1 files changed, 101 insertions, 0 deletions

diff --git a/lib/rbcodec/codecs/libpcm/adpcm_seek.c b/lib/rbcodec/codecs/libpcm/adpcm_seek.c
new file mode 100644
index 0000000000..ce49d5fcd3
--- /dev/null
+++ b/lib/rbcodec/codecs/libpcm/adpcm_seek.c
@@ -0,0 +1,101 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2010 Yoshihisa Uchida
+ *
+ * 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#include "adpcm_seek.h"
+#include "codeclib.h"
+
+/*
+ * The helper functions in order to seek for the adpcm codec
+ * which does not include the header each the data block.
+ */
+
+#define MAX_STORE_COUNT 1000
+
+static struct adpcm_data seek_table[MAX_STORE_COUNT];
+static int seek_count;
+static int cur_count;
+static int max_ratio;
+static int cur_ratio;
+
+void init_seek_table(uint32_t max_count)
+{
+    int i = 0;
+
+    for ( ; i < MAX_STORE_COUNT; i++)
+    {
+        seek_table[i].is_valid = false;
+    }
+    seek_count = max_count / MAX_STORE_COUNT + 1;
+    max_ratio  = max_count / seek_count + 1;
+    cur_count  = 0;
+    cur_ratio  = -1;
+}
+
+void add_adpcm_data(struct adpcm_data *data)
+{
+    if (--cur_count <= 0)
+    {
+        cur_count = seek_count;
+        if (++cur_ratio >= max_ratio)
+            cur_ratio = max_ratio - 1;
+
+        if (!seek_table[cur_ratio].is_valid)
+        {
+            seek_table[cur_ratio].pcmdata[0] = data->pcmdata[0];
+            seek_table[cur_ratio].pcmdata[1] = data->pcmdata[1];
+            seek_table[cur_ratio].step[0]    = data->step[0];
+            seek_table[cur_ratio].step[1]    = data->step[1];
+            seek_table[cur_ratio].is_valid   = true;
+        }
+    }
+}
+
+uint32_t seek(uint32_t count, struct adpcm_data *seek_data,
+              uint8_t *(*read_buffer)(size_t *realsize),
+              int (*decode)(const uint8_t *inbuf, size_t inbufsize))
+{
+    int new_ratio = count / seek_count;
+
+    if (new_ratio >= max_ratio)
+        new_ratio = max_ratio - 1;
+
+    if (!seek_table[new_ratio].is_valid)
+    {
+        uint8_t *buffer;
+        size_t n;
+
+        do
+        {
+            buffer = read_buffer(&n);
+            if (n == 0)
+                break;
+            decode(buffer, n);
+        } while (cur_ratio < new_ratio);
+    }
+
+    seek_data->pcmdata[0] = seek_table[new_ratio].pcmdata[0];
+    seek_data->pcmdata[1] = seek_table[new_ratio].pcmdata[1];
+    seek_data->step[0]    = seek_table[new_ratio].step[0];
+    seek_data->step[1]    = seek_table[new_ratio].step[1];
+
+    cur_ratio = new_ratio;
+    cur_count = seek_count;
+    return cur_ratio * seek_count;
+}