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-rw-r--r--engines/sci/scicore/decompress0.cpp336
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diff --git a/engines/sci/scicore/decompress0.cpp b/engines/sci/scicore/decompress0.cpp
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-/* ScummVM - Graphic Adventure Engine
- *
- * ScummVM is the legal property of its developers, whose names
- * are too numerous to list here. Please refer to the COPYRIGHT
- * file distributed with this source distribution.
- *
- * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
- *
- * $URL$
- * $Id$
- *
- */
-
-/* Reads data from a resource file and stores the result in memory.
-** This is for SCI version 0 style compression.
-*/
-
-#include "common/stream.h"
-#include "common/endian.h"
-
-#include "sci/sci_memory.h"
-#include "sci/scicore/resource.h"
-
-namespace Sci {
-
-//#define _SCI_DECOMPRESS_DEBUG
-
-// 9-12 bit LZW encoding
-int unpackLZW(uint8 *dest, uint8 *src, int length, int complength) {
- // Doesn't do length checking yet
- /* Theory: Considering the input as a bit stream, we get a series of
- ** 9 bit elements in the beginning. Every one of them is a 'token'
- ** and either represents a literal (if < 0x100), or a link to a previous
- ** token (tokens start at 0x102, because 0x101 is the end-of-stream
- ** indicator and 0x100 is used to reset the bit stream decoder).
- ** If it's a link, the indicated token and the character following it are
- ** placed into the output stream. Note that the 'indicated token' may
- ** very well consist of a link-token-plus-literal construct again, so
- ** it's possible to represent strings longer than 2 recursively.
- ** If the maximum number of tokens has been reached, the bit length is
- ** increased by one, up to a maximum of 12 bits.
- ** This implementation remembers the position each token was print to in
- ** the output array, and the length of this token. This method should
- ** be faster than the recursive approach.
- */
-
- uint16 bitlen = 9; // no. of bits to read (max. 12)
- uint16 bitmask = 0x01ff;
- uint16 bitctr = 0; // current bit position
- uint16 bytectr = 0; // current byte position
- uint16 token; // The last received value
- uint16 maxtoken = 0x200; // The biggest token
-
- uint16 tokenlist[4096]; // pointers to dest[]
- uint16 tokenlengthlist[4096]; // char length of each token
- uint16 tokenctr = 0x102; // no. of registered tokens (starts here)
-
- uint16 tokenlastlength = 0;
-
- uint16 destctr = 0;
-
- while (bytectr < complength) {
-
- uint32 tokenmaker = src[bytectr++] >> bitctr;
- if (bytectr < complength)
- tokenmaker |= (src[bytectr] << (8 - bitctr));
- if (bytectr + 1 < complength)
- tokenmaker |= (src[bytectr+1] << (16 - bitctr));
-
- token = tokenmaker & bitmask;
-
- bitctr += bitlen - 8;
-
- while (bitctr >= 8) {
- bitctr -= 8;
- bytectr++;
- }
-
- if (token == 0x101)
- return 0; // terminator
- if (token == 0x100) { // reset command
- maxtoken = 0x200;
- bitlen = 9;
- bitmask = 0x01ff;
- tokenctr = 0x0102;
- } else {
- {
- int i;
-
- if (token > 0xff) {
- if (token >= tokenctr) {
-#ifdef _SCI_DECOMPRESS_DEBUG
- warning("unpackLZW: Bad token %x", token);
-#endif
- // Well this is really bad
- // May be it should throw something like SCI_ERROR_DECOMPRESSION_INSANE
- } else {
- tokenlastlength = tokenlengthlist[token] + 1;
- if (destctr + tokenlastlength > length) {
-#ifdef _SCI_DECOMPRESS_DEBUG
- // For me this seems a normal situation, It's necessary to handle it
- warning("unpackLZW: Trying to write beyond the end of array(len=%d, destctr=%d, tok_len=%d)",
- length, destctr, tokenlastlength);
-#endif
- i = 0;
- for (; destctr < length; destctr++) {
- dest[destctr++] = dest [tokenlist[token] + i];
- i++;
- }
- } else
- for (i = 0; i < tokenlastlength; i++) {
- dest[destctr++] = dest[tokenlist[token] + i];
- }
- }
- } else {
- tokenlastlength = 1;
- if (destctr >= length) {
-#ifdef _SCI_DECOMPRESS_DEBUG
- warning("unpackLZW: Try to write single byte beyond end of array");
-#endif
- } else
- dest[destctr++] = (byte)token;
- }
-
- }
-
- if (tokenctr == maxtoken) {
- if (bitlen < 12) {
- bitlen++;
- bitmask <<= 1;
- bitmask |= 1;
- maxtoken <<= 1;
- } else
- continue; // no further tokens allowed
- }
-
- tokenlist[tokenctr] = destctr - tokenlastlength;
- tokenlengthlist[tokenctr++] = tokenlastlength;
- }
- }
-
- return 0;
-}
-
-// Huffman-style token encoding
-/***************************************************************************/
-/* This code was taken from Carl Muckenhoupt's sde.c, with some minor */
-/* modifications. */
-/***************************************************************************/
-
-// unpackHuffman helper function
-int16 getc2(uint8 *node, uint8 *src, uint16 *bytectr, uint16 *bitctr, int complength) {
- uint16 next;
-
- while (node[1] != 0) {
- int16 value = (src[*bytectr] << (*bitctr));
- (*bitctr)++;
- if (*bitctr == 8) {
- (*bitctr) = 0;
- (*bytectr)++;
- }
-
- if (value & 0x80) {
- next = node[1] & 0x0f; // low 4 bits
- if (next == 0) {
- uint16 result = (src[*bytectr] << (*bitctr));
-
- if (++(*bytectr) > complength)
- return -1;
- else if (*bytectr < complength)
- result |= src[*bytectr] >> (8 - (*bitctr));
-
- result &= 0x0ff;
- return (result | 0x100);
- }
- } else {
- next = node[1] >> 4; // high 4 bits
- }
- node += next << 1;
- }
-
- return (int16)READ_LE_UINT16(node);
-}
-
-// Huffman token decryptor
-int unpackHuffman(uint8* dest, uint8* src, int length, int complength) {
- // no complength checking atm */
- uint8 numnodes, terminator;
- uint8 *nodes;
- int16 c;
- uint16 bitctr = 0, bytectr;
-
- numnodes = src[0];
- terminator = src[1];
- bytectr = 2 + (numnodes << 1);
- nodes = src + 2;
-
- while (((c = getc2(nodes, src, &bytectr, &bitctr, complength)) != (0x0100 | terminator)) && (c >= 0)) {
- if (length-- == 0)
- return SCI_ERROR_DECOMPRESSION_OVERFLOW;
-
- *dest = (uint8)c;
- dest++;
- }
-
- return (c == -1) ? SCI_ERROR_DECOMPRESSION_OVERFLOW : 0;
-
-}
-
-// Carl Muckenhoupt's decompression code ends here
-
-int sci0_get_compression_method(Common::ReadStream &stream) {
- uint16 compressionMethod;
-
- stream.readUint16LE();
- stream.readUint16LE();
- stream.readUint16LE();
- compressionMethod = stream.readUint16LE();
- if (stream.err())
- return SCI_ERROR_IO_ERROR;
-
- return compressionMethod;
-}
-
-int decompress0(Resource *result, Common::ReadStream &stream, int sci_version) {
- uint16 compressedLength;
- uint16 compressionMethod;
- uint8 *buffer;
- uint8 type;
-
- result->id = stream.readUint16LE();
- if (stream.err())
- return SCI_ERROR_IO_ERROR;
-
- result->number = result->id & 0x07ff;
- type = result->id >> 11;
-
- result->type = (ResourceType)type;
-
- if ((result->number > sci_max_resource_nr[sci_version]) || (type > kResourceTypeInvalid))
- return SCI_ERROR_DECOMPRESSION_INSANE;
-
- compressedLength = stream.readUint16LE();
- result->size = stream.readUint16LE();
- compressionMethod = stream.readUint16LE();
- if (stream.err())
- return SCI_ERROR_IO_ERROR;
-
- if (result->size > 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 = (uint8 *)sci_malloc(compressedLength);
- result->data = (unsigned char *)sci_malloc(result->size);
-
- if (stream.read(buffer, compressedLength) != compressedLength) {
- free(result->data);
- free(buffer);
- result->data = 0;
- return SCI_ERROR_IO_ERROR;
- };
-
-
-#ifdef _SCI_DECOMPRESS_DEBUG
- debug("Resource %s.%03hi encrypted with method %hi at %.2f%% ratio",
- getResourceTypeName(result->type), result->number, compressionMethod,
- (result->size == 0) ? -1.0 :
- (100.0 * compressedLength / result->size));
- debug(" compressedLength = 0x%hx, actualLength=0x%hx",
- compressedLength, result->size);
-#endif
-
- bool overflow = false;
-
- switch (compressionMethod) {
- case 0: // no compression
- if (result->size != compressedLength)
- overflow = true;
- else
- memcpy(result->data, buffer, compressedLength);
- break;
-
- case 1: // LZW compression
- if (unpackLZW(result->data, buffer, result->size, compressedLength))
- overflow = true;
- break;
-
- case 2: // Some sort of Huffman encoding
- if (unpackHuffman(result->data, buffer, result->size, compressedLength))
- overflow = true;
- break;
-
- default:
- warning("Resource %s.%03hi: Compression method %hi not supported",
- getResourceTypeName(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;
- }
-
- if (overflow) {
- 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;
- free(buffer);
- return 0;
-}
-
-} // End of namespace Sci
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