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calculate result directly from source_size and sizeof(T)

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seshWCS 2023-09-05 12:21:05 +00:00
parent 8ca51bf39d
commit cba3457a3a
1 changed files with 8 additions and 15 deletions
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23
src/Compression/CompressionCodecGCD.cpp
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@ -54,7 +54,6 @@ UInt32 CompressionCodecGCD::getMaxCompressedDataSize(UInt32 uncompressed_size) c
{
return uncompressed_size
+ gcd_bytes_size // To store gcd
+ gcd_bytes_size // Max bytes_to_skip
+ 2; // Local header
}
@ -78,9 +77,8 @@ namespace
{
template <typename T>
UInt32 compressDataForType(const char * source, UInt32 source_size, char * dest)
void compressDataForType(const char * source, UInt32 source_size, char * dest)
{
size_t result = 0;
if (source_size % sizeof(T) != 0)
throw Exception(ErrorCodes::CANNOT_COMPRESS, "Cannot GCD compress, data size {} is not aligned to {}", source_size, sizeof(T));
@ -103,7 +101,6 @@ UInt32 compressDataForType(const char * source, UInt32 source_size, char * dest)
unalignedStore<T>(dest, gcd_divider);
dest += sizeof(T);
result += sizeof(T);
if (sizeof(T) <= 8)
{
@ -116,7 +113,6 @@ UInt32 compressDataForType(const char * source, UInt32 source_size, char * dest)
unalignedStore<T>(dest, static_cast<T>(static_cast<TUInt32Or64>(unalignedLoad<T>(cur_source)) / divider));
cur_source += sizeof(T);
dest += sizeof(T);
result += sizeof(T);
}
}
else
@ -127,10 +123,8 @@ UInt32 compressDataForType(const char * source, UInt32 source_size, char * dest)
unalignedStore<T>(dest, unalignedLoad<T>(cur_source) / gcd_divider);
cur_source += sizeof(T);
dest += sizeof(T);
result += sizeof(T);
}
}
return static_cast<UInt32>(result);
}
template <typename T>
@ -167,29 +161,28 @@ UInt32 CompressionCodecGCD::doCompressData(const char * source, UInt32 source_si
dest[1] = bytes_to_skip; /// unused (backward compatibility)
memcpy(&dest[2], source, bytes_to_skip);
size_t start_pos = 2 + bytes_to_skip;
UInt32 result_size = 0;
switch (gcd_bytes_size)
{
case 1:
result_size = compressDataForType<UInt8>(&source[bytes_to_skip], source_size - bytes_to_skip, &dest[start_pos]);
compressDataForType<UInt8>(&source[bytes_to_skip], source_size - bytes_to_skip, &dest[start_pos]);
break;
case 2:
result_size = compressDataForType<UInt16>(&source[bytes_to_skip], source_size - bytes_to_skip, &dest[start_pos]);
compressDataForType<UInt16>(&source[bytes_to_skip], source_size - bytes_to_skip, &dest[start_pos]);
break;
case 4:
result_size = compressDataForType<UInt32>(&source[bytes_to_skip], source_size - bytes_to_skip, &dest[start_pos]);
compressDataForType<UInt32>(&source[bytes_to_skip], source_size - bytes_to_skip, &dest[start_pos]);
break;
case 8:
result_size = compressDataForType<UInt64>(&source[bytes_to_skip], source_size - bytes_to_skip, &dest[start_pos]);
compressDataForType<UInt64>(&source[bytes_to_skip], source_size - bytes_to_skip, &dest[start_pos]);
break;
case 16:
result_size = compressDataForType<UInt128>(&source[bytes_to_skip], source_size - bytes_to_skip, &dest[start_pos]);
compressDataForType<UInt128>(&source[bytes_to_skip], source_size - bytes_to_skip, &dest[start_pos]);
break;
case 32:
result_size = compressDataForType<UInt256>(&source[bytes_to_skip], source_size - bytes_to_skip, &dest[start_pos]);
compressDataForType<UInt256>(&source[bytes_to_skip], source_size - bytes_to_skip, &dest[start_pos]);
break;
}
return 2 + bytes_to_skip + result_size;
return 2 + gcd_bytes_size + source_size;
}
void CompressionCodecGCD::doDecompressData(const char * source, UInt32 source_size, char * dest, UInt32 uncompressed_size) const