package cn.org.hentai.jtt1078.codec.g726;

import cn.org.hentai.jtt1078.codec.G711Codec;
import cn.org.hentai.jtt1078.codec.G711UCodec;

/** G726_24 encoder and decoder.
  * <p>
  * These routines comprise an implementation of the CCITT G.726 24kbps
  * ADPCM coding algorithm.  Essentially, this implementation is identical to
  * the bit level description except for a few deviations which take advantage
  * of workstation attributes, such as hardware 2's complement arithmetic.
  * <p>
  * This implementation is based on the ANSI-C language reference implementations
  * of the CCITT (International Telegraph and Telephone Consultative Committee)
  * G.711, G.721 and G.723 voice compressions, provided by Sun Microsystems, Inc.
  * <p>
  * Acknowledgement to Sun Microsystems, Inc. for having released the original
  * ANSI-C source code to the public domain.
  */
public class G726_24 extends G726 {
	
	// ##### C-to-Java conversion: #####
	// short becomes int
	// char becomes int
	// unsigned char becomes int


	// *************************** STATIC ***************************

	/*
	 * Maps G726_24 code word to reconstructed scale factor normalized log
	 * magnitude values.
	 */
	static /*short*/int[] _dqlntab={-2048, 135, 273, 373, 373, 273, 135, -2048};
	
	/* Maps G726_24 code word to log of scale factor multiplier. */
	static /*short*/int[] _witab={-128, 960, 4384, 18624, 18624, 4384, 960, -128};
	
	/*
	 * Maps G726_24 code words to a set of values whose long and short
	 * term averages are computed and then compared to give an indication
	 * how stationary (steady state) the signal is.
	 */
	static /*short*/int[] _fitab={0, 0x200, 0x400, 0xE00, 0xE00, 0x400, 0x200, 0};
	
	static /*short*/int[] qtab_723_24={8, 218, 331};
	
	/** Encodes a linear PCM, A-law or u-law input sample and returns its 3-bit code.
	  * Returns -1 if invalid input coding value. */
	public static int encode(int sl, int in_coding, G726State state) {
		
		/*short*/int sei, sezi, se, sez; /* ACCUM */
		/*short*/int d; /* SUBTA */
		/*short*/int y; /* MIX */
		/*short*/int sr; /* ADDB */
		/*short*/int dqsez; /* ADDC */
		/*short*/int dq, i;
	
		switch (in_coding) {
			/* linearize input sample to 14-bit PCM */
			case AUDIO_ENCODING_ALAW:
				sl= G711Codec.alaw2linear((byte)sl) >> 2;
				break;
			case AUDIO_ENCODING_ULAW:
				sl= G711UCodec.ulaw2linear((byte)sl) >> 2;
				break;
			case AUDIO_ENCODING_LINEAR:
				sl >>= 2; /* sl of 14-bit dynamic range */
				break;
			default:
				return (-1);
		}
	
		sezi=state.predictor_zero();
		sez=sezi >> 1;
		sei=sezi+state.predictor_pole();
		se=sei >> 1; /* se=estimated signal */
	
		d=sl-se; /* d=estimation diff. */
	
		/* quantize prediction difference d */
		y=state.step_size();  /* quantizer step size */
		i=quantize(d, y, qtab_723_24, 3); /* i=ADPCM code */
		dq=reconstruct(i & 4, _dqlntab[i], y); /* quantized diff. */
	
		sr=(dq<0)? se-(dq & 0x3FFF) : se+dq; /* reconstructed signal */
	
		dqsez=sr+sez-se;     /* pole prediction diff. */
	
		update(3, y, _witab[i], _fitab[i], dq, sr, dqsez, state);
	
		return (i);
	}
	

	/** Decodes a 3-bit CCITT G.726 24kbps ADPCM code and returns
	  * the resulting 16-bit linear PCM, A-law or u-law sample value.
	  * -1 is returned if the output coding is unknown. */
	public static int decode(int i, int out_coding, G726State state) {
		
		/*short*/int sezi, sei, sez, se; /* ACCUM */
		/*short*/int y; /* MIX */
		/*short*/int sr; /* ADDB */
		/*short*/int dq;
		/*short*/int dqsez;
	
		i &= 0x07; /* mask to get proper bits */
		sezi=state.predictor_zero();
		sez=sezi >> 1;
		sei=sezi+state.predictor_pole();
		se=sei >> 1; /* se=estimated signal */
	
		y=state.step_size();  /* adaptive quantizer step size */
		dq=reconstruct(i & 0x04, _dqlntab[i], y); /* unquantize pred diff */
	
		sr=(dq<0)? (se-(dq & 0x3FFF)) : (se+dq); /* reconst. signal */
	
		dqsez=sr-se+sez; /* pole prediction diff. */
	
		update(3, y, _witab[i], _fitab[i], dq, sr, dqsez, state);
	
		switch (out_coding) {
			
			case AUDIO_ENCODING_ALAW:
				return (tandem_adjust_alaw(sr, se, y, i, 4, qtab_723_24));
			case AUDIO_ENCODING_ULAW:
				return (tandem_adjust_ulaw(sr, se, y, i, 4, qtab_723_24));
			case AUDIO_ENCODING_LINEAR:
				return (sr << 2); /* sr was of 14-bit dynamic range */
			default:
				return (-1);
		}
	}


	/** Encodes the input chunk in_buff of linear PCM, A-law or u-law data and returns
	  * the G726_24 encoded chuck into out_buff. <br>
	  * It returns the actual size of the output data, or -1 in case of unknown
	  * in_coding value. */
	public static int encode(byte[] in_buff, int in_offset, int in_len, int in_coding, byte[] out_buff, int out_offset, G726State state) {
		
		if (in_coding==AUDIO_ENCODING_ALAW || in_coding==AUDIO_ENCODING_ULAW) {
			
			int len_div_8=in_len/8;
			for (int i=0; i<len_div_8; i++) {
				int value8=0;
				int i8=i*8;
				for (int j=0; j<8; j++) {
					int in_value=unsignedInt(in_buff[in_offset+i8+j]);
					int out_value=encode(in_value,in_coding,state);
					value8+=out_value<<(3*(7-j));
				}
				int index=out_offset+i*3;
				for (int k=0; k<3; k++) {
					out_buff[index+k]=(byte)(value8>>(8*(2-k)));
				}
			}
			return len_div_8*3;
		}
		else
		if (in_coding==AUDIO_ENCODING_LINEAR) {
			
			int len_div_16=in_len/16;
			for (int i=0; i<len_div_16; i++) {
				int value16=0;
				int in_index=in_offset+i*16;
				for (int j=0; j<8; j++) {
					int j2=j*2;
					int in_value=signedIntLittleEndian(in_buff[in_index+j2+1],in_buff[in_index+j2]);
					//int out_value=encode(G711.linear2ulaw(in_value),AUDIO_ENCODING_ULAW,state);
					int out_value=encode(in_value,in_coding,state);
					value16+=out_value<<(3*(7-j));
				}
				int out_index=out_offset+i*3;
				for (int k=0; k<3; k++) {
					out_buff[out_index+k]=(byte)(value16>>(8*(2-k)));
				}
			}
			return len_div_16*3;
		}
		else return -1;
	}


	/** Decodes the input chunk in_buff of G726_24 encoded data and returns
	  * the linear PCM, A-law or u-law chunk into out_buff. <br>
	  * It returns the actual size of the output data, or -1 in case of unknown
	  * out_coding value. */
	public static int decode(byte[] in_buff, int in_offset, int in_len, int out_coding, byte[] out_buff, int out_offset, G726State state) {
		
		if (out_coding==AUDIO_ENCODING_ALAW || out_coding==AUDIO_ENCODING_ULAW) {
			
			int len_div_3=in_len/3;
			for (int i=0; i<len_div_3; i++) {
				int value8=0;
				int in_index=in_offset+i*3;
				for (int j=0; j<3; j++) {
					value8+=unsignedInt(in_buff[in_index+j])<<(8*(2-j));
				}
				int out_index=out_offset+i*8;
				for (int k=0; k<8; k++) {
					int in_value=(value8>>(3*(7-k)))&0x7;
					int out_value=decode(in_value,out_coding,state);
					out_buff[out_index+k]=(byte)out_value;
				}
			}
			return len_div_3*8;
		}
		else
		if (out_coding==AUDIO_ENCODING_LINEAR) {
			
			int len_div_3=in_len/3;
			for (int i=0; i<len_div_3; i++) {
				int value16=0;
				int in_index=in_offset+i*3;
				for (int j=0; j<3; j++) {
					value16+=unsignedInt(in_buff[in_index+j])<<(8*(2-j));
				}
				int out_index=out_offset+i*16;
				for (int k=0; k<8; k++) {
					int k2=k*2;
					int in_value=(value16>>(3*(7-k)))&0x7;
					//int out_value=G711.ulaw2linear(decode(in_value,AUDIO_ENCODING_ULAW,state));
					int out_value=decode(in_value,out_coding,state);
					out_buff[out_index+k2]=(byte)(out_value&0xFF);
					out_buff[out_index+k2+1]=(byte)(out_value>>8);
				}
			}
			return len_div_3*16;
		}
		else return -1;
	}


	// ************************* NON-STATIC *************************

	/** Creates a new G726_24 processor, that can be used to encode from or decode do PCM audio data. */
	public G726_24() {
		super(24000);
	}


	/** Encodes a linear PCM, A-law or u-law input sample and returns its 3-bit code.
	  * Returns -1 if invalid input coding value. */
	public int encode(int sl, int in_coding) {
		return encode(sl,in_coding,state);
	}


	/** Encodes the input chunk in_buff of linear PCM, A-law or u-law data and returns
	  * the G726_24 encoded chuck into out_buff. <br>
	  * It returns the actual size of the output data, or -1 in case of unknown
	  * in_coding value. */
	public int encode(byte[] in_buff, int in_offset, int in_len, int in_coding, byte[] out_buff, int out_offset) {
		return encode(in_buff,in_offset,in_len,in_coding,out_buff,out_offset,state);
	}


	/** Decodes a 3-bit CCITT G.726 24kbps ADPCM code and returns
	  * the resulting 16-bit linear PCM, A-law or u-law sample value.
	  * -1 is returned if the output coding is unknown. */
	public int decode(int i, int out_coding) {
		return decode(i,out_coding,state);
	}


	/** Decodes the input chunk in_buff of G726_24 encoded data and returns
	  * the linear PCM, A-law or u-law chunk into out_buff. <br>
	  * It returns the actual size of the output data, or -1 in case of unknown
	  * out_coding value. */
	public int decode(byte[] in_buff, int in_offset, int in_len, int out_coding, byte[] out_buff, int out_offset) {
		return decode(in_buff,in_offset,in_len,out_coding,out_buff,out_offset,state);
	}

}