Add Jsonx example for converting JSON into JSONx (a XML format)

example/CMakeLists.txt

@@ -6,6 +6,7 @@ cmake_minimum_required(VERSION 2.8)
 set(EXAMPLES
     capitalize
     condense
+    jsonx
     messagereader
     pretty
     prettyauto
@@ -18,6 +19,8 @@ set(EXAMPLES
 
 include_directories("../include/")
 
+add_definitions(-D__STDC_FORMAT_MACROS)
+
 if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror -Wall -Wextra -Weffc++ -Wswitch-default")
 elseif (CMAKE_CXX_COMPILER_ID MATCHES "Clang")

example/jsonx/jsonx.cpp

@@ -0,0 +1,200 @@
+// JSON to JSONx conversion exmaple, using SAX API.
+// JSONx is an IBM standard format to represent JSON as XML.
+// https://www-01.ibm.com/support/knowledgecenter/SS9H2Y_7.1.0/com.ibm.dp.doc/json_jsonx.html
+// This example parses JSON text from stdin with validation, 
+// and convert to JSONx format to stdout.
+// Need compile with -D__STDC_FORMAT_MACROS for defining PRId64 and PRIu64 macros.
+
+#include "rapidjson/reader.h"
+#include "rapidjson/stringbuffer.h"
+#include "rapidjson/filereadstream.h"
+#include "rapidjson/filewritestream.h"
+#include "rapidjson/error/en.h"
+#include <cstdio>
+
+using namespace rapidjson;
+
+// For simplicity, this example only read/write in UTF-8 encoding
+template <typename OutputStream>
+class JsonxWriter {
+public:
+    JsonxWriter(OutputStream& os) : os_(os), name_(), level_(0), hasName_(false) {
+    }
+
+    bool Null() {
+        return WriteStartElement("null", true);
+    }
+
+    bool Bool(bool b) {
+        return 
+            WriteStartElement("boolean") &&
+            WriteString(b ? "true" : "false") &&
+            WriteEndElement("boolean");
+    }
+
+    bool Int(int i) {
+        char buffer[12];
+        return WriteNumberElement(buffer, sprintf(buffer, "%d", i));
+    }
+
+    bool Uint(unsigned i) {
+        char buffer[11];
+        return WriteNumberElement(buffer, sprintf(buffer, "%u", i));
+    }
+
+    bool Int64(int64_t i) {
+        char buffer[21];
+        return WriteNumberElement(buffer, sprintf(buffer, "%" PRId64, i));
+    }
+
+    bool Uint64(uint64_t i) {
+        char buffer[21];
+        return WriteNumberElement(buffer, sprintf(buffer, "%" PRIu64, i));
+    }
+
+    bool Double(double d) {
+        char buffer[30];
+        return WriteNumberElement(buffer, sprintf(buffer, "%.17g", d));
+    }
+
+    bool String(const char* str, SizeType length, bool) {
+        return
+            WriteStartElement("string") &&
+            WriteEscapedText(str, length) &&
+            WriteEndElement("string");
+    }
+
+    bool StartObject() {
+        return WriteStartElement("object");
+    }
+
+    bool Key(const char* str, SizeType length, bool) {
+        // backup key to name_
+        name_.Clear();
+        for (SizeType i = 0; i < length; i++)
+            name_.Put(str[i]);
+        hasName_ = true;
+        return true;
+    }
+
+    bool EndObject(SizeType) {
+        return WriteEndElement("object");
+    }
+
+    bool StartArray() {
+        return WriteStartElement("array");
+    }
+
+    bool EndArray(SizeType) {
+        return WriteEndElement("array");
+    }
+
+private:
+    bool WriteString(const char* s) {
+        while (*s)
+            os_.Put(*s++);
+        return true;
+    }
+
+    bool WriteEscapedAttributeValue(const char* s, size_t length) {
+        for (size_t i = 0; i < length; i++) {
+            switch (s[i]) {
+                case '&': WriteString("&amp;"); break;
+                case '<': WriteString("&lt;"); break;
+                case '"': WriteString("&quot;"); break;
+                default: os_.Put(s[i]); break;
+            }
+        }
+        return true;
+    }
+
+    bool WriteEscapedText(const char* s, size_t length) {
+        for (size_t i = 0; i < length; i++) {
+            switch (s[i]) {
+                case '&': WriteString("&amp;"); break;
+                case '<': WriteString("&lt;"); break;
+                default: os_.Put(s[i]); break;
+            }
+        }
+        return true;
+    }
+
+    bool WriteStartElement(const char* type, bool emptyElement = false) {
+        if (level_ == 0)
+            if (!WriteString("<?xml version=\"1.0\" encoding=\"UTF-8\"?>"))
+                return false;
+
+        if (!WriteString("<json:") || !WriteString(type))
+            return false;
+
+        // For root element, need to add declarations
+        if (level_ == 0) {
+            if (!WriteString(
+                " xsi:schemaLocation=\"http://www.datapower.com/schemas/json jsonx.xsd\""
+                " xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\""
+                " xmlns:json=\"http://www.ibm.com/xmlns/prod/2009/jsonx\""))
+                return false;
+        }
+
+        if (hasName_) {
+            hasName_ = false;
+            if (!WriteString(" name=\"") ||
+                !WriteEscapedAttributeValue(name_.GetString(), name_.GetSize()) ||
+                !WriteString("\""))
+                return false;
+        }
+
+        if (emptyElement)
+            return WriteString("/>");
+        else {
+            level_++;
+            return WriteString(">");
+        }
+    }
+
+    bool WriteEndElement(const char* type) {
+        if (!WriteString("</json:") ||
+            !WriteString(type) ||
+            !WriteString(">"))
+            return false;
+
+        // For the last end tag, flush the output stream.
+        if (--level_ == 0)
+            os_.Flush();
+
+        return true;
+    }
+
+    bool WriteNumberElement(const char* buffer, int length) {
+        if (!WriteStartElement("number"))
+            return false;
+        for (int j = 0; j < length; j++)
+            os_.Put(buffer[j]);
+        return WriteEndElement("number");
+    }
+
+    OutputStream& os_;
+    StringBuffer name_;
+    unsigned level_;
+    bool hasName_;
+};
+
+int main(int, char*[]) {
+    // Prepare JSON reader and input stream.
+    Reader reader;
+    char readBuffer[65536];
+    FileReadStream is(stdin, readBuffer, sizeof(readBuffer));
+
+    // Prepare JSON writer and output stream.
+    char writeBuffer[65536];
+    FileWriteStream os(stdout, writeBuffer, sizeof(writeBuffer));
+    JsonxWriter<FileWriteStream> writer(os);
+
+    // JSON reader parse from the input stream and let writer generate the output.
+    if (!reader.Parse(is, writer)) {
+        fprintf(stderr, "\nError(%u): %s\n", static_cast<unsigned>(reader.GetErrorOffset()), GetParseError_En(reader.GetParseErrorCode()));
+        return 1;
+    }
+
+    return 0;
+}