tools/perf/util/strbuf.c

   1 #include "cache.h"
   2
   3 int prefixcmp(const char *str, const char *prefix)
   4 {
   5         for (; ; str++, prefix++)
   6                 if (!*prefix)
   7                         return 0;
   8                 else if (*str != *prefix)
   9                         return (unsigned char)*prefix - (unsigned char)*str;
  10 }
  11
  12 /*
  13  * Used as the default ->buf value, so that people can always assume
  14  * buf is non NULL and ->buf is NUL terminated even for a freshly
  15  * initialized strbuf.
  16  */
  17 char strbuf_slopbuf[1];
  18
  19 void strbuf_init(struct strbuf *sb, ssize_t hint)
  20 {
  21         sb->alloc = sb->len = 0;
  22         sb->buf = strbuf_slopbuf;
  23         if (hint)
  24                 strbuf_grow(sb, hint);
  25 }
  26
  27 void strbuf_release(struct strbuf *sb)
  28 {
  29         if (sb->alloc) {
  30                 free(sb->buf);
  31                 strbuf_init(sb, 0);
  32         }
  33 }
  34
  35 char *strbuf_detach(struct strbuf *sb, size_t *sz)
  36 {
  37         char *res = sb->alloc ? sb->buf : NULL;
  38         if (sz)
  39                 *sz = sb->len;
  40         strbuf_init(sb, 0);
  41         return res;
  42 }
  43
  44 void strbuf_grow(struct strbuf *sb, size_t extra)
  45 {
  46         if (sb->len + extra + 1 <= sb->len)
  47                 die("you want to use way too much memory");
  48         if (!sb->alloc)
  49                 sb->buf = NULL;
  50         ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc);
  51 }
  52
  53 static void strbuf_splice(struct strbuf *sb, size_t pos, size_t len,
  54                                    const void *data, size_t dlen)
  55 {
  56         if (pos + len < pos)
  57                 die("you want to use way too much memory");
  58         if (pos > sb->len)
  59                 die("`pos' is too far after the end of the buffer");
  60         if (pos + len > sb->len)
  61                 die("`pos + len' is too far after the end of the buffer");
  62
  63         if (dlen >= len)
  64                 strbuf_grow(sb, dlen - len);
  65         memmove(sb->buf + pos + dlen,
  66                         sb->buf + pos + len,
  67                         sb->len - pos - len);
  68         memcpy(sb->buf + pos, data, dlen);
  69         strbuf_setlen(sb, sb->len + dlen - len);
  70 }
  71
  72 void strbuf_remove(struct strbuf *sb, size_t pos, size_t len)
  73 {
  74         strbuf_splice(sb, pos, len, NULL, 0);
  75 }
  76
  77 void strbuf_add(struct strbuf *sb, const void *data, size_t len)
  78 {
  79         strbuf_grow(sb, len);
  80         memcpy(sb->buf + sb->len, data, len);
  81         strbuf_setlen(sb, sb->len + len);
  82 }
  83
  84 void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
  85 {
  86         int len;
  87         va_list ap;
  88
  89         if (!strbuf_avail(sb))
  90                 strbuf_grow(sb, 64);
  91         va_start(ap, fmt);
  92         len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
  93         va_end(ap);
  94         if (len < 0)
  95                 die("your vsnprintf is broken");
  96         if (len > strbuf_avail(sb)) {
  97                 strbuf_grow(sb, len);
  98                 va_start(ap, fmt);
  99                 len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
 100                 va_end(ap);
 101                 if (len > strbuf_avail(sb)) {
 102                         die("this should not happen, your snprintf is broken");
 103                 }
 104         }
 105         strbuf_setlen(sb, sb->len + len);
 106 }
 107
 108 ssize_t strbuf_read(struct strbuf *sb, int fd, ssize_t hint)
 109 {
 110         size_t oldlen = sb->len;
 111         size_t oldalloc = sb->alloc;
 112
 113         strbuf_grow(sb, hint ? hint : 8192);
 114         for (;;) {
 115                 ssize_t cnt;
 116
 117                 cnt = read(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
 118                 if (cnt < 0) {
 119                         if (oldalloc == 0)
 120                                 strbuf_release(sb);
 121                         else
 122                                 strbuf_setlen(sb, oldlen);
 123                         return -1;
 124                 }
 125                 if (!cnt)
 126                         break;
 127                 sb->len += cnt;
 128                 strbuf_grow(sb, 8192);
 129         }
 130
 131         sb->buf[sb->len] = '\0';
 132         return sb->len - oldlen;
 133 }