Commit FS#10423 by Yoshihisa Uchida. Adds support for floating point PCM to libpcm.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24348 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 147 insertions, 0 deletions

diff --git a/apps/codecs/libpcm/ieee_float.c b/apps/codecs/libpcm/ieee_float.c
new file mode 100644
index 0000000000..a5c50e845e
--- /dev/null
+++ b/apps/codecs/libpcm/ieee_float.c
@@ -0,0 +1,147 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2009 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 "codeclib.h"
+#include "pcm_common.h"
+
+/*
+ * IEEE float
+ */
+
+static struct pcm_format *fmt;
+
+static bool set_format(struct pcm_format *format, const unsigned char *fmtpos)
+{
+    fmt = format;
+
+    (void)fmtpos;
+
+    if (fmt->bitspersample != 32 && fmt->bitspersample != 64)
+    {
+        DEBUGF("CODEC_ERROR: ieee float must be 32 or 64 bitspersample %d\n", fmt->bitspersample);
+        return false;
+    }
+
+    fmt->bytespersample = fmt->bitspersample >> 3;
+    fmt->blockalign = fmt->bytespersample;
+
+    /* chunksize is computed so that one chunk is about 1/50s. */
+    fmt->chunksize = (ci->id3->frequency * fmt->channels / 50) * fmt->blockalign;
+
+    return true;
+}
+
+static uint32_t get_seek_pos(long seek_time)
+{
+    uint32_t newpos;
+
+    newpos = ((uint64_t)(seek_time * ci->id3->frequency * fmt->channels / 1000LL))*fmt->blockalign;
+    return newpos;
+}
+
+static int decode(const uint8_t *inbuf, size_t inbufsize,
+                  int32_t *outbuf, int *outbufsize)
+{
+    uint32_t i;
+    int32_t pcm;
+    int16_t exp;
+    int sgn;
+
+    if (fmt->bitspersample == 32)
+    {
+        for (i = 0; i < inbufsize; i += 4)
+        {
+            if (fmt->is_little_endian)
+            {
+                pcm = (inbuf[0]<<5)|(inbuf[1]<<13)|((inbuf[2]|0x80)<<21);
+                exp = ((inbuf[2]>>7)|((inbuf[3]&0x7f)<<1)) - 127;
+                sgn = inbuf[3] & 0x80;
+            }
+            else
+            {
+                pcm = (inbuf[3]<<5)|(inbuf[2]<<13)|((inbuf[1]|0x80)<<21);
+                exp = ((inbuf[1]>>7)|((inbuf[0]&0x7f)<<1)) - 127;
+                sgn = inbuf[0] & 0x80;
+            }
+            if (exp > -29 && exp < 0)
+            {
+                pcm >>= -exp;
+                if (sgn)
+                    pcm = -pcm;
+            }
+            else if (exp < -28)
+                pcm = 0;
+            else
+                pcm = (sgn)?-(1<<28):(1<<28)-1;
+
+            outbuf[i/4] = pcm;
+            inbuf += 4;
+        }
+        *outbufsize = inbufsize >> 2;
+    }
+    else
+    {
+        for (i = 0; i < inbufsize; i += 8)
+        {
+            if (fmt->is_little_endian)
+            {
+                pcm = inbuf[3]|(inbuf[4]<<8)|(inbuf[5]<<16)|(((inbuf[6]&0x0f)|0x10)<<24);
+                exp = (((inbuf[6]&0xf0)>>4)|((inbuf[7]&0x7f)<<4)) - 1023;
+                sgn = inbuf[7] & 0x80;
+            }
+            else
+            {
+                pcm = inbuf[4]|(inbuf[3]<<8)|(inbuf[2]<<16)|(((inbuf[1]&0x0f)|0x10)<<24);
+                exp = (((inbuf[1]&0xf0)>>4)|((inbuf[0]&0x7f)<<4)) - 1023;
+                sgn = inbuf[0] & 0x80;
+            }
+            if (exp > -29 && exp < 0)
+            {
+                pcm >>= -exp;
+                if (sgn)
+                    pcm = -pcm;
+            }
+            else if (exp < -28)
+                pcm = 0;
+            else
+                pcm = (sgn)?-(1<<28):(1<<28)-1;
+
+            outbuf[i/8] = pcm;
+            inbuf += 8;
+        }
+        *outbufsize = inbufsize >> 3;
+    }
+
+    if (fmt->channels == 2)
+        *outbufsize >>= 1;
+
+    return CODEC_OK;
+}
+
+static const struct pcm_codec codec = {
+                                          set_format,
+                                          get_seek_pos,
+                                          decode,
+                                      };
+
+const struct pcm_codec *get_ieee_float_codec(void)
+{
+    return &codec;
+}