From d7e95515b8515bf9c2ea58579a0b8133194aaa4b Mon Sep 17 00:00:00 2001
From: Andre Noll <maan@systemlinux.org>
Date: Sat, 21 May 2011 21:06:01 +0200
Subject: [PATCH] Simplify ogg_post_select().

Currently, in each invocation of post_select(), we allocate a
640K buffer and shrink it afterwards to the actual size of the
decoded data. This is ugly and unnecessary.

This patch changes ogg_post_select() to allocate and fill 32K
buffers until the maximal output size is reached or there is
nothing left to decode.
---
 oggdec_filter.c | 64 ++++++++++++++++++++++---------------------------
 1 file changed, 29 insertions(+), 35 deletions(-)

diff --git a/oggdec_filter.c b/oggdec_filter.c
index 44d299fe..042e13b0 100644
--- a/oggdec_filter.c
+++ b/oggdec_filter.c
@@ -113,8 +113,6 @@ static void ogg_close(struct filter_node *fn)
 	fn->private_data = NULL;
 }
 
-#define OGGDEC_OUTPUT_CHUNK_SIZE (640 * 1024)
-
 static int oggdec_execute(struct btr_node *btrn, const char *cmd, char **result)
 {
 	struct filter_node *fn = btr_context(btrn);
@@ -194,18 +192,18 @@ static void ogg_pre_select(__a_unused struct sched *s, struct task *t)
 		sched_request_timeout_ms(100, s);
 }
 
+#define OGGDEC_MAX_OUTPUT_SIZE (128 * 1024)
+#define OGGDEC_OUTPUT_CHUNK_SIZE (32 * 1024)
+
 static void ogg_post_select(__a_unused struct sched *s, struct task *t)
 {
 	struct filter_node *fn = container_of(t, struct filter_node, task);
 	struct private_oggdec_data *pod = fn->private_data;
 	struct btr_node *btrn = fn->btrn;
-	int ret, ns;
-	char *out;
-	ssize_t read_ret, have;
+	int ret, have;
+	char *buf;
 
-	pod->converted = 0;
-	t->error = 0;
-	ret = ns = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
+	ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
 	if (ret <= 0)
 		goto out;
 	if (!pod->vf) {
@@ -213,44 +211,40 @@ static void ogg_post_select(__a_unused struct sched *s, struct task *t)
 			goto out;
 		btr_merge(btrn, fn->min_iqs);
 		ret = ogg_init(fn);
-		if (ret <= 0)
-			goto out;
+		goto out;
 	}
-	out = para_malloc(OGGDEC_OUTPUT_CHUNK_SIZE);
-	for (have = 0;;) {
-		read_ret = ov_read(pod->vf, out + have,
-			OGGDEC_OUTPUT_CHUNK_SIZE - have,
+	have = 0;
+	buf = para_malloc(OGGDEC_OUTPUT_CHUNK_SIZE);
+	for (;;) {
+		ret = ov_read(pod->vf, buf + have, OGGDEC_OUTPUT_CHUNK_SIZE - have,
 			ENDIAN, 2 /* 16 bit */, 1 /* signed */, NULL);
 		btr_consume(btrn, pod->converted);
 		pod->converted = 0;
-		if (read_ret <= 0)
-			break;
-		have += read_ret;
-		if (have >= OGGDEC_OUTPUT_CHUNK_SIZE)
+		if (ret <= 0)
 			break;
-	}
-	if (have == 0)
-		free(out);
-	else if (have < OGGDEC_OUTPUT_CHUNK_SIZE)
-		out = para_realloc(out, have);
-	if (have > 0) {
-		btr_add_output(out, have, btrn);
 		fn->min_iqs = 0;
+		have += ret;
+		if (have < OGGDEC_OUTPUT_CHUNK_SIZE)
+			continue;
+		if (btr_get_output_queue_size(btrn) > OGGDEC_MAX_OUTPUT_SIZE)
+			break;
+		btr_add_output(buf, have, btrn);
+		buf = para_malloc(OGGDEC_OUTPUT_CHUNK_SIZE);
+		have = 0;
 	}
-	ret = ns;
-	if (read_ret == OV_HOLE) /* avoid buffer underruns */
+	if (have > 0)
+		btr_add_output(buf, have, btrn);
+	else
+		free(buf);
+	if (ret == OV_HOLE) /* avoid buffer underruns */
 		fn->min_iqs = 9000;
-	if (read_ret == 0 || read_ret == OV_HOLE)
-		goto out;
+	if (ret >= 0 || ret == OV_HOLE)
+		return;
 	ret = -E_OGGDEC_BADLINK;
-	if (read_ret < 0)
-		goto out;
-	ret = 0;
 out:
-	if (ret < 0) {
-		t->error = ret;
+	t->error = ret;
+	if (ret < 0)
 		btr_remove_node(btrn);
-	}
 }
 
 /**
-- 
2.39.5