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-rw-r--r--docs/samples/save_custom_writer.cpp112
1 files changed, 112 insertions, 0 deletions
diff --git a/docs/samples/save_custom_writer.cpp b/docs/samples/save_custom_writer.cpp
new file mode 100644
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--- /dev/null
+++ b/docs/samples/save_custom_writer.cpp
@@ -0,0 +1,112 @@
+#include "pugixml.hpp"
+
+#include <string>
+
+#include <stdio.h>
+
+struct xml_string_writer: pugi::xml_writer
+{
+ std::string result;
+
+ virtual void write(const void* data, size_t size)
+ {
+ result += std::string(static_cast<const char*>(data), size);
+ }
+};
+
+struct xml_memory_writer: pugi::xml_writer
+{
+ char* buffer;
+ size_t capacity;
+
+ size_t result;
+
+ xml_memory_writer(): buffer(0), capacity(0), result(0)
+ {
+ }
+
+ xml_memory_writer(char* buffer, size_t capacity): buffer(buffer), capacity(capacity), result(0)
+ {
+ }
+
+ size_t written_size() const
+ {
+ return result < capacity ? result : capacity;
+ }
+
+ virtual void write(const void* data, size_t size)
+ {
+ if (result < capacity)
+ {
+ size_t chunk = (capacity - result < size) ? capacity - result : size;
+
+ memcpy(buffer + result, data, chunk);
+ }
+
+ result += size;
+ }
+};
+
+std::string node_to_string(pugi::xml_node node)
+{
+ xml_string_writer writer;
+ node.print(writer);
+
+ return writer.result;
+}
+
+char* node_to_buffer(pugi::xml_node node, char* buffer, size_t size)
+{
+ if (size == 0) return buffer;
+
+ // leave one character for null terminator
+ xml_memory_writer writer(buffer, size - 1);
+ node.print(writer);
+
+ // null terminate
+ buffer[writer.written_size()] = 0;
+
+ return buffer;
+}
+
+char* node_to_buffer_heap(pugi::xml_node node)
+{
+ // first pass: get required memory size
+ xml_memory_writer counter;
+ node.print(counter);
+
+ // allocate necessary size (+1 for null termination)
+ char* buffer = new char[counter.result + 1];
+
+ // second pass: actual printing
+ xml_memory_writer writer(buffer, counter.result);
+ node.print(writer);
+
+ // null terminate
+ buffer[writer.written_size()] = 0;
+
+ return buffer;
+}
+
+int main()
+{
+ // get a test document
+ pugi::xml_document doc;
+ doc.load("<foo bar='baz'>hey</foo>");
+
+ // get contents as std::string (single pass)
+ printf("contents: [%s]\n", node_to_string(doc).c_str());
+
+ // get contents into fixed-size buffer (single pass)
+ char large_buf[128];
+ printf("contents: [%s]\n", node_to_buffer(doc, large_buf, sizeof(large_buf)));
+
+ // get contents into fixed-size buffer (single pass, shows truncating behavior)
+ char small_buf[22];
+ printf("contents: [%s]\n", node_to_buffer(doc, small_buf, sizeof(small_buf)));
+
+ // get contents into heap-allocated buffer (two passes)
+ char* heap_buf = node_to_buffer_heap(doc);
+ printf("contents: [%s]\n", heap_buf);
+ delete[] heap_buf;
+}