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 0000000..3e678e8
--- /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++;
+    }
+}