+++ /dev/null
-// 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;
-}
projects / ceph.git / blobdiff