70 lines
3.0 KiB
C
70 lines
3.0 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 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/calls/calls.h"
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#include "libc/calls/struct/iovec.h"
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#include "libc/errno.h"
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#include "libc/sock/sock.h"
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#include "libc/stdio/internal.h"
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#include "libc/stdio/stdio.h"
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/* TODO(jart): Delete or rework */
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/**
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* Fills empty space in buffer with whatever's available.
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*
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* This can be used alongside functions like select() or poll() to
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* perform reads at opportune moments, thereby minimizing latency.
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*/
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int freplenish(FILE *f) {
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ssize_t rc;
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size_t got;
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struct iovec iov[2];
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if (f->beg == f->end) {
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f->beg = f->end = 0;
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}
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if (f->beg <= f->end) {
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if (f->beg) {
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iov[0].iov_base = f->buf + f->end;
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iov[0].iov_len = f->size - f->end;
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iov[1].iov_base = f->buf;
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iov[1].iov_len = f->beg - 1;
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rc = readv(f->fd, iov, 2);
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} else {
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rc = read(f->fd, f->buf, f->size - (f->end - f->beg) - 1);
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}
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} else {
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if (f->end + 1 == f->beg) return 0;
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rc = read(f->fd, f->buf + f->end, f->beg - f->end - 1);
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}
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if (rc != -1) {
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if (rc) {
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got = rc;
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f->end = (f->end + got) % f->size;
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return got;
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} else {
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return __fseteof(f);
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}
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} else if (errno == EINTR || errno == EAGAIN) {
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return 0;
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} else {
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return __fseterrno(f);
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}
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}
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