mirror of https://github.com/nodejs/node.git
125 lines
3.6 KiB
C
125 lines
3.6 KiB
C
/*
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* nghttp3
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*
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* Copyright (c) 2019 nghttp3 contributors
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* Copyright (c) 2013 nghttp2 contributors
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in 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,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#include "nghttp3_qpack_huffman.h"
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#include <string.h>
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#include <assert.h>
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#include <stdio.h>
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#include "nghttp3_conv.h"
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size_t nghttp3_qpack_huffman_encode_count(const uint8_t *src, size_t len) {
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size_t i;
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size_t nbits = 0;
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for (i = 0; i < len; ++i) {
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nbits += huffman_sym_table[src[i]].nbits;
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}
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/* pad the prefix of EOS (256) */
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return (nbits + 7) / 8;
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}
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uint8_t *nghttp3_qpack_huffman_encode(uint8_t *dest, const uint8_t *src,
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size_t srclen) {
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const nghttp3_qpack_huffman_sym *sym;
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const uint8_t *end = src + srclen;
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uint64_t code = 0;
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size_t nbits = 0;
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uint32_t x;
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for (; src != end;) {
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sym = &huffman_sym_table[*src++];
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code |= (uint64_t)sym->code << (32 - nbits);
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nbits += sym->nbits;
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if (nbits < 32) {
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continue;
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}
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x = htonl((uint32_t)(code >> 32));
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memcpy(dest, &x, 4);
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dest += 4;
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code <<= 32;
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nbits -= 32;
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}
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for (; nbits >= 8;) {
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*dest++ = (uint8_t)(code >> 56);
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code <<= 8;
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nbits -= 8;
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}
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if (nbits) {
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*dest++ = (uint8_t)((uint8_t)(code >> 56) | ((1 << (8 - nbits)) - 1));
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}
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return dest;
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}
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void nghttp3_qpack_huffman_decode_context_init(
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nghttp3_qpack_huffman_decode_context *ctx) {
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ctx->fstate = NGHTTP3_QPACK_HUFFMAN_ACCEPTED;
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}
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nghttp3_ssize
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nghttp3_qpack_huffman_decode(nghttp3_qpack_huffman_decode_context *ctx,
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uint8_t *dest, const uint8_t *src, size_t srclen,
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int fin) {
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uint8_t *p = dest;
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const uint8_t *end = src + srclen;
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nghttp3_qpack_huffman_decode_node node = {ctx->fstate, 0};
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const nghttp3_qpack_huffman_decode_node *t = &node;
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uint8_t c;
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/* We use the decoding algorithm described in
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- http://graphics.ics.uci.edu/pub/Prefix.pdf [!!! NO LONGER VALID !!!]
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- https://ics.uci.edu/~dan/pubs/Prefix.pdf
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- https://github.com/nghttp2/nghttp2/files/15141264/Prefix.pdf */
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for (; src != end;) {
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c = *src++;
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t = &qpack_huffman_decode_table[t->fstate & 0x1ff][c >> 4];
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if (t->fstate & NGHTTP3_QPACK_HUFFMAN_SYM) {
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*p++ = t->sym;
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}
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t = &qpack_huffman_decode_table[t->fstate & 0x1ff][c & 0xf];
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if (t->fstate & NGHTTP3_QPACK_HUFFMAN_SYM) {
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*p++ = t->sym;
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}
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}
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ctx->fstate = t->fstate;
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if (fin && !(ctx->fstate & NGHTTP3_QPACK_HUFFMAN_ACCEPTED)) {
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return NGHTTP3_ERR_QPACK_FATAL;
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}
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return p - dest;
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}
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int nghttp3_qpack_huffman_decode_failure_state(
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nghttp3_qpack_huffman_decode_context *ctx) {
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return ctx->fstate == 0x100;
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}
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