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ARCHIVE.CPP
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C/C++ Source or Header
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1997-07-05
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104 lines
// +++Date last modified: 05-Jul-1997
/*
** ARCHIVE.CPP
**
** Written by Jari Laaksonen (2:221/360.20), 2 Sep 1994
** Based on the code by Heinz Ozwirk and David Gersic.
**
** Free for all participants of the C_ECHO & other conferences where
** this code is posted. Released to SNIPPETS by the authors.
**
** See the file WhichArc.DOC about archive types and file offsets
** for self extracting archives.
*/
#include "archive.hpp"
#include "whicharc.h"
int Archive::Scan (FILE *fp, char *szBuff, long flen)
{
if (offset > flen)
return 0;
int rc;
rc = SeekFile (fp, szBuff, offset);
if (rc > 0)
rc = Check (szBuff);
return (rc > UNKNOWN ? sfxtype : rc);
}
// Generic fingerprint check.
// LHA and PAK/ARC needs more complicated checking
// If some new archiver needs different check algorithm, derive a new
// class from class Archive and write a new Check() function.
int Archive::Check (char *szBuff)
{
char *p;
p = fingerprint;
while (*p)
{
if (*p != *szBuff)
return UNKNOWN;
p++;
szBuff++;
}
return type;
}
int LhaArchive::Check (char *szBuff)
{
int i, c;
for (c = 0, i = szBuff[0]; i--; c += (szBuff + 2)[i])
;
if (
((unsigned char) (c & 0x00FF)) == szBuff[1]
&& szBuff[2] == fingerprint[0]
&& szBuff[3] == fingerprint[1]
&& szBuff[4] == fingerprint[2]
&& szBuff[6] == fingerprint[3]
)
{
if (szBuff[5] > '1')
{
sfxtype = SFXLHA;
return LHA;
}
else
{
sfxtype = SFXLHARC;
return LHARC;
}
}
else return UNKNOWN;
}
int PakArchive::Check (char *szBuff)
{
if (szBuff[0] == 0x1A)
{
if (szBuff[1] == 0x0A || szBuff[1] == 0x0B)
{
sfxtype = SFXPAK;
return PAK;
}
else if (szBuff[1] > 0x14)
{
sfxtype = SFXARC6;
return ARC6;
}
else
{
sfxtype = SFXARC;
return ARC;
}
}
else return UNKNOWN;
}