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| 14 | pmbaty | 1 | //==- BLAKE3.h - BLAKE3 C++ wrapper for LLVM ---------------------*- C++ -*-==// |
| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // |
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| 9 | // This is a C++ wrapper of the BLAKE3 C interface. |
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| 10 | // |
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| 11 | //===----------------------------------------------------------------------===// |
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| 12 | |||
| 13 | #ifndef LLVM_SUPPORT_BLAKE3_H |
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| 14 | #define LLVM_SUPPORT_BLAKE3_H |
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| 15 | |||
| 16 | #include "llvm-c/blake3.h" |
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| 17 | #include "llvm/ADT/ArrayRef.h" |
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| 18 | #include "llvm/ADT/StringRef.h" |
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| 19 | |||
| 20 | namespace llvm { |
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| 21 | |||
| 22 | /// The constant \p LLVM_BLAKE3_OUT_LEN provides the default output length, |
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| 23 | /// 32 bytes, which is recommended for most callers. |
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| 24 | /// |
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| 25 | /// Outputs shorter than the default length of 32 bytes (256 bits) provide |
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| 26 | /// less security. An N-bit BLAKE3 output is intended to provide N bits of |
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| 27 | /// first and second preimage resistance and N/2 bits of collision |
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| 28 | /// resistance, for any N up to 256. Longer outputs don't provide any |
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| 29 | /// additional security. |
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| 30 | /// |
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| 31 | /// Shorter BLAKE3 outputs are prefixes of longer ones. Explicitly |
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| 32 | /// requesting a short output is equivalent to truncating the default-length |
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| 33 | /// output. |
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| 34 | template <size_t NumBytes = LLVM_BLAKE3_OUT_LEN> |
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| 35 | using BLAKE3Result = std::array<uint8_t, NumBytes>; |
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| 36 | |||
| 37 | /// A class that wraps the BLAKE3 algorithm. |
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| 38 | class BLAKE3 { |
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| 39 | public: |
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| 40 | BLAKE3() { init(); } |
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| 41 | |||
| 42 | /// Reinitialize the internal state |
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| 43 | void init() { llvm_blake3_hasher_init(&Hasher); } |
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| 44 | |||
| 45 | /// Digest more data. |
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| 46 | void update(ArrayRef<uint8_t> Data) { |
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| 47 | llvm_blake3_hasher_update(&Hasher, Data.data(), Data.size()); |
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| 48 | } |
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| 49 | |||
| 50 | /// Digest more data. |
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| 51 | void update(StringRef Str) { |
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| 52 | llvm_blake3_hasher_update(&Hasher, Str.data(), Str.size()); |
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| 53 | } |
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| 54 | |||
| 55 | /// Finalize the hasher and put the result in \p Result. |
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| 56 | /// This doesn't modify the hasher itself, and it's possible to finalize again |
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| 57 | /// after adding more input. |
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| 58 | template <size_t NumBytes = LLVM_BLAKE3_OUT_LEN> |
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| 59 | void final(BLAKE3Result<NumBytes> &Result) { |
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| 60 | llvm_blake3_hasher_finalize(&Hasher, Result.data(), Result.size()); |
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| 61 | } |
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| 62 | |||
| 63 | /// Finalize the hasher and return an output of any length, given in bytes. |
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| 64 | /// This doesn't modify the hasher itself, and it's possible to finalize again |
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| 65 | /// after adding more input. |
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| 66 | template <size_t NumBytes = LLVM_BLAKE3_OUT_LEN> |
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| 67 | BLAKE3Result<NumBytes> final() { |
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| 68 | BLAKE3Result<NumBytes> Result; |
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| 69 | llvm_blake3_hasher_finalize(&Hasher, Result.data(), Result.size()); |
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| 70 | return Result; |
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| 71 | } |
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| 72 | |||
| 73 | /// Return the current output for the digested data since the last call to |
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| 74 | /// init(). |
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| 75 | /// |
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| 76 | /// Other hash functions distinguish between \p result() and \p final(), with |
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| 77 | /// \p result() allowing more calls into \p update(), but there's no |
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| 78 | // difference for the BLAKE3 hash function. |
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| 79 | template <size_t NumBytes = LLVM_BLAKE3_OUT_LEN> |
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| 80 | BLAKE3Result<NumBytes> result() { |
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| 81 | return final<NumBytes>(); |
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| 82 | } |
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| 83 | |||
| 84 | /// Returns a BLAKE3 hash for the given data. |
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| 85 | template <size_t NumBytes = LLVM_BLAKE3_OUT_LEN> |
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| 86 | static BLAKE3Result<NumBytes> hash(ArrayRef<uint8_t> Data) { |
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| 87 | BLAKE3 Hasher; |
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| 88 | Hasher.update(Data); |
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| 89 | return Hasher.final<NumBytes>(); |
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| 90 | } |
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| 91 | |||
| 92 | private: |
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| 93 | llvm_blake3_hasher Hasher; |
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| 94 | }; |
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| 95 | |||
| 96 | /// Like \p BLAKE3 but using a class-level template parameter for specifying the |
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| 97 | /// hash size of the \p final() and \p result() functions. |
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| 98 | /// |
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| 99 | /// This is useful for using BLAKE3 as the hasher type for \p HashBuilder with |
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| 100 | /// non-default hash sizes. |
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| 101 | template <size_t NumBytes> class TruncatedBLAKE3 : public BLAKE3 { |
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| 102 | public: |
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| 103 | /// Finalize the hasher and put the result in \p Result. |
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| 104 | /// This doesn't modify the hasher itself, and it's possible to finalize again |
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| 105 | /// after adding more input. |
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| 106 | void final(BLAKE3Result<NumBytes> &Result) { return BLAKE3::final(Result); } |
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| 107 | |||
| 108 | /// Finalize the hasher and return an output of any length, given in bytes. |
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| 109 | /// This doesn't modify the hasher itself, and it's possible to finalize again |
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| 110 | /// after adding more input. |
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| 111 | BLAKE3Result<NumBytes> final() { return BLAKE3::final<NumBytes>(); } |
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| 112 | |||
| 113 | /// Return the current output for the digested data since the last call to |
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| 114 | /// init(). |
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| 115 | /// |
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| 116 | /// Other hash functions distinguish between \p result() and \p final(), with |
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| 117 | /// \p result() allowing more calls into \p update(), but there's no |
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| 118 | // difference for the BLAKE3 hash function. |
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| 119 | BLAKE3Result<NumBytes> result() { return BLAKE3::result<NumBytes>(); } |
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| 120 | }; |
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| 121 | |||
| 122 | } // namespace llvm |
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| 123 | |||
| 124 | #endif |