mirror of
https://github.com/jart/cosmopolitan.git
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75 lines
3.6 KiB
C
75 lines
3.6 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 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/assert.h"
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#include "libc/calls/struct/iovec.h"
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#include "libc/intrin/atomic.h"
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#include "libc/intrin/likely.h"
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#include "libc/limits.h"
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#include "libc/runtime/zipos.internal.h"
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#include "libc/stdio/sysparam.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/s.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/thread/tls.h"
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#include "libc/zip.h"
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static ssize_t __zipos_read_impl(struct ZiposHandle *h, const struct iovec *iov,
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size_t iovlen, ssize_t opt_offset) {
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int i;
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int64_t b, x, y, start_pos;
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if (h->cfile == ZIPOS_SYNTHETIC_DIRECTORY ||
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S_ISDIR(GetZipCfileMode(h->zipos->map + h->cfile)))
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return eisdir();
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if (opt_offset == -1) {
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Restart:
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start_pos = atomic_load_explicit(&h->pos, memory_order_relaxed);
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do {
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if (UNLIKELY(start_pos == SIZE_MAX))
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goto Restart;
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} while (!LIKELY(atomic_compare_exchange_weak_explicit(
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&h->pos, &start_pos, SIZE_MAX, memory_order_acquire,
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memory_order_relaxed)));
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x = y = start_pos;
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} else {
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x = y = opt_offset;
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}
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for (i = 0; i < iovlen && y < h->size; ++i, y += b) {
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b = MIN(iov[i].iov_len, h->size - y);
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if (b)
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memcpy(iov[i].iov_base, h->mem + y, b);
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}
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if (opt_offset == -1) {
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unassert(y != SIZE_MAX);
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atomic_store_explicit(&h->pos, y, memory_order_release);
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}
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return y - x;
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}
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/**
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* Reads data from zip store object.
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*
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* @return [1..size] bytes on success, 0 on EOF, or -1 w/ errno; with
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* exception of size==0, in which case return zero means no error
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* @asyncsignalsafe
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*/
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ssize_t __zipos_read(struct ZiposHandle *h, const struct iovec *iov,
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size_t iovlen, ssize_t opt_offset) {
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unassert(opt_offset >= 0 || opt_offset == -1);
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return __zipos_read_impl(h, iov, iovlen, opt_offset);
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}
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