Added TBTempBuffer::AppendSpace and tuned reserve size.

src/tb/tb_tempbuffer.cpp

@@ -45,21 +45,30 @@ bool TBTempBuffer::Reserve(int size)
 	return true;
 }
 
+int TBTempBuffer::GetAppendReserveSize(int needed_size) const
+{
+	// Reserve some extra memory to reduce the reserve calls.
+	needed_size *= 2;
+	return needed_size < 32 ? 32 : needed_size;
+}
+
 bool TBTempBuffer::Append(const char *data, int size)
 {
-	int needed_size = m_append_pos + size;
-	if (needed_size > m_data_size)
-	{
-		// Reserve some extra memory to reduce the reserve calls.
-		needed_size = needed_size + size + 32;
-		if (!Reserve(needed_size))
-			return false;
-	}
+	if (m_append_pos + size > m_data_size && !Reserve(GetAppendReserveSize(m_append_pos + size)))
+		return false;
 	memcpy(m_data + m_append_pos, data, size);
 	m_append_pos += size;
 	return true;
 }
 
+bool TBTempBuffer::AppendSpace(int size)
+{
+	if (m_append_pos + size > m_data_size && !Reserve(GetAppendReserveSize(m_append_pos + size)))
+		return false;
+	m_append_pos += size;
+	return true;
+}
+
 bool TBTempBuffer::AppendString(const char *str)
 {
 	// Add 1 to include the null termination in the data.

src/tb/tb_tempbuffer.h

@@ -34,6 +34,12 @@ class TBTempBuffer
 		Returns false on OOM. */
 	bool Append(const char *data, int size);
 
+	/** Increase the append position with size bytes without
+		writing any data. This is useful if you want to write
+		the data later and want to make sure space is reserved.
+		Returns false on OOM. */
+	bool AppendSpace(int size);
+
 	/** Append a null terminated string (including the null termination)
 		at the end of the buffer. The append position will be increased
 		with the length of the text (excluding the null termination) so
@@ -55,6 +61,7 @@ class TBTempBuffer
 	/** Return the current append position in in bytes. */
 	int GetAppendPos() const { return m_append_pos; }
 private:
+	int GetAppendReserveSize(int needed_size) const;
 	char *m_data;
 	int m_data_size;
 	int m_append_pos;