Adding strbuf.

lifting a portion of the strbuf api/implementation found in archived.
This will serve as a base for an generic buffer api.

strbuf.h

@@ -0,0 +1,98 @@
+/* strbuf.h
+ *
+ *   Copyright (C) 2010-2011   Henrik Hautakoski <henrik@fiktivkod.org>
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ *   MA 02110-1301, USA.
+ */
+
+#ifndef __STRBUF_H
+#define __STRBUF_H
+
+#include <string.h>
+#include <stddef.h>
+
+typedef struct {
+	char  *buf;
+	size_t len;
+	size_t size;
+} strbuf_t;
+
+extern char strbuf_null;
+
+#define STRBUF_INIT { &strbuf_null, 0, 0 }
+
+void strbuf_init(strbuf_t *s);
+
+static inline size_t strbuf_avail(strbuf_t *s) {
+
+	return s->size ? s->size - (s->len + 1) : 0;
+}
+
+void strbuf_expand(strbuf_t *s, size_t len);
+
+static inline void strbuf_setlen(strbuf_t *s, size_t len) {
+
+	if (!s->size)
+		return;
+
+	if (len >= s->size)
+		len = s->size - 1;
+	s->len = len;
+	s->buf[s->len] = '\0';
+}
+
+static inline void strbuf_reduce(strbuf_t *s, size_t len) {
+
+	if (len > s->len)
+		len = s->len;
+
+	strbuf_setlen(s, s->len - len);
+}
+
+char* strbuf_release(strbuf_t *s);
+
+void strbuf_free(strbuf_t *s);
+
+void strbuf_attach(strbuf_t *s, void *str, size_t len, size_t size);
+
+void strbuf_append(strbuf_t *s, const void *ptr, size_t len);
+
+static inline void strbuf_append_str(strbuf_t *s, const char *str) {
+
+	strbuf_append(s, str, strlen(str));
+}
+
+static inline void strbuf_append_ch(strbuf_t *s, char ch) {
+
+	strbuf_expand(s, 1);
+	s->buf[s->len++] = ch;
+	s->buf[s->len] = '\0';
+}
+
+static inline void strbuf_append_repeat(strbuf_t *s, char ch, size_t len) {
+
+	strbuf_expand(s, len);
+	memset(s->buf + s->len, ch, len);
+	strbuf_setlen(s, s->len + len);
+}
+
+static inline void strbuf_term(strbuf_t *s, char ch) {
+
+	if (s->buf[s->len-1] != ch)
+		strbuf_append_ch(s, ch);
+}
+
+#endif /* __STRBUF_H */