strbuf API additions and enhancements.

Add strbuf_remove, change strbuf_insert:
  As both are special cases of strbuf_splice, implement them as such.
  gcc is able to do the math and generate almost optimal code this way.

Add strbuf_swap:
  Exchange the values of its arguments.
  Use it in fast-import.c

Also fix spacing issues in strbuf.h

Signed-off-by: Pierre Habouzit <madcoder@debian.org>

commit.c

@@ -656,7 +656,7 @@ static char *replace_encoding_header(char *buf, const char *encoding)
 	strbuf_attach(&tmp, buf, strlen(buf), strlen(buf) + 1);
 	if (is_encoding_utf8(encoding)) {
 		/* we have re-coded to UTF-8; drop the header */
-		strbuf_splice(&tmp, start, len, NULL, 0);
+		strbuf_remove(&tmp, start, len);
 	} else {
 		/* just replaces XXXX in 'encoding XXXX\n' */
 		strbuf_splice(&tmp, start + strlen("encoding "),

fast-import.c

@@ -1111,9 +1111,7 @@ static int store_object(
 		if (last->no_swap) {
 			last->data = *dat;
 		} else {
-			struct strbuf tmp = *dat;
+			strbuf_swap(&last->data, dat);
-			*dat = last->data;
-			last->data = tmp;
 		}
 		last->offset = e->offset;
 	}

strbuf.c

@@ -50,16 +50,6 @@ 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)
-{
-	strbuf_grow(sb, len);
-	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_splice(struct strbuf *sb, size_t pos, size_t len,
 				   const void *data, size_t dlen)
 {
@@ -79,6 +69,16 @@ void strbuf_splice(struct strbuf *sb, size_t pos, size_t len,
 	strbuf_setlen(sb, sb->len + dlen - len);
 }
 
+void strbuf_insert(struct strbuf *sb, size_t pos, const void *data, size_t len)
+{
+	strbuf_splice(sb, pos, 0, data, len);
+}
+
+void strbuf_remove(struct strbuf *sb, size_t pos, size_t len)
+{
+	strbuf_splice(sb, pos, len, NULL, 0);
+}
+
 void strbuf_add(struct strbuf *sb, const void *data, size_t len)
 {
 	strbuf_grow(sb, len);

strbuf.h

@@ -55,15 +55,20 @@ 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);
+static inline void strbuf_swap(struct strbuf *a, struct strbuf *b) {
+	struct strbuf tmp = *a;
+	*a = *b;
+	*b = tmp;
+}
 
 /*----- strbuf size related -----*/
 static inline size_t strbuf_avail(struct strbuf *sb) {
-    return sb->alloc ? sb->alloc - sb->len - 1 : 0;
+	return sb->alloc ? sb->alloc - sb->len - 1 : 0;
 }
 static inline void strbuf_setlen(struct strbuf *sb, size_t len) {
-    assert (len < sb->alloc);
+	assert (len < sb->alloc);
-    sb->len = len;
+	sb->len = len;
-    sb->buf[len] = '\0';
+	sb->buf[len] = '\0';
 }
 
 extern void strbuf_grow(struct strbuf *, size_t);
@@ -78,12 +83,12 @@ static inline void strbuf_addch(struct strbuf *sb, int c) {
 	sb->buf[sb->len] = '\0';
 }
 
-/* inserts after pos, or appends if pos >= sb->len */
 extern void strbuf_insert(struct strbuf *, size_t pos, const void *, size_t);
+extern void strbuf_remove(struct strbuf *, size_t pos, size_t len);
 
 /* splice pos..pos+len with given data */
 extern void strbuf_splice(struct strbuf *, size_t pos, size_t len,
-						  const void *, size_t);
+                          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) {