sbuf.c

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