Initial revision

1 files changed, 214 insertions, 0 deletions

diff --git a/basecode.cpp b/basecode.cpp
new file mode 100644
index 00000000..51347b60
--- /dev/null
+++ b/basecode.cpp
@@ -0,0 +1,214 @@
+// basecode.cpp - written and placed in the public domain by Wei Dai
+
+#include "pch.h"
+#include "basecode.h"
+#include "fltrimpl.h"
+#include <ctype.h>
+
+NAMESPACE_BEGIN(CryptoPP)
+
+void BaseN_Encoder::IsolatedInitialize(const NameValuePairs &parameters)
+{
+	parameters.GetRequiredParameter("BaseN_Encoder", "EncodingLookupArray", m_alphabet);
+
+	parameters.GetRequiredIntParameter("BaseN_Encoder", "Log2Base", m_bitsPerChar);
+	if (m_bitsPerChar <= 0 || m_bitsPerChar >= 8)
+		throw InvalidArgument("BaseN_Encoder: Log2Base must be between 1 and 7 inclusive");
+
+	byte padding;
+	bool pad;
+	if (parameters.GetValue("PaddingByte", padding))
+		pad = parameters.GetValueWithDefault("Pad", true);
+	else
+		pad = false;
+	m_padding = pad ? padding : -1;
+
+	m_bytePos = m_bitPos = 0;
+
+	int i = 8;
+	while (i%m_bitsPerChar != 0)
+		i += 8;
+	m_outputBlockSize = i/m_bitsPerChar;
+
+	m_outBuf.New(m_outputBlockSize);
+}
+
+unsigned int BaseN_Encoder::Put2(const byte *begin, unsigned int length, int messageEnd, bool blocking)
+{
+	FILTER_BEGIN;
+	while (m_inputPosition < length)
+	{
+		if (m_bytePos == 0)
+			memset(m_outBuf, 0, m_outputBlockSize);
+
+		m_outBuf[m_bytePos] |= begin[m_inputPosition] >> (8-m_bitsPerChar+m_bitPos);
+		m_outBuf[m_bytePos+1] |= ((begin[m_inputPosition] << (m_bitsPerChar-m_bitPos)) & 0xff) >> (8-m_bitsPerChar);
+		++m_inputPosition;
+
+		m_bitPos += 8;
+		while (m_bitPos >= m_bitsPerChar)
+		{
+			m_bitPos -= m_bitsPerChar;
+			++m_bytePos;
+		}
+
+		if (m_bytePos == m_outputBlockSize)
+		{
+			int i;
+			for (i=0; i<m_bytePos; i++)
+			{
+				assert(m_outBuf[i] < (1 << m_bitsPerChar));
+				m_outBuf[i] = m_alphabet[m_outBuf[i]];
+			}
+			FILTER_OUTPUT(1, m_outBuf, m_outputBlockSize, 0);
+			
+			m_bytePos = m_bitPos = 0;
+		}
+	}
+	if (messageEnd)
+	{
+		if (m_bitPos > 0)
+			++m_bytePos;
+
+		int i;
+		for (i=0; i<m_bytePos; i++)
+			m_outBuf[i] = m_alphabet[m_outBuf[i]];
+
+		if (m_padding != -1 && m_bytePos > 0)
+		{
+			memset(m_outBuf+m_bytePos, m_padding, m_outputBlockSize-m_bytePos);
+			m_bytePos = m_outputBlockSize;
+		}
+		FILTER_OUTPUT(2, m_outBuf, m_bytePos, messageEnd);
+		m_bytePos = m_bitPos = 0;
+	}
+	FILTER_END;
+}
+
+void BaseN_Decoder::IsolatedInitialize(const NameValuePairs &parameters)
+{
+	parameters.GetRequiredParameter("BaseN_Decoder", "DecodingLookupArray", m_lookup);
+
+	parameters.GetRequiredIntParameter("BaseN_Decoder", "Log2Base", m_bitsPerChar);
+	if (m_bitsPerChar <= 0 || m_bitsPerChar >= 8)
+		throw InvalidArgument("BaseN_Decoder: Log2Base must be between 1 and 7 inclusive");
+
+	m_bytePos = m_bitPos = 0;
+
+	int i = m_bitsPerChar;
+	while (i%8 != 0)
+		i += m_bitsPerChar;
+	m_outputBlockSize = i/8;
+
+	m_outBuf.New(m_outputBlockSize);
+}
+
+unsigned int BaseN_Decoder::Put2(const byte *begin, unsigned int length, int messageEnd, bool blocking)
+{
+	FILTER_BEGIN;
+	while (m_inputPosition < length)
+	{
+		unsigned int value;
+		value = m_lookup[begin[m_inputPosition++]];
+		if (value >= 256)
+			continue;
+
+		if (m_bytePos == 0 && m_bitPos == 0)
+			memset(m_outBuf, 0, m_outputBlockSize);
+
+		{
+			int newBitPos = m_bitPos + m_bitsPerChar;
+			if (newBitPos <= 8)
+				m_outBuf[m_bytePos] |= value << (8-newBitPos);
+			else
+			{
+				m_outBuf[m_bytePos] |= value >> (newBitPos-8);
+				m_outBuf[m_bytePos+1] |= value << (16-newBitPos);
+			}
+
+			m_bitPos = newBitPos;
+			while (m_bitPos >= 8)
+			{
+				m_bitPos -= 8;
+				++m_bytePos;
+			}
+		}
+
+		if (m_bytePos == m_outputBlockSize)
+		{
+			FILTER_OUTPUT(1, m_outBuf, m_outputBlockSize, 0);
+			m_bytePos = m_bitPos = 0;
+		}
+	}
+	if (messageEnd)
+	{
+		FILTER_OUTPUT(2, m_outBuf, m_bytePos, messageEnd);
+		m_bytePos = m_bitPos = 0;
+	}
+	FILTER_END_NO_MESSAGE_END;
+}
+
+void BaseN_Decoder::InitializeDecodingLookupArray(int *lookup, const byte *alphabet, unsigned int base, bool caseInsensitive)
+{
+	std::fill(lookup, lookup+256, -1);
+
+	for (unsigned int i=0; i<base; i++)
+	{
+		if (caseInsensitive && isalpha(alphabet[i]))
+		{
+			assert(lookup[toupper(alphabet[i])] == -1);
+			lookup[toupper(alphabet[i])] = i;
+			assert(lookup[tolower(alphabet[i])] == -1);
+			lookup[tolower(alphabet[i])] = i;
+		}
+		else
+		{
+			assert(lookup[alphabet[i]] == -1);
+			lookup[alphabet[i]] = i;
+		}
+	}
+}
+
+void Grouper::IsolatedInitialize(const NameValuePairs &parameters)
+{
+	m_groupSize = parameters.GetIntValueWithDefault("GroupSize", 0);
+	ConstByteArrayParameter seperator, terminator;
+	if (m_groupSize)
+		parameters.GetRequiredParameter("Grouper", "Seperator", seperator);
+	else
+		parameters.GetValue("Seperator", seperator);
+	parameters.GetValue("Terminator", terminator);
+
+	m_seperator.Assign(seperator.begin(), seperator.size());
+	m_terminator.Assign(terminator.begin(), terminator.size());
+	m_counter = 0;
+}
+
+unsigned int Grouper::Put2(const byte *begin, unsigned int length, int messageEnd, bool blocking)
+{
+	if (m_groupSize)
+	{
+		FILTER_BEGIN;
+		while (m_inputPosition < length)
+		{
+			if (m_counter == m_groupSize)
+			{
+				FILTER_OUTPUT(1, m_seperator, m_seperator.size(), 0);
+				m_counter = 0;
+			}
+
+			unsigned int len;
+			FILTER_OUTPUT2(2, len = STDMIN(length-m_inputPosition, m_groupSize-m_counter),
+				begin+m_inputPosition, len, 0);
+			m_inputPosition += len;
+			m_counter += len;
+		}
+		if (messageEnd)
+			FILTER_OUTPUT(3, m_terminator, m_terminator.size(), messageEnd);
+		FILTER_END_NO_MESSAGE_END
+	}
+	else
+		return Output(0, begin, length, messageEnd, blocking);
+}
+
+NAMESPACE_END