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Avoid memory allocation in CryptoHash #9474

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Merged
maskit merged 3 commits into from
Mar 13, 2023
Merged

Avoid memory allocation in CryptoHash #9474

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07ac26d
Avoid memory allocation in CryptoHash
maskit Feb 28, 2023
52ed2e0
Add static_assert to ensure _base is big enough
maskit Mar 1, 2023
d874ac5
Fix static_assert condition
maskit Mar 7, 2023
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13 changes: 5 additions & 8 deletions include/tscore/CryptoHash.h
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Original file line number Diff line number Diff line change
Expand Up @@ -168,26 +168,23 @@ class CryptoContext : public CryptoContextBase
}; ///< What type of hash we really are.
static HashType Setting;

~CryptoContext()
{
delete _base;
_base = nullptr;
}
~CryptoContext() { reinterpret_cast<CryptoContextBase *>(_base)->~CryptoContextBase(); }

private:
CryptoContextBase *_base = nullptr;
static size_t constexpr OBJ_SIZE = 256;
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@maskit maskit Mar 1, 2023

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I thought I may be able to calculate the minimal size but realized that it requires including header files for SHA256 and MD5.

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@SolidWallOfCode SolidWallOfCode Mar 7, 2023

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It would probably be good to have some test or debug logic that does calculate the minimum size.

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@maskit maskit Mar 7, 2023

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AC_CHECK_SIZEOF? Then maybe we can do std::max. Try it if you are interested.

char _base[OBJ_SIZE];
};

inline bool
CryptoContext::update(void const *data, int length)
{
return _base->update(data, length);
return reinterpret_cast<CryptoContextBase *>(_base)->update(data, length);
}

inline bool
CryptoContext::finalize(CryptoHash &hash)
{
return _base->finalize(hash);
return reinterpret_cast<CryptoContextBase *>(_base)->finalize(hash);
}

ts::BufferWriter &bwformat(ts::BufferWriter &w, ts::BWFSpec const &spec, ats::CryptoHash const &hash);
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6 changes: 4 additions & 2 deletions src/tscore/CryptoHash.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -45,11 +45,13 @@ CryptoContext::CryptoContext()
case UNSPECIFIED:
#if TS_ENABLE_FIPS == 0
case MD5:
_base = new MD5Context;
static_assert(OBJ_SIZE >= sizeof(MD5Context));
new (_base) MD5Context;
break;
#else
case SHA256:
_base = new SHA256Context;
static_assert(OBJ_SIZE >= sizeof(SHA256Context));
new (_base) SHA256Context;
break;
#endif
default:
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