ReplayGain support files.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@7233 a1c6a512-1295-4272-9138-f99709370657

2 files changed, 354 insertions, 0 deletions

diff --git a/firmware/export/replaygain.h b/firmware/export/replaygain.h
new file mode 100644
index 0000000..09b0776
--- /dev/null
+++ b/firmware/export/replaygain.h
@@ -0,0 +1,26 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2005 Magnus Holmgren
+ *
+ * All files in this archive are subject to the GNU General Public License.
+ * See the file COPYING in the source tree root for full license agreement.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#ifndef _REPLAYGAIN_H
+#define _REPLAYGAIN_H
+
+long get_replaygain(const char* str);
+long get_replaypeak(const char* str);
+
+#endif
diff --git a/firmware/replaygain.c b/firmware/replaygain.c
new file mode 100644
index 0000000..23a25cc
--- /dev/null
+++ b/firmware/replaygain.c
@@ -0,0 +1,328 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2005 Magnus Holmgren
+ *
+ * All files in this archive are subject to the GNU General Public License.
+ * See the file COPYING in the source tree root for full license agreement.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+#include <ctype.h>
+#include <inttypes.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include "debug.h"
+
+/* The fixed point math routines (with the exception of fp_atof) are based
+ * on oMathFP by Dan Carter (http://orbisstudios.com).
+ */
+
+/* 12 bits of precision gives fairly accurate result, but still allows a
+ * compact implementation. The math code supports up to 13...
+ */
+
+#define FP_BITS         (12)
+#define FP_MASK         ((1 << FP_BITS) - 1)
+#define FP_ONE          (1 << FP_BITS)
+#define FP_TWO          (2 << FP_BITS)
+#define FP_HALF         (1 << (FP_BITS - 1))
+#define FP_LN2          ( 45426 >> (16 - FP_BITS))
+#define FP_LN2_INV      ( 94548 >> (16 - FP_BITS))
+#define FP_EXP_ZERO     ( 10922 >> (16 - FP_BITS))
+#define FP_EXP_ONE      (  -182 >> (16 - FP_BITS))
+#define FP_EXP_TWO      (     4 >> (16 - FP_BITS))
+#define FP_INF          (0x7fffffff)
+#define FP_LN10         (150902 >> (16 - FP_BITS))
+
+#define FP_MAX_DIGITS       (4)
+#define FP_MAX_DIGITS_INT   (10000)
+
+#define FP_FAST_MUL_DIV
+
+#ifdef FP_FAST_MUL_DIV
+
+/* These macros can easily overflow, but they are good enough for our uses,
+ * and saves some code.
+ */
+#define fp_mul(x, y) (((x) * (y)) >> FP_BITS)
+#define fp_div(x, y) (((x) << FP_BITS) / (y))
+
+#else
+
+static long fp_mul(long x, long y)
+{
+    long x_neg = 0;
+    long y_neg = 0;
+    long rc;
+
+    if ((x == 0) || (y == 0))
+    {
+        return 0;
+    }
+
+    if (x < 0)
+    {
+        x_neg = 1;
+        x = -x;
+    }
+
+    if (y < 0)
+    {
+        y_neg = 1;
+        y = -y;
+    }
+
+    rc = (((x >> FP_BITS) * (y >> FP_BITS)) << FP_BITS)
+        + (((x & FP_MASK) * (y & FP_MASK)) >> FP_BITS)
+        + ((x & FP_MASK) * (y >> FP_BITS))
+        + ((x >> FP_BITS) * (y & FP_MASK));
+
+    if ((x_neg ^ y_neg) == 1)
+    {
+        rc = -rc;
+    }
+
+    return rc;
+}
+
+static long fp_div(long x, long y)
+{
+    long x_neg = 0;
+    long y_neg = 0;
+    long shifty;
+    long rc;
+    int msb = 0;
+    int lsb = 0;
+
+    if (x == 0)
+    {
+        return 0;
+    }
+
+    if (y == 0)
+    {
+        return (x < 0) ? -FP_INF : FP_INF;
+    }
+
+    if (x < 0)
+    {
+        x_neg = 1;
+        x = -x;
+    }
+
+    if (y < 0)
+    {
+        y_neg = 1;
+        y = -y;
+    }
+
+    while ((x & (1 << (30 - msb))) == 0)
+    {
+        msb++;
+    }
+
+    while ((y & (1 << lsb)) == 0)
+    {
+        lsb++;
+    }
+
+    shifty = FP_BITS - (msb + lsb);
+    rc = ((x << msb) / (y >> lsb));
+
+    if (shifty > 0)
+    {
+        rc <<= shifty;
+    }
+    else
+    {
+        rc >>= -shifty;
+    }
+
+    if ((x_neg ^ y_neg) == 1)
+    {
+        rc = -rc;
+    }
+
+    return rc;
+}
+
+#endif /* FP_FAST_MUL_DIV */
+
+static long fp_exp(long x)
+{
+    long k;
+    long z;
+    long R;
+    long xp;
+
+    if (x == 0)
+    {
+        return FP_ONE;
+    }
+
+    k = (fp_mul(abs(x), FP_LN2_INV) + FP_HALF) & ~FP_MASK;
+
+    if (x < 0)
+    {
+        k = -k;
+    }
+
+    x -= fp_mul(k, FP_LN2);
+    z = fp_mul(x, x);
+    R = FP_TWO + fp_mul(z, FP_EXP_ZERO + fp_mul(z, FP_EXP_ONE
+        + fp_mul(z, FP_EXP_TWO)));
+    xp = FP_ONE + fp_div(fp_mul(FP_TWO, x), R - x);
+
+    if (k < 0)
+    {
+        k = FP_ONE >> (-k >> FP_BITS);
+    }
+    else
+    {
+        k = FP_ONE << (k >> FP_BITS);
+    }
+
+    return fp_mul(k, xp);
+}
+
+static long fp_exp10(long x)
+{
+    if (x == 0)
+    {
+        return FP_ONE;
+    }
+
+    return fp_exp(fp_mul(FP_LN10, x));
+}
+
+static long fp_atof(const char* s, int precision)
+{
+    long int_part = 0;
+    long int_one = 1 << precision;
+    long frac_part = 0;
+    long frac_count = 0;
+    long frac_max = ((precision * 4) + 12) / 13;
+    long frac_max_int = 1;
+    long sign = 1;
+    bool point = false;
+
+    while ((*s != '\0') && isspace(*s))
+    {
+        s++;
+    }
+
+    if (*s == '-')
+    {
+        sign = -1;
+        s++;
+    }
+    else if (*s == '+')
+    {
+        s++;
+    }
+
+    while (*s != '\0')
+    {
+        if (*s == '.')
+        {
+            if (point)
+            {
+                break;
+            }
+
+            point = true;
+        }
+        else if (isdigit(*s))
+        {
+            if (point)
+            {
+                if (frac_count < frac_max)
+                {
+                    frac_part = frac_part * 10 + (*s - '0');
+                    frac_count++;
+                    frac_max_int *= 10;
+                }
+            }
+            else
+            {
+                int_part = int_part * 10 + (*s - '0');
+            }
+        }
+        else
+        {
+            break;
+        }
+
+        s++;
+    }
+
+    while (frac_count < frac_max)
+    {
+      frac_part *= 10;
+      frac_count++;
+      frac_max_int *= 10;
+    }
+
+    return sign * ((int_part * int_one) 
+        + (((int64_t) frac_part * int_one) / frac_max_int));
+}
+
+static long convert_gain(long gain)
+{
+    if (gain != 0)
+    {
+        /* Don't allow unreasonably low or high gain changes. 
+         * Our math code can't handle it properly anyway. :)
+         */
+        if (gain < (-23 * FP_ONE))
+        {
+            gain = -23 * FP_ONE;
+        }
+    
+        if (gain > (17 * FP_ONE))
+        {
+            gain = 17 * FP_ONE;
+        }
+
+        gain = fp_exp10(gain / 20) << (24 - FP_BITS);
+    }
+    
+    return gain;
+}
+
+long get_replaygain(const char* str)
+{
+    long gain = 0;
+    
+    if (str)
+    {
+        gain = fp_atof(str, FP_BITS);
+        gain = convert_gain(gain);
+    }
+    
+    return gain;
+}
+
+long get_replaypeak(const char* str)
+{
+    long peak = 0;
+    
+    if (str)
+    {
+        peak = fp_atof(str, 24);
+    }
+    
+    return peak;
+}