From 15318cad33835e4e2dc620d033e43cd930676cdd Mon Sep 17 00:00:00 2001
From: kergoth <kergoth>
Date: Fri, 25 Jan 2002 22:14:26 +0000
Subject: Initial revision

---
(limited to 'core/multimedia/opieplayer/libmpeg3/audio/exponents.c')

diff --git a/core/multimedia/opieplayer/libmpeg3/audio/exponents.c b/core/multimedia/opieplayer/libmpeg3/audio/exponents.c
new file mode 100644
index 0000000..deda9b9
--- a/dev/null
+++ b/core/multimedia/opieplayer/libmpeg3/audio/exponents.c
@@ -0,0 +1,141 @@
+/* 
+ *
+ *	exponents.c Copyright (C) Aaron Holtzman - May 1999
+ *
+ *  This file is part of libmpeg3
+ *	
+ *  libmpeg3 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, or (at your option)
+ *  any later version.
+ *   
+ *  libmpeg3 is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *   
+ *  You should have received a copy of the GNU General Public License
+ *  along with GNU Make; see the file COPYING.  If not, write to
+ *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. 
+ *
+ */
+
+#include "mpeg3audio.h"
+#include "../libmpeg3.h"
+#include "../mpeg3protos.h"
+#include <stdio.h>
+
+/* Exponent defines */
+#define UNPACK_FBW  1
+#define UNPACK_CPL  2
+#define UNPACK_LFE  4
+
+static inline int mpeg3audio_ac3_exp_unpack_ch(unsigned int type,
+		unsigned int expstr,
+		unsigned int ngrps,
+		unsigned int initial_exp, 
+		unsigned short exps[], 
+		unsigned short *dest)
+{
+	int i, j;
+	int exp_acc;
+	int exp_1, exp_2, exp_3;
+
+	if(expstr == MPEG3_EXP_REUSE)
+		return 0;
+
+/* Handle the initial absolute exponent */
+	exp_acc = initial_exp;
+	j = 0;
+
+/* In the case of a fbw channel then the initial absolute value is 
+ * also an exponent */
+	if(type != UNPACK_CPL)
+		dest[j++] = exp_acc;
+
+/* Loop through the groups and fill the dest array appropriately */
+	for(i = 0; i < ngrps; i++)
+	{
+		if(exps[i] > 124)
+		{
+			fprintf(stderr, "mpeg3audio_ac3_exp_unpack_ch: Invalid exponent %d\n", exps[i]);
+			return 1;
+		}
+
+		exp_1 = exps[i] / 25;
+		exp_2 = (exps[i] % 25) / 5;
+		exp_3 = (exps[i] % 25) % 5;
+
+		exp_acc += (exp_1 - 2);
+
+		switch(expstr)
+		{
+			case MPEG3_EXP_D45:
+				dest[j++] = exp_acc;
+				dest[j++] = exp_acc;
+			case MPEG3_EXP_D25:
+				dest[j++] = exp_acc;
+			case MPEG3_EXP_D15:
+				dest[j++] = exp_acc;
+		}
+
+		exp_acc += (exp_2 - 2);
+
+		switch(expstr)
+		{
+			case MPEG3_EXP_D45:
+				dest[j++] = exp_acc;
+				dest[j++] = exp_acc;
+			case MPEG3_EXP_D25:
+				dest[j++] = exp_acc;
+			case MPEG3_EXP_D15:
+				dest[j++] = exp_acc;
+		}
+
+		exp_acc += (exp_3 - 2);
+
+		switch(expstr)
+		{
+			case MPEG3_EXP_D45:
+				dest[j++] = exp_acc;
+				dest[j++] = exp_acc;
+			case MPEG3_EXP_D25:
+				dest[j++] = exp_acc;
+			case MPEG3_EXP_D15:
+				dest[j++] = exp_acc;
+		}
+	}
+	return 0;
+}
+
+int mpeg3audio_ac3_exponent_unpack(mpeg3audio_t *audio,
+		mpeg3_ac3bsi_t *bsi,
+		mpeg3_ac3audblk_t *audblk)
+{
+	int i, result = 0;
+
+	for(i = 0; i < bsi->nfchans; i++)
+		result |= mpeg3audio_ac3_exp_unpack_ch(UNPACK_FBW, 
+			audblk->chexpstr[i], 
+			audblk->nchgrps[i], 
+			audblk->exps[i][0], 
+			&audblk->exps[i][1], 
+			audblk->fbw_exp[i]);
+
+	if(audblk->cplinu && !result)
+		result |= mpeg3audio_ac3_exp_unpack_ch(UNPACK_CPL, 
+			audblk->cplexpstr, 
+			audblk->ncplgrps, 
+			audblk->cplabsexp << 1,	
+			audblk->cplexps, 
+			&audblk->cpl_exp[audblk->cplstrtmant]);
+
+	if(bsi->lfeon && !result)
+		result |= mpeg3audio_ac3_exp_unpack_ch(UNPACK_LFE, 
+			audblk->lfeexpstr, 
+			2, 
+			audblk->lfeexps[0], 
+			&audblk->lfeexps[1], 
+			audblk->lfe_exp);
+	return result;
+}
--
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