sbuf.c

   1 /* variable length string buffer */
   2 #include <stdarg.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6 #include "post.h"
   7
   8 #define SBUFSZ          128
   9 #define ALIGN(n, a)     (((n) + (a) - 1) & ~((a) - 1))
  10 #define NEXTSZ(o, r)    ALIGN(MAX((o) * 2, (o) + (r)), SBUFSZ)
  11
  12 struct sbuf {
  13         char *s;                /* allocated buffer */
  14         int s_n;                /* length of the string stored in s[] */
  15         int s_sz;               /* size of memory allocated for s[] */
  16 };
  17
  18 static void sbuf_extend(struct sbuf *sbuf, int newsz)
  19 {
  20         char *s = sbuf->s;
  21         sbuf->s_sz = newsz;
  22         sbuf->s = malloc(sbuf->s_sz);
  23         if (sbuf->s_n)
  24                 memcpy(sbuf->s, s, sbuf->s_n);
  25         free(s);
  26 }
  27
  28 struct sbuf *sbuf_make(void)
  29 {
  30         struct sbuf *sb = malloc(sizeof(*sb));
  31         memset(sb, 0, sizeof(*sb));
  32         return sb;
  33 }
  34
  35 char *sbuf_buf(struct sbuf *sb)
  36 {
  37         if (!sb->s)
  38                 sbuf_extend(sb, 1);
  39         sb->s[sb->s_n] = '\0';
  40         return sb->s;
  41 }
  42
  43 char *sbuf_done(struct sbuf *sb)
  44 {
  45         char *s = sbuf_buf(sb);
  46         free(sb);
  47         return s;
  48 }
  49
  50 void sbuf_free(struct sbuf *sb)
  51 {
  52         free(sb->s);
  53         free(sb);
  54 }
  55
  56 void sbuf_chr(struct sbuf *sbuf, int c)
  57 {
  58         if (sbuf->s_n + 2 >= sbuf->s_sz)
  59                 sbuf_extend(sbuf, NEXTSZ(sbuf->s_sz, 1));
  60         sbuf->s[sbuf->s_n++] = c;
  61 }
  62
  63 void sbuf_mem(struct sbuf *sbuf, char *s, int len)
  64 {
  65         if (sbuf->s_n + len + 1 >= sbuf->s_sz)
  66                 sbuf_extend(sbuf, NEXTSZ(sbuf->s_sz, len + 1));
  67         memcpy(sbuf->s + sbuf->s_n, s, len);
  68         sbuf->s_n += len;
  69 }
  70
  71 void sbuf_str(struct sbuf *sbuf, char *s)
  72 {
  73         sbuf_mem(sbuf, s, strlen(s));
  74 }
  75
  76 int sbuf_len(struct sbuf *sbuf)
  77 {
  78         return sbuf->s_n;
  79 }
  80
  81 void sbuf_cut(struct sbuf *sb, int len)
  82 {
  83         if (sb->s_n > len)
  84                 sb->s_n = len;
  85 }
  86
  87 void sbuf_printf(struct sbuf *sbuf, char *s, ...)
  88 {
  89         char buf[256];
  90         va_list ap;
  91         va_start(ap, s);
  92         vsnprintf(buf, sizeof(buf), s, ap);
  93         va_end(ap);
  94         sbuf_str(sbuf, buf);
  95 }