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 void strbuf_addch(struct strbuf *sb, int c)
  55 {
  56         strbuf_grow(sb, 1);
  57         sb->buf[sb->len++] = c;
  58         sb->buf[sb->len] = '\0';
  59 }
  60
  61 void strbuf_add(struct strbuf *sb, const void *data, size_t len)
  62 {
  63         strbuf_grow(sb, len);
  64         memcpy(sb->buf + sb->len, data, len);
  65         strbuf_setlen(sb, sb->len + len);
  66 }
  67
  68 static void strbuf_addv(struct strbuf *sb, const char *fmt, va_list ap)
  69 {
  70         int len;
  71         va_list ap_saved;
  72
  73         if (!strbuf_avail(sb))
  74                 strbuf_grow(sb, 64);
  75
  76         va_copy(ap_saved, ap);
  77         len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
  78         if (len < 0)
  79                 die("your vsnprintf is broken");
  80         if (len > strbuf_avail(sb)) {
  81                 strbuf_grow(sb, len);
  82                 len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap_saved);
  83                 va_end(ap_saved);
  84                 if (len > strbuf_avail(sb)) {
  85                         die("this should not happen, your vsnprintf is broken");
  86                 }
  87         }
  88         strbuf_setlen(sb, sb->len + len);
  89 }
  90
  91 void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
  92 {
  93         va_list ap;
  94
  95         va_start(ap, fmt);
  96         strbuf_addv(sb, fmt, ap);
  97         va_end(ap);
  98 }
  99
 100 ssize_t strbuf_read(struct strbuf *sb, int fd, ssize_t hint)
 101 {
 102         size_t oldlen = sb->len;
 103         size_t oldalloc = sb->alloc;
 104
 105         strbuf_grow(sb, hint ? hint : 8192);
 106         for (;;) {
 107                 ssize_t cnt;
 108
 109                 cnt = read(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
 110                 if (cnt < 0) {
 111                         if (oldalloc == 0)
 112                                 strbuf_release(sb);
 113                         else
 114                                 strbuf_setlen(sb, oldlen);
 115                         return -1;
 116                 }
 117                 if (!cnt)
 118                         break;
 119                 sb->len += cnt;
 120                 strbuf_grow(sb, 8192);
 121         }
 122
 123         sb->buf[sb->len] = '\0';
 124         return sb->len - oldlen;
 125 }