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Initial commit of Command & Conquer Red Alert source code.
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LFeenanEA
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WINVQ/VQM32/MIXFILE.CPP
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WINVQ/VQM32/MIXFILE.CPP
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/*
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** Command & Conquer Red Alert(tm)
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** Copyright 2025 Electronic Arts Inc.
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**
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** This program is free software: you can redistribute it and/or modify
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** it under the terms of the GNU General Public License as published by
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** the Free Software Foundation, either version 3 of the License, or
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** (at your option) any later version.
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**
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** This program is distributed in the hope that it will be useful,
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** but WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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** GNU General Public License for more details.
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**
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** You should have received a copy of the GNU General Public License
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** along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/****************************************************************************
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*
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* C O N F I D E N T I A L -- W E S T W O O D S T U D I O S
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*
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*----------------------------------------------------------------------------
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*
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* FILE
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* mixfile.c
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*
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* DESCRIPTION
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* A mix file is basically a group of files concatinated together
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* proceeded by a header describing where in the file each individual
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* entry is located. These routines are provided to simplify the access
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* to these file entries.
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*
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* PROGRAMMER
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* Denzil E. Long, Jr.
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*
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* DATE
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* January 26, 1995
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*
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*----------------------------------------------------------------------------
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*
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* MixFile format:
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*
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* HEADER
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* (2 bytes) Count - The number of entries in this file.
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* (4 bytes) Size - Size of the mix file in bytes.
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*
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* SUBBLOCKS (There are "Count" number of these.)
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* (4 bytes) CRC - Entry descriptor (CRC of filename).
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* (4 bytes) Offset - Offset in bytes from beginning of the DATA chunk.
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* (4 bytes) Size - Size of entry.
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*
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* DATA
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* Entry data.
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*
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*----------------------------------------------------------------------------
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*
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* PUBLIC
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* OpenMix - Open mix file for access.
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* CloseMix - Close a mix file.
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* OpenMixEntry - Open a mix file entry.
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*
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****************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <fcntl.h>
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#include <io.h>
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#include <mem.h>
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#include <string.h>
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#include "mixfile.h"
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#include "crc.h"
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/*---------------------------------------------------------------------------
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* PRIVATE DECLARATIONS
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*-------------------------------------------------------------------------*/
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int compfunc(void const *ptr1, void const *ptr2);
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/****************************************************************************
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*
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* NAME
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* OpenMix - Open mix file for access.
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*
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* SYNOPSIS
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* MixHandle = OpenMix(Name)
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*
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* MixHandle *OpenMix(char *);
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*
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* FUNCTION
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* Open a mix file for access.
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*
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* INPUTS
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* Name - Pointer to name of mix file to open.
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*
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* RESULT
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* MixHandle - Pointer to handle for mix file.
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*
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****************************************************************************/
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MIXHandle *OpenMix(char *name)
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{
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MIXHeader mfhdr;
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MIXHandle *mix = NULL;
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long fh;
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long sbsize;
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long size;
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/* Open mix file and read in header. */
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if ((fh = open(name, (O_RDONLY|O_BINARY))) != -1) {
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if (read(fh, &mfhdr, sizeof(MIXHeader)) == sizeof(MIXHeader)) {
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/* Allocate handle based on the number of SubBlocks. */
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sbsize = (mfhdr.Count * sizeof(MIXSubBlock));
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size = sbsize + sizeof(MIXHandle);
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if ((mix = (MIXHandle *)malloc(size)) != NULL) {
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memset(mix, 0, size);
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mix->Name = name;
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mix->Size = mfhdr.Size;
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mix->Count = mfhdr.Count;
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/* Read in the SubBlock entries. */
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if (read(fh, &mix->Entries[0], sbsize) != sbsize) {
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free(mix);
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mix = NULL;
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}
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}
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}
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close(fh);
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}
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return (mix);
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}
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/****************************************************************************
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*
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* NAME
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* CloseMix - Close a mix file.
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*
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* SYNOPSIS
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* CloseMix(MixHandle)
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*
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* void CloseMix(MixHandle *);
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*
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* FUNCTION
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* Close a mix file by freeing its handle.
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*
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* INPUTS
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* MixHandle - Pointer to MixHandle returned by OpenMix().
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*
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* RESULT
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* NONE
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*
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****************************************************************************/
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void CloseMix(MIXHandle *mix)
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{
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free(mix);
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}
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/****************************************************************************
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*
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* NAME
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* OpenMixEntry - Open a mix file entry.
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*
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* SYNOPSIS
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* FH = OpenMixEntry(MixHandle, EntryName)
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*
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* short OpenMixEntry(MIXHandle *, char *);
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*
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* FUNCTION
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* Opens an entry from the specified mix file handle. Use close() to close
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* the file when done.
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*
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* INPUTS
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* MixHandle - Pointer to MIXHandle containing entry to open.
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* EntryName - Pointer to name of mix file entry to open.
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*
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* RESULT
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* FH - DOS filehandle, -1 if unable to open.
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*
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****************************************************************************/
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long OpenMixEntry(MIXHandle *mix, char *name)
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{
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MIXSubBlock key;
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MIXSubBlock *block;
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long fh;
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/* Search for the specified file in the mix file. */
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key.CRC = Calculate_CRC(name, strlen(name));
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block = (MIXSubBlock *)bsearch(&key, &mix->Entries[0], mix->Count,
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sizeof(MIXSubBlock), compfunc);
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/* If the block exists for the requested filename. */
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if (block != NULL) {
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/* Initialize the key for file access. */
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key.Offset = block->Offset;
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key.Offset += (mix->Count * sizeof(MIXSubBlock)) + sizeof(MIXHeader);
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/* Open the mix file. */
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if ((fh = open(mix->Name, (O_RDONLY|O_BINARY))) != -1) {
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/* Seek to the start of the file. */
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if (lseek(fh, key.Offset, SEEK_SET) == -1) {
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close(fh);
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fh = -1;
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}
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}
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}
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return (fh);
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}
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/****************************************************************************
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*
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* NAME
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* compfunc - Compare function for bsearch().
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*
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* SYNOPSIS
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* Result = compfunc(Entry1, Entry2);
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*
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* int compfunc(void const *, void const *);
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*
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* FUNCTION
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*
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* INPUTS
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* Entry1 - Pointer to first entry to compare.
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* Entry2 - Pointer to second entry to compare.
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*
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* RESULT
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* Result -
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*
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****************************************************************************/
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int compfunc(void const *ptr1, void const *ptr2)
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{
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if (((MIXSubBlock *)ptr1)->CRC < ((MIXSubBlock *)ptr2)->CRC) return -1;
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if (((MIXSubBlock *)ptr1)->CRC > ((MIXSubBlock *)ptr2)->CRC) return 1;
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return(0);
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}
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