mirror of
https://github.com/jart/cosmopolitan.git
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65 lines
2.1 KiB
C
65 lines
2.1 KiB
C
/*
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* QuickJS Javascript Engine
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*
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* Copyright (c) 2017-2021 Fabrice Bellard
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* Copyright (c) 2017-2021 Charlie Gordon
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "libc/intrin/likely.h"
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#include "third_party/quickjs/leb128.h"
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asm(".ident\t\"\\n\\n\
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QuickJS (MIT License)\\n\
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Copyright (c) 2017-2021 Fabrice Bellard\\n\
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Copyright (c) 2017-2021 Charlie Gordon\"");
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asm(".include \"libc/disclaimer.inc\"");
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/* clang-format off */
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int get_leb128(uint32_t *pval, const uint8_t *buf, const uint8_t *buf_end)
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{
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const uint8_t *ptr = buf;
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uint32_t v, a, i;
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v = 0;
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for(i = 0; i < 5; i++) {
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if (UNLIKELY(ptr >= buf_end))
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break;
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a = *ptr++;
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v |= (a & 0x7f) << (i * 7);
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if (!(a & 0x80)) {
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*pval = v;
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return ptr - buf;
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}
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}
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*pval = 0;
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return -1;
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}
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int get_sleb128(int32_t *pval, const uint8_t *buf, const uint8_t *buf_end)
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{
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int ret;
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uint32_t val;
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ret = get_leb128(&val, buf, buf_end);
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if (ret < 0) {
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*pval = 0;
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return -1;
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}
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*pval = (val >> 1) ^ -(val & 1);
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return ret;
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}
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