zxing-cpp: strip to core library only (remove tests/wrappers/examples/docs); .gitignore: fix /core to allow zxing-cpp/core/ dir

tools/chatgui/zxing-cpp/core/src/JSON.h

@@ -0,0 +1,66 @@
+/*
+* Copyright 2025 Axel Waggershauser
+*/
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include "ZXAlgorithms.h"
+
+#include <cstring>
+#ifdef __cpp_lib_format // not available on gcc 12
+#include <format>
+#endif
+#include <optional>
+#include <string>
+#include <string_view>
+
+namespace ZXing {
+
+std::string JsonEscapeStr(std::string_view str);
+std::string JsonUnEscapeStr(std::string_view str);
+
+template<typename T>
+inline std::string JsonProp(std::string_view key, const T& val, const T& ignore = {})
+{
+	#define ZX_JSON_KEY_VAL(...) StrCat("\"", key, "\":", __VA_ARGS__, ',')
+#if !defined(__cpp_lib_to_chars) || !defined(__cpp_lib_format) // not available on older macOS / gcc 12
+	#define ZX_JSON_FMT_FLOAT(val) (std::to_string(int(val)) + '.' + std::to_string(int(val * 100) % 100))
+#else
+	#define ZX_JSON_FMT_FLOAT(val) std::format("{:.2f}", val)
+#endif
+
+	if constexpr (std::is_same_v<T, bool>)
+		return val != ignore ? ZX_JSON_KEY_VAL(val ? "true" : "false") : "";
+	else if constexpr (std::is_floating_point_v<T>)
+		return val != ignore ? ZX_JSON_KEY_VAL(ZX_JSON_FMT_FLOAT(val)) : "";
+	else if constexpr (std::is_integral_v<T>)
+		return val != ignore ? ZX_JSON_KEY_VAL(std::to_string(val)) : "";
+	else if constexpr (std::is_convertible_v<T, std::string_view>)
+		return std::string_view(val) != std::string_view(ignore) ? ZX_JSON_KEY_VAL("\"", JsonEscapeStr(val), "\"") : "";
+	else
+		static_assert("unsupported JSON value type");
+	#undef ZX_JSON_KEY_VAL
+}
+
+// Finds the (potentially escaped / raw) value of the provided key
+std::string_view JsonFind(std::string_view json, std::string_view key);
+
+template <typename T>
+inline std::optional<T> JsonGet(std::string_view json, std::string_view key)
+{
+	auto str = JsonFind(json, key);
+	if (!str.data())
+		return std::nullopt;
+
+	if constexpr (std::is_same_v<bool, T>)
+		return str.empty() || Contains("1tT", str.front()) ? std::optional(true) : std::nullopt;
+	else if constexpr (std::is_arithmetic_v<T>)
+		return str.empty() ? std::nullopt : std::optional(FromString<T>(str));
+	else if constexpr (std::is_same_v<std::string, T>)
+		return JsonUnEscapeStr(str);
+	else
+		static_assert("unsupported JSON value type");
+}
+
+} // ZXing