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

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

/** G726_16 encoder and decoder.
 * <p>
 * These routines comprise an implementation of the CCITT G.726 16kbps
 * 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>
 * The deviation from the bit level specification (lookup tables),
 * preserves the bit level performance specifications.
 * <p>
 * As outlined in the G.723 Recommendation, the algorithm is broken
 * down into modules.  Each section of code below is preceded by
 * the name of the module which it is implementing.
 * <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_16 extends G726 {

    // ##### C-to-Java conversion: #####
    // short becomes int
    // char becomes int
    // unsigned char becomes int


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

    /*
     * Maps G723_16 code word to ructeconstructed scale factor normalized log
     * magnitude values.
     */
    static /*short*/int[] _dqlntab={116, 365, 365, 116};

    /* Maps G723_16 code word to log of scale factor multiplier. */
    static /*short*/int[] _witab={-704, 14048, 14048, -704};

    /*
     * Maps G723_16 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={ 0x000, 0xE00, 0xE00, 0x000};

    static /*short*/int[] qtab_723_16={261};

    /** Encodes a 16-bit linear PCM, A-law or u-law input sample and retuens
     * the resulting 5-bit CCITT G726 16kbps code.
     * Returns -1 if the input coding value is invalid. */
    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 difference */

        /* quantize prediction difference */
        y=state.step_size();  /* adaptive quantizer step size */
        i=quantize(d, y, qtab_723_16, 1);   /* i=ADPCM code */

        dq=reconstruct(i & 0x02, _dqlntab[i], y);  /* quantized diff */

        sr=(dq<0)? se-(dq & 0x3FFF) : se+dq; /* reconstructed signal */

        dqsez=sr+sez-se;     /* dqsez=pole prediction diff. */

        update(2, y, _witab[i], _fitab[i], dq, sr, dqsez, state);

        return (i);
    }


    /** Decodes a 5-bit CCITT G.726 40kbps 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, dif; /* MIX */
        /*short*/int sr; /* ADDB */
        /*short*/int dq;
        /*short*/int dqsez;

        i &= 0x03; /* 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 & 0x02, _dqlntab[i], y);  /* estimation diff. */

        sr=(dq<0)? (se-(dq & 0x3FFF)) : (se+dq); /* reconst. signal */

        dqsez=sr-se+sez; /* pole prediction diff. */

        update(2, y, _witab[i], _fitab[i], dq, sr, dqsez, state);

        switch (out_coding) {

            case AUDIO_ENCODING_ALAW:
                return (tandem_adjust_alaw(sr, se, y, i, 0x02, qtab_723_16));
            case AUDIO_ENCODING_ULAW:
                return (tandem_adjust_ulaw(sr, se, y, i, 0x02, qtab_723_16));
            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_16 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++) {
                long value8=0;
                int in_index=in_offset+i*8;
                for (int j=0; j<8; j++) {
                    int in_value=unsignedInt(in_buff[in_index+j]);
                    int out_value=encode(in_value,in_coding,state);
                    value8+=((long)out_value)<<(2*(7-j));
                }
                int out_index=out_offset+i*2;
                for (int k=0; k<2; k++) {
                    out_buff[out_index+k]=(byte)(value8>>(8*(1-k)));
                }
            }
            return len_div_8*2;
        }
        else
        if (in_coding==AUDIO_ENCODING_LINEAR) {

            int len_div_16=in_len/16;
            for (int i=0; i<len_div_16; i++) {
                long 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(in_value,in_coding,state);
                    value16+=((long)out_value)<<(2*(7-j));
                }
                int out_index=out_offset+i*2;
                for (int k=0; k<2; k++) {
                    out_buff[out_index+k]=(byte)(value16>>(8*(1-k)));
                }
            }
            return len_div_16*2;
        }
        else return -1;
    }


    /** Decodes the input chunk in_buff of G726_16 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_2=in_len/2;
            for (int i=0; i<len_div_2; i++) {
                int value8=0;
                int in_index=in_offset+i*2;
                for (int j=0; j<2; j++) {
                    value8+=unsignedInt(in_buff[in_index+j])<<(8*(1-j));
                }
                int out_index=out_offset+i*8;
                for (int k=0; k<8; k++) {
                    int in_value=(value8>>(2*(7-k)))&0x3;
                    int out_value=decode(in_value,out_coding,state);
                    out_buff[out_index+k]=(byte)out_value;
                }
            }
            return len_div_2*8;
        }
        else
        if (out_coding==AUDIO_ENCODING_LINEAR) {

            int len_div_2=in_len/2;
            for (int i=0; i<len_div_2; i++) {
                int value16=0;
                int in_index=in_offset+i*2;
                for (int j=0; j<2; j++) {
                    value16+=unsignedInt(in_buff[in_index+j])<<(8*(1-j));
                }
                int out_index=out_offset+i*16;
                for (int k=0; k<8; k++) {
                    int k2=k*2;
                    int in_value=(value16>>(2*(7-k)))&0x3;
                    //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_2*16;
        }
        else return -1;
    }


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

    /** Creates a new G726_16 processor, that can be used to encode from or decode do PCM audio data. */
    public G726_16() {
        super(16000);
    }


    /** Encodes a 16-bit linear PCM, A-law or u-law input sample and retuens
     * the resulting 5-bit CCITT G.726 40kbps code.
     * Returns -1 if the input coding value is invalid. */
    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_16 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 5-bit CCITT G.726 40kbps 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_16 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);
    }
}