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authorPierre Habouzit <madcoder@debian.org>2007-09-06 11:20:05 (GMT)
committerJunio C Hamano <gitster@pobox.com>2007-09-07 06:57:44 (GMT)
commitb449f4cfc972929b638b90d375b8960c37790618 (patch)
tree4cc9b5425447e4b34966b033a6326ebb50b1e635 /strbuf.c
parentb5ef6ac978012475660a36583b2174e9bd8188a5 (diff)
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Rework strbuf API and semantics.
The gory details are explained in strbuf.h. The change of semantics this patch enforces is that the embeded buffer has always a '\0' character after its last byte, to always make it a C-string. The offs-by-one changes are all related to that very change. A strbuf can be used to store byte arrays, or as an extended string library. The `buf' member can be passed to any C legacy string function, because strbuf operations always ensure there is a terminating \0 at the end of the buffer, not accounted in the `len' field of the structure. A strbuf can be used to generate a string/buffer whose final size is not really known, and then "strbuf_detach" can be used to get the built buffer, and keep the wrapping "strbuf" structure usable for further work again. Other interesting feature: strbuf_grow(sb, size) ensure that there is enough allocated space in `sb' to put `size' new octets of data in the buffer. It helps avoiding reallocating data for nothing when the problem the strbuf helps to solve has a known typical size. Signed-off-by: Pierre Habouzit <madcoder@debian.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'strbuf.c')
-rw-r--r--strbuf.c101
1 files changed, 87 insertions, 14 deletions
diff --git a/strbuf.c b/strbuf.c
index e33d06b..7136de1 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -2,40 +2,113 @@
#include "strbuf.h"
void strbuf_init(struct strbuf *sb) {
- sb->buf = NULL;
- sb->eof = sb->alloc = sb->len = 0;
+ memset(sb, 0, sizeof(*sb));
}
-static void strbuf_begin(struct strbuf *sb) {
+void strbuf_release(struct strbuf *sb) {
free(sb->buf);
+ memset(sb, 0, sizeof(*sb));
+}
+
+void strbuf_reset(struct strbuf *sb) {
+ if (sb->len)
+ strbuf_setlen(sb, 0);
+ sb->eof = 0;
+}
+
+char *strbuf_detach(struct strbuf *sb) {
+ char *res = sb->buf;
strbuf_init(sb);
+ return res;
+}
+
+void strbuf_grow(struct strbuf *sb, size_t extra) {
+ if (sb->len + extra + 1 <= sb->len)
+ die("you want to use way too much memory");
+ ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc);
+}
+
+void strbuf_add(struct strbuf *sb, const void *data, size_t len) {
+ strbuf_grow(sb, len);
+ memcpy(sb->buf + sb->len, data, len);
+ strbuf_setlen(sb, sb->len + len);
+}
+
+void strbuf_addf(struct strbuf *sb, const char *fmt, ...) {
+ int len;
+ va_list ap;
+
+ va_start(ap, fmt);
+ len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
+ va_end(ap);
+ if (len < 0) {
+ len = 0;
+ }
+ if (len >= strbuf_avail(sb)) {
+ strbuf_grow(sb, len);
+ va_start(ap, fmt);
+ len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
+ va_end(ap);
+ if (len >= strbuf_avail(sb)) {
+ die("this should not happen, your snprintf is broken");
+ }
+ }
+ strbuf_setlen(sb, sb->len + len);
}
-static void inline strbuf_add(struct strbuf *sb, int ch) {
- if (sb->alloc <= sb->len) {
- sb->alloc = sb->alloc * 3 / 2 + 16;
- sb->buf = xrealloc(sb->buf, sb->alloc);
+size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f) {
+ size_t res;
+
+ strbuf_grow(sb, size);
+ res = fread(sb->buf + sb->len, 1, size, f);
+ if (res > 0) {
+ strbuf_setlen(sb, sb->len + res);
}
- sb->buf[sb->len++] = ch;
+ return res;
}
-static void strbuf_end(struct strbuf *sb) {
- strbuf_add(sb, 0);
+ssize_t strbuf_read(struct strbuf *sb, int fd)
+{
+ size_t oldlen = sb->len;
+
+ for (;;) {
+ ssize_t cnt;
+
+ strbuf_grow(sb, 8192);
+ cnt = xread(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
+ if (cnt < 0) {
+ strbuf_setlen(sb, oldlen);
+ return -1;
+ }
+ if (!cnt)
+ break;
+ sb->len += cnt;
+ }
+
+ sb->buf[sb->len] = '\0';
+ return sb->len - oldlen;
}
void read_line(struct strbuf *sb, FILE *fp, int term) {
int ch;
- strbuf_begin(sb);
if (feof(fp)) {
+ strbuf_release(sb);
sb->eof = 1;
return;
}
+
+ strbuf_reset(sb);
while ((ch = fgetc(fp)) != EOF) {
if (ch == term)
break;
- strbuf_add(sb, ch);
+ strbuf_grow(sb, 1);
+ sb->buf[sb->len++] = ch;
}
- if (ch == EOF && sb->len == 0)
+ if (ch == EOF && sb->len == 0) {
+ strbuf_release(sb);
sb->eof = 1;
- strbuf_end(sb);
+ }
+
+ strbuf_grow(sb, 1);
+ sb->buf[sb->len] = '\0';
}