//Copyright Paul Reiche, Fred Ford. 1992-2002

/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */
 
 /*
 * LZHUF.C English version 1.0
 * Based on Japanese version 29-NOV-1988
 * LZSS coded by Haruhiko OKUMURA
 * Adaptive Huffman Coding coded by Haruyasu YOSHIZAKI
 * Edited and translated to English by Kenji RIKITAKE
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "lzh.h"
#include "libs/reslib.h"

PLZHCODE_DESC _lpCurCodeDesc;
STREAM_TYPE _StreamType;
BYTE* _Stream;
UWORD _workbuf;
BYTE _workbuflen;

/* get one bit */
static SWORD
GetBit (void)
{
	SWORD i;

	while (_workbuflen <= 8)
	{
		if ((i = InChar ()) < 0)
			i = 0;
		_workbuf |= i << (8 - _workbuflen);
		_workbuflen += 8;
	}
	i = (_workbuf & 0xFFFF) >> (16 - 1);
	_workbuf = (_workbuf << 1) & 0xFFFF;
	_workbuflen--;

	return (i);
}

static UWORD
GetBits (BYTE num_bits)
{
	SWORD i;

	while (_workbuflen <= 8)
	{
		if ((i = InChar ()) < 0)
			i = 0;
		_workbuf |= i << (8 - _workbuflen);
		_workbuflen += 8;
	}
	i = (_workbuf & 0xFFFF) >> (16 - num_bits);
	_workbuf = (_workbuf << num_bits) & 0xFFFF;
	_workbuflen -= num_bits;

	return (i);
}

/* initialize freq tree */

void
StartHuff (void)
{
	COUNT i, j;

	for (i = 0; i < N_CHAR; i++)
	{
		_lpCurCodeDesc->freq[i] = 1;
		_lpCurCodeDesc->son[i] = i + T;
		_lpCurCodeDesc->prnt[i + T] = i;
	}
	i = 0; j = N_CHAR;
	while (j <= R)
	{
		_lpCurCodeDesc->freq[j] = _lpCurCodeDesc->freq[i] + _lpCurCodeDesc->freq[i + 1];
		_lpCurCodeDesc->son[j] = i;
		_lpCurCodeDesc->prnt[i] = _lpCurCodeDesc->prnt[i + 1] = j;
		i += 2; j++;
	}
	_lpCurCodeDesc->freq[T] = 0xffff;
	_lpCurCodeDesc->prnt[R] = 0;
}

DECODE_REF
copen (void *InStream, STREAM_TYPE SType, STREAM_MODE SMode)
{
	DWORD StreamLength;

	_StreamType = SType;
	_Stream = InStream;
	if (SMode == STREAM_WRITE) /* writing */
	{
		OutChar (0); /* skip future StreamLength */
		OutChar (0);
		OutChar (0);
		OutChar (0);

		StreamLength = 0;
	}
	else /* reading */
	{
		BYTE lobyte, hibyte;
		UWORD loword, hiword;

		lobyte = (BYTE)InChar ();
		hibyte = (BYTE)InChar ();
		loword = MAKE_WORD (lobyte, hibyte);
		lobyte = (BYTE)InChar ();
		hibyte = (BYTE)InChar ();
		hiword = MAKE_WORD (lobyte, hibyte);

		StreamLength = MAKE_DWORD (loword, hiword);
	}

	if (StreamLength == 0xFFFFFFFF
			|| (_lpCurCodeDesc = AllocCodeDesc ()) == NULL)
	{
		FreeCodeDesc (_lpCurCodeDesc);
		_lpCurCodeDesc = NULL;
	}
	else
	{
		_lpCurCodeDesc->Stream = _Stream;
		_lpCurCodeDesc->StreamType = _StreamType;
		_lpCurCodeDesc->StreamMode = SMode;
		_lpCurCodeDesc->StreamLength = StreamLength;
		_lpCurCodeDesc->buf_index = N - F;
		memset (&_lpCurCodeDesc->text_buf[0], ' ', N - F);

		StartHuff ();
	}

	return ((DECODE_REF)_lpCurCodeDesc);
}

DWORD
cclose (PLZHCODE_DESC lpCodeDesc)
{
	_lpCurCodeDesc = lpCodeDesc;
	if (_lpCurCodeDesc)
	{
		DWORD StreamIndex;

		if (_lpCurCodeDesc->CleanupFunc)
			(*_lpCurCodeDesc->CleanupFunc) ();

		StreamIndex = lpCodeDesc->StreamIndex;
		FreeCodeDesc (lpCodeDesc);
		_lpCurCodeDesc = NULL;

		return (StreamIndex);
	}

	return (0);
}

void
cfilelength (PLZHCODE_DESC lpCodeDesc, DWORD *pfilelen)
{
	if (lpCodeDesc == 0)
		*pfilelen = 0;
	else
		*pfilelen = lpCodeDesc->StreamLength;
}

		/* decoder table */
static const BYTE d_code[256] =
{
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
	0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
	0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
	0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
	0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
	0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
	0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
	0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
	0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09,
	0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A, 0x0A,
	0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B,
	0x0C, 0x0C, 0x0C, 0x0C, 0x0D, 0x0D, 0x0D, 0x0D,
	0x0E, 0x0E, 0x0E, 0x0E, 0x0F, 0x0F, 0x0F, 0x0F,
	0x10, 0x10, 0x10, 0x10, 0x11, 0x11, 0x11, 0x11,
	0x12, 0x12, 0x12, 0x12, 0x13, 0x13, 0x13, 0x13,
	0x14, 0x14, 0x14, 0x14, 0x15, 0x15, 0x15, 0x15,
	0x16, 0x16, 0x16, 0x16, 0x17, 0x17, 0x17, 0x17,
	0x18, 0x18, 0x19, 0x19, 0x1A, 0x1A, 0x1B, 0x1B,
	0x1C, 0x1C, 0x1D, 0x1D, 0x1E, 0x1E, 0x1F, 0x1F,
	0x20, 0x20, 0x21, 0x21, 0x22, 0x22, 0x23, 0x23,
	0x24, 0x24, 0x25, 0x25, 0x26, 0x26, 0x27, 0x27,
	0x28, 0x28, 0x29, 0x29, 0x2A, 0x2A, 0x2B, 0x2B,
	0x2C, 0x2C, 0x2D, 0x2D, 0x2E, 0x2E, 0x2F, 0x2F,
	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
	0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
};
static const BYTE d_len[256] =
{
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
	0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
	0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
	0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
	0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
	0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
	0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
	0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
	0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
	0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
	0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
	0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
	0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
	0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
	0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
	0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
	0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
	0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
	0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
	0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
	0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
	0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
};

	/* decode upper 6 bits from given table */
#define DecodePosition(p) \
{ \
	while (_workbuflen <= 8) \
	{ \
		*(p) = InChar (); \
		_workbuf |= *(p) << (8 - _workbuflen); \
		_workbuflen += 8; \
	} \
	*(p) = HIBYTE (_workbuf); \
	_workbuf = (_workbuf << 8) & 0xFFFF; \
	_workbuflen -= 8; \
	\
	/* input lower 6 bits directly */ \
	j = d_len[*(p)]; \
	*(p) = ((UWORD)d_code[*(p)] << 6) \
			| (((*(p) << j) | GetBits (j)) & 0x3f); \
}

	/* start searching tree from the root to leaves.
	 * choose node #(son[]) if input bit == 0
	 * else choose #(son[]+1) (input bit == 1)
	 */
#define DecodeChar(c) \
{ \
	for (*(c) = lpCodeDesc->son[R]; \
			*(c) < T; \
			*(c) = lpCodeDesc->son[*(c) + GetBit ()]) \
		; \
	_update (*(c)); \
	*(c) -= T; \
}

COUNT
cread (void *buf, COUNT size, COUNT count, PLZHCODE_DESC lpCodeDesc)
{
	COUNT r, j, i;
	BYTE *lpStr;

	if ((_lpCurCodeDesc = lpCodeDesc) == 0)
		return (0);

	size *= count;
	if (lpCodeDesc->StreamIndex + size > lpCodeDesc->StreamLength)
	{
		size /= count;
		count = (COUNT)((lpCodeDesc->StreamLength
				- lpCodeDesc->StreamIndex) / size);

		size *= count;
	}

	if (size == 0)
		return (0);

	lpStr = (BYTE*)buf;
	_StreamType = lpCodeDesc->StreamType;

	_Stream = lpCodeDesc->Stream;
	_workbuf = lpCodeDesc->workbuf;
	_workbuflen = lpCodeDesc->workbuflen;

	lpCodeDesc->StreamIndex += size;
	r = lpCodeDesc->buf_index;
	j = lpCodeDesc->bytes_left;
	if (j)
	{
		lpCodeDesc->bytes_left = 0;
		i = lpCodeDesc->restart_index;

		goto ReenterRun;
	}

	do
	{
		COUNT c;

		DecodeChar (&c);

		if (c < 256)
		{
			size--;

			*lpStr++ = lpCodeDesc->text_buf[r++ & (N - 1)] = (BYTE)c;
		}
		else
		{
			COUNT copy_size;

			//i is a COUNT;
				DecodePosition(&i);
			i = r - i - 1;
			j = c - 255 + THRESHOLD;
ReenterRun:
			if (j > size)
			{
				lpCodeDesc->bytes_left = j - size;
				lpCodeDesc->restart_index = i + size;
				j = size;
			}

			size -= j;
			do
			{
				COUNT loc_size;

				i &= (N - 1);
				r &= (N - 1);
				if ((i < r && i + j > r) || (i > r && i + j > r + N))
					copy_size = (r - i) & (N - 1);
				else if ((copy_size = j) > N)
					copy_size = N;

				loc_size = copy_size;
				if (i + loc_size > N)
				{
					COUNT k;

					k = N - i;
					memcpy (lpStr, &lpCodeDesc->text_buf[i], k);
					lpStr += k;
					loc_size -= k;
					i = 0;
				}

				memcpy (lpStr, &lpCodeDesc->text_buf[i], loc_size);
				lpStr += loc_size;
				i += loc_size;

				lpStr -= copy_size;

				loc_size = copy_size;
				if (r + loc_size > N)
				{
					COUNT k;

					k = N - r;
					memcpy (&lpCodeDesc->text_buf[r], lpStr, k);
					lpStr += k;
					loc_size -= k;
					r = 0;
				}

				memcpy (&lpCodeDesc->text_buf[r], lpStr, loc_size);
				lpStr += loc_size;
				r += loc_size;
			} while (j -= copy_size);
		}
	} while (size);

	lpCodeDesc->buf_index = r;
	lpCodeDesc->Stream = _Stream;
	lpCodeDesc->workbuf = _workbuf;
	lpCodeDesc->workbuflen = _workbuflen;

	return (count);
}