/***************************************************************************
 decompress01.c Copyright (C) 1999 The FreeSCI project


 This program may be modified and copied freely according to the terms of
 the GNU general public license (GPL), as long as the above copyright
 notice and the licensing information contained herein are preserved.

 Please refer to www.gnu.org for licensing details.

 This work is provided AS IS, without warranty of any kind, expressed or
 implied, including but not limited to the warranties of merchantibility,
 noninfringement, and fitness for a specific purpose. The author will not
 be held liable for any damage caused by this work or derivatives of it.

 By using this source code, you agree to the licensing terms as stated
 above.


 Please contact the maintainer for bug reports or inquiries.

 Current Maintainer:

    Christoph Reichenbach (CJR) [creichen@rbg.informatik.tu-darmstadt.de]

***************************************************************************/
/* Reads data from a resource file and stores the result in memory */

#include "sci/include/sci_memory.h"
#include "sci/include/sciresource.h"

/***************************************************************************
* The following code was originally created by Carl Muckenhoupt for his
* SCI decoder. It has been ported to the FreeSCI environment by Sergey Lapin.
***************************************************************************/

/* TODO: Clean up, re-organize, improve speed-wise */

struct tokenlist {
	guint8 data;
	gint16 next;
} tokens[0x1004];

static gint8 stak[0x1014] = {0};
static gint8 lastchar = 0;
static gint16 stakptr = 0;
static guint16 numbits, s_bitstring, lastbits, decryptstart;
static gint16 curtoken, endtoken;


guint32 gbits(int numbits,  guint8 * data, int dlen);

void decryptinit3(void) {
	int i;
	lastchar = lastbits = s_bitstring = stakptr = 0;
	numbits = 9;
	curtoken = 0x102;
	endtoken = 0x1ff;
	decryptstart = 0;
	gbits(0, 0, 0);
	for (i = 0;i < 0x1004;i++) {
		tokens[i].next = 0;
		tokens[i].data = 0;
	}
}

int decrypt3(guint8 *dest, guint8 *src, int length, int complength) {
	static gint16 token;
	while (length != 0) {

		switch (decryptstart) {
		case 0:
		case 1:
			s_bitstring = gbits(numbits, src, complength);
			if (s_bitstring == 0x101) { /* found end-of-data signal */
				decryptstart = 4;
				return 0;
			}
			if (decryptstart == 0) { /* first char */
				decryptstart = 1;
				lastbits = s_bitstring;
				*(dest++) = lastchar = (s_bitstring & 0xff);
				if (--length != 0) continue;
				return 0;
			}
			if (s_bitstring == 0x100) { /* start-over signal */
				numbits = 9;
				endtoken = 0x1ff;
				curtoken = 0x102;
				decryptstart = 0;
				continue;
			}
			token = s_bitstring;
			if (token >= curtoken) { /* index past current point */
				token = lastbits;
				stak[stakptr++] = lastchar;
			}
			while ((token > 0xff) && (token < 0x1004)) { /* follow links back in data */
				stak[stakptr++] = tokens[token].data;
				token = tokens[token].next;
			}
			lastchar = stak[stakptr++] = token & 0xff;
		case 2:
			while (stakptr > 0) { /* put stack in buffer */
				*(dest++) = stak[--stakptr];
				length--;
				if (length == 0) {
					decryptstart = 2;
					return 0;
				}
			}
			decryptstart = 1;
			if (curtoken <= endtoken) { /* put token into record */
				tokens[curtoken].data = lastchar;
				tokens[curtoken].next = lastbits;
				curtoken++;
				if (curtoken == endtoken && numbits != 12) {
					numbits++;
					endtoken <<= 1;
					endtoken++;
				}
			}
			lastbits = s_bitstring;
			continue; /* When are "break" and "continue" synonymous? */
		case 4:
			return 0;
		}
	}
	return 0;     /* [DJ] shut up compiler warning */
}

guint32 gbits(int numbits,  guint8 * data, int dlen) {
	int place; /* indicates location within byte */
	guint32 bitstring;
	static guint32 whichbit = 0;
	int i;

	if (numbits == 0) {whichbit = 0; return 0;}

	place = whichbit >> 3;
	bitstring = 0;
	for (i = (numbits >> 3) + 1;i >= 0;i--) {
		if (i + place < dlen)
			bitstring |= data[place+i] << (8 * (2 - i));
	}
	/*  bitstring = data[place+2] | (long)(data[place+1])<<8
	    | (long)(data[place])<<16;*/
	bitstring >>= 24 - (whichbit & 7) - numbits;
	bitstring &= (0xffffffff >> (32 - numbits));
	/* Okay, so this could be made faster with a table lookup.
	   It doesn't matter. It's fast enough as it is. */
	whichbit += numbits;
	return bitstring;
}

/***************************************************************************
* Carl Muckenhoupt's code ends here
***************************************************************************/

enum {
	PIC_OP_SET_COLOR = 0xf0,
	PIC_OP_DISABLE_VISUAL = 0xf1,
	PIC_OP_SET_PRIORITY = 0xf2,
	PIC_OP_DISABLE_PRIORITY = 0xf3,
	PIC_OP_SHORT_PATTERNS = 0xf4,
	PIC_OP_MEDIUM_LINES = 0xf5,
	PIC_OP_LONG_LINES = 0xf6,
	PIC_OP_SHORT_LINES = 0xf7,
	PIC_OP_FILL = 0xf8,
	PIC_OP_SET_PATTERN = 0xf9,
	PIC_OP_ABSOLUTE_PATTERN = 0xfa,
	PIC_OP_SET_CONTROL = 0xfb,
	PIC_OP_DISABLE_CONTROL = 0xfc,
	PIC_OP_MEDIUM_PATTERNS = 0xfd,
	PIC_OP_OPX = 0xfe,
	PIC_OP_TERMINATE = 0xff
};

enum {
	PIC_OPX_SET_PALETTE_ENTRIES = 0,
	PIC_OPX_EMBEDDED_VIEW = 1,
	PIC_OPX_SET_PALETTE = 2,
	PIC_OPX_PRIORITY_TABLE_EQDIST = 3,
	PIC_OPX_PRIORITY_TABLE_EXPLICIT = 4
};

#define PAL_SIZE 1284
#define CEL_HEADER_SIZE 7
#define EXTRA_MAGIC_SIZE 15

static
void decode_rle(byte **rledata, byte **pixeldata, byte *outbuffer, int size) {
	int pos = 0;
	char nextbyte;
	byte *rd = *rledata;
	byte *ob = outbuffer;
	byte *pd = *pixeldata;

	while (pos < size) {
		nextbyte = *(rd++);
		*(ob++) = nextbyte;
		pos ++;
		switch (nextbyte&0xC0) {
		case 0x40 :
		case 0x00 :
			memcpy(ob, pd, nextbyte);
			pd += nextbyte;
			ob += nextbyte;
			pos += nextbyte;
			break;
		case 0xC0 :
			break;
		case 0x80 :
			nextbyte = *(pd++);
			*(ob++) = nextbyte;
			pos ++;
			break;
		}
	}

	*rledata = rd;
	*pixeldata = pd;
}

/*
 * Does the same this as above, only to determine the length of the compressed
 * source data.
 *
 * Yes, this is inefficient.
 */
static
int rle_size(byte *rledata, int dsize) {
	int pos = 0;
	char nextbyte;
	int size = 0;

	while (pos < dsize) {
		nextbyte = *(rledata++);
		pos ++;
		size ++;

		switch (nextbyte&0xC0) {
		case 0x40 :
		case 0x00 :
			pos += nextbyte;
			break;
		case 0xC0 :
			break;
		case 0x80 :
			pos ++;
			break;
		}
	}

	return size;
}

byte *pic_reorder(byte *inbuffer, int dsize) {
	byte *reorderBuffer;
	int view_size;
	int view_start;
	int cdata_size;
	int i;
	byte *seeker = inbuffer;
	byte *writer;
	char viewdata[CEL_HEADER_SIZE];
	byte *cdata, *cdata_start;

	writer = reorderBuffer = (byte *) malloc(dsize);

	*(writer++) = PIC_OP_OPX;
	*(writer++) = PIC_OPX_SET_PALETTE;

	for (i = 0;i < 256;i++) /* Palette translation map */
		*(writer++) = i;

	putInt16(writer, 0); /* Palette stamp */
	writer += 2;
	putInt16(writer, 0);
	writer += 2;

	view_size = getUInt16(seeker);
	seeker += 2;
	view_start = getUInt16(seeker);
	seeker += 2;
	cdata_size = getUInt16(seeker);
	seeker += 2;

	memcpy(viewdata, seeker, sizeof(viewdata));
	seeker += sizeof(viewdata);

	memcpy(writer, seeker, 4*256); /* Palette */
	seeker += 4 * 256;
	writer += 4 * 256;

	if (view_start != PAL_SIZE + 2) { /* +2 for the opcode */
		memcpy(writer, seeker, view_start - PAL_SIZE - 2);
		seeker += view_start - PAL_SIZE - 2;
		writer += view_start - PAL_SIZE - 2;
	}

	if (dsize != view_start + EXTRA_MAGIC_SIZE + view_size) {
		memcpy(reorderBuffer + view_size + view_start + EXTRA_MAGIC_SIZE, seeker,
		       dsize - view_size - view_start - EXTRA_MAGIC_SIZE);
		seeker += dsize - view_size - view_start - EXTRA_MAGIC_SIZE;
	}

	cdata_start = cdata = (byte *) malloc(cdata_size);
	memcpy(cdata, seeker, cdata_size);
	seeker += cdata_size;

	writer = reorderBuffer + view_start;
	*(writer++) = PIC_OP_OPX;
	*(writer++) = PIC_OPX_EMBEDDED_VIEW;
	*(writer++) = 0;
	*(writer++) = 0;
	*(writer++) = 0;
	putInt16(writer, view_size + 8);
	writer += 2;

	memcpy(writer, viewdata, sizeof(viewdata));
	writer += sizeof(viewdata);

	*(writer++) = 0;

	decode_rle(&seeker, &cdata, writer, view_size);

	free(cdata_start);
	free(inbuffer);
	return reorderBuffer;
}

#define VIEW_HEADER_COLORS_8BIT 0x80

static
void build_cel_headers(byte **seeker, byte **writer, int celindex, int *cc_lengths, int max) {
	int c, w;

	for (c = 0;c < max;c++) {
		w = getUInt16(*seeker);
		putInt16(*writer, w);
		*seeker += 2;
		*writer += 2;
		w = getUInt16(*seeker);
		putInt16(*writer, w);
		*seeker += 2;
		*writer += 2;
		w = getUInt16(*seeker);
		putInt16(*writer, w);
		*seeker += 2;
		*writer += 2;
		w = *((*seeker)++);
		putInt16(*writer, w); /* Zero extension */
		*writer += 2;

		*writer += cc_lengths[celindex];
		celindex ++;
	}
}



byte *view_reorder(byte *inbuffer, int dsize) {
	byte *cellengths;
	int loopheaders;
	int lh_present;
	int lh_mask;
	int pal_offset;
	int cel_total;
	int unknown;
	byte *seeker = inbuffer;
	char celcounts[100];
	byte *outbuffer = (byte *) malloc(dsize);
	byte *writer = outbuffer;
	byte *lh_ptr;
	byte *rle_ptr, *pix_ptr;
	int l, lb, c, celindex, lh_last = -1;
	int chptr;
	int w;
	int *cc_lengths;
	byte **cc_pos;

	/* Parse the main header */
	cellengths = inbuffer + getUInt16(seeker) + 2;
	seeker += 2;
	loopheaders = *(seeker++);
	lh_present = *(seeker++);
	lh_mask = getUInt16(seeker);
	seeker += 2;
	unknown = getUInt16(seeker);
	seeker += 2;
	pal_offset = getUInt16(seeker);
	seeker += 2;
	cel_total = getUInt16(seeker);
	seeker += 2;

	cc_pos = (byte **) malloc(sizeof(byte *) * cel_total);
	cc_lengths = (int *) malloc(sizeof(int) * cel_total);

	for (c = 0;c < cel_total;c++)
		cc_lengths[c] = getUInt16(cellengths + 2 * c);

	*(writer++) = loopheaders;
	*(writer++) = VIEW_HEADER_COLORS_8BIT;
	putInt16(writer, lh_mask);
	writer += 2;
	putInt16(writer, unknown);
	writer += 2;
	putInt16(writer, pal_offset);
	writer += 2;

	lh_ptr = writer;
	writer += 2 * loopheaders; /* Make room for the loop offset table */

	pix_ptr = writer;

	memcpy(celcounts, seeker, lh_present);
	seeker += lh_present;

	lb = 1;
	celindex = 0;

	rle_ptr = pix_ptr = cellengths + (2 * cel_total);
	w = 0;

	for (l = 0;l < loopheaders;l++) {
		if (lh_mask & lb) { /* The loop is _not_ present */
			if (lh_last == -1) {
				fprintf(stderr, "Error: While reordering view: Loop not present, but can't re-use last loop!\n");
				lh_last = 0;
			}
			putInt16(lh_ptr, lh_last);
			lh_ptr += 2;
		} else {
			lh_last = writer - outbuffer;
			putInt16(lh_ptr, lh_last);
			lh_ptr += 2;
			putInt16(writer, celcounts[w]);
			writer += 2;
			putInt16(writer, 0);
			writer += 2;

			/* Now, build the cel offset table */
			chptr = (writer - outbuffer) + (2 * celcounts[w]);

			for (c = 0;c < celcounts[w];c++) {
				putInt16(writer, chptr);
				writer += 2;
				cc_pos[celindex+c] = outbuffer + chptr;
				chptr += 8 + getUInt16(cellengths + 2 * (celindex + c));
			}

			build_cel_headers(&seeker, &writer, celindex, cc_lengths, celcounts[w]);

			celindex += celcounts[w];
			w++;
		}

		lb = lb << 1;
	}

	if (celindex < cel_total) {
		fprintf(stderr, "View decompression generated too few (%d / %d) headers!\n", celindex, cel_total);
		return NULL;
	}

	/* Figure out where the pixel data begins. */
	for (c = 0;c < cel_total;c++)
		pix_ptr += rle_size(pix_ptr, cc_lengths[c]);

	rle_ptr = cellengths + (2 * cel_total);
	for (c = 0;c < cel_total;c++)
		decode_rle(&rle_ptr, &pix_ptr, cc_pos[c] + 8, cc_lengths[c]);

	*(writer++) = 'P';
	*(writer++) = 'A';
	*(writer++) = 'L';

	for (c = 0;c < 256;c++)
		*(writer++) = c;

	seeker -= 4; /* The missing four. Don't ask why. */
	memcpy(writer, seeker, 4*256 + 4);

	free(cc_pos);
	free(cc_lengths);
	free(inbuffer);
	return outbuffer;
}



int decompress01(resource_t *result, int resh, int sci_version) {
	guint16 compressedLength, result_size;
	guint16 compressionMethod;
	guint8 *buffer;

	if (read(resh, &(result->id), 2) != 2)
		return SCI_ERROR_IO_ERROR;

#ifdef WORDS_BIGENDIAN
	result->id = GUINT16_SWAP_LE_BE_CONSTANT(result->id);
#endif

	result->number = result->id & 0x07ff;
	result->type = result->id >> 11;

	if ((result->number > sci_max_resource_nr[sci_version] || (result->type > sci_invalid_resource)))
		return SCI_ERROR_DECOMPRESSION_INSANE;

	if ((read(resh, &compressedLength, 2) != 2) ||
	        (read(resh, &result_size, 2) != 2) ||
	        (read(resh, &compressionMethod, 2) != 2))
		return SCI_ERROR_IO_ERROR;

#ifdef WORDS_BIGENDIAN
	compressedLength = GUINT16_SWAP_LE_BE_CONSTANT(compressedLength);
	result_size = GUINT16_SWAP_LE_BE_CONSTANT(result_size);
	compressionMethod = GUINT16_SWAP_LE_BE_CONSTANT(compressionMethod);
#endif
	result->size = result_size;

	/*  if ((result->size < 0) || (compressedLength < 0))
	    return SCI_ERROR_DECOMPRESSION_INSANE; */
	/* This return will never happen in SCI0 or SCI1 (does it have any use?) */

	if ((result->size > SCI_MAX_RESOURCE_SIZE) ||
	        (compressedLength > SCI_MAX_RESOURCE_SIZE))
		return SCI_ERROR_RESOURCE_TOO_BIG;

	if (compressedLength > 4)
		compressedLength -= 4;
	else { /* Object has size zero (e.g. view.000 in sq3) (does this really exist?) */
		result->data = 0;
		result->status = SCI_STATUS_NOMALLOC;
		return SCI_ERROR_EMPTY_OBJECT;
	}

	buffer = (guint8*)sci_malloc(compressedLength);
	result->data = (unsigned char*)sci_malloc(result->size);

	if (read(resh, buffer, compressedLength) != compressedLength) {
		free(result->data);
		free(buffer);
		return SCI_ERROR_IO_ERROR;
	};


#ifdef _SCI_DECOMPRESS_DEBUG
	fprintf(stderr, "Resource %s.%03hi encrypted with method SCI01/%hi at %.2f%%"
	        " ratio\n",
	        sci_resource_types[result->type], result->number, compressionMethod,
	        (result->size == 0) ? -1.0 :
	        (100.0 * compressedLength / result->size));
	fprintf(stderr, "  compressedLength = 0x%hx, actualLength=0x%hx\n",
	        compressedLength, result->size);
#endif

	switch (compressionMethod) {

	case 0: /* no compression */
		if (result->size != compressedLength) {
			free(result->data);
			result->data = NULL;
			result->status = SCI_STATUS_NOMALLOC;
			free(buffer);
			return SCI_ERROR_DECOMPRESSION_OVERFLOW;
		}
		memcpy(result->data, buffer, compressedLength);
		result->status = SCI_STATUS_ALLOCATED;
		break;

	case 1: /* Some huffman encoding */
		if (decrypt2(result->data, buffer, result->size, compressedLength)) {
			free(result->data);
			result->data = 0; /* So that we know that it didn't work */
			result->status = SCI_STATUS_NOMALLOC;
			free(buffer);
			return SCI_ERROR_DECOMPRESSION_OVERFLOW;
		}
		result->status = SCI_STATUS_ALLOCATED;
		break;

	case 2: /* ??? */
		decryptinit3();
		if (decrypt3(result->data, buffer, result->size, compressedLength)) {
			free(result->data);
			result->data = 0; /* So that we know that it didn't work */
			result->status = SCI_STATUS_NOMALLOC;
			free(buffer);
			return SCI_ERROR_DECOMPRESSION_OVERFLOW;
		}
		result->status = SCI_STATUS_ALLOCATED;
		break;

	case 3:
		decryptinit3();
		if (decrypt3(result->data, buffer, result->size, compressedLength)) {
			free(result->data);
			result->data = 0; /* So that we know that it didn't work */
			result->status = SCI_STATUS_NOMALLOC;
			free(buffer);
			return SCI_ERROR_DECOMPRESSION_OVERFLOW;
		}
		result->data = view_reorder(result->data, result->size);
		result->status = SCI_STATUS_ALLOCATED;
		break;

	case 4:
		decryptinit3();
		if (decrypt3(result->data, buffer, result->size, compressedLength)) {
			free(result->data);
			result->data = 0; /* So that we know that it didn't work */
			result->status = SCI_STATUS_NOMALLOC;
			free(buffer);
			return SCI_ERROR_DECOMPRESSION_OVERFLOW;
		}
		result->data = pic_reorder(result->data, result->size);
		result->status = SCI_STATUS_ALLOCATED;
		break;

	default:
		fprintf(stderr, "Resource %s.%03hi: Compression method SCI1/%hi not "
		        "supported!\n", sci_resource_types[result->type], result->number,
		        compressionMethod);
		free(result->data);
		result->data = 0; /* So that we know that it didn't work */
		result->status = SCI_STATUS_NOMALLOC;
		free(buffer);
		return SCI_ERROR_UNKNOWN_COMPRESSION;
	}

	free(buffer);
	return 0;
}