GEEKING

App/util/Base64BinaryOutputStream.cpp

@@ -0,0 +1,65 @@
+#include "stdafx.h"
+#include "Util/Base64BinaryOutputStream.h"
+
+#include "Rbx/Debug.h"
+
+namespace RBX {
+
+const char* Base64BinaryOutputStream::kTranslateToBase64 = 
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	"abcdefghijklmnopqrstuvwxyz"
+	"0123456789"
+	"+/";
+
+Base64BinaryOutputStream::Base64BinaryOutputStream() : buffer(0), bitsUsed(0) {}
+
+size_t Base64BinaryOutputStream::GetNumberOfBytesUsed() const {
+	// for the time being, only needed to satisfy templatization
+	RBXASSERT(false);
+    throw std::runtime_error("Base64BinaryOutputStream::GetNumberOfBytesUsed Not Implemented");
+}
+
+void Base64BinaryOutputStream::WriteBits(
+		const unsigned char* doNotReadFromThisVariableAfterFirstRead,
+		size_t numBitsToAdd) {
+	RBXASSERT(numBitsToAdd <= 8);
+    RBXASSERT(numBitsToAdd >= 1);
+    RBXASSERT(doNotReadFromThisVariableAfterFirstRead);
+
+	unsigned char dataCopy = *doNotReadFromThisVariableAfterFirstRead;
+
+	while (numBitsToAdd > 0) {
+		// clip off higher order bits: only the "numBitsToAdd" (remaining)
+		// least significant bits should be put into the stream
+		dataCopy &= ((1 << numBitsToAdd) - 1);
+
+		size_t bitsThatFit = std::min(numBitsToAdd, 6 - bitsUsed);
+
+		buffer <<= bitsThatFit;
+		buffer |= dataCopy >> (numBitsToAdd - bitsThatFit);
+
+		bitsUsed += bitsThatFit;
+        RBXASSERT(bitsUsed <= 6);
+		if (bitsUsed == 6) {
+			result << ((const char)kTranslateToBase64[buffer]);
+		
+			buffer = 0;
+			bitsUsed = 0;
+		}
+
+		numBitsToAdd -= bitsThatFit;
+	}
+}
+
+void Base64BinaryOutputStream::done(std::string* out) {
+	if (bitsUsed > 0) {
+		unsigned char zero = 0;
+		WriteBits(&zero, 6 - bitsUsed);
+	}
+	RBXASSERT(bitsUsed == 0);
+	RBXASSERT(buffer == 0);
+
+	(*out) = result.str();
+}
+
+}