61 lines
2.0 KiB
C++
61 lines
2.0 KiB
C++
#include "uncompress.hh"
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#include "bitpack.hh"
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#include "common.hh"
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#include <cassert>
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#include <cstdio>
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#include <cstdlib>
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#include <fstream>
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#include <iterator>
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using std::fclose;
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using std::fopen;
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using std::fseek;
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using std::string;
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using std::uint16_t;
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using std::vector;
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using ustring = std::basic_string<unsigned char>;
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using vuint16 = vector<uint16_t>;
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[[nodiscard]] ustring lzw_uncompress(vuint16 &&t_compressed) {
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ustring ret{};
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uint16_t old = 0;
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std::map<uint16_t, ustring> dict{};
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ret.append({static_cast<unsigned char>(t_compressed[0])});
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old = t_compressed[0];
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for (auto it = t_compressed.begin() + 1; it != t_compressed.end(); ++it) {
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const auto uncompressed{dico_uncompress(dict, *it, old)};
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ret.insert(ret.end(), uncompressed.begin(), uncompressed.end());
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old = *it;
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}
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return ret;
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}
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void uncompress(const string &t_input_name, const char *t_output_name) {
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FILE *const input = std::fopen(t_input_name.c_str(), "rb");
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assert(input);
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std::ofstream output{(t_output_name != nullptr)
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? t_output_name
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: t_input_name + "_uncompressed",
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std::ios::out | std::ios::binary};
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assert(output.is_open());
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uint16_t nb_chunks = 0;
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std::fread(&nb_chunks, sizeof(nb_chunks), 1, input);
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for (uint16_t i = 0; i < nb_chunks; ++i) {
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uncompress_chunk(input, output);
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}
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output.close();
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std::fclose(input);
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}
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void uncompress_chunk(FILE *const t_input, std::ofstream &t_output) {
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uint32_t size_chunk = 0;
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fread(&size_chunk, sizeof(size_chunk), 1, t_input);
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auto chunk = std::make_unique<unsigned char[]>(size_chunk);
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fread(chunk.get(), sizeof(unsigned char), size_chunk, t_input);
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auto unpacked = unpack(ustring{chunk.get(), chunk.get() + size_chunk});
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auto uncompressed_chunk = lzw_uncompress(std::move(unpacked));
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t_output.write(reinterpret_cast<const char *>(uncompressed_chunk.data()),
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sizeof(uncompressed_chunk[0]) * uncompressed_chunk.size());
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}
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