/* 
 * FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
 * Copyright (C) 2005/2006, Anthony Minessale II <anthmct@yahoo.com>
 *
 * Version: MPL 1.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is FreeSWITCH Modular Media Switching Software Library / Soft-Switch Application
 *
 * The Initial Developer of the Original Code is
 * Anthony Minessale II <anthmct@yahoo.com>
 * Portions created by the Initial Developer are Copyright (C)
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 * 
 * Brian K. West <brian.west@mac.com>
 * 
 *
 * mod_g726.c -- G726 Codec Module
 *
 */  
#include "switch.h"
#include "g72x.h"
#include "switch_bitpack.h"

static const char modname[] = "mod_g726";

typedef int (*encoder_t)(int, int, g726_state *);
typedef int (*decoder_t)(int, int, g726_state *);


typedef struct {
	g726_state context;
	switch_byte_t bits_per_frame;
	encoder_t encoder;
	decoder_t decoder;
	switch_bitpack_t pack;
	switch_bitpack_t unpack;
	switch_bitpack_mode_t mode;
	switch_byte_t loops;
	switch_byte_t bytes;
	switch_byte_t buf[160];
} g726_handle_t;

static switch_status_t switch_g726_init(switch_codec_t *codec, switch_codec_flag_t flags,
									  const switch_codec_settings_t *codec_settings) 
{
	uint32_t encoding, decoding;
	g726_handle_t *handle;

	encoding = (flags & SWITCH_CODEC_FLAG_ENCODE);
	decoding = (flags & SWITCH_CODEC_FLAG_DECODE);

	if (!(encoding || decoding) || (!(handle = switch_core_alloc(codec->memory_pool, sizeof(*handle))))) {
		return SWITCH_STATUS_FALSE;
	} else {
		handle->bytes = (switch_byte_t) codec->implementation->encoded_bytes_per_frame;
		
		switch(handle->bytes) {
		case 100:
			handle->encoder = g726_40_encoder;
			handle->decoder = g726_40_decoder;
			handle->loops = 160;
			break;
		case 80:
			handle->encoder = g726_32_encoder;
			handle->decoder = g726_32_decoder;
			handle->loops = 40;
			break;
		case 60:
			handle->encoder = g726_24_encoder;
			handle->decoder = g726_24_decoder;
			handle->loops = 160;
			break;
		case 40:
			handle->encoder = g726_16_encoder;
			handle->decoder = g726_16_decoder;
			handle->loops = 160;
			break;
		default:
			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "invalid Encoding Size %d!\n", codec->implementation->encoded_bytes_per_frame);
			return SWITCH_STATUS_FALSE;
			break;
		}

		g726_init_state(&handle->context);
		codec->private_info = handle;
		handle->bits_per_frame = (switch_byte_t) (codec->implementation->bits_per_second / (codec->implementation->samples_per_second));
		handle->mode = (flags & SWITCH_CODEC_FLAG_AAL2 || strstr(codec->implementation->iananame, "AAL2")) 
			? SWITCH_BITPACK_MODE_AAL2 : SWITCH_BITPACK_MODE_RFC3551;
		return SWITCH_STATUS_SUCCESS;
	}
}


static switch_status_t switch_g726_destroy(switch_codec_t *codec) 
{
	codec->private_info = NULL;
	return SWITCH_STATUS_SUCCESS;
}



static switch_status_t switch_g726_encode(switch_codec_t *codec, 
										switch_codec_t *other_codec, 
										void *decoded_data,

										uint32_t decoded_data_len, 
										uint32_t decoded_rate, 
										void *encoded_data,

										uint32_t *encoded_data_len, 
										uint32_t *encoded_rate, 
										unsigned int *flag) 
{

	g726_handle_t *handle = codec->private_info;
	g726_state *context = &handle->context;
	uint32_t len = codec->implementation->bytes_per_frame;
	//uint32_t elen = codec->implementation->encoded_bytes_per_frame;

	if (!context) {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Error!\n");
		return SWITCH_STATUS_FALSE;
	}

	if (decoded_data_len % len == 0) {
		uint32_t new_len = 0;
		int16_t *ddp = decoded_data;
		switch_byte_t *edp = encoded_data;
		uint32_t x, loops = decoded_data_len / (sizeof(*ddp));

		switch_bitpack_init(&handle->pack, handle->bits_per_frame, edp, *encoded_data_len, handle->mode);

		for (x = 0; x < loops && new_len < *encoded_data_len; x++) {
			int edata = handle->encoder(*ddp, AUDIO_ENCODING_LINEAR, context);
			switch_bitpack_in(&handle->pack, (switch_byte_t) edata);
			ddp++;
		}
		switch_bitpack_done(&handle->pack);
		new_len = handle->pack.bytes;

		if (new_len <= *encoded_data_len) {
			*encoded_data_len = new_len;
		} else {
			switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "buffer overflow!!! %u >= %u\n", new_len, *encoded_data_len);
			return SWITCH_STATUS_FALSE;
		}
	}

	return SWITCH_STATUS_SUCCESS;
}



static switch_status_t switch_g726_decode(switch_codec_t *codec, 
										switch_codec_t *other_codec, 
										void *encoded_data,

										uint32_t encoded_data_len, 
										uint32_t encoded_rate, 
										void *decoded_data,

										uint32_t *decoded_data_len, 
										uint32_t *decoded_rate, 
										unsigned int *flag) 
{

	g726_handle_t *handle = codec->private_info;
	g726_state *context = &handle->context;
	int16_t *ddp = decoded_data;
	uint32_t new_len = 0, z = 0, y;

	switch_byte_t *in = (switch_byte_t *) encoded_data;

	if (!handle || !context) {
		return SWITCH_STATUS_FALSE;
	}

	while (z < encoded_data_len && new_len <= *decoded_data_len) {
		switch_bitpack_init(&handle->unpack, handle->bits_per_frame, handle->buf, sizeof(handle->buf), handle->mode);
		for (y = 0; y < handle->loops; y++) {
			switch_bitpack_out(&handle->unpack, in[z++]);
		}
		for(y = 0; y < handle->bytes; y++) {
			*ddp++ = (int16_t) handle->decoder(handle->buf[y], AUDIO_ENCODING_LINEAR, context);
            new_len += 2;
		}
		switch_bitpack_done(&handle->unpack);
	}
	
	if (new_len <= *decoded_data_len) {
		*decoded_data_len = new_len;
	} else {
		switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "buffer overflow!!!\n");
		return SWITCH_STATUS_FALSE;
	}


	return SWITCH_STATUS_SUCCESS;

}



/* Registration */ 

static const switch_codec_implementation_t g726_16k_implementation = { 
	/*.codec_type */ SWITCH_CODEC_TYPE_AUDIO, 
	/*.ianacode */ 127, 
	/*.iananame */ "G726-16", 
	/*.fmtp */ NULL,
	/*.samples_per_second */ 8000, 
	/*.bits_per_second */ 16000, 
	/*.microseconds_per_frame */ 20000, 
	/*.samples_per_frame */ 160, 
	/*.bytes_per_frame */ 320, 
	/*.encoded_bytes_per_frame */ 40, 
	/*.number_of_channels */ 1, 
	/*.pref_frames_per_packet */ 1, 
	/*.max_frames_per_packet */ 1, 
	/*.init */ switch_g726_init, 
	/*.encode */ switch_g726_encode, 
	/*.decode */ switch_g726_decode, 
	/*.destroy */ switch_g726_destroy, 
};


static const switch_codec_implementation_t g726_24k_implementation = { 
	/*.codec_type */ SWITCH_CODEC_TYPE_AUDIO, 
	/*.ianacode */ 126, 
	/*.iananame */ "G726-24", 
	/*.fmtp */ NULL,
	/*.samples_per_second */ 8000, 
	/*.bits_per_second */ 24000, 
	/*.microseconds_per_frame */ 20000, 
	/*.samples_per_frame */ 160, 
	/*.bytes_per_frame */ 320, 
	/*.encoded_bytes_per_frame */ 60, 
	/*.number_of_channels */ 1, 
	/*.pref_frames_per_packet */ 1, 
	/*.max_frames_per_packet */ 1, 
	/*.init */ switch_g726_init, 
	/*.encode */ switch_g726_encode, 
	/*.decode */ switch_g726_decode, 
	/*.destroy */ switch_g726_destroy, 
};

static const switch_codec_implementation_t g726_32k_implementation = { 
	/*.codec_type */ SWITCH_CODEC_TYPE_AUDIO, 
	/*.ianacode */ 2, 
	/*.iananame */ "G726-32", 
	/*.fmtp */ NULL,
	/*.samples_per_second */ 8000, 
	/*.bits_per_second */ 32000, 
	/*.microseconds_per_frame */ 20000, 
	/*.samples_per_frame */ 160, 
	/*.bytes_per_frame */ 320, 
	/*.encoded_bytes_per_frame */ 80, 
	/*.number_of_channels */ 1, 
	/*.pref_frames_per_packet */ 1, 
	/*.max_frames_per_packet */ 1, 
	/*.init */ switch_g726_init, 
	/*.encode */ switch_g726_encode, 
	/*.decode */ switch_g726_decode, 
	/*.destroy */ switch_g726_destroy, 
};

static const switch_codec_implementation_t g726_40k_implementation = { 
	/*.codec_type */ SWITCH_CODEC_TYPE_AUDIO, 
	/*.ianacode */ 125, 
	/*.iananame */ "G726-40", 
	/*.fmtp */ NULL,
	/*.samples_per_second */ 8000,
	/*.bits_per_second */ 40000, 
	/*.microseconds_per_frame */ 20000, 
	/*.samples_per_frame */ 160, 
	/*.bytes_per_frame */ 320, 
	/*.encoded_bytes_per_frame */ 100, 
	/*.number_of_channels */ 1, 
	/*.pref_frames_per_packet */ 1, 
	/*.max_frames_per_packet */ 1, 
	/*.init */ switch_g726_init, 
	/*.encode */ switch_g726_encode, 
	/*.decode */ switch_g726_decode, 
	/*.destroy */ switch_g726_destroy, 
};



static const switch_codec_implementation_t aal2_g726_16k_implementation = { 
	/*.codec_type */ SWITCH_CODEC_TYPE_AUDIO, 
	/*.ianacode */ 124, 
	/*.iananame */ "AAL2-G726-16", 
	/*.fmtp */ NULL,
	/*.samples_per_second */ 8000, 
	/*.bits_per_second */ 16000, 
	/*.microseconds_per_frame */ 20000, 
	/*.samples_per_frame */ 160, 
	/*.bytes_per_frame */ 320, 
	/*.encoded_bytes_per_frame */ 40, 
	/*.number_of_channels */ 1, 
	/*.pref_frames_per_packet */ 1, 
	/*.max_frames_per_packet */ 1, 
	/*.init */ switch_g726_init, 
	/*.encode */ switch_g726_encode, 
	/*.decode */ switch_g726_decode, 
	/*.destroy */ switch_g726_destroy, 
};


static const switch_codec_implementation_t aal2_g726_24k_implementation = { 
	/*.codec_type */ SWITCH_CODEC_TYPE_AUDIO, 
	/*.ianacode */ 123, 
	/*.iananame */ "AAL2-G726-24", 
	/*.fmtp */ NULL,
	/*.samples_per_second */ 8000, 
	/*.bits_per_second */ 24000, 
	/*.microseconds_per_frame */ 20000, 
	/*.samples_per_frame */ 160, 
	/*.bytes_per_frame */ 320, 
	/*.encoded_bytes_per_frame */ 60, 
	/*.number_of_channels */ 1, 
	/*.pref_frames_per_packet */ 1, 
	/*.max_frames_per_packet */ 1, 
	/*.init */ switch_g726_init, 
	/*.encode */ switch_g726_encode, 
	/*.decode */ switch_g726_decode, 
	/*.destroy */ switch_g726_destroy, 
};

static const switch_codec_implementation_t aal2_g726_32k_implementation = { 
	/*.codec_type */ SWITCH_CODEC_TYPE_AUDIO, 
	/*.ianacode */ 2, 
	/*.iananame */ "AAL2-G726-32", 
	/*.fmtp */ NULL,
	/*.samples_per_second */ 8000, 
	/*.bits_per_second */ 32000, 
	/*.microseconds_per_frame */ 20000, 
	/*.samples_per_frame */ 160, 
	/*.bytes_per_frame */ 320, 
	/*.encoded_bytes_per_frame */ 80, 
	/*.number_of_channels */ 1, 
	/*.pref_frames_per_packet */ 1, 
	/*.max_frames_per_packet */ 1, 
	/*.init */ switch_g726_init, 
	/*.encode */ switch_g726_encode, 
	/*.decode */ switch_g726_decode, 
	/*.destroy */ switch_g726_destroy, 
};

static const switch_codec_implementation_t aal2_g726_40k_implementation = { 
	/*.codec_type */ SWITCH_CODEC_TYPE_AUDIO, 
	/*.ianacode */ 122, 
	/*.iananame */ "AAL2-G726-40", 
	/*.fmtp */ NULL,
	/*.samples_per_second */ 8000,
	/*.bits_per_second */ 40000, 
	/*.microseconds_per_frame */ 20000, 
	/*.samples_per_frame */ 160, 
	/*.bytes_per_frame */ 320, 
	/*.encoded_bytes_per_frame */ 100, 
	/*.number_of_channels */ 1, 
	/*.pref_frames_per_packet */ 1, 
	/*.max_frames_per_packet */ 1, 
	/*.init */ switch_g726_init, 
	/*.encode */ switch_g726_encode, 
	/*.decode */ switch_g726_decode, 
	/*.destroy */ switch_g726_destroy, 
};

const switch_codec_interface_t g726_16k_codec_interface = { 
	/*.interface_name */ "G.726 16k", 
	/*.implementations */ &g726_16k_implementation, 
};

const switch_codec_interface_t g726_24k_codec_interface = { 
	/*.interface_name */ "G.726 24k", 
	/*.implementations */ &g726_24k_implementation, 
	/*.next */ &g726_16k_codec_interface
};

const switch_codec_interface_t g726_32k_codec_interface = { 
	/*.interface_name */ "G.726 32k", 
	/*.implementations */ &g726_32k_implementation, 
	/*.next */ &g726_24k_codec_interface
};

const switch_codec_interface_t g726_40k_codec_interface = { 
	/*.interface_name */ "G.726 40k", 
	/*.implementations */ &g726_40k_implementation, 
	/*.next */ &g726_32k_codec_interface
};



const switch_codec_interface_t aal2_g726_16k_codec_interface = { 
	/*.interface_name */ "G.726 16k (aal2)", 
	/*.implementations */ &aal2_g726_16k_implementation, 
	/*.next */ &g726_40k_codec_interface
};

const switch_codec_interface_t aal2_g726_24k_codec_interface = { 
	/*.interface_name */ "G.726 24k (aal2)", 
	/*.implementations */ &aal2_g726_24k_implementation, 
	/*.next */ &aal2_g726_16k_codec_interface
};

const switch_codec_interface_t aal2_g726_32k_codec_interface = { 
	/*.interface_name */ "G.726 32k (aal2)", 
	/*.implementations */ &aal2_g726_32k_implementation, 
	/*.next */ &aal2_g726_24k_codec_interface
};

const switch_codec_interface_t aal2_g726_40k_codec_interface = { 
	/*.interface_name */ "G.726 40k (aal2)", 
	/*.implementations */ &aal2_g726_40k_implementation, 
	/*.next */ &aal2_g726_32k_codec_interface
};



static switch_loadable_module_interface_t g726_module_interface = { 
	/*.module_name */ modname, 
	/*.endpoint_interface */ NULL, 
	/*.timer_interface */ NULL, 
	/*.dialplan_interface */ NULL, 
	/*.codec_interface */ &aal2_g726_40k_codec_interface, 
	/*.application_interface */ NULL 
};

SWITCH_MOD_DECLARE(switch_status_t) switch_module_load(const switch_loadable_module_interface_t **module_interface,
													 char *filename)
{
	/* connect my internal structure to the blank pointer passed to me */ 
	*module_interface = &g726_module_interface;

	/* indicate that the module should continue to be loaded */ 
	return SWITCH_STATUS_SUCCESS;
}
