mirror of
https://github.com/aaru-dps/Aaru.Compression.Native.git
synced 2026-07-09 02:16:14 +00:00
Natalia Portillo
1228eea822
- Introduced a new header file `vm.h` for the RAR 3.0 virtual machine, defining its architecture, instruction set, and API. - Implemented the core functionality for executing RAR decompression filters. - Added test cases for RAR formats 1.5, 2.0, 3.0, and 5.0, verifying decompression and CRC checks. - Included necessary binary test data files for RAR formats in the test directory. - Updated CMake configuration to include new test files and data.
71 lines
1.9 KiB
C
71 lines
1.9 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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#include "bitstream.h"
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void rar_bs_init(rar_bitstream_t *bs, const uint8_t *data, size_t len)
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{
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bs->data = data;
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bs->len = len;
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bs->byte_pos = 0;
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bs->bits_left = 0;
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bs->bit_buf = 0;
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}
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/**
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* Refill the bit buffer to contain at least 25 bits if possible.
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* We keep bits in the top of bit_buf: the next bit to extract is always at bit 31.
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*/
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static void rar_bs_refill(rar_bitstream_t *bs)
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{
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while(bs->bits_left <= 24 && bs->byte_pos < bs->len)
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{
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bs->bit_buf |= (uint32_t)bs->data[bs->byte_pos] << (24 - bs->bits_left);
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bs->bits_left += 8;
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bs->byte_pos++;
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}
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}
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uint32_t rar_bs_read_bits(rar_bitstream_t *bs, int n)
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{
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uint32_t result;
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if(n <= 0) return 0;
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rar_bs_refill(bs);
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/* Extract the top n bits */
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result = bs->bit_buf >> (32 - n);
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bs->bit_buf <<= n;
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bs->bits_left -= n;
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if(bs->bits_left < 0) bs->bits_left = 0;
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return result;
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}
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void rar_bs_skip_to_byte_boundary(rar_bitstream_t *bs)
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{
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int skip = bs->bits_left & 7;
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if(skip > 0)
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{
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bs->bit_buf <<= skip;
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bs->bits_left -= skip;
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}
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}
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