46 lines
2.4 KiB
C
46 lines
2.4 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/fmt/conv.h"
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/**
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* Decodes a GNU-style varint from a buffer.
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*
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* The GNU Assembler is able to encode numbers this way, since it's used
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* by the DWARF debug format.
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*/
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int unsleb128(const void *buf, size_t size, int64_t *out) {
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int b;
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int64_t r, w;
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unsigned char c;
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const unsigned char *p, *pe;
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pe = (p = buf) + size;
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r = b = 0;
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do {
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if (size && p == pe) return -1;
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c = *p++;
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w = c & 0x7f;
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r |= w << b;
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b += 7;
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} while (c & 0x80);
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if (c & 0x40) r |= -1ull << b;
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if (out) *out = r;
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return p - (const unsigned char *)buf;
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}
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