Coverage Report

Created: 2020-02-14 15:38

/src/botan/build/include/botan/hash.h
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/*
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* Hash Function Base Class
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* (C) 1999-2008 Jack Lloyd
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*
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* Botan is released under the Simplified BSD License (see license.txt)
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*/
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#ifndef BOTAN_HASH_FUNCTION_BASE_CLASS_H_
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#define BOTAN_HASH_FUNCTION_BASE_CLASS_H_
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#include <botan/buf_comp.h>
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#include <string>
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#include <memory>
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namespace Botan {
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/**
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* This class represents hash function (message digest) objects
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*/
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class BOTAN_PUBLIC_API(2,0) HashFunction : public Buffered_Computation
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   {
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   public:
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      /**
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      * Create an instance based on a name, or return null if the
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      * algo/provider combination cannot be found. If provider is
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      * empty then best available is chosen.
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      */
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      static std::unique_ptr<HashFunction>
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         create(const std::string& algo_spec,
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                const std::string& provider = "");
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      /**
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      * Create an instance based on a name
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      * If provider is empty then best available is chosen.
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      * @param algo_spec algorithm name
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      * @param provider provider implementation to use
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      * Throws Lookup_Error if not found.
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      */
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      static std::unique_ptr<HashFunction>
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         create_or_throw(const std::string& algo_spec,
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                         const std::string& provider = "");
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      /**
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      * @return list of available providers for this algorithm, empty if not available
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      * @param algo_spec algorithm name
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      */
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      static std::vector<std::string> providers(const std::string& algo_spec);
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      /**
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      * @return new object representing the same algorithm as *this
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      */
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      virtual HashFunction* clone() const = 0;
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      /**
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      * @return provider information about this implementation. Default is "base",
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      * might also return "sse2", "avx2", "openssl", or some other arbitrary string.
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      */
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      virtual std::string provider() const { return "base"; }
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      virtual ~HashFunction() = default;
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      /**
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      * Reset the state.
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      */
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      virtual void clear() = 0;
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      /**
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      * @return the hash function name
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      */
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      virtual std::string name() const = 0;
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      /**
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      * @return hash block size as defined for this algorithm
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      */
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      virtual size_t hash_block_size() const { return 0; }
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      /**
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      * Return a new hash object with the same state as *this. This
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      * allows computing the hash of several messages with a common
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      * prefix more efficiently than would otherwise be possible.
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      *
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      * This function should be called `clone` but that was already
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      * used for the case of returning an uninitialized object.
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      * @return new hash object
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      */
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      virtual std::unique_ptr<HashFunction> copy_state() const = 0;
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   };
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}
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#endif