OXYGENHUB
◆ main openmsx / src / utils / HexDump.cc
2.0 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
#include "HexDump.hh"
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#include "narrow.hh"
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#include "strCat.hh"
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#include "xrange.hh"
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#include <algorithm>
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#include <cassert>
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namespace HexDump {
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using openmsx::MemBuffer;
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[[nodiscard]] static constexpr char encode2(uint8_t x)
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{
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	return (x < 10) ? char(x + '0') : char(x - 10 + 'A');
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}
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[[nodiscard]] static auto encode(uint8_t x)
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{
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	return tmpStrCat(encode2(x >> 4), encode2(x & 15));
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}
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std::string encode(std::span<const uint8_t> input, bool newlines)
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{
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	std::string ret;
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	size_t in = 0;
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	auto len = input.size();
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	while (len) {
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		if (newlines && !ret.empty()) ret += '\n';
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		auto t = int(std::min<size_t>(16, len));
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		for (auto i : xrange(t)) {
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			ret += encode(input[in++]);
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			if (i != (t - 1)) ret += ' ';
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		}
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		len -= t;
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	}
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	return ret;
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}
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[[nodiscard]] static constexpr int decode(char x)
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{
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	if (('0' <= x) && (x <= '9')) {
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		return x - '0';
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	} else if (('A' <= x) && (x <= 'F')) {
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		return x - 'A' + 10;
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	} else if (('a' <= x) && (x <= 'f')) {
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		return x - 'a' + 10;
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	} else {
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		return -1;
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	}
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}
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MemBuffer<uint8_t> decode(std::string_view input)
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{
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	auto inSize = input.size();
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	auto outSize = inSize / 2; // overestimation
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	MemBuffer<uint8_t> ret(outSize); // too big
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	size_t out = 0;
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	bool flip = true;
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	uint8_t tmp = 0;
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	for (char c : input) {
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		int d = decode(c);
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		if (d == -1) continue;
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		assert(d >= 0);
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		assert(d <= 15);
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		if (flip) {
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			tmp = narrow<uint8_t>(d);
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		} else {
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			ret[out++] = narrow<uint8_t>((tmp << 4) | d);
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		}
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		flip = !flip;
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	}
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	assert(outSize >= out);
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	ret.resize(out); // shrink to correct size
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	return ret;
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}
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bool decode_inplace(std::string_view input, std::span<uint8_t> output)
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{
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	size_t out = 0;
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	auto outSize = output.size();
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	bool flip = true;
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	uint8_t tmp = 0;
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	for (char c : input) {
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		int d = decode(c);
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		if (d == -1) continue;
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		assert(d >= 0);
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		assert(d <= 15);
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		if (flip) {
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			tmp = narrow<uint8_t>(d);
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		} else {
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			if (out == outSize) [[unlikely]] return false;
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			output[out++] = narrow<uint8_t>((tmp << 4) | d);
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		}
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		flip = !flip;
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	}
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	return out == outSize;
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}
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} // namespace HexDump