From a007a41b0deb780eb5e923c3af5fe71e0c1339df Mon Sep 17 00:00:00 2001
From: Andrew Belt <andrewpbelt@gmail.com>
Date: Tue, 22 Oct 2019 20:24:44 -0400
Subject: [PATCH] Add json.hpp.

---
 include/json.hpp | 139 +++++++++++++++++++++++++++++++++++++++++++++++
 include/rack.hpp |   1 +
 2 files changed, 140 insertions(+)
 create mode 100644 include/json.hpp

diff --git a/include/json.hpp b/include/json.hpp
new file mode 100644
index 00000000..f6491435
--- /dev/null
+++ b/include/json.hpp
@@ -0,0 +1,139 @@
+#pragma once
+#include <common.hpp>
+#include <jansson.h>
+
+
+namespace rack {
+
+
+/** JSON helpers */
+namespace json {
+
+
+/** Checks that a JSON type can be cast to the C++ type */
+template <typename T>
+bool is(json_t* valueJ);
+template <>
+inline bool is<std::string>(json_t* valueJ) {
+	return json_is_string(valueJ);
+}
+template <>
+inline bool is<json_int_t>(json_t* valueJ) {
+	return json_is_integer(valueJ);
+}
+template <>
+inline bool is<int>(json_t* valueJ) {
+	return json_is_integer(valueJ);
+}
+template <>
+inline bool is<double>(json_t* valueJ) {
+	return json_is_number(valueJ);
+}
+template <>
+inline bool is<float>(json_t* valueJ) {
+	return json_is_number(valueJ);
+}
+template <>
+inline bool is<bool>(json_t* valueJ) {
+	return json_is_boolean(valueJ);
+}
+
+/** Converts C++ types to the JSON type */
+template <typename T>
+json_t* to(T value);
+template <>
+inline json_t* to(const std::string& value) {
+	return json_stringn(value.c_str(), value.size());
+}
+template <>
+inline json_t* to(json_int_t value) {
+	return json_integer(value);
+}
+template <>
+inline json_t* to(int value) {
+	return json_integer(value);
+}
+template <>
+inline json_t* to(double value) {
+	return json_real(value);
+}
+template <>
+inline json_t* to(float value) {
+	return json_real(value);
+}
+template <>
+inline json_t* to(bool value) {
+	return json_boolean(value);
+}
+
+/** Converts the JSON type to C++ types */
+template <typename T>
+T from(json_t* valueJ);
+template <>
+inline std::string from(json_t* valueJ) {
+	return std::string(json_string_value(valueJ), json_string_length(valueJ));
+}
+template <>
+inline json_int_t from(json_t* valueJ) {
+	return json_integer_value(valueJ);
+}
+template <>
+inline int from(json_t* valueJ) {
+	return json_integer_value(valueJ);
+}
+template <>
+inline double from(json_t* valueJ) {
+	return json_number_value(valueJ);
+}
+template <>
+inline float from(json_t* valueJ) {
+	return json_number_value(valueJ);
+}
+template <>
+inline bool from(json_t* valueJ) {
+	return json_boolean_value(valueJ);
+}
+
+/** Helper template function for array functions */
+inline int multiplyDims() {
+	return 1;
+}
+template <typename... Dims>
+int multiplyDims(int dim, Dims... dims) {
+	return dim * multiplyDims(dims...);
+}
+
+/** Converts a C++ array to a JSON multidimensional array */
+template <typename T>
+json_t* toArray(const T* x) {
+	return to(*x);
+}
+template <typename T, typename... Dims>
+json_t* toArray(const T* x, int dim, Dims... dims) {
+	int stride = multiplyDims(dims...);
+	json_t* arrayJ = json_array();
+	for (int i = 0; i < dim; i++) {
+		json_array_insert_new(arrayJ, i, toArray(&x[i * stride], dims...));
+	}
+	return arrayJ;
+}
+
+/** Converts a JSON multidimensional array to a C++ array */
+template <typename T>
+void fromArray(json_t* arrayJ, T* x) {
+	*x = from<T>(arrayJ);
+}
+template <typename T, typename... Dims>
+void fromArray(json_t* arrayJ, T* x, int dim, Dims... dims) {
+	int stride = multiplyDims(dims...);
+	for (int i = 0; i < dim; i++) {
+		json_t* elJ = json_array_get(arrayJ, i);
+		if (elJ) {
+			fromArray(elJ, &x[i * stride], dims...);
+		}
+	}
+}
+
+
+} // namespace json
+} // namespace rack
diff --git a/include/rack.hpp b/include/rack.hpp
index d590dbaa..f8f652cf 100644
--- a/include/rack.hpp
+++ b/include/rack.hpp
@@ -13,6 +13,7 @@
 #include <window.hpp>
 #include <app.hpp>
 #include <midi.hpp>
+#include <json.hpp>
 #include <helpers.hpp>
 #include <componentlibrary.hpp>