patch-pre2.0.6 linux/drivers/isdn/isdn_audio.c
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- Lines: 429
- Date:
Sun May 19 15:29:29 1996
- Orig file:
pre2.0.5/linux/drivers/isdn/isdn_audio.c
- Orig date:
Thu Jan 1 02:00:00 1970
diff -u --recursive --new-file pre2.0.5/linux/drivers/isdn/isdn_audio.c linux/drivers/isdn/isdn_audio.c
@@ -0,0 +1,428 @@
+/* $Id: isdn_audio.c,v 1.4 1996/05/17 03:48:01 fritz Exp $
+ *
+ * Linux ISDN subsystem, audio conversion and compression (linklevel).
+ *
+ * Copyright 1994,95,96 by Fritz Elfert (fritz@wuemaus.franken.de)
+ *
+ * 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, or (at your option)
+ * any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Log: isdn_audio.c,v $
+ * Revision 1.4 1996/05/17 03:48:01 fritz
+ * Removed some test statements.
+ * Added revision string.
+ *
+ * Revision 1.3 1996/05/10 08:48:11 fritz
+ * Corrected adpcm bugs.
+ *
+ * Revision 1.2 1996/04/30 09:31:17 fritz
+ * General rewrite.
+ *
+ * Revision 1.1.1.1 1996/04/28 12:25:40 fritz
+ * Taken under CVS control
+ *
+ */
+
+#define __NO_VERSION__
+#include <linux/module.h>
+#include <linux/isdn.h>
+#include "isdn_audio.h"
+
+char *isdn_audio_revision = "$Revision: 1.4 $";
+
+/*
+ * Misc. lookup-tables.
+ */
+
+/* ulaw -> signed 16-bit */
+static short isdn_audio_ulaw_to_s16[] = {
+ 0x8284, 0x8684, 0x8a84, 0x8e84, 0x9284, 0x9684, 0x9a84, 0x9e84,
+ 0xa284, 0xa684, 0xaa84, 0xae84, 0xb284, 0xb684, 0xba84, 0xbe84,
+ 0xc184, 0xc384, 0xc584, 0xc784, 0xc984, 0xcb84, 0xcd84, 0xcf84,
+ 0xd184, 0xd384, 0xd584, 0xd784, 0xd984, 0xdb84, 0xdd84, 0xdf84,
+ 0xe104, 0xe204, 0xe304, 0xe404, 0xe504, 0xe604, 0xe704, 0xe804,
+ 0xe904, 0xea04, 0xeb04, 0xec04, 0xed04, 0xee04, 0xef04, 0xf004,
+ 0xf0c4, 0xf144, 0xf1c4, 0xf244, 0xf2c4, 0xf344, 0xf3c4, 0xf444,
+ 0xf4c4, 0xf544, 0xf5c4, 0xf644, 0xf6c4, 0xf744, 0xf7c4, 0xf844,
+ 0xf8a4, 0xf8e4, 0xf924, 0xf964, 0xf9a4, 0xf9e4, 0xfa24, 0xfa64,
+ 0xfaa4, 0xfae4, 0xfb24, 0xfb64, 0xfba4, 0xfbe4, 0xfc24, 0xfc64,
+ 0xfc94, 0xfcb4, 0xfcd4, 0xfcf4, 0xfd14, 0xfd34, 0xfd54, 0xfd74,
+ 0xfd94, 0xfdb4, 0xfdd4, 0xfdf4, 0xfe14, 0xfe34, 0xfe54, 0xfe74,
+ 0xfe8c, 0xfe9c, 0xfeac, 0xfebc, 0xfecc, 0xfedc, 0xfeec, 0xfefc,
+ 0xff0c, 0xff1c, 0xff2c, 0xff3c, 0xff4c, 0xff5c, 0xff6c, 0xff7c,
+ 0xff88, 0xff90, 0xff98, 0xffa0, 0xffa8, 0xffb0, 0xffb8, 0xffc0,
+ 0xffc8, 0xffd0, 0xffd8, 0xffe0, 0xffe8, 0xfff0, 0xfff8, 0x0000,
+ 0x7d7c, 0x797c, 0x757c, 0x717c, 0x6d7c, 0x697c, 0x657c, 0x617c,
+ 0x5d7c, 0x597c, 0x557c, 0x517c, 0x4d7c, 0x497c, 0x457c, 0x417c,
+ 0x3e7c, 0x3c7c, 0x3a7c, 0x387c, 0x367c, 0x347c, 0x327c, 0x307c,
+ 0x2e7c, 0x2c7c, 0x2a7c, 0x287c, 0x267c, 0x247c, 0x227c, 0x207c,
+ 0x1efc, 0x1dfc, 0x1cfc, 0x1bfc, 0x1afc, 0x19fc, 0x18fc, 0x17fc,
+ 0x16fc, 0x15fc, 0x14fc, 0x13fc, 0x12fc, 0x11fc, 0x10fc, 0x0ffc,
+ 0x0f3c, 0x0ebc, 0x0e3c, 0x0dbc, 0x0d3c, 0x0cbc, 0x0c3c, 0x0bbc,
+ 0x0b3c, 0x0abc, 0x0a3c, 0x09bc, 0x093c, 0x08bc, 0x083c, 0x07bc,
+ 0x075c, 0x071c, 0x06dc, 0x069c, 0x065c, 0x061c, 0x05dc, 0x059c,
+ 0x055c, 0x051c, 0x04dc, 0x049c, 0x045c, 0x041c, 0x03dc, 0x039c,
+ 0x036c, 0x034c, 0x032c, 0x030c, 0x02ec, 0x02cc, 0x02ac, 0x028c,
+ 0x026c, 0x024c, 0x022c, 0x020c, 0x01ec, 0x01cc, 0x01ac, 0x018c,
+ 0x0174, 0x0164, 0x0154, 0x0144, 0x0134, 0x0124, 0x0114, 0x0104,
+ 0x00f4, 0x00e4, 0x00d4, 0x00c4, 0x00b4, 0x00a4, 0x0094, 0x0084,
+ 0x0078, 0x0070, 0x0068, 0x0060, 0x0058, 0x0050, 0x0048, 0x0040,
+ 0x0038, 0x0030, 0x0028, 0x0020, 0x0018, 0x0010, 0x0008, 0x0000
+};
+
+/* alaw -> signed 16-bit */
+static short isdn_audio_alaw_to_s16[] = {
+ 0x13fc, 0xec04, 0x0144, 0xfebc, 0x517c, 0xae84, 0x051c, 0xfae4,
+ 0x0a3c, 0xf5c4, 0x0048, 0xffb8, 0x287c, 0xd784, 0x028c, 0xfd74,
+ 0x1bfc, 0xe404, 0x01cc, 0xfe34, 0x717c, 0x8e84, 0x071c, 0xf8e4,
+ 0x0e3c, 0xf1c4, 0x00c4, 0xff3c, 0x387c, 0xc784, 0x039c, 0xfc64,
+ 0x0ffc, 0xf004, 0x0104, 0xfefc, 0x417c, 0xbe84, 0x041c, 0xfbe4,
+ 0x083c, 0xf7c4, 0x0008, 0xfff8, 0x207c, 0xdf84, 0x020c, 0xfdf4,
+ 0x17fc, 0xe804, 0x018c, 0xfe74, 0x617c, 0x9e84, 0x061c, 0xf9e4,
+ 0x0c3c, 0xf3c4, 0x0084, 0xff7c, 0x307c, 0xcf84, 0x030c, 0xfcf4,
+ 0x15fc, 0xea04, 0x0164, 0xfe9c, 0x597c, 0xa684, 0x059c, 0xfa64,
+ 0x0b3c, 0xf4c4, 0x0068, 0xff98, 0x2c7c, 0xd384, 0x02cc, 0xfd34,
+ 0x1dfc, 0xe204, 0x01ec, 0xfe14, 0x797c, 0x8684, 0x07bc, 0xf844,
+ 0x0f3c, 0xf0c4, 0x00e4, 0xff1c, 0x3c7c, 0xc384, 0x03dc, 0xfc24,
+ 0x11fc, 0xee04, 0x0124, 0xfedc, 0x497c, 0xb684, 0x049c, 0xfb64,
+ 0x093c, 0xf6c4, 0x0028, 0xffd8, 0x247c, 0xdb84, 0x024c, 0xfdb4,
+ 0x19fc, 0xe604, 0x01ac, 0xfe54, 0x697c, 0x9684, 0x069c, 0xf964,
+ 0x0d3c, 0xf2c4, 0x00a4, 0xff5c, 0x347c, 0xcb84, 0x034c, 0xfcb4,
+ 0x12fc, 0xed04, 0x0134, 0xfecc, 0x4d7c, 0xb284, 0x04dc, 0xfb24,
+ 0x09bc, 0xf644, 0x0038, 0xffc8, 0x267c, 0xd984, 0x026c, 0xfd94,
+ 0x1afc, 0xe504, 0x01ac, 0xfe54, 0x6d7c, 0x9284, 0x06dc, 0xf924,
+ 0x0dbc, 0xf244, 0x00b4, 0xff4c, 0x367c, 0xc984, 0x036c, 0xfc94,
+ 0x0f3c, 0xf0c4, 0x00f4, 0xff0c, 0x3e7c, 0xc184, 0x03dc, 0xfc24,
+ 0x07bc, 0xf844, 0x0008, 0xfff8, 0x1efc, 0xe104, 0x01ec, 0xfe14,
+ 0x16fc, 0xe904, 0x0174, 0xfe8c, 0x5d7c, 0xa284, 0x05dc, 0xfa24,
+ 0x0bbc, 0xf444, 0x0078, 0xff88, 0x2e7c, 0xd184, 0x02ec, 0xfd14,
+ 0x14fc, 0xeb04, 0x0154, 0xfeac, 0x557c, 0xaa84, 0x055c, 0xfaa4,
+ 0x0abc, 0xf544, 0x0058, 0xffa8, 0x2a7c, 0xd584, 0x02ac, 0xfd54,
+ 0x1cfc, 0xe304, 0x01cc, 0xfe34, 0x757c, 0x8a84, 0x075c, 0xf8a4,
+ 0x0ebc, 0xf144, 0x00d4, 0xff2c, 0x3a7c, 0xc584, 0x039c, 0xfc64,
+ 0x10fc, 0xef04, 0x0114, 0xfeec, 0x457c, 0xba84, 0x045c, 0xfba4,
+ 0x08bc, 0xf744, 0x0018, 0xffe8, 0x227c, 0xdd84, 0x022c, 0xfdd4,
+ 0x18fc, 0xe704, 0x018c, 0xfe74, 0x657c, 0x9a84, 0x065c, 0xf9a4,
+ 0x0cbc, 0xf344, 0x0094, 0xff6c, 0x327c, 0xcd84, 0x032c, 0xfcd4
+};
+
+/* alaw -> ulaw */
+static char isdn_audio_alaw_to_ulaw[] = {
+ 0xab, 0x2b, 0xe3, 0x63, 0x8b, 0x0b, 0xc9, 0x49,
+ 0xba, 0x3a, 0xf6, 0x76, 0x9b, 0x1b, 0xd7, 0x57,
+ 0xa3, 0x23, 0xdd, 0x5d, 0x83, 0x03, 0xc1, 0x41,
+ 0xb2, 0x32, 0xeb, 0x6b, 0x93, 0x13, 0xcf, 0x4f,
+ 0xaf, 0x2f, 0xe7, 0x67, 0x8f, 0x0f, 0xcd, 0x4d,
+ 0xbe, 0x3e, 0xfe, 0x7e, 0x9f, 0x1f, 0xdb, 0x5b,
+ 0xa7, 0x27, 0xdf, 0x5f, 0x87, 0x07, 0xc5, 0x45,
+ 0xb6, 0x36, 0xef, 0x6f, 0x97, 0x17, 0xd3, 0x53,
+ 0xa9, 0x29, 0xe1, 0x61, 0x89, 0x09, 0xc7, 0x47,
+ 0xb8, 0x38, 0xf2, 0x72, 0x99, 0x19, 0xd5, 0x55,
+ 0xa1, 0x21, 0xdc, 0x5c, 0x81, 0x01, 0xbf, 0x3f,
+ 0xb0, 0x30, 0xe9, 0x69, 0x91, 0x11, 0xce, 0x4e,
+ 0xad, 0x2d, 0xe5, 0x65, 0x8d, 0x0d, 0xcb, 0x4b,
+ 0xbc, 0x3c, 0xfa, 0x7a, 0x9d, 0x1d, 0xd9, 0x59,
+ 0xa5, 0x25, 0xde, 0x5e, 0x85, 0x05, 0xc3, 0x43,
+ 0xb4, 0x34, 0xed, 0x6d, 0x95, 0x15, 0xd1, 0x51,
+ 0xac, 0x2c, 0xe4, 0x64, 0x8c, 0x0c, 0xca, 0x4a,
+ 0xbb, 0x3b, 0xf8, 0x78, 0x9c, 0x1c, 0xd8, 0x58,
+ 0xa4, 0x24, 0xde, 0x5e, 0x84, 0x04, 0xc2, 0x42,
+ 0xb3, 0x33, 0xec, 0x6c, 0x94, 0x14, 0xd0, 0x50,
+ 0xb0, 0x30, 0xe8, 0x68, 0x90, 0x10, 0xce, 0x4e,
+ 0xbf, 0x3f, 0xfe, 0x7e, 0xa0, 0x20, 0xdc, 0x5c,
+ 0xa8, 0x28, 0xe0, 0x60, 0x88, 0x08, 0xc6, 0x46,
+ 0xb7, 0x37, 0xf0, 0x70, 0x98, 0x18, 0xd4, 0x54,
+ 0xaa, 0x2a, 0xe2, 0x62, 0x8a, 0x0a, 0xc8, 0x48,
+ 0xb9, 0x39, 0xf4, 0x74, 0x9a, 0x1a, 0xd6, 0x56,
+ 0xa2, 0x22, 0xdd, 0x5d, 0x82, 0x02, 0xc0, 0x40,
+ 0xb1, 0x31, 0xea, 0x6a, 0x92, 0x12, 0xcf, 0x4f,
+ 0xae, 0x2e, 0xe6, 0x66, 0x8e, 0x0e, 0xcc, 0x4c,
+ 0xbd, 0x3d, 0xfc, 0x7c, 0x9e, 0x1e, 0xda, 0x5a,
+ 0xa6, 0x26, 0xdf, 0x5f, 0x86, 0x06, 0xc4, 0x44,
+ 0xb5, 0x35, 0xee, 0x6e, 0x96, 0x16, 0xd2, 0x52
+};
+
+/* ulaw -> alaw */
+static char isdn_audio_ulaw_to_alaw[] = {
+ 0xab, 0x55, 0xd5, 0x15, 0x95, 0x75, 0xf5, 0x35,
+ 0xb5, 0x45, 0xc5, 0x05, 0x85, 0x65, 0xe5, 0x25,
+ 0xa5, 0x5d, 0xdd, 0x1d, 0x9d, 0x7d, 0xfd, 0x3d,
+ 0xbd, 0x4d, 0xcd, 0x0d, 0x8d, 0x6d, 0xed, 0x2d,
+ 0xad, 0x51, 0xd1, 0x11, 0x91, 0x71, 0xf1, 0x31,
+ 0xb1, 0x41, 0xc1, 0x01, 0x81, 0x61, 0xe1, 0x21,
+ 0x59, 0xd9, 0x19, 0x99, 0x79, 0xf9, 0x39, 0xb9,
+ 0x49, 0xc9, 0x09, 0x89, 0x69, 0xe9, 0x29, 0xa9,
+ 0xd7, 0x17, 0x97, 0x77, 0xf7, 0x37, 0xb7, 0x47,
+ 0xc7, 0x07, 0x87, 0x67, 0xe7, 0x27, 0xa7, 0xdf,
+ 0x9f, 0x7f, 0xff, 0x3f, 0xbf, 0x4f, 0xcf, 0x0f,
+ 0x8f, 0x6f, 0xef, 0x2f, 0x53, 0x13, 0x73, 0x33,
+ 0xb3, 0x43, 0xc3, 0x03, 0x83, 0x63, 0xe3, 0x23,
+ 0xa3, 0x5b, 0xdb, 0x1b, 0x9b, 0x7b, 0xfb, 0x3b,
+ 0xbb, 0xbb, 0x4b, 0x4b, 0xcb, 0xcb, 0x0b, 0x0b,
+ 0x8b, 0x8b, 0x6b, 0x6b, 0xeb, 0xeb, 0x2b, 0x2b,
+ 0xab, 0x54, 0xd4, 0x14, 0x94, 0x74, 0xf4, 0x34,
+ 0xb4, 0x44, 0xc4, 0x04, 0x84, 0x64, 0xe4, 0x24,
+ 0xa4, 0x5c, 0xdc, 0x1c, 0x9c, 0x7c, 0xfc, 0x3c,
+ 0xbc, 0x4c, 0xcc, 0x0c, 0x8c, 0x6c, 0xec, 0x2c,
+ 0xac, 0x50, 0xd0, 0x10, 0x90, 0x70, 0xf0, 0x30,
+ 0xb0, 0x40, 0xc0, 0x00, 0x80, 0x60, 0xe0, 0x20,
+ 0x58, 0xd8, 0x18, 0x98, 0x78, 0xf8, 0x38, 0xb8,
+ 0x48, 0xc8, 0x08, 0x88, 0x68, 0xe8, 0x28, 0xa8,
+ 0xd6, 0x16, 0x96, 0x76, 0xf6, 0x36, 0xb6, 0x46,
+ 0xc6, 0x06, 0x86, 0x66, 0xe6, 0x26, 0xa6, 0xde,
+ 0x9e, 0x7e, 0xfe, 0x3e, 0xbe, 0x4e, 0xce, 0x0e,
+ 0x8e, 0x6e, 0xee, 0x2e, 0x52, 0x12, 0x72, 0x32,
+ 0xb2, 0x42, 0xc2, 0x02, 0x82, 0x62, 0xe2, 0x22,
+ 0xa2, 0x5a, 0xda, 0x1a, 0x9a, 0x7a, 0xfa, 0x3a,
+ 0xba, 0xba, 0x4a, 0x4a, 0xca, 0xca, 0x0a, 0x0a,
+ 0x8a, 0x8a, 0x6a, 0x6a, 0xea, 0xea, 0x2a, 0x2a
+};
+
+#if ((CPU == 386) || (CPU == 486) || (CPU == 586))
+static inline void
+isdn_audio_tlookup(const void *table, void *buff, unsigned long n)
+{
+ __asm__("cld\n"
+ "1:\tlodsb\n\t"
+ "xlatb\n\t"
+ "stosb\n\t"
+ "loop 1b\n\t"
+ ::"b" ((long)table), "c" (n), "D" ((long)buff), "S" ((long)buff)
+ :"bx","cx","di","si","ax");
+}
+#else
+static inline void
+isdn_audio_tlookup(const char *table, char *buff, unsigned long n)
+{
+ while (n--)
+ *buff++ = table[*buff];
+}
+#endif
+
+void
+isdn_audio_ulaw2alaw(unsigned char *buff, unsigned long len)
+{
+ isdn_audio_tlookup(isdn_audio_ulaw_to_alaw, buff, len);
+}
+
+void
+isdn_audio_alaw2ulaw(unsigned char *buff, unsigned long len)
+{
+ isdn_audio_tlookup(isdn_audio_alaw_to_ulaw, buff, len);
+}
+
+/*
+ * linear <-> adpcm conversion stuff
+ * Most parts from the mgetty-package.
+ * (C) by Gert Doering and Klaus Weidner
+ * Used by permission of Gert Doering
+ */
+
+
+#define ZEROTRAP /* turn on the trap as per the MIL-STD */
+#undef ZEROTRAP
+#define BIAS 0x84 /* define the add-in bias for 16 bit samples */
+#define CLIP 32635
+
+static unsigned char
+isdn_audio_linear2ulaw(int sample) {
+ static int exp_lut[256] = {
+ 0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,
+ 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
+ 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
+ 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
+ 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+ 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+ 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+ 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+ 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
+ };
+ int sign, exponent, mantissa;
+ unsigned char ulawbyte;
+
+ /* Get the sample into sign-magnitude. */
+ sign = (sample >> 8) & 0x80; /* set aside the sign */
+ if(sign != 0) sample = -sample; /* get magnitude */
+ if(sample > CLIP) sample = CLIP; /* clip the magnitude */
+
+ /* Convert from 16 bit linear to ulaw. */
+ sample = sample + BIAS;
+ exponent = exp_lut[( sample >> 7 ) & 0xFF];
+ mantissa = (sample >> (exponent + 3)) & 0x0F;
+ ulawbyte = ~(sign | (exponent << 4) | mantissa);
+#ifdef ZEROTRAP
+ /* optional CCITT trap */
+ if (ulawbyte == 0) ulawbyte = 0x02;
+#endif
+ return(ulawbyte);
+}
+
+
+static int Mx[3][8] = {
+ { 0x3800, 0x5600, 0,0,0,0,0,0 },
+ { 0x399a, 0x3a9f, 0x4d14, 0x6607, 0,0,0,0 },
+ { 0x3556, 0x3556, 0x399A, 0x3A9F, 0x4200, 0x4D14, 0x6607, 0x6607 },
+};
+
+static int bitmask[9] = {
+ 0, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff
+};
+
+static int
+isdn_audio_get_bits (adpcm_state *s, unsigned char **in, int *len)
+{
+ while( s->nleft < s->nbits) {
+ int d = *((*in)++);
+ (*len)--;
+ s->word = (s->word << 8) | d;
+ s->nleft += 8;
+ }
+ s->nleft -= s->nbits;
+ return (s->word >> s->nleft) & bitmask[s->nbits];
+}
+
+static void
+isdn_audio_put_bits (int data, int nbits, adpcm_state *s,
+ unsigned char **out, int *len)
+{
+ s->word = (s->word << nbits) | (data & bitmask[nbits]);
+ s->nleft += nbits;
+ while(s->nleft >= 8) {
+ int d = (s->word >> (s->nleft-8));
+ *(out[0]++) = d & 255;
+ (*len)++;
+ s->nleft -= 8;
+ }
+}
+
+adpcm_state *
+isdn_audio_adpcm_init(int nbits)
+{
+static adpcm_state *s;
+
+#ifdef ATEST
+ s = (adpcm_state *) malloc(sizeof(adpcm_state));
+#else
+ s = (adpcm_state *) kmalloc(sizeof(adpcm_state), GFP_ATOMIC);
+#endif
+ if (s) {
+ s->a = 0;
+ s->d = 5;
+ s->word = 0;
+ s->nleft = 0;
+ s->nbits = nbits;
+ }
+ return s;
+}
+
+/*
+ * Decompression of adpcm data to a/u-law
+ *
+ */
+
+int
+isdn_audio_adpcm2xlaw (adpcm_state *s, int fmt, unsigned char *in,
+ unsigned char *out, int len)
+{
+ int a = s->a;
+ int d = s->d;
+ int nbits = s->nbits;
+ int olen = 0;
+
+ while (len) {
+ int e = isdn_audio_get_bits(s, &in, &len);
+ int sign;
+
+ if (nbits == 4 && e == 0)
+ d = 4;
+ sign = (e >> (nbits-1))?-1:1;
+ e &= bitmask[nbits-1];
+ a += sign * ((e << 1) + 1) * d >> 1;
+ if (d & 1)
+ a++;
+ if (fmt)
+ *out++ = isdn_audio_ulaw_to_alaw[
+ isdn_audio_linear2ulaw(a << 2)];
+ else
+ *out++ = isdn_audio_linear2ulaw(a << 2);
+ olen++;
+ d = (d * Mx[nbits-2][ e ] + 0x2000) >> 14;
+ if ( d < 5 )
+ d = 5;
+ }
+ s->a = a;
+ s->d = d;
+ return olen;
+}
+
+int
+isdn_audio_2adpcm_flush (adpcm_state *s, unsigned char *out)
+{
+ int olen = 0;
+
+ if (s->nleft)
+ isdn_audio_put_bits(0, 8-s->nleft, s, &out, &olen);
+ return olen;
+}
+
+int
+isdn_audio_xlaw2adpcm (adpcm_state *s, int fmt, unsigned char *in,
+ unsigned char *out, int len)
+{
+ int a = s->a;
+ int d = s->d;
+ int nbits = s->nbits;
+ int olen = 0;
+
+ while (len--) {
+ int e = 0, nmax = 1 << (nbits - 1);
+ int sign, delta;
+
+ if (fmt)
+ delta = (isdn_audio_alaw_to_s16[*in++] >> 2) - a;
+ else
+ delta = (isdn_audio_ulaw_to_s16[*in++] >> 2) - a;
+ if (delta < 0) {
+ e = nmax;
+ delta = -delta;
+ }
+ while( --nmax && delta > d ) {
+ delta -= d;
+ e++;
+ }
+ if (nbits == 4 && ((e & 0x0f) == 0))
+ e = 8;
+ isdn_audio_put_bits(e, nbits, s, &out, &olen);
+ sign = (e >> (nbits-1))?-1:1 ;
+ e &= bitmask[nbits-1];
+
+ a += sign * ((e << 1) + 1) * d >> 1;
+ if (d & 1)
+ a++;
+ d = (d * Mx[nbits-2][ e ] + 0x2000) >> 14;
+ if (d < 5)
+ d=5;
+ }
+ s->a = a;
+ s->d = d;
+ return olen;
+}
+
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen, slshen@lbl.gov
with Sam's (original) version of this