Initial import of libwavpack

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@6056 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 83 insertions, 0 deletions

diff --git a/apps/codecs/libwavpack/float.c b/apps/codecs/libwavpack/float.c
new file mode 100644
index 0000000000..3e678e824d
--- /dev/null
+++ b/apps/codecs/libwavpack/float.c
@@ -0,0 +1,83 @@
+////////////////////////////////////////////////////////////////////////////
+//                           **** WAVPACK ****                            //
+//                  Hybrid Lossless Wavefile Compressor                   //
+//              Copyright (c) 1998 - 2004 Conifer Software.               //
+//                          All Rights Reserved.                          //
+//      Distributed under the BSD Software License (see license.txt)      //
+////////////////////////////////////////////////////////////////////////////
+
+// float.c
+
+#include "wavpack.h"
+
+int read_float_info (WavpackStream *wps, WavpackMetadata *wpmd)
+{
+    int bytecnt = wpmd->byte_length;
+    char *byteptr = wpmd->data;
+
+    if (bytecnt != 4)
+        return FALSE;
+
+    wps->float_flags = *byteptr++;
+    wps->float_shift = *byteptr++;
+    wps->float_max_exp = *byteptr++;
+    wps->float_norm_exp = *byteptr;
+    return TRUE;
+}
+
+void float_values (WavpackStream *wps, long *values, long num_values)
+{
+    while (num_values--) {
+        int shift_count = 0, exp = wps->float_max_exp;
+        f32 outval = { 0, 0, 0 };
+
+        if (*values) {
+            *values <<= wps->float_shift;
+
+            if (*values < 0) {
+                *values = -*values;
+                outval.sign = 1;
+            }
+
+            if (*values == 0x1000000)
+                outval.exponent = 255;
+            else {
+                if (exp)
+                    while (!(*values & 0x800000) && --exp) {
+                        shift_count++;
+                        *values <<= 1;
+                    }
+
+                if (shift_count && (wps->float_flags & FLOAT_SHIFT_ONES))
+                    *values |= ((1 << shift_count) - 1);
+
+                outval.mantissa = *values;
+                outval.exponent = exp;
+            }
+        }
+
+        * (f32 *) values++ = outval;
+    }
+}
+
+void float_normalize (long *values, long num_values, int delta_exp)
+{
+    f32 *fvalues = (f32 *) values, fzero = { 0, 0, 0 };
+    int exp;
+
+    if (!delta_exp)
+        return;
+
+    while (num_values--) {
+        if ((exp = fvalues->exponent) == 0 || exp + delta_exp <= 0)
+            *fvalues = fzero;
+        else if (exp == 255 || (exp += delta_exp) >= 255) {
+            fvalues->exponent = 255;
+            fvalues->mantissa = 0;
+        }
+        else
+            fvalues->exponent = exp;
+
+        fvalues++;
+    }
+}