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https://github.com/aaru-dps/Aaru.Compression.Native.git
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72 lines
1.7 KiB
C
72 lines
1.7 KiB
C
/*$Source: /usr/home/dhesi/zoo/RCS/decode.c,v $*/
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/*$Id: decode.c,v 1.6 91/07/09 01:39:49 dhesi Exp $*/
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/***********************************************************
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decode.c
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Adapted from "ar" archiver written by Haruhiko Okumura.
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***********************************************************/
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// Modified for in-memory decompression by Natalia Portillo, 2025
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#include <limits.h>
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#include <stdint.h>
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#include "ar.h"
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#include "lzh.h"
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extern int decoded; /* from huf.c */
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static int j; /* remaining bytes to copy */
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void decode_start()
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{
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huf_decode_start();
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j = 0;
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decoded = 0;
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}
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/*
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decodes; returns no. of chars decoded
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*/
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int decode(uint32_t count, uint8_t *buffer)
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/* The calling function must keep the number of
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bytes to be processed. This function decodes
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either 'count' bytes or 'DICSIZ' bytes, whichever
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is smaller, into the array 'buffer[]' of size
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'DICSIZ' or more.
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Call decode_start() once for each new file
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before calling this function. */
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{
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static uint32_t i;
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uint32_t r, c;
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r = 0;
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while(--j >= 0)
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{
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buffer[r] = buffer[i];
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i = (i + 1) & (DICSIZ - 1);
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if(++r == count) return r;
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}
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for(;;)
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{
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c = decode_c();
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if(decoded) return r;
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if(c <= UCHAR_MAX)
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{
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buffer[r] = c;
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if(++r == count) return r;
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}
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else
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{
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j = c - (UCHAR_MAX + 1 - THRESHOLD);
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i = (r - decode_p() - 1) & (DICSIZ - 1);
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while(--j >= 0)
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{
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buffer[r] = buffer[i];
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i = (i + 1) & (DICSIZ - 1);
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if(++r == count) return r;
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}
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}
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}
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}
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