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◆ main openmsx / Contrib / base64.cc
2.5 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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// compile with:
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//   g++ -std=c++23 -Wall -Os base64.cc -I ../src/utils/ ../src/utils/Base64.cc -lz -o encode-gz-base64
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//   g++ -std=c++23 -Wall -Os base64.cc -I ../src/utils/ ../src/utils/Base64.cc -lz -o decode-gz-base64
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#include "Base64.hh"
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#include <zlib.h>
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#include <bit>
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#include <cstdio>
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#include <cstdlib>
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#include <cstring>
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#include <iostream>
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#include <memory>
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#include <span>
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#include <sys/stat.h>
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#include <vector>
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std::string encode(std::span<const char> src)
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{
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	auto len = src.size();
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	uLongf dstLen = len + len / 1000 + 12 + 1; // worst-case
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	std::vector<unsigned char> buf(dstLen);
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	if (compress2(buf.data(), &dstLen,
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	              std::bit_cast<const Bytef*>(src.data()), len, 9)
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	    != Z_OK) {
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		std::cerr << "Error while compressing blob.\n";
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		exit(1);
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	}
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	return Base64::encode(std::span(buf.data(), dstLen));
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}
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std::string decode(std::span<const char> src)
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{
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	static const unsigned MAX_SIZE = 1024 * 1024; // 1MB
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	auto decBuf = Base64::decode(std::string_view(src.data(), src.size()));
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	std::vector<char> buf(MAX_SIZE);
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	uLongf dstLen = MAX_SIZE;
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	if (uncompress(std::bit_cast<Bytef*>(buf.data()), &dstLen,
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	               std::bit_cast<const Bytef*>(decBuf.data()), uLong(decBuf.size()))
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	    != Z_OK) {
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		std::cerr << "Error while decompressing blob.\n";
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		exit(1);
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	}
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	return {buf.data(), dstLen};
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}
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int main(int argc, const char** argv)
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{
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	std::span<const char*> arg(argv, argc);
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	if (arg.size() != 3) {
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		std::cerr << "Usage: " << arg[0] << " <input> <output>\n";
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		exit(1);
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	}
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	using FILE_t = std::unique_ptr<FILE, decltype([](FILE* f) { fclose(f); })>;
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	FILE_t inf(fopen(arg[1], "rb"));
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	if (!inf) {
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		std::cerr << "Error while opening " << arg[1] << '\n';
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		exit(1);
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	}
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	struct stat st;
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	fstat(fileno(inf.get()), &st);
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	size_t size = st.st_size;
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	std::vector<char> inBuf(size);
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	if (fread(inBuf.data(), size, 1, inf.get()) != 1) {
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		std::cerr << "Error while reading " << arg[1] << '\n';
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		exit(1);
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	}
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	std::string result;
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	if        (strstr(arg[0], "encode-gz-base64")) {
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		result = encode(inBuf);
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	} else if (strstr(arg[0], "decode-gz-base64")) {
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		result = decode(inBuf);
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	} else {
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		std::cerr << "This executable should be named 'encode-gz-base64' or "
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		             "'decode-gz-base64'.\n";
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		exit(1);
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	}
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	FILE_t outf(fopen(arg[2], "wb+"));
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	if (!outf) {
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		std::cerr << "Error while opening " << arg[2] << '\n';
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		exit(1);
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	}
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	if (fwrite(result.data(), result.size(), 1, outf.get()) != 1) {
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		std::cerr << "Error while writing " << arg[2] << '\n';
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		exit(1);
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	}
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}