79 lines
2.2 KiB
C++
79 lines
2.2 KiB
C++
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#include "InflateReader.h"
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#include <cstring>
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#include <type_traits>
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namespace {
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constexpr size_t INFLATE_DICT_SIZE = 32768;
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}
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// Guarantee the cast pattern in the header comment is valid.
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static_assert(std::is_standard_layout<InflateReader>::value,
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"InflateReader must be standard-layout for the uzlib callback cast to work");
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InflateReader::~InflateReader() { deinit(); }
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bool InflateReader::init(const bool streaming) {
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deinit(); // free any previously allocated ring buffer and reset state
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if (streaming) {
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ringBuffer = static_cast<uint8_t*>(malloc(INFLATE_DICT_SIZE));
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if (!ringBuffer) return false;
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memset(ringBuffer, 0, INFLATE_DICT_SIZE);
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}
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uzlib_uncompress_init(&decomp, ringBuffer, ringBuffer ? INFLATE_DICT_SIZE : 0);
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return true;
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}
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void InflateReader::deinit() {
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if (ringBuffer) {
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free(ringBuffer);
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ringBuffer = nullptr;
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}
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memset(&decomp, 0, sizeof(decomp));
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}
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void InflateReader::setSource(const uint8_t* src, size_t len) {
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decomp.source = src;
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decomp.source_limit = src + len;
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}
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void InflateReader::setReadCallback(int (*cb)(struct uzlib_uncomp*)) { decomp.source_read_cb = cb; }
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void InflateReader::skipZlibHeader() {
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uzlib_get_byte(&decomp);
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uzlib_get_byte(&decomp);
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}
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bool InflateReader::read(uint8_t* dest, size_t len) {
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if (!ringBuffer) {
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// One-shot mode: back-references use absolute offset from dest_start.
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// Valid only when read() is called once with the full output buffer.
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decomp.dest_start = dest;
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}
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decomp.dest = dest;
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decomp.dest_limit = dest + len;
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const int res = uzlib_uncompress(&decomp);
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if (res < 0) return false;
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return decomp.dest == decomp.dest_limit;
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}
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InflateStatus InflateReader::readAtMost(uint8_t* dest, size_t maxLen, size_t* produced) {
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if (!ringBuffer) {
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// One-shot mode: back-references use absolute offset from dest_start.
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// Valid only when readAtMost() is called once with the full output buffer.
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decomp.dest_start = dest;
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}
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decomp.dest = dest;
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decomp.dest_limit = dest + maxLen;
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const int res = uzlib_uncompress(&decomp);
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*produced = static_cast<size_t>(decomp.dest - dest);
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if (res == TINF_DONE) return InflateStatus::Done;
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if (res < 0) return InflateStatus::Error;
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return InflateStatus::Ok;
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}
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