73 lines
3.6 KiB
C
73 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 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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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/str/str.h"
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#include "net/http/http.h"
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/**
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* Parses HTTP Range request header.
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*/
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bool ParseHttpRange(const char *p, size_t n, long resourcelength,
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long *out_start, long *out_length) {
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long start, length, ending;
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*out_start = 0;
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*out_length = 0;
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if (memchr(p, ',', n)) return false;
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if (n < 7 || memcmp(p, "bytes=", 6) != 0) return false;
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p += 6, n -= 6;
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if (n && *p == '-') {
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++p, --n;
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length = 0;
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while (n && '0' <= *p && *p <= '9') {
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if (__builtin_mul_overflow(length, 10, &length)) return false;
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if (__builtin_add_overflow(length, *p - '0', &length)) return false;
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++p, --n;
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}
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if (__builtin_sub_overflow(resourcelength, length, &start)) return false;
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} else {
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start = 0;
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while (n && '0' <= *p && *p <= '9') {
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if (__builtin_mul_overflow(start, 10, &start)) return false;
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if (__builtin_add_overflow(start, *p - '0', &start)) return false;
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++p, --n;
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}
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if (n && *p == '-') {
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++p, --n;
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length = 0;
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while (n && '0' <= *p && *p <= '9') {
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if (__builtin_mul_overflow(length, 10, &length)) return false;
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if (__builtin_add_overflow(length, *p - '0', &length)) return false;
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++p, --n;
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}
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if (__builtin_add_overflow(length, 1, &length)) return false;
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if (__builtin_sub_overflow(length, start, &length)) return false;
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} else if (__builtin_sub_overflow(resourcelength, start, &length)) {
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return false;
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}
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}
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if (n) return false;
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if (start < 0) return false;
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if (length < 0) return false;
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*out_start = start;
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*out_length = length;
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if (__builtin_add_overflow(start, length, &ending)) return false;
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if (ending > resourcelength) return false;
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return true;
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}
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