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5d180d1f99
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED) Since all of these checks are done in release builds as well, let's rename them to VERIFY to prevent confusion, as everyone is used to assertions being compiled out in release. We can introduce a new ASSERT macro that is specifically for debug checks, but I'm doing this wholesale conversion first since we've accumulated thousands of these already, and it's not immediately obvious which ones are suitable for ASSERT.
161 lines
5.0 KiB
C++
161 lines
5.0 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <AK/ByteBuffer.h>
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#include <AK/Debug.h>
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#include <AK/Optional.h>
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#include <LibCore/Gzip.h>
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#include <LibCore/puff.h>
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#include <limits.h>
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#include <stddef.h>
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namespace Core {
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bool Gzip::is_compressed(const ByteBuffer& data)
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{
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return data.size() > 2 && data[0] == 0x1F && data[1] == 0x8b;
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}
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// skips the gzip header
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// see: https://tools.ietf.org/html/rfc1952#page-5
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static Optional<ByteBuffer> get_gzip_payload(const ByteBuffer& data)
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{
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size_t current = 0;
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auto read_byte = [&]() {
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if (current >= data.size()) {
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VERIFY_NOT_REACHED();
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return (u8)0;
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}
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return data[current++];
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};
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#if GZIP_DEBUG
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dbgln("get_gzip_payload: Skipping over gzip header.");
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#endif
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// Magic Header
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if (read_byte() != 0x1F || read_byte() != 0x8B) {
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dbgln("get_gzip_payload: Wrong magic number.");
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return Optional<ByteBuffer>();
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}
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// Compression method
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auto method = read_byte();
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if (method != 8) {
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dbgln("get_gzip_payload: Wrong compression method={}", method);
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return Optional<ByteBuffer>();
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}
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u8 flags = read_byte();
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// Timestamp, Extra flags, OS
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current += 6;
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// FEXTRA
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if (flags & 4) {
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u16 length = read_byte() & read_byte() << 8;
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dbgln("get_gzip_payload: Header has FEXTRA flag set. length={}", length);
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current += length;
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}
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// FNAME
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if (flags & 8) {
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dbgln("get_gzip_payload: Header has FNAME flag set.");
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while (read_byte() != '\0')
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;
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}
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// FCOMMENT
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if (flags & 16) {
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dbgln("get_gzip_payload: Header has FCOMMENT flag set.");
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while (read_byte() != '\0')
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;
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}
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// FHCRC
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if (flags & 2) {
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dbgln("get_gzip_payload: Header has FHCRC flag set.");
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current += 2;
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}
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auto new_size = data.size() - current;
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dbgln_if(GZIP_DEBUG, "get_gzip_payload: Returning slice from {} with size {}", current, new_size);
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return data.slice(current, new_size);
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}
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Optional<ByteBuffer> Gzip::decompress(const ByteBuffer& data)
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{
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VERIFY(is_compressed(data));
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dbgln_if(GZIP_DEBUG, "Gzip::decompress: Decompressing gzip compressed data. size={}", data.size());
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auto optional_payload = get_gzip_payload(data);
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if (!optional_payload.has_value()) {
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return Optional<ByteBuffer>();
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}
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auto source = optional_payload.value();
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unsigned long source_len = source.size();
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auto destination = ByteBuffer::create_uninitialized(1024);
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while (true) {
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unsigned long destination_len = destination.size();
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if constexpr (GZIP_DEBUG) {
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dbgln("Gzip::decompress: Calling puff()");
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dbgln(" destination_data = {}", destination.data());
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dbgln(" destination_len = {}", destination_len);
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dbgln(" source_data = {}", source.data());
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dbgln(" source_len = {}", source_len);
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}
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auto puff_ret = puff(
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destination.data(), &destination_len,
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source.data(), &source_len);
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if (puff_ret == 0) {
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#if GZIP_DEBUG
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dbgln("Gzip::decompress: Decompression success.");
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#endif
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destination.trim(destination_len);
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break;
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}
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if (puff_ret == 1) {
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// FIXME: Find a better way of decompressing without needing to try over and over again.
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#if GZIP_DEBUG
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dbgln("Gzip::decompress: Output buffer exhausted. Growing.");
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#endif
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destination.grow(destination.size() * 2);
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} else {
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dbgln("Gzip::decompress: Error. puff() returned: {}", puff_ret);
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VERIFY_NOT_REACHED();
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}
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}
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return destination;
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}
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}
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