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https://github.com/jart/cosmopolitan.git
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8bfd56b59e
Now that these functions are behind _COSMO_SOURCE there's no reason for having the ugly underscore anymore. To use these functions, you need to pass -mcosmo to cosmocc.
47 lines
2.6 KiB
C
47 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 et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2023 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/bsr.h"
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#include "libc/str/str.h"
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static const uint16_t kTpEnc[32 - 7] = {
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1 | 0300 << 8, 1 | 0300 << 8, 1 | 0300 << 8, 1 | 0300 << 8, 2 | 0340 << 8,
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2 | 0340 << 8, 2 | 0340 << 8, 2 | 0340 << 8, 2 | 0340 << 8, 3 | 0360 << 8,
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3 | 0360 << 8, 3 | 0360 << 8, 3 | 0360 << 8, 3 | 0360 << 8, 4 | 0370 << 8,
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4 | 0370 << 8, 4 | 0370 << 8, 4 | 0370 << 8, 4 | 0370 << 8, 5 | 0374 << 8,
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5 | 0374 << 8, 5 | 0374 << 8, 5 | 0374 << 8, 5 | 0374 << 8, 5 | 0374 << 8,
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};
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/**
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* Encodes Thompson-Pike variable-length integer.
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*/
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uint64_t tpenc(uint32_t c) {
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int e, n;
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uint64_t w;
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if (0 <= c && c <= 127) return c;
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e = kTpEnc[bsr(c) - 7];
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n = e & 0xff;
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w = 0;
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do {
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w |= 0200 | (c & 077);
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w <<= 8;
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c >>= 6;
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} while (--n);
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return c | w | e >> 8;
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}
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