tools/perf/util/strbuf.c

   1 #include "cache.h"
   2 #include <linux/kernel.h>
   3
   4 int prefixcmp(const char *str, const char *prefix)
   5 {
   6         for (; ; str++, prefix++)
   7                 if (!*prefix)
   8                         return 0;
   9                 else if (*str != *prefix)
  10                         return (unsigned char)*prefix - (unsigned char)*str;
  11 }
  12
  13 /*
  14  * Used as the default ->buf value, so that people can always assume
  15  * buf is non NULL and ->buf is NUL terminated even for a freshly
  16  * initialized strbuf.
  17  */
  18 char strbuf_slopbuf[1];
  19
  20 void strbuf_init(struct strbuf *sb, ssize_t hint)
  21 {
  22         sb->alloc = sb->len = 0;
  23         sb->buf = strbuf_slopbuf;
  24         if (hint)
  25                 strbuf_grow(sb, hint);
  26 }
  27
  28 void strbuf_release(struct strbuf *sb)
  29 {
  30         if (sb->alloc) {
  31                 zfree(&sb->buf);
  32                 strbuf_init(sb, 0);
  33         }
  34 }
  35
  36 char *strbuf_detach(struct strbuf *sb, size_t *sz)
  37 {
  38         char *res = sb->alloc ? sb->buf : NULL;
  39         if (sz)
  40                 *sz = sb->len;
  41         strbuf_init(sb, 0);
  42         return res;
  43 }
  44
  45 void strbuf_grow(struct strbuf *sb, size_t extra)
  46 {
  47         if (sb->len + extra + 1 <= sb->len)
  48                 die("you want to use way too much memory");
  49         if (!sb->alloc)
  50                 sb->buf = NULL;
  51         ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc);
  52 }
  53
  54 static void strbuf_splice(struct strbuf *sb, size_t pos, size_t len,
  55                                    const void *data, size_t dlen)
  56 {
  57         if (pos + len < pos)
  58                 die("you want to use way too much memory");
  59         if (pos > sb->len)
  60                 die("`pos' is too far after the end of the buffer");
  61         if (pos + len > sb->len)
  62                 die("`pos + len' is too far after the end of the buffer");
  63
  64         if (dlen >= len)
  65                 strbuf_grow(sb, dlen - len);
  66         memmove(sb->buf + pos + dlen,
  67                         sb->buf + pos + len,
  68                         sb->len - pos - len);
  69         memcpy(sb->buf + pos, data, dlen);
  70         strbuf_setlen(sb, sb->len + dlen - len);
  71 }
  72
  73 void strbuf_remove(struct strbuf *sb, size_t pos, size_t len)
  74 {
  75         strbuf_splice(sb, pos, len, NULL, 0);
  76 }
  77
  78 void strbuf_add(struct strbuf *sb, const void *data, size_t len)
  79 {
  80         strbuf_grow(sb, len);
  81         memcpy(sb->buf + sb->len, data, len);
  82         strbuf_setlen(sb, sb->len + len);
  83 }
  84
  85 void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
  86 {
  87         int len;
  88         va_list ap;
  89
  90         if (!strbuf_avail(sb))
  91                 strbuf_grow(sb, 64);
  92         va_start(ap, fmt);
  93         len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
  94         va_end(ap);
  95         if (len < 0)
  96                 die("your vsnprintf is broken");
  97         if (len > strbuf_avail(sb)) {
  98                 strbuf_grow(sb, len);
  99                 va_start(ap, fmt);
 100                 len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
 101                 va_end(ap);
 102                 if (len > strbuf_avail(sb)) {
 103                         die("this should not happen, your vsnprintf is broken");
 104                 }
 105         }
 106         strbuf_setlen(sb, sb->len + len);
 107 }
 108
 109 ssize_t strbuf_read(struct strbuf *sb, int fd, ssize_t hint)
 110 {
 111         size_t oldlen = sb->len;
 112         size_t oldalloc = sb->alloc;
 113
 114         strbuf_grow(sb, hint ? hint : 8192);
 115         for (;;) {
 116                 ssize_t cnt;
 117
 118                 cnt = read(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
 119                 if (cnt < 0) {
 120                         if (oldalloc == 0)
 121                                 strbuf_release(sb);
 122                         else
 123                                 strbuf_setlen(sb, oldlen);
 124                         return -1;
 125                 }
 126                 if (!cnt)
 127                         break;
 128                 sb->len += cnt;
 129                 strbuf_grow(sb, 8192);
 130         }
 131
 132         sb->buf[sb->len] = '\0';
 133         return sb->len - oldlen;
 134 }