[PATCH] New strbuf APIs: splice and attach.
From: Pierre Habouzit <hidden>
Date: 2016-06-15 22:43:34
Subsystem:
the rest · Maintainer:
Linus Torvalds
* strbuf_splice replace a portion of the buffer with another. * strbuf_attach replace a strbuf buffer with the given one, that should be malloc'ed. Then it enforces strbuf's invariants. If alloc > len, then this function has negligible cost, else it will perform a realloc, possibly with a cost. Also some style issues are fixed now. Signed-off-by: Pierre Habouzit <redacted> --- strbuf.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++------------- strbuf.h | 5 ++++ 2 files changed, 57 insertions(+), 15 deletions(-)
diff --git a/strbuf.c b/strbuf.c
index d919047..ff551ac 100644
--- a/strbuf.c
+++ b/strbuf.c@@ -1,30 +1,45 @@ #include "cache.h" #include "strbuf.h" -void strbuf_init(struct strbuf *sb, size_t hint) { +void strbuf_init(struct strbuf *sb, size_t hint) +{ memset(sb, 0, sizeof(*sb)); if (hint) strbuf_grow(sb, hint); } -void strbuf_release(struct strbuf *sb) { +void strbuf_release(struct strbuf *sb) +{ free(sb->buf); memset(sb, 0, sizeof(*sb)); } -void strbuf_reset(struct strbuf *sb) { +void strbuf_reset(struct strbuf *sb) +{ if (sb->len) strbuf_setlen(sb, 0); sb->eof = 0; } -char *strbuf_detach(struct strbuf *sb) { +char *strbuf_detach(struct strbuf *sb) +{ char *res = sb->buf; strbuf_init(sb, 0); return res; } -void strbuf_grow(struct strbuf *sb, size_t extra) { +void strbuf_attach(struct strbuf *sb, void *buf, size_t len, size_t alloc) +{ + strbuf_release(sb); + sb->buf = buf; + sb->len = len; + sb->alloc = alloc; + strbuf_grow(sb, 0); + sb->buf[sb->len] = '\0'; +} + +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);
@@ -37,24 +52,44 @@ void strbuf_rtrim(struct strbuf *sb) sb->buf[sb->len] = '\0'; } -void strbuf_insert(struct strbuf *sb, size_t pos, const void *data, size_t len) { +void strbuf_insert(struct strbuf *sb, size_t pos, const void *data, size_t len) +{ strbuf_grow(sb, len); - if (pos >= sb->len) { - pos = sb->len; - } else { - memmove(sb->buf + pos + len, sb->buf + pos, sb->len - pos); - } + if (pos > sb->len) + die("`pos' is too far after the end of the buffer"); + memmove(sb->buf + pos + len, sb->buf + pos, sb->len - pos); memcpy(sb->buf + pos, data, len); strbuf_setlen(sb, sb->len + len); } -void strbuf_add(struct strbuf *sb, const void *data, size_t len) { +void strbuf_splice(struct strbuf *sb, size_t pos, size_t len, + const void *data, size_t dlen) +{ + if (pos + len < pos) + die("you want to use way too much memory"); + if (pos > sb->len) + die("`pos' is too far after the end of the buffer"); + if (pos + len > sb->len) + die("`pos + len' is too far after the end of the buffer"); + + if (dlen >= len) + strbuf_grow(sb, dlen - len); + memmove(sb->buf + pos + dlen, + sb->buf + pos + len, + sb->len - pos - len); + memcpy(sb->buf + pos, data, dlen); + strbuf_setlen(sb, sb->len + dlen - len); +} + +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, ...) { +void strbuf_addf(struct strbuf *sb, const char *fmt, ...) +{ int len; va_list ap;
@@ -76,7 +111,8 @@ void strbuf_addf(struct strbuf *sb, const char *fmt, ...) { strbuf_setlen(sb, sb->len + len); } -size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f) { +size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f) +{ size_t res; strbuf_grow(sb, size);
@@ -110,7 +146,8 @@ ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint) return sb->len - oldlen; } -void read_line(struct strbuf *sb, FILE *fp, int term) { +void read_line(struct strbuf *sb, FILE *fp, int term) +{ int ch; if (feof(fp)) { strbuf_release(sb);
diff --git a/strbuf.h b/strbuf.h
index 21fc111..f163c63 100644
--- a/strbuf.h
+++ b/strbuf.h@@ -55,6 +55,7 @@ extern void strbuf_init(struct strbuf *, size_t); extern void strbuf_release(struct strbuf *); extern void strbuf_reset(struct strbuf *); extern char *strbuf_detach(struct strbuf *); +extern void strbuf_attach(struct strbuf *, void *, size_t, size_t); /*----- strbuf size related -----*/ static inline size_t strbuf_avail(struct strbuf *sb) {
@@ -81,6 +82,10 @@ static inline void strbuf_addch(struct strbuf *sb, int c) { /* inserts after pos, or appends if pos >= sb->len */ extern void strbuf_insert(struct strbuf *, size_t pos, const void *, size_t); +/* splice pos..pos+len with given data */ +extern void strbuf_splice(struct strbuf *, size_t pos, size_t len, + const void *, size_t); + extern void strbuf_add(struct strbuf *, const void *, size_t); static inline void strbuf_addstr(struct strbuf *sb, const char *s) { strbuf_add(sb, s, strlen(s));
--
1.5.3.1