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b449f4cfc9
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>
115 lines
2.2 KiB
C
115 lines
2.2 KiB
C
#include "cache.h"
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#include "strbuf.h"
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void strbuf_init(struct strbuf *sb) {
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memset(sb, 0, sizeof(*sb));
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}
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void strbuf_release(struct strbuf *sb) {
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free(sb->buf);
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memset(sb, 0, sizeof(*sb));
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}
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void strbuf_reset(struct strbuf *sb) {
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if (sb->len)
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strbuf_setlen(sb, 0);
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sb->eof = 0;
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}
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char *strbuf_detach(struct strbuf *sb) {
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char *res = sb->buf;
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strbuf_init(sb);
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return res;
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}
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void strbuf_grow(struct strbuf *sb, size_t extra) {
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if (sb->len + extra + 1 <= sb->len)
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die("you want to use way too much memory");
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ALLOC_GROW(sb->buf, sb->len + extra + 1, sb->alloc);
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}
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void strbuf_add(struct strbuf *sb, const void *data, size_t len) {
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strbuf_grow(sb, len);
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memcpy(sb->buf + sb->len, data, len);
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strbuf_setlen(sb, sb->len + len);
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}
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void strbuf_addf(struct strbuf *sb, const char *fmt, ...) {
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int len;
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va_list ap;
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va_start(ap, fmt);
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len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
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va_end(ap);
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if (len < 0) {
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len = 0;
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}
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if (len >= strbuf_avail(sb)) {
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strbuf_grow(sb, len);
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va_start(ap, fmt);
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len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
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va_end(ap);
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if (len >= strbuf_avail(sb)) {
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die("this should not happen, your snprintf is broken");
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}
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}
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strbuf_setlen(sb, sb->len + len);
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}
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size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f) {
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size_t res;
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strbuf_grow(sb, size);
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res = fread(sb->buf + sb->len, 1, size, f);
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if (res > 0) {
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strbuf_setlen(sb, sb->len + res);
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}
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return res;
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}
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ssize_t strbuf_read(struct strbuf *sb, int fd)
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{
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size_t oldlen = sb->len;
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for (;;) {
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ssize_t cnt;
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strbuf_grow(sb, 8192);
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cnt = xread(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
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if (cnt < 0) {
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strbuf_setlen(sb, oldlen);
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return -1;
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}
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if (!cnt)
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break;
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sb->len += cnt;
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}
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sb->buf[sb->len] = '\0';
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return sb->len - oldlen;
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}
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void read_line(struct strbuf *sb, FILE *fp, int term) {
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int ch;
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if (feof(fp)) {
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strbuf_release(sb);
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sb->eof = 1;
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return;
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}
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strbuf_reset(sb);
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while ((ch = fgetc(fp)) != EOF) {
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if (ch == term)
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break;
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strbuf_grow(sb, 1);
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sb->buf[sb->len++] = ch;
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}
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if (ch == EOF && sb->len == 0) {
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strbuf_release(sb);
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sb->eof = 1;
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}
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strbuf_grow(sb, 1);
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sb->buf[sb->len] = '\0';
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}
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