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