OXYGENHUB
◆ main openmsx / src / utils / escape_newline.hh
1.7 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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#ifndef ESCAPE_NEWLINE_HH
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#define ESCAPE_NEWLINE_HH
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#include "one_of.hh"
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#include <cassert>
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#include <cstring>
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#include <string>
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#include <string_view>
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namespace escape_newline {
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[[nodiscard]] inline std::string encode(std::string_view input)
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{
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	std::string result;
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	result.reserve(input.size());
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	for (char c : input) {
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		if (c == one_of('\n', '\\'))  {
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			if (c == '\n') c = 'n';
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			result += '\\';
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		}
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		result += c;
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	}
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	return result;
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}
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[[nodiscard]] inline std::string decode(std::string_view input)
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{
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	std::string result;
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	result.resize_and_overwrite(input.size(), [&](char* buf, size_t) {
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		size_t out = 0;
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		for (size_t i = 0; i < input.size(); ++i) {
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			char c = input[i];
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			if (c == '\\') {
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				if (++i == input.size()) break; // incomplete escape, drop
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				c = input[i];
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				if (c == 'n') c = '\n';
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			}
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			buf[out++] = c;
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		}
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		return out;
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	});
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	return result;
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}
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inline void decode_inplace(std::string& str)
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{
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	auto rdPos = str.find('\\');
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	if (rdPos == std::string::npos) {
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		// No escapes at all, done
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		return;
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	}
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	auto size = str.size();
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	auto wrPos = rdPos;
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	do {
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		assert(rdPos < size);
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		assert(str[rdPos] == '\\');
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		if (rdPos + 1 == size) {
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			// Trailing backslash, shouldn't happen, drop it
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			break;
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		}
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		// Decode escape sequence
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		auto c = str[rdPos + 1];
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		str[wrPos] = (c == 'n') ? '\n' : c;
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		rdPos += 2;
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		wrPos += 1;
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		// Find next backslash
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		auto next_backslash = str.find('\\', rdPos);
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		// Copy the intermediate non-backslash chunk
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		auto chunk_end = (next_backslash == std::string::npos) ? size : next_backslash;
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		auto chunk_len = chunk_end - rdPos;
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		memmove(&str[wrPos], &str[rdPos], chunk_len);
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		rdPos += chunk_len;
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		wrPos += chunk_len;
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	} while (rdPos < size);
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	str.resize(wrPos);
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}
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} // namespace escape_newline
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#endif