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38 lines
2.5 KiB
C
38 lines
2.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2021 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/intrin/bits.h"
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#include "libc/zip.h"
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/**
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* Returns true if zip end of central directory header seems legit.
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*/
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bool IsZipCdir32(const uint8_t *p, size_t n, size_t i) {
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if (i > n || n - i < kZipCdirHdrMinSize) return false;
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if (READ32LE(p + i) != kZipCdirHdrMagic) return false;
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if (i + ZIP_CDIR_HDRSIZE(p + i) > n) return false;
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if (ZIP_CDIR_DISK(p + i) != ZIP_CDIR_STARTINGDISK(p + i)) return false;
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if (ZIP_CDIR_RECORDSONDISK(p + i) != ZIP_CDIR_RECORDS(p + i)) return false;
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if (ZIP_CDIR_RECORDS(p + i) * kZipCfileHdrMinSize > ZIP_CDIR_SIZE(p + i)) {
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return false;
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}
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if (ZIP_CDIR_OFFSET(p + i) + ZIP_CDIR_SIZE(p + i) > i) {
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return false;
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}
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return true;
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}
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