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 "mail.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 #define MAX(a, b)       ((a) < (b) ? (b) : (a))
  12
  13 struct sbuf {
  14         char *s;                /* allocated buffer */
  15         int s_n;                /* length of the string stored in s[] */
  16         int s_sz;               /* size of memory allocated for s[] */
  17 };
  18
  19 static void sbuf_extend(struct sbuf *sbuf, int newsz)
  20 {
  21         char *s = sbuf->s;
  22         sbuf->s_sz = newsz;
  23         sbuf->s = malloc(sbuf->s_sz);
  24         if (sbuf->s_n)
  25                 memcpy(sbuf->s, s, sbuf->s_n);
  26         free(s);
  27 }
  28
  29 struct sbuf *sbuf_make(void)
  30 {
  31         struct sbuf *sb = malloc(sizeof(*sb));
  32         memset(sb, 0, sizeof(*sb));
  33         return sb;
  34 }
  35
  36 char *sbuf_buf(struct sbuf *sb)
  37 {
  38         if (!sb->s)
  39                 sbuf_extend(sb, 1);
  40         sb->s[sb->s_n] = '\0';
  41         return sb->s;
  42 }
  43
  44 char *sbuf_done(struct sbuf *sb)
  45 {
  46         char *s = sbuf_buf(sb);
  47         free(sb);
  48         return s;
  49 }
  50
  51 void sbuf_free(struct sbuf *sb)
  52 {
  53         free(sb->s);
  54         free(sb);
  55 }
  56
  57 void sbuf_chr(struct sbuf *sbuf, int c)
  58 {
  59         if (sbuf->s_n + 2 >= sbuf->s_sz)
  60                 sbuf_extend(sbuf, NEXTSZ(sbuf->s_sz, 1));
  61         sbuf->s[sbuf->s_n++] = c;
  62 }
  63
  64 void sbuf_mem(struct sbuf *sbuf, char *s, int len)
  65 {
  66         if (sbuf->s_n + len + 1 >= sbuf->s_sz)
  67                 sbuf_extend(sbuf, NEXTSZ(sbuf->s_sz, len + 1));
  68         memcpy(sbuf->s + sbuf->s_n, s, len);
  69         sbuf->s_n += len;
  70 }
  71
  72 void sbuf_str(struct sbuf *sbuf, char *s)
  73 {
  74         sbuf_mem(sbuf, s, strlen(s));
  75 }
  76
  77 int sbuf_len(struct sbuf *sbuf)
  78 {
  79         return sbuf->s_n;
  80 }
  81
  82 void sbuf_cut(struct sbuf *sb, int len)
  83 {
  84         if (sb->s_n > len)
  85                 sb->s_n = len;
  86 }
  87
  88 void sbuf_printf(struct sbuf *sbuf, char *s, ...)
  89 {
  90         char buf[256];
  91         va_list ap;
  92         va_start(ap, s);
  93         vsnprintf(buf, sizeof(buf), s, ap);
  94         va_end(ap);
  95         sbuf_str(sbuf, buf);
  96 }