first commit

2022-10-20 20:29:11 +08:00
commit 4d531f8044
3238 changed files with 1387862 additions and 0 deletions
@@ -0,0 +1,152 @@
+/*
+ * iaxclient: a cross-platform IAX softphone library
+ *
+ * Copyrights:
+ * Copyright (C) 2003-2006, Horizon Wimba, Inc.
+ * Copyright (C) 2007, Wimba, Inc.
+ *
+ * Contributors:
+ * Steve Kann <stevek@stevek.com>
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU Lesser (Library) General Public License.
+ */
+
+#include "codec_ulaw.h"
+#include "iaxclient_lib.h"
+
+struct state {
+    plc_state_t plc;
+};
+
+static short ulaw_2lin [256];
+static unsigned char lin_2ulaw [16384];
+static int initialized=0;
+
+/* this looks similar to asterisk, but comes from public domain code by craig reese
+   I've just followed asterisk's table sizes for lin_2u, and also too lazy to do binary arith to decide which
+   iterations to skip -- this way we get the same result.. */
+static void initialize() {
+    int i;
+
+    /* ulaw_2lin */
+    for(i=0;i<256;i++) {
+	  int b = ~i;
+	  int exp_lut[8] = {0,132,396,924,1980,4092,8316,16764};
+	  int sign, exponent, mantissa, sample;
+
+	  sign = (b & 0x80);
+	  exponent = (b >> 4) & 0x07;
+	  mantissa = b & 0x0F;
+	  sample = exp_lut[exponent] + (mantissa << (exponent + 3));
+	  if (sign != 0) sample = -sample;
+	  ulaw_2lin[i] = sample;
+    }
+
+    /* lin_2ulaw */
+    for(i=-32767;i<32768;i+=4) {
+	int sample = i;
+	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 > 32635) sample = 32635;		/* clip the magnitude */
+
+	/* Convert from 16 bit linear to ulaw. */
+	sample = sample + 0x84;
+	exponent = exp_lut[(sample >> 7) & 0xFF];
+	mantissa = (sample >> (exponent + 3)) & 0x0F;
+	ulawbyte = ~(sign | (exponent << 4) | mantissa);
+	if (ulawbyte == 0) ulawbyte = 0x02;	/* optional CCITT trap */
+
+	lin_2ulaw[((unsigned short)i) >> 2] = ulawbyte;
+    }
+
+    initialized = 1;
+}
+
+static void destroy ( struct iaxc_audio_codec *c) {
+	if ( c->decstate )
+		free(c->decstate);
+	free(c);
+}
+
+
+static int decode ( struct iaxc_audio_codec *c,
+    int *inlen, unsigned char *in, int *outlen, short *out ) {
+    struct state *state = (struct state *)c->decstate;
+    short *orig_out = out;
+    short sample;
+
+    if(*inlen == 0) {
+	int interp_len = 160;
+	if(*outlen < interp_len) interp_len = *outlen;
+	plc_fillin(&state->plc,out,interp_len);
+	*outlen -= interp_len;
+	return 0;
+    }
+
+    while ((*inlen > 0) && (*outlen > 0)) {
+	sample = ulaw_2lin[(unsigned char)*(in++)];
+	*(out++) = sample;
+	(*inlen)--; (*outlen)--;
+    }
+    plc_rx(&state->plc, orig_out, (int)(out - orig_out));
+
+    return 0;
+}
+
+static int encode ( struct iaxc_audio_codec *c,
+    int *inlen, short *in, int *outlen, unsigned char *out ) {
+
+    while ((*inlen > 0) && (*outlen > 0)) {
+	*(out++) = lin_2ulaw[((unsigned short)*(in++)) >> 2];
+	(*inlen)--; (*outlen)--;
+    }
+
+    return 0;
+}
+
+
+struct iaxc_audio_codec *codec_audio_ulaw_new() {
+
+  struct iaxc_audio_codec *c = (struct iaxc_audio_codec *)calloc(sizeof(struct iaxc_audio_codec),1);
+
+  if(!c) return c;
+
+  if(!initialized) initialize();
+
+  strcpy(c->name,"ulaw");
+  c->format = IAXC_FORMAT_ULAW;
+  c->encode = encode;
+  c->decode = decode;
+  c->destroy = destroy;
+
+  /* really, we can use less, but don't want to */
+  c->minimum_frame_size = 160;
+
+  /* decoder state, used for interpolation */
+  c->decstate = calloc(sizeof(struct state),1);
+  plc_init(&((struct state *)c->decstate)->plc);
+
+  return c;
+}
+