mirror of
https://github.com/aaru-dps/Aaru.Compression.Native.git
synced 2026-09-18 04:37:00 +00:00
Natalia Portillo
ba39191e07
- Implemented range coder in `rangecoder.c` and `rangecoder.h` for efficient encoding/decoding. - Added RLE90 decoding in `rle90.c` for handling StuffIt method 1. - Introduced `stuffit.h` and `stuffit_internal.h` to define compression methods and internal structures. - Implemented x86 address transformation in `x86.c` for StuffIt X preprocessing. - Updated CMakeLists to include new test data files for various StuffIt methods. - Created comprehensive tests in `stuffit.cpp` for validating decompression of multiple StuffIt formats. - Added binary test data for StuffIt methods including compress, method 13, arsenic, and StuffIt X variants.
133 lines
3.7 KiB
C
133 lines
3.7 KiB
C
/*
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* This file is part of the Aaru Data Preservation Suite.
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* Copyright (c) 2019-2026 Natalia Portillo.
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation; either version 2.1 of the
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* License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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/* StuffIt method 2: UNIX compress LZW (flags=0x8E: block mode, 14-bit max) */
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#include <stdlib.h>
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#include <string.h>
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#include "stuffit.h"
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#include "stuffit_internal.h"
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#define COMPRESS_BLOCKMODE 0x80
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#define COMPRESS_MAX_BITS 14
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#define COMPRESS_FIRST_CODE 257 /* 256 literals + clear code */
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#define COMPRESS_CLEAR_CODE 256
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typedef struct CompressEntry
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{
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uint16_t prefix;
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uint8_t byte;
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} CompressEntry;
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int stuffit_compress_decode_buffer(uint8_t *dst, size_t *dst_size, const uint8_t *src, size_t src_size)
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{
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size_t limit = *dst_size;
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size_t di = 0;
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StuffitBitReaderLE br;
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stuffit_bits_le_init(&br, src, src_size);
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int max_symbols = 1 << COMPRESS_MAX_BITS;
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int blockmode = 1; /* flags & 0x80 */
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CompressEntry *dict = calloc(max_symbols, sizeof(CompressEntry));
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if(!dict) return -1;
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uint8_t *stack = malloc(max_symbols);
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if(!stack)
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{
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free(dict);
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return -1;
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}
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/* Initialize dictionary with single-byte entries */
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for(int i = 0; i < 256; i++)
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{
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dict[i].prefix = 0xffff;
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dict[i].byte = (uint8_t)i;
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}
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int next_code = COMPRESS_FIRST_CODE;
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int bits = 9;
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int symbol_count = 0;
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int prev_code = -1;
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uint8_t first_byte = 0;
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while(di < limit)
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{
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int code = stuffit_bits_le_read(&br, bits);
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symbol_count++;
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if(br.byte_pos > br.data_len + 2) break;
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if(code == COMPRESS_CLEAR_CODE && blockmode)
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{
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/* Skip padding bits to byte boundary */
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int symbolsize = bits;
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if(symbol_count % 8) stuffit_bits_le_skip(&br, symbolsize * (8 - symbol_count % 8));
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/* Reset dictionary */
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next_code = COMPRESS_FIRST_CODE;
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bits = 9;
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symbol_count = 0;
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prev_code = -1;
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continue;
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}
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if(code < 0 || code > next_code) break;
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/* Decode string to stack */
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int stack_ptr = 0;
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int c = code;
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if(c == next_code)
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{
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/* Special case: code not yet in table */
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stack[stack_ptr++] = first_byte;
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c = prev_code;
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}
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while(c >= 256 && stack_ptr < max_symbols)
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{
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stack[stack_ptr++] = dict[c].byte;
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c = dict[c].prefix;
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}
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stack[stack_ptr++] = (uint8_t)c;
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first_byte = (uint8_t)c;
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/* Output in reverse order */
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for(int i = stack_ptr - 1; i >= 0 && di < limit; i--) dst[di++] = stack[i];
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/* Add new dictionary entry */
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if(prev_code >= 0 && next_code < max_symbols)
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{
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dict[next_code].prefix = prev_code;
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dict[next_code].byte = first_byte;
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next_code++;
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if(next_code >= (1 << bits) && bits < COMPRESS_MAX_BITS) bits++;
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}
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prev_code = code;
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}
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free(dict);
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free(stack);
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*dst_size = di;
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return 0;
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}
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