aupcm_codec.c

a-law u-law pcm间的转换

/*
 * MODULE NAME:    hci_sco_codec.c
 * DESCRIPTION:    HCI Callback Functions From HCI Transport Layer
 * AUTHOR:         Martin Mellody
 *
 * SOURCE CONTROL: $Id: hci_callbacks.c,v 1.1.1.1 2006/10/17 11:36:47 mjoang Exp $
 *
 * LICENSE:
 *     This source code is copyright (c) 2000-2002 Parthus Technologies.
 *     All rights reserved.
 *
 */


/*
    HCIT Host Controller to Host flow control should be implemented here, when supported.
*/
#include "hci_callbacks.h"
#include "hci_encoder.h"
#include "papi.h"
#include "host_ctrl.h"

#include "mgr_core.h"
#include "mgr_utils.h"
/*
#include "host_config.h"
#include "hci_callbacks.h"
#include "host_types.h"
#include "host_error.h"
#include "host_buf.h"
#include "hci_constants.h"
#include "hci_debug.h"
#include "papi.h"
#include "mgr_utils.h"
#include "hci_primitives.h"
#include "hci_flow_ctrl.h"
#include "mgr_core.h"
*/
#define 	SIGN_BIT 		(0x80)  /* Sign bit for a A-law byte. */
#define 	QUANT_MASK 	(0xf)  /* Quantization field mask. */
#define 	NSEGS  			(8)  /* Number of A-law segments. */
#define 	SEG_SHIFT 		(4)  /* Left shift for segment number. */
#define 	SEG_MASK 		(0x70)  /* Segment field mask. */


static short seg_end[8] = {0xFF, 0x1FF, 0x3FF, 0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF};

 /* u- to A-law conversions */
unsigned char _u2a[128] = {
 1, 1, 2, 2, 3, 3, 4, 4,
 5, 5, 6, 6, 7, 7, 8, 8,
 9, 10, 11, 12, 13, 14, 15, 16,
 17, 18, 19, 20, 21, 22, 23, 24,
 25, 27, 29, 31, 33, 34, 35, 36,
 37, 38, 39, 40, 41, 42, 43, 44,
 46, 48, 49, 50, 51, 52, 53, 54,
 55, 56, 57, 58, 59, 60, 61, 62,
 64, 65, 66, 67, 68, 69, 70, 71,
 72, 73, 74, 75, 76, 77, 78, 79,
 81, 82, 83, 84, 85, 86, 87, 88,
 89, 90, 91, 92, 93, 94, 95, 96,
 97, 98, 99, 100, 101, 102, 103, 104,
 105, 106, 107, 108, 109, 110, 111, 112,
 113, 114, 115, 116, 117, 118, 119, 120,
 121, 122, 123, 124, 125, 126, 127, 128};

/* A- to u-law conversions */ 
unsigned char _a2u[128] = {
 1, 3, 5, 7, 9, 11, 13, 15,
 16, 17, 18, 19, 20, 21, 22, 23,
 24, 25, 26, 27, 28, 29, 30, 31,
 32, 32, 33, 33, 34, 34, 35, 35,
 36, 37, 38, 39, 40, 41, 42, 43,
 44, 45, 46, 47, 48, 48, 49, 49,
 50, 51, 52, 53, 54, 55, 56, 57,
 58, 59, 60, 61, 62, 63, 64, 64,
 65, 66, 67, 68, 69, 70, 71, 72,
 73, 74, 75, 76, 77, 78, 79, 79,
 80, 81, 82, 83, 84, 85, 86, 87,
 88, 89, 90, 91, 92, 93, 94, 95,
 96, 97, 98, 99, 100, 101, 102, 103,
 104, 105, 106, 107, 108, 109, 110, 111,
 112, 113, 114, 115, 116, 117, 118, 119,
 120, 121, 122, 123, 124, 125, 126, 127};
 
static int search( int  val, short  *table, int  size)
{
	int  i;
	
	for (i = 0; i < size; i++) {
		if (val <= *table++)
		return (i);
	}
	return (size);
}
/*
 * linear2alaw() - Convert a 16-bit linear PCM value to 8-bit A-law
 *
 * linear2alaw() accepts an 16-bit integer and encodes it as A-law data.
 *
 *  Linear Input Code Compressed Code
 * ------------------------ ---------------
 * 0000000wxyza   000wxyz
 * 0000001wxyza   001wxyz
 * 000001wxyzab   010wxyz
 * 00001wxyzabc   011wxyz
 * 0001wxyzabcd   100wxyz
 * 001wxyzabcde   101wxyz
 * 01wxyzabcdef   110wxyz
 * 1wxyzabcdefg   111wxyz
 *
 * For further information see John C. Bellamy's Digital Telephony, 1982,
 * John Wiley & Sons, pps 98-111 and 472-476.
 */

 /* 2's complement (16-bit range) */
APIDECL1 unsigned char APIDECL2 HCI_linear2alaw( int  pcm_val)
{
	int  mask;
	int  seg;
	unsigned char aval;
	
	if (pcm_val >= 0) {
		mask = 0xD5;  /* sign (7th) bit = 1 */
	} 
	else {
		mask = 0x55;  /* sign bit = 0 */
		pcm_val = -pcm_val - 8;
	}
	/* Convert the scaled magnitude to segment number. */
	seg = search(pcm_val, seg_end, 8);
	
	/* Combine the sign, segment, and quantization bits. */
	if (seg >= 8)  /* out of range, return maximum value. */
		return (0x7F ^ mask);
	else {
		aval = seg << SEG_SHIFT;
		if (seg < 2)
			aval |= (pcm_val >> 4) & QUANT_MASK;
		else
			aval |= (pcm_val >> (seg + 3)) & QUANT_MASK;
		return (aval ^ mask);
	}
}
/*
 * alaw2linear() - Convert an A-law value to 16-bit linear PCM
 *
 */

int HCI_alaw2linear( unsigned char a_val)
{
	int  t;
	int  seg;
	
	a_val ^= 0x55;
	t = (a_val & QUANT_MASK) << 4;

	seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
	switch (seg) {
	case 0:
		t += 8;
		break;
	case 1:
		t += 0x108;
		break;
	default:
		t += 0x108;
		t <<= seg - 1;
	}
	return ((a_val & SIGN_BIT) ? t : -t);
}

#define BIAS  (0x84)  /* Bias for linear code. */
/*
 * linear2ulaw() - Convert a linear PCM value to u-law
 *
 * In order to simplify the encoding process, the original linear magnitude
 * is biased by adding 33 which shifts the encoding range from (0 - 8158) to
 * (33 - 8191). The result can be seen in the following encoding table:
 *
 * Biased Linear Input Code Compressed Code
 * ------------------------ ---------------
 * 00000001wxyza   000wxyz
 * 0000001wxyzab   001wxyz
 * 000001wxyzabc   010wxyz
 * 00001wxyzabcd   011wxyz
 * 0001wxyzabcde   100wxyz
 * 001wxyzabcdef   101wxyz
 * 01wxyzabcdefg   110wxyz
 * 1wxyzabcdefgh   111wxyz
 *
 * Each biased linear code has a leading 1 which identifies the segment
 * number. The value of the segment number is equal to 7 minus the number
 * of leading 0's. The quantization interval is directly available as the
 * four bits wxyz.  * The trailing bits (a - h) are ignored.
 *
 * Ordinarily the complement of the resulting code word is used for
 * transmission, and so the code word is complemented before it is returned.
 *
 * For further information see John C. Bellamy's Digital Telephony, 1982,
 * John Wiley & Sons, pps 98-111 and 472-476.
 */

 /* 2's complement (16-bit range) */
APIDECL1 unsigned char APIDECL2  HCI_linear2ulaw( int  pcm_val)
{
	int  mask;
	int  seg;
	unsigned char uval;
	
	/* Get the sign and the magnitude of the value. */
	if (pcm_val < 0) {
		pcm_val = BIAS - pcm_val;
		mask = 0x7F;
	} else {
		pcm_val += BIAS;
		mask = 0xFF;
	}
	/* Convert the scaled magnitude to segment number. */
	seg = search(pcm_val, seg_end, 8);
	/*
	* Combine the sign, segment, quantization bits;
	* and complement the code word.
	*/
	if (seg >= 8)  /* out of range, return maximum value. */
		return (0x7F ^ mask);
	else {
		uval = (seg << 4) | ((pcm_val >> (seg + 3)) & 0xF);
		return (uval ^ mask);
	}
}
/*
 * ulaw2linear() - Convert a u-law value to 16-bit linear PCM
 *
 * First, a biased linear code is derived from the code word. An unbiased
 * output can then be obtained by subtracting 33 from the biased code.
 *
 * Note that this function expects to be passed the complement of the
 * original code word. This is in keeping with ISDN conventions.
 */
int HCI_ulaw2linear( unsigned char u_val)
{
	int  t;
	
	/* Complement to obtain normal u-law value. */
	u_val = ~u_val;
	/*
	* Extract and bias the quantization bits. Then
	* shift up by the segment number and subtract out the bias.
	*/
	t = ((u_val & QUANT_MASK) << 3) + BIAS;
	t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
	
	return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
}
/* A-law to u-law conversion */
unsigned char HCI_alaw2ulaw( unsigned char aval)
{
	aval &= 0xff;
	return ((aval & 0x80) ? (0xFF ^ _a2u[aval ^ 0xD5]) :(0x7F ^ _a2u[aval ^ 0x55]));
}
/* u-law to A-law conversion */
unsigned char HCI_ulaw2alaw( unsigned char uval)
{
	uval &= 0xff;
	return ((uval & 0x80) ? (0xD5 ^ (_u2a[0xFF ^ uval] - 1)) :	(0x55 ^ (_u2a[0x7F ^ uval] - 1)));
}

APIDECL1 int  APIDECL2  HCI_scoRead(u_int16 scoHandle, u_int16 voiceSetting, u_int8 *in, u_int32 inLen, u_int16 *out, u_int32 outLen)
{
}
APIDECL1 int APIDECL2  HCI_scoWrite(u_int16 scoHandle, u_int16 voiceSetting, u_int16 *in, u_int32 inLen, u_int16 *out, u_int32 outLen)
{
 	struct host_buf* hci_data;
	u_int16 handle;
	u_int8 airCoding;
	int ret;
	int i,j;

	for( j=0; j < 160; j++ )
	{
		
		ret = HCI_GetWriteBuffer(handle|HCI_SCO_HANDLE, inLen+HCI_pduSCODATAHEADER, (struct st_t_dataBuf **)&hci_data);
		if( ret )
			return 0;
		airCoding = voiceSetting&0x03;
		switch( airCoding )
		{
		case 0://cvsd
			break;
			
		case 1://u-law
		
	    		host_buf_reserve_header(hci_data,HCI_pduSCODATAHEADER);
			for( i=0; i<inLen; i++ )
			{
				hci_data->data[i]=HCI_linear2ulaw( in[i] );
			}
			host_buf_release_header(hci_data,HCI_pduSCODATAHEADER);
			break;
			
		case 2://a-law
	    		host_buf_reserve_header(hci_data,HCI_pduSCODATAHEADER);
			for( i=0; i<inLen; i++ )
			{
				hci_data->data[i]=HCI_linear2alaw( in[i] );
			}
			host_buf_release_header(hci_data,HCI_pduSCODATAHEADER);
			break;
			
		default:
			break;
		}

		BT_WRITE_LE_UINT16(hci_data,handle);
		BT_WRITE_LE_UINT8(hci_data,inLen+HCI_pduSCODATAHEADER);

		/* Pass straight through to HCI */
		HCI_SendRawPDU(HCI_pduSCODATA, (t_DataBuf *)hci_data);
	}

}