1 files changed, 77 insertions, 16 deletions

diff --git a/lib/dpkg/varbuf.c b/lib/dpkg/varbuf.c
index a5d3d31..5829a6f 100644
--- a/lib/dpkg/varbuf.c
+++ b/lib/dpkg/varbuf.c
@@ -46,10 +46,12 @@ varbuf_init(struct varbuf *v, size_t size)
 {
 	v->used = 0;
 	v->size = size;
-	if (size)
+	if (size) {
 		v->buf = m_malloc(size);
-	else
+		v->buf[0] = '\0';
+	} else {
 		v->buf = NULL;
+	}
 }
 
 void
@@ -83,18 +85,23 @@ varbuf_trunc(struct varbuf *v, size_t used_size)
 		internerr("varbuf new_used(%zu) > size(%zu)", used_size, v->size);
 
 	v->used = used_size;
+	if (v->buf)
+		v->buf[v->used] = '\0';
 }
 
 void
 varbuf_reset(struct varbuf *v)
 {
 	v->used = 0;
+	if (v->buf)
+		v->buf[0] = '\0';
 }
 
 const char *
-varbuf_get_str(struct varbuf *v)
+varbuf_str(struct varbuf *v)
 {
-	varbuf_end_str(v);
+	if (v->buf == NULL)
+		return "";
 
 	return v->buf;
 }
@@ -104,7 +111,6 @@ varbuf_set_buf(struct varbuf *v, const void *buf, size_t size)
 {
 	varbuf_reset(v);
 	varbuf_add_buf(v, buf, size);
-	varbuf_end_str(v);
 }
 
 void
@@ -116,16 +122,18 @@ varbuf_set_varbuf(struct varbuf *v, struct varbuf *other)
 void
 varbuf_add_varbuf(struct varbuf *v, const struct varbuf *other)
 {
-	varbuf_grow(v, other->used);
+	varbuf_grow(v, other->used + 1);
 	memcpy(v->buf + v->used, other->buf, other->used);
 	v->used += other->used;
+	v->buf[v->used] = '\0';
 }
 
 void
 varbuf_add_char(struct varbuf *v, int c)
 {
-	varbuf_grow(v, 1);
+	varbuf_grow(v, 2);
 	v->buf[v->used++] = c;
+	v->buf[v->used] = '\0';
 }
 
 void
@@ -133,9 +141,10 @@ varbuf_dup_char(struct varbuf *v, int c, size_t n)
 {
 	if (n == 0)
 		return;
-	varbuf_grow(v, n);
+	varbuf_grow(v, n + 1);
 	memset(v->buf + v->used, c, n);
 	v->used += n;
+	v->buf[v->used] = '\0';
 }
 
 void
@@ -161,16 +170,68 @@ varbuf_add_buf(struct varbuf *v, const void *s, size_t size)
 {
 	if (size == 0)
 		return;
-	varbuf_grow(v, size);
+	varbuf_grow(v, size + 1);
 	memcpy(v->buf + v->used, s, size);
 	v->used += size;
+	v->buf[v->used] = '\0';
+}
+
+bool
+varbuf_has_prefix(struct varbuf *v, struct varbuf *prefix)
+{
+	if (prefix->used > v->used)
+		return false;
+
+	if (prefix->used == 0)
+		return true;
+	if (v->used == 0)
+		return false;
+
+	return strncmp(v->buf, prefix->buf, prefix->used) == 0;
+}
+
+bool
+varbuf_has_suffix(struct varbuf *v, struct varbuf *suffix)
+{
+	const char *slice;
+
+	if (suffix->used > v->used)
+		return false;
+
+	if (suffix->used == 0)
+		return true;
+	if (v->used == 0)
+		return false;
+
+	slice = v->buf + v->used - suffix->used;
+
+	return strcmp(slice, suffix->buf) == 0;
 }
 
 void
-varbuf_end_str(struct varbuf *v)
+varbuf_trim_varbuf_prefix(struct varbuf *v, struct varbuf *prefix)
 {
-	varbuf_grow(v, 1);
-	v->buf[v->used] = '\0';
+	if (!varbuf_has_prefix(v, prefix))
+		return;
+
+	memmove(v->buf, v->buf + prefix->used, v->used - prefix->used);
+	varbuf_trunc(v, v->used - prefix->used);
+}
+
+void
+varbuf_trim_char_prefix(struct varbuf *v, int prefix)
+{
+	const char *str = v->buf;
+	size_t len = v->used;
+
+	while (str[0] == prefix && len > 0) {
+		str++;
+		len--;
+	}
+	if (str != v->buf) {
+		memmove(v->buf, str, len);
+		varbuf_trunc(v, len);
+	}
 }
 
 int
@@ -239,10 +300,7 @@ varbuf_rollback_start(struct varbuf_state *vs)
 		if (vs->used)
 			internerr("varbuf buf(NULL) state_used(%zu) > 0",
 			          vs->used);
-		/* XXX: Ideally this would be handled by varbuf always having
-		 * a valid buf or switching all users to the getter, but for
-		 * now this will do. */
-		return "";
+		return varbuf_str(vs->v);
 	}
 	return vs->v->buf + vs->used;
 }
@@ -256,6 +314,9 @@ varbuf_detach(struct varbuf *v)
 	v->size = 0;
 	v->used = 0;
 
+	if (buf == NULL)
+		buf = m_strdup("");
+
 	return buf;
 }