sbuf.c

   1 #include <stdarg.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include "sbuf.h"
   6
   7 #define MAX(a, b)       ((a) < (b) ? (b) : (a))
   8 #define SBUF_SZ         512
   9
  10 static void sbuf_extend(struct sbuf *sbuf, int amount)
  11 {
  12         char *s = sbuf->s;
  13         sbuf->sz = (MAX(1, amount) + SBUF_SZ - 1) & ~(SBUF_SZ - 1);
  14         sbuf->s = malloc(sbuf->sz);
  15         if (sbuf->n)
  16                 memcpy(sbuf->s, s, sbuf->n);
  17         free(s);
  18 }
  19
  20 void sbuf_init(struct sbuf *sbuf)
  21 {
  22         memset(sbuf, 0, sizeof(*sbuf));
  23         sbuf_extend(sbuf, SBUF_SZ);
  24 }
  25
  26 void sbuf_add(struct sbuf *sbuf, int c)
  27 {
  28         if (sbuf->n + 2 >= sbuf->sz)
  29                 sbuf_extend(sbuf, sbuf->sz * 2);
  30         sbuf->s[sbuf->n++] = c;
  31 }
  32
  33 void sbuf_append(struct sbuf *sbuf, char *s)
  34 {
  35         int len = strlen(s);
  36         if (sbuf->n + len + 1 >= sbuf->sz)
  37                 sbuf_extend(sbuf, sbuf->n + len + 1);
  38         memcpy(sbuf->s + sbuf->n, s, len);
  39         sbuf->n += len;
  40 }
  41
  42 void sbuf_printf(struct sbuf *sbuf, char *s, ...)
  43 {
  44         char buf[1024];
  45         va_list ap;
  46         va_start(ap, s);
  47         vsprintf(buf, s, ap);
  48         va_end(ap);
  49         sbuf_append(sbuf, buf);
  50 }
  51
  52 void sbuf_putnl(struct sbuf *sbuf)
  53 {
  54         if (sbuf->n && sbuf->s[sbuf->n - 1] != '\n')
  55                 sbuf_add(sbuf, '\n');
  56 }
  57
  58 int sbuf_empty(struct sbuf *sbuf)
  59 {
  60         return !sbuf->n;
  61 }
  62
  63 char *sbuf_buf(struct sbuf *sbuf)
  64 {
  65         sbuf->s[sbuf->n] = '\0';
  66         return sbuf->s;
  67 }
  68
  69 int sbuf_len(struct sbuf *sbuf)
  70 {
  71         return sbuf->n;
  72 }
  73
  74 /* shorten the sbuf */
  75 void sbuf_cut(struct sbuf *sbuf, int n)
  76 {
  77         if (sbuf->n > n)
  78                 sbuf->n = n;
  79 }
  80
  81 void sbuf_done(struct sbuf *sbuf)
  82 {
  83         free(sbuf->s);
  84 }