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https://github.com/aaru-dps/Aaru.Compression.Native.git
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95 lines
2.5 KiB
C
95 lines
2.5 KiB
C
/*
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* This file is part of the Aaru Data Preservation Suite.
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* Copyright (c) 2019-2025 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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/* lh5_mem.c
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*
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* In-memory I/O glue for LH5 decompression.
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* Implements mem_getc(), mem_putc(), and the top-level
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* lh5_decompress() entry point.
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*/
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#include "lh5.h"
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#include <stddef.h>
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#include <stdint.h>
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#include <stdio.h>
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#include "../library.h"
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/* Forward-declaration of the decompression driver in lzh.c */
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extern int lzh_decode(void);
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/* Buffer I/O state (see lh5_mem.h for externs) */
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const uint8_t *in_ptr;
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size_t in_left;
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uint8_t *out_ptr;
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size_t out_left;
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int mem_error;
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/*
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* mem_getc(): return next compressed byte, or 0 when in_left==0.
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* Never sets mem_error on input underflow.
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*/
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int mem_getc(void)
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{
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if(in_left == 0) { return 0; /* mimic feof → subbitbuf = 0 */ }
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int c = *in_ptr++;
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in_left--;
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return c;
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}
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/*
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* mem_putc(): write one output byte, set mem_error on overflow.
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*/
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int mem_putc(int c)
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{
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if(out_left == 0)
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{
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mem_error = 1;
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return EOF;
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}
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*out_ptr++ = (uint8_t)c;
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out_left--;
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return c;
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}
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/*
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* Top-level in-memory decompressor.
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*
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* in_buf points to 'in_len' bytes of compressed data.
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* out_buf must have at least *out_len bytes available.
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* On return *out_len is set to the number of bytes written.
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*
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* Returns 0 on success
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* -1 on error (bad stream or output too small)
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*/
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AARU_EXPORT int AARU_CALL lh5_decompress(const uint8_t *in_buf, size_t in_len, uint8_t *out_buf, size_t *out_len)
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{
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/* Initialize buffer pointers and error flag */
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in_ptr = in_buf;
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in_left = in_len;
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out_ptr = out_buf;
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out_left = *out_len;
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mem_error = 0;
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/* Invoke the core LH5 decode routine (now buffer-based) */
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if(lzh_decode() != 0 || mem_error) { return -1; }
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/* Compute actual output size */
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*out_len = (size_t)(out_ptr - out_buf);
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return 0;
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}
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