mirror of
https://github.com/jart/cosmopolitan.git
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57 lines
2.6 KiB
C
57 lines
2.6 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/calls/calls.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/thread/thread.h"
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#include "libc/zip.h"
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#include "libc/zipos/zipos.internal.h"
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/**
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* Changes current position of zip file handle.
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*
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* @param offset is the relative byte count
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* @param whence can be SEEK_SET, SEEK_CUR, or SEEK_END
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* @return new position relative to beginning, or -1 on error
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* @asyncsignalsafe
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*/
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int64_t __zipos_lseek(struct ZiposHandle *h, int64_t offset, unsigned whence) {
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int64_t rc;
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pthread_mutex_lock(&h->lock);
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switch (whence) {
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case SEEK_SET:
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rc = offset;
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break;
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case SEEK_CUR:
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rc = h->pos + offset;
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break;
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case SEEK_END:
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rc = h->size - offset;
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break;
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default:
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rc = -1;
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break;
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}
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if (rc >= 0) {
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h->pos = rc;
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} else {
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rc = einval();
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}
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pthread_mutex_unlock(&h->lock);
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return rc;
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}
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