From 764e787bc065694b2e9b05159a92104d585f59eb Mon Sep 17 00:00:00 2001
From: Andre Noll <maan@systemlinux.org>
Date: Sun, 3 Jan 2010 22:44:19 +0100
Subject: [PATCH] Add btr support for the amp filter.

---
 amp_filter.c  | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 buffer_tree.c | 11 +++++++++++
 buffer_tree.h |  2 ++
 3 files changed, 64 insertions(+)

diff --git a/amp_filter.c b/amp_filter.c
index b3aa2700..0ed2d8e0 100644
--- a/amp_filter.c
+++ b/amp_filter.c
@@ -98,6 +98,55 @@ static void amp_open(struct filter_node *fn)
 	fn->buf = para_malloc(fn->bufsize);
 }
 
+static void amp_post_select(__a_unused struct sched *s, struct task *t)
+{
+	struct filter_node *fn = container_of(t, struct filter_node, task);
+	struct private_amp_data *pad = fn->private_data;
+	struct btr_node *btrn = fn->btrn;
+	int ret, factor = 64 + pad->amp;
+	char *in;
+	size_t in_len = btr_next_buffer(btrn, &in);
+	size_t i, length = in_len / 2;
+	int16_t *ip = (int16_t *)in, *op;
+	bool inplace = btr_inplace_ok(btrn);
+
+	ret = prepare_filter_node(fn);
+	if (ret < 0)
+		goto err;
+	if (ret == 0)
+		return;
+
+	if (inplace)
+		op = ip;
+	else
+		op = para_malloc(length * 2);
+	if (pad->amp == 0) {
+		memcpy(op, ip, length * 2);
+		goto success;
+	}
+	for (i = 0; i < length; i++) {
+		int x = (ip[i] * factor) >> 6;
+
+		op[i] = x;
+		if (op[i] != x)
+			op[i] = (x >= 32768)? 32767 : -32768;
+	}
+success:
+	t->error = 0;
+	if (inplace)
+		btr_pushdown_one(btrn);
+	else {
+		btr_consume(btrn, length * 2);
+		btr_add_output((char *)op, length * 2, btrn);
+	}
+	return;
+err:
+	assert(ret < 0);
+	amp_close(fn);
+	t->error = ret;
+	btr_del_node(btrn);
+}
+
 /**
  * The init function of the amplify filter.
  *
@@ -111,6 +160,8 @@ void amp_filter_init(struct filter *f)
 	f->open = amp_open;
 	f->close = amp_close;
 	f->convert = amp_convert;
+	f->pre_select = generic_filter_pre_select;
+	f->post_select = amp_post_select;
 	f->parse_config = amp_parse_config;
 	f->help = (struct ggo_help) {
 		.short_help = amp_filter_args_info_help,
diff --git a/buffer_tree.c b/buffer_tree.c
index 5d8e33fc..1a6b6e60 100644
--- a/buffer_tree.c
+++ b/buffer_tree.c
@@ -137,6 +137,17 @@ void btr_pushdown(struct btr_node *btrn)
 		btr_pushdown_br(br, btrn);
 }
 
+int btr_pushdown_one(struct btr_node *btrn)
+{
+	struct btr_buffer_reference *br;
+
+	if (list_empty(&btrn->input_queue))
+		return 0;
+	br = list_first_entry(&btrn->input_queue, struct btr_buffer_reference, node);
+	btr_pushdown_br(br, btrn);
+	return 1;
+}
+
 /* Return true if this node has no children. */
 bool btr_no_children(struct btr_node *btrn)
 {
diff --git a/buffer_tree.h b/buffer_tree.h
index 77343f83..785cd272 100644
--- a/buffer_tree.h
+++ b/buffer_tree.h
@@ -22,3 +22,5 @@ void *btr_context(struct btr_node *btrn);
 void btr_merge(struct btr_node *btrn, size_t dest_size);
 bool btr_eof(struct btr_node *btrn);
 void btr_log_tree(struct btr_node *btrn, int loglevel);
+int btr_pushdown_one(struct btr_node *btrn);
+bool btr_inplace_ok(struct btr_node *btrn);
-- 
2.39.2