *sb, const char *s) {
  90         strbuf_add(sb, s, strlen(s));
  91 }
  92
  93 extern void strbuf_insert(struct strbuf *, size_t pos, const void *, size_t);
  94 extern void strbuf_remove(struct strbuf *, size_t pos, size_t len);
  95
  96 /* splice pos..pos+len with given data */
  97 extern void strbuf_splice(struct strbuf *, size_t pos, size_t len,
  98                           const void *, size_t);
  99
 100 extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
 101
 102 #endif /* STRBUF_H */