Initial commit

ext/vjson/block_allocator.cpp

@@ -0,0 +1,50 @@
+#include <memory.h>
+#include <algorithm>
+#include "block_allocator.h"
+
+block_allocator::block_allocator(size_t blocksize): m_head(0), m_blocksize(blocksize)
+{
+}
+
+block_allocator::~block_allocator()
+{
+	while (m_head)
+	{
+		block *temp = m_head->next;
+		::free(m_head);
+		m_head = temp;
+	}
+}
+
+void block_allocator::swap(block_allocator &rhs)
+{
+	std::swap(m_blocksize, rhs.m_blocksize);
+	std::swap(m_head, rhs.m_head);
+}
+
+void *block_allocator::malloc(size_t size)
+{
+	if ((m_head && m_head->used + size > m_head->size) || !m_head)
+	{
+		// calc needed size for allocation
+		size_t alloc_size = std::max(sizeof(block) + size, m_blocksize);
+
+		// create new block
+		char *buffer = (char *)::malloc(alloc_size);
+		block *b = reinterpret_cast<block *>(buffer);
+		b->size = alloc_size;
+		b->used = sizeof(block);
+		b->buffer = buffer;
+		b->next = m_head;
+		m_head = b;
+	}
+
+	void *ptr = m_head->buffer + m_head->used;
+	m_head->used += size;
+	return ptr;
+}
+
+void block_allocator::free()
+{
+	block_allocator(0).swap(*this);
+}