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147 lines
5.5 KiB
147 lines
5.5 KiB
![]()
4 years ago
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// basecode.h - originally written and placed in the public domain by Wei Dai
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/// \file
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/// \brief Base classes for working with encoders and decoders.
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#ifndef CRYPTOPP_BASECODE_H
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#define CRYPTOPP_BASECODE_H
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#include "cryptlib.h"
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#include "filters.h"
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#include "algparam.h"
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#include "argnames.h"
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NAMESPACE_BEGIN(CryptoPP)
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/// \brief Encoder for bases that are a power of 2
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class CRYPTOPP_DLL BaseN_Encoder : public Unflushable<Filter>
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{
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public:
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/// \brief Construct a BaseN_Encoder
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/// \param attachment a BufferedTransformation to attach to this object
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BaseN_Encoder(BufferedTransformation *attachment=NULLPTR)
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: m_alphabet(NULLPTR), m_padding(0), m_bitsPerChar(0)
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, m_outputBlockSize(0), m_bytePos(0), m_bitPos(0)
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{Detach(attachment);}
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/// \brief Construct a BaseN_Encoder
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/// \param alphabet table of ASCII characters to use as the alphabet
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/// \param log2base the log<sub>2</sub>base
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/// \param attachment a BufferedTransformation to attach to this object
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/// \param padding the character to use as padding
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/// \pre log2base must be between 1 and 7 inclusive
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/// \throws InvalidArgument if log2base is not between 1 and 7
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BaseN_Encoder(const byte *alphabet, int log2base, BufferedTransformation *attachment=NULLPTR, int padding=-1)
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: m_alphabet(NULLPTR), m_padding(0), m_bitsPerChar(0)
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, m_outputBlockSize(0), m_bytePos(0), m_bitPos(0)
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{
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Detach(attachment);
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BaseN_Encoder::IsolatedInitialize(
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MakeParameters
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(Name::EncodingLookupArray(), alphabet)
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(Name::Log2Base(), log2base)
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(Name::Pad(), padding != -1)
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(Name::PaddingByte(), byte(padding)));
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}
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void IsolatedInitialize(const NameValuePairs ¶meters);
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size_t Put2(const byte *begin, size_t length, int messageEnd, bool blocking);
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private:
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const byte *m_alphabet;
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int m_padding, m_bitsPerChar, m_outputBlockSize;
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int m_bytePos, m_bitPos;
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SecByteBlock m_outBuf;
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};
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/// \brief Decoder for bases that are a power of 2
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class CRYPTOPP_DLL BaseN_Decoder : public Unflushable<Filter>
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{
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public:
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/// \brief Construct a BaseN_Decoder
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/// \param attachment a BufferedTransformation to attach to this object
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/// \details padding is set to -1, which means use default padding. If not
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/// required, then the value must be set via IsolatedInitialize().
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BaseN_Decoder(BufferedTransformation *attachment=NULLPTR)
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: m_lookup(NULLPTR), m_bitsPerChar(0)
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, m_outputBlockSize(0), m_bytePos(0), m_bitPos(0)
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{Detach(attachment);}
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/// \brief Construct a BaseN_Decoder
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/// \param lookup table of values
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/// \param log2base the log<sub>2</sub>base
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/// \param attachment a BufferedTransformation to attach to this object
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/// \details log2base is the exponent (like 5 in 2<sup>5</sup>), and not
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/// the number of elements (like 32).
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/// \details padding is set to -1, which means use default padding. If not
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/// required, then the value must be set via IsolatedInitialize().
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BaseN_Decoder(const int *lookup, int log2base, BufferedTransformation *attachment=NULLPTR)
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: m_lookup(NULLPTR), m_bitsPerChar(0)
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, m_outputBlockSize(0), m_bytePos(0), m_bitPos(0)
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{
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Detach(attachment);
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BaseN_Decoder::IsolatedInitialize(
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MakeParameters
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(Name::DecodingLookupArray(), lookup)
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(Name::Log2Base(), log2base));
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}
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void IsolatedInitialize(const NameValuePairs ¶meters);
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size_t Put2(const byte *begin, size_t length, int messageEnd, bool blocking);
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/// \brief Initializes BaseN lookup array
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/// \param lookup table of values
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/// \param alphabet table of ASCII characters
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/// \param base the base for the encoder
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/// \param caseInsensitive flag indicating whether the alphabet is case sensitivie
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/// \pre COUNTOF(lookup) == 256
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/// \pre COUNTOF(alphabet) == base
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/// \details Internally, the function sets the first 256 elements in the lookup table to
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/// their value from the alphabet array or -1. base is the number of element (like 32),
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/// and not an exponent (like 5 in 2<sup>5</sup>)
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static void CRYPTOPP_API InitializeDecodingLookupArray(int *lookup, const byte *alphabet, unsigned int base, bool caseInsensitive);
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private:
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const int *m_lookup;
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int m_bitsPerChar, m_outputBlockSize;
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int m_bytePos, m_bitPos;
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SecByteBlock m_outBuf;
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};
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/// \brief Filter that breaks input stream into groups of fixed size
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class CRYPTOPP_DLL Grouper : public Bufferless<Filter>
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{
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public:
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/// \brief Construct a Grouper
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/// \param attachment a BufferedTransformation to attach to this object
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Grouper(BufferedTransformation *attachment=NULLPTR)
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: m_groupSize(0), m_counter(0) {Detach(attachment);}
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/// \brief Construct a Grouper
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/// \param groupSize the size of the grouping
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/// \param separator the separator to use between groups
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/// \param terminator the terminator appeand after processing
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/// \param attachment a BufferedTransformation to attach to this object
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Grouper(int groupSize, const std::string &separator, const std::string &terminator, BufferedTransformation *attachment=NULLPTR)
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: m_groupSize(0), m_counter(0)
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{
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Detach(attachment);
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Grouper::IsolatedInitialize(
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MakeParameters
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(Name::GroupSize(), groupSize)
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(Name::Separator(), ConstByteArrayParameter(separator))
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(Name::Terminator(), ConstByteArrayParameter(terminator)));
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}
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void IsolatedInitialize(const NameValuePairs ¶meters);
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size_t Put2(const byte *begin, size_t length, int messageEnd, bool blocking);
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private:
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SecByteBlock m_separator, m_terminator;
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size_t m_groupSize, m_counter;
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};
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NAMESPACE_END
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#endif
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