51 lines
1.3 KiB
C++
51 lines
1.3 KiB
C++
#pragma once
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#include <map>
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#include <string>
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#include <algorithm>
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#include <optional>
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namespace mbgl {
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namespace util {
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const static std::string tokenReservedChars = "{}";
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// Replaces {tokens} in a string by calling the lookup function.
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template <typename Lookup>
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std::string replaceTokens(const std::string &source, const Lookup &lookup) {
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std::string result;
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result.reserve(source.size());
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auto pos = source.begin();
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const auto end = source.end();
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while (pos != end) {
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auto brace = std::find(pos, end, '{');
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result.append(pos, brace);
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pos = brace;
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if (pos != end) {
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for (brace++; brace != end && tokenReservedChars.find(*brace) == std::string::npos; brace++)
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;
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if (brace != end && *brace == '}') {
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std::string key{pos + 1, brace};
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if (std::optional<std::string> replacement = lookup(key)) {
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result.append(*replacement);
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} else {
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result.append("{");
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result.append(key);
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result.append("}");
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}
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pos = brace + 1;
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} else {
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result.append(pos, brace);
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pos = brace;
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}
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}
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}
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return result;
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}
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} // end namespace util
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} // end namespace mbgl
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