1 files changed, 151 insertions, 0 deletions
diff --git a/src/rapidjson/example/tutorial/tutorial.cpp b/src/rapidjson/example/tutorial/tutorial.cpp
new file mode 100644
index 00000000..c8bfcc14
--- /dev/null
+++ b/src/rapidjson/example/tutorial/tutorial.cpp
@@ -0,0 +1,151 @@
+// Hello World example
+// This example shows basic usage of DOM-style API.
+
+#include "rapidjson/document.h"     // rapidjson's DOM-style API
+#include "rapidjson/prettywriter.h" // for stringify JSON
+#include <cstdio>
+
+using namespace rapidjson;
+using namespace std;
+
+int main(int, char*[]) {
+    ////////////////////////////////////////////////////////////////////////////
+    // 1. Parse a JSON text string to a document.
+
+    const char json[] = " { \"hello\" : \"world\", \"t\" : true , \"f\" : false, \"n\": null, \"i\":123, \"pi\": 3.1416, \"a\":[1, 2, 3, 4] } ";
+    printf("Original JSON:\n %s\n", json);
+
+    Document document;  // Default template parameter uses UTF8 and MemoryPoolAllocator.
+
+#if 0
+    // "normal" parsing, decode strings to new buffers. Can use other input stream via ParseStream().
+    if (document.Parse(json).HasParseError())
+        return 1;
+#else
+    // In-situ parsing, decode strings directly in the source string. Source must be string.
+    char buffer[sizeof(json)];
+    memcpy(buffer, json, sizeof(json));
+    if (document.ParseInsitu(buffer).HasParseError())
+        return 1;
+#endif
+
+    printf("\nParsing to document succeeded.\n");
+
+    ////////////////////////////////////////////////////////////////////////////
+    // 2. Access values in document. 
+
+    printf("\nAccess values in document:\n");
+    assert(document.IsObject());    // Document is a JSON value represents the root of DOM. Root can be either an object or array.
+
+    assert(document.HasMember("hello"));
+    assert(document["hello"].IsString());
+    printf("hello = %s\n", document["hello"].GetString());
+
+    // Since version 0.2, you can use single lookup to check the existing of member and its value:
+    Value::MemberIterator hello = document.FindMember("hello");
+    assert(hello != document.MemberEnd());
+    assert(hello->value.IsString());
+    assert(strcmp("world", hello->value.GetString()) == 0);
+    (void)hello;
+
+    assert(document["t"].IsBool());     // JSON true/false are bool. Can also uses more specific function IsTrue().
+    printf("t = %s\n", document["t"].GetBool() ? "true" : "false");
+
+    assert(document["f"].IsBool());
+    printf("f = %s\n", document["f"].GetBool() ? "true" : "false");
+
+    printf("n = %s\n", document["n"].IsNull() ? "null" : "?");
+
+    assert(document["i"].IsNumber());   // Number is a JSON type, but C++ needs more specific type.
+    assert(document["i"].IsInt());      // In this case, IsUint()/IsInt64()/IsUInt64() also return true.
+    printf("i = %d\n", document["i"].GetInt()); // Alternative (int)document["i"]
+
+    assert(document["pi"].IsNumber());
+    assert(document["pi"].IsDouble());
+    printf("pi = %g\n", document["pi"].GetDouble());
+
+    {
+        const Value& a = document["a"]; // Using a reference for consecutive access is handy and faster.
+        assert(a.IsArray());
+        for (SizeType i = 0; i < a.Size(); i++) // rapidjson uses SizeType instead of size_t.
+            printf("a[%d] = %d\n", i, a[i].GetInt());
+        
+        int y = a[0].GetInt();
+        (void)y;
+
+        // Iterating array with iterators
+        printf("a = ");
+        for (Value::ConstValueIterator itr = a.Begin(); itr != a.End(); ++itr)
+            printf("%d ", itr->GetInt());
+        printf("\n");
+    }
+
+    // Iterating object members
+    static const char* kTypeNames[] = { "Null", "False", "True", "Object", "Array", "String", "Number" };
+    for (Value::ConstMemberIterator itr = document.MemberBegin(); itr != document.MemberEnd(); ++itr)
+        printf("Type of member %s is %s\n", itr->name.GetString(), kTypeNames[itr->value.GetType()]);
+
+    ////////////////////////////////////////////////////////////////////////////
+    // 3. Modify values in document.
+
+    // Change i to a bigger number
+    {
+        uint64_t f20 = 1;   // compute factorial of 20
+        for (uint64_t j = 1; j <= 20; j++)
+            f20 *= j;
+        document["i"] = f20;    // Alternate form: document["i"].SetUint64(f20)
+        assert(!document["i"].IsInt()); // No longer can be cast as int or uint.
+    }
+
+    // Adding values to array.
+    {
+        Value& a = document["a"];   // This time we uses non-const reference.
+        Document::AllocatorType& allocator = document.GetAllocator();
+        for (int i = 5; i <= 10; i++)
+            a.PushBack(i, allocator);   // May look a bit strange, allocator is needed for potentially realloc. We normally uses the document's.
+
+        // Fluent API
+        a.PushBack("Lua", allocator).PushBack("Mio", allocator);
+    }
+
+    // Making string values.
+
+    // This version of SetString() just store the pointer to the string.
+    // So it is for literal and string that exists within value's life-cycle.
+    {
+        document["hello"] = "rapidjson";    // This will invoke strlen()
+        // Faster version:
+        // document["hello"].SetString("rapidjson", 9);
+    }
+
+    // This version of SetString() needs an allocator, which means it will allocate a new buffer and copy the the string into the buffer.
+    Value author;
+    {
+        char buffer2[10];
+        int len = sprintf(buffer2, "%s %s", "Milo", "Yip");  // synthetic example of dynamically created string.
+
+        author.SetString(buffer2, static_cast<SizeType>(len), document.GetAllocator());
+        // Shorter but slower version:
+        // document["hello"].SetString(buffer, document.GetAllocator());
+
+        // Constructor version: 
+        // Value author(buffer, len, document.GetAllocator());
+        // Value author(buffer, document.GetAllocator());
+        memset(buffer2, 0, sizeof(buffer2)); // For demonstration purpose.
+    }
+    // Variable 'buffer' is unusable now but 'author' has already made a copy.
+    document.AddMember("author", author, document.GetAllocator());
+
+    assert(author.IsNull());        // Move semantic for assignment. After this variable is assigned as a member, the variable becomes null.
+
+    ////////////////////////////////////////////////////////////////////////////
+    // 4. Stringify JSON
+
+    printf("\nModified JSON with reformatting:\n");
+    StringBuffer sb;
+    PrettyWriter<StringBuffer> writer(sb);
+    document.Accept(writer);    // Accept() traverses the DOM and generates Handler events.
+    puts(sb.GetString());
+
+    return 0;
+}