/*-----------------------------------------------------------------------------

	ST-Sound ( YM files player library )

	LZH depacking routine
	Original LZH code by Haruhiko Okumura (1991) and Kerwin F. Medina (1996)

	I changed to C++ object to remove global vars, so it should be thread safe now.

-----------------------------------------------------------------------------*/

/*-----------------------------------------------------------------------------
* ST-Sound, ATARI-ST Music Emulator
* Copyright (c) 1995-1999 Arnaud Carre ( http://leonard.oxg.free.fr )
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
-----------------------------------------------------------------------------*/

#include <string.h>
#include "YmTypes.h"
#include "LZH.H"

/*
 * Additions
 */



int		CLzhDepacker::DataIn(void *pBuffer,int nBytes)
{
	const int np = (nBytes <= m_srcSize) ? nBytes : m_srcSize;
	if (np > 0)
	{
		memcpy(pBuffer,m_pSrc,np);
		m_pSrc += np;
		m_srcSize -= np;
	}
	return np;
}

int		CLzhDepacker::DataOut(void *pBuffer,int nBytes)
{
	const int np = (nBytes <= m_dstSize) ? nBytes : m_dstSize;
	if (np > 0)
	{
		memcpy(m_pDst,pBuffer,np);
		m_pDst += np;
		m_dstSize -= np;
	}
	return np;
}



/*
 * io.c
 */


/** Shift bitbuf n bits left, read n bits */
void CLzhDepacker::fillbuf (int n)
{
    bitbuf = (bitbuf << n) & 0xffff;
    while (n > bitcount)
    {
        bitbuf |= subbitbuf << (n -= bitcount);
        if (fillbufsize == 0)
        {
			fillbuf_i = 0;
            fillbufsize = DataIn(buf, BUFSIZE - 32);
		}
		if (fillbufsize > 0)
            fillbufsize--, subbitbuf = buf[fillbuf_i++];
        else
            subbitbuf = 0;
        bitcount = CHAR_BIT;
    }
    bitbuf |= subbitbuf >> (bitcount -= n);
}

ushort CLzhDepacker::getbits (int n)
{
    ushort x;
    x = bitbuf >> (BITBUFSIZ - n);
    fillbuf (n);
    return x;
}

void CLzhDepacker::init_getbits (void)
{
    bitbuf = 0;
    subbitbuf = 0;
    bitcount = 0;
    fillbuf (BITBUFSIZ);
}

/*
 * maketbl.c
 */

int CLzhDepacker::make_table (int nchar, uchar *bitlen,
                       int tablebits, ushort *table)
{
    ushort count[17], weight[17], start[18], *p;
    uint jutbits, avail, mask;
	int i,ch,len,nextcode;

    for (i = 1; i <= 16; i++)
        count[i] = 0;
    for (i = 0; i < nchar; i++)
        count[bitlen[i]]++;

    start[1] = 0;
    for (i = 1; i <= 16; i++)
        start[i + 1] = start[i] + (count[i] << (16 - i));
    if (start[17] != (ushort) (1U << 16))
        return (1); /* error: bad table */

    jutbits = 16 - tablebits;
    for (i = 1; i <= tablebits; i++)
    {
        start[i] >>= jutbits;
        weight[i] = 1U << (tablebits - i);
    }
	while (i <= 16)
	{
		weight[i] = 1U << (16 - i);
		i++;
	}

    i = start[tablebits + 1] >> jutbits;
    if (i != (ushort) (1U << 16))
    {
        int k = 1U << tablebits;
        while (i != k)
            table[i++] = 0;
    }

    avail = nchar;
    mask = 1U << (15 - tablebits);
    for (ch = 0; ch < nchar; ch++)
    {
        if ((len = bitlen[ch]) == 0)
            continue;
        nextcode = start[len] + weight[len];
        if (len <= tablebits)
        {
            for (i = start[len]; i < nextcode; i++)
                table[i] = ch;
        }
        else
        {
            uint k = start[len];
            p = &table[k >> jutbits];
            i = len - tablebits;
            while (i != 0)
            {
                if (*p == 0)
                {
                    right[avail] = left[avail] = 0;
                    *p = avail++;
                }
                if (k & mask)
                    p = &right[*p];
                else
                    p = &left[*p];
                k <<= 1;
                i--;
            }
            *p = ch;
        }
        start[len] = nextcode;
    }
    return (0);
}

/*
 * huf.c
 */


void CLzhDepacker::read_pt_len (int nn, int nbit, int i_special)
{
    int i, n;
    short c;
    ushort mask;

    n = getbits (nbit);
    if (n == 0)
    {
        c = getbits (nbit);
        for (i = 0; i < nn; i++)
            pt_len[i] = 0;
        for (i = 0; i < 256; i++)
            pt_table[i] = c;
    }
    else
    {
        i = 0;
        while (i < n)
        {
            c = bitbuf >> (BITBUFSIZ - 3);
            if (c == 7)
            {
                mask = 1U << (BITBUFSIZ - 1 - 3);
                while (mask & bitbuf)
                {
                    mask >>= 1;
                    c++;
                }
            }
            fillbuf ((c < 7) ? 3 : c - 3);
            pt_len[i++] = uchar(c);
            if (i == i_special)
            {
                c = getbits (2);
                while (--c >= 0)
                    pt_len[i++] = 0;
            }
        }
        while (i < nn)
            pt_len[i++] = 0;
        make_table (nn, pt_len, 8, pt_table);
    }
}

void CLzhDepacker::read_c_len (void)
{
    short i, c, n;
    ushort mask;

    n = getbits (CBIT);
    if (n == 0)
    {
        c = getbits (CBIT);
        for (i = 0; i < NC; i++)
            c_len[i] = 0;
        for (i = 0; i < 4096; i++)
            c_table[i] = c;
    }
    else
    {
        i = 0;
        while (i < n)
        {
            c = pt_table[bitbuf >> (BITBUFSIZ - 8)];
            if (c >= NT)
            {
                mask = 1U << (BITBUFSIZ - 1 - 8);
                do
                {
                    if (bitbuf & mask)
			c = right[c];
                    else
			c = left[c];
                    mask >>= 1;
                } while (c >= NT);
            }
            fillbuf (pt_len[c]);
            if (c <= 2)
            {
                if (c == 0)
                    c = 1;
                else if (c == 1)
                    c = getbits (4) + 3;
                else
                    c = getbits (CBIT) + 20;
                while (--c >= 0)
                    c_len[i++] = 0;
            }
            else
                c_len[i++] = c - 2;
        }
        while (i < NC)
            c_len[i++] = 0;
        make_table (NC, c_len, 12, c_table);
    }
}

ushort CLzhDepacker::decode_c (void)
{
    ushort j, mask;

    if (blocksize == 0)
    {
        blocksize = getbits (16);
        read_pt_len (NT, TBIT, 3);
        read_c_len ();
        read_pt_len (NP, PBIT, -1);
    }
    blocksize--;
    j = c_table[bitbuf >> (BITBUFSIZ - 12)];
    if (j >= NC)
    {
        mask = 1U << (BITBUFSIZ - 1 - 12);
        do
        {
            if (bitbuf & mask)
				j = right[j];
            else
				j = left[j];
            mask >>= 1;
        }
		while (j >= NC);
    }
    fillbuf (c_len[j]);
    return j;
}

ushort CLzhDepacker::decode_p (void)
{
    ushort j, mask;

    j = pt_table[bitbuf >> (BITBUFSIZ - 8)];
    if (j >= NP)
    {
        mask = 1U << (BITBUFSIZ - 1 - 8);
        do
        {
            if (bitbuf & mask)
		j = right[j];
            else
		j = left[j];
            mask >>= 1;
        } while (j >= NP);
    }
    fillbuf (pt_len[j]);
    if (j != 0)
        j = (1U << (j - 1)) + getbits (j - 1);
    return j;
}

void CLzhDepacker::huf_decode_start (void)
{
    init_getbits ();
    blocksize = 0;
}

/*
 * decode.c
 */


void CLzhDepacker::decode_start (void)
{
    fillbufsize = 0;
    huf_decode_start ();
    decode_j = 0;
}

/*
 * The calling function must keep the number of bytes to be processed.  This
 * function decodes either 'count' bytes or 'DICSIZ' bytes, whichever is
 * smaller, into the array 'buffer[]' of size 'DICSIZ' or more. Call
 * decode_start() once for each new file before calling this function.
 */
void CLzhDepacker::decode (uint count, uchar buffer[])
{
    uint r, c;

    r = 0;
    while (--decode_j >= 0)
    {
        buffer[r] = buffer[decode_i];
        decode_i = (decode_i + 1) & (DICSIZ - 1);
        if (++r == count)
            return;
    }
    for (;;)
    {
        c = decode_c ();
        if (c <= UCHAR_MAX)
        {
            buffer[r] = c;
            if (++r == count)
                return;
        }
        else
        {
            decode_j = c - (UCHAR_MAX + 1 - THRESHOLD);
            decode_i = (r - decode_p () - 1) & (DICSIZ - 1);
            while (--decode_j >= 0)
            {
                buffer[r] = buffer[decode_i];
                decode_i = (decode_i + 1) & (DICSIZ - 1);
                if (++r == count)
                    return;
            }
        }
    }
}

bool	CLzhDepacker::LzUnpack(void *pSrc,int srcSize,void *pDst,int dstSize)
{

    with_error = 0;

	m_pSrc = (uchar*)pSrc;
	m_srcSize = srcSize;
	m_pDst = (uchar*)pDst;
	m_dstSize = dstSize;

    decode_start ();

	unsigned int origsize = dstSize;
    while (origsize != 0)
    {
        int n = (uint) ((origsize > DICSIZ) ? DICSIZ : origsize);
        decode (n, outbuf);
		if (with_error)
			break;

		DataOut(outbuf,n);
        origsize -= n;
		if (with_error)
			break;
    }

    return (0 == with_error);
}