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Return seed when given invalid data, re-order and rename parameters to make more sense

This commit is contained in:
Phillip Stephens 2018-02-15 17:07:50 -08:00
parent 5126c603b0
commit 80008cadcd
2 changed files with 20 additions and 17 deletions
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6
include/athena/Checksums.hpp
View File

@ -5,9 +5,9 @@
namespace athena::Checksums namespace athena::Checksums
{ {
atUint64 crc64(const atUint8* data, atUint64 length, atUint64 mask = 0xFFFFFFFFFFFFFFFF, atUint64 seed = 0xFFFFFFFFFFFFFFFF); atUint64 crc64(const atUint8* data, atUint64 length, atUint64 seed = 0xFFFFFFFFFFFFFFFF, atUint64 final = 0xFFFFFFFFFFFFFFFF);
atUint32 crc32(const atUint8* data, atUint64 length, atUint32 mask = 0xFFFFFFFF, atUint32 seed = 0xFFFFFFFF); atUint32 crc32(const atUint8* data, atUint64 length, atUint32 seed = 0xFFFFFFFF, atUint32 final = 0xFFFFFFFF);
atUint16 crc16CCITT(const atUint8* data, atUint64 length, atUint16 seed = 0xFFFF, atUint16 final = 0); atUint16 crc16CCITT(const atUint8* data, atUint64 length, atUint16 seed = 0xFFFF, atUint16 final = 0);
atUint16 crc16(const atUint8* data, atUint64 length); atUint16 crc16(const atUint8* data, atUint64 length, atUint16 seed = 0, atUint16 final = 0);
} }
#endif // CHECKSUMS_HPP #endif // CHECKSUMS_HPP

31
src/athena/Checksums.cpp
View File

@ -5,14 +5,8 @@
namespace athena::Checksums namespace athena::Checksums
{ {
atUint64 crc64(const atUint8* data, atUint64 length, atUint64 mask, atUint64 seed) atUint64 crc64(const atUint8* data, atUint64 length, atUint64 seed, atUint64 final)
{ {
if (!data)
return 0;
atUint64 checksum = seed;
int pos = 0;
static const atUint64 crc64Table[256] = static const atUint64 crc64Table[256] =
{ {
0x0000000000000000, 0x42F0E1EBA9EA3693, 0x85E1C3D753D46D26, 0xC711223CFA3E5BB5, 0x0000000000000000, 0x42F0E1EBA9EA3693, 0x85E1C3D753D46D26, 0xC711223CFA3E5BB5,
@ -81,13 +75,19 @@ atUint64 crc64(const atUint8* data, atUint64 length, atUint64 mask, atUint64 see
0x5DEDC41A34BBEEB2, 0x1F1D25F19D51D821, 0xD80C07CD676F8394, 0x9AFCE626CE85B507, 0x5DEDC41A34BBEEB2, 0x1F1D25F19D51D821, 0xD80C07CD676F8394, 0x9AFCE626CE85B507,
}; };
if (!data)
return seed;
atUint64 checksum = seed;
int pos = 0;
while (length--) while (length--)
checksum = crc64Table[((checksum >> 56) ^ data[pos++]) & 0xff] ^ (checksum << 8); checksum = crc64Table[((checksum >> 56) ^ data[pos++]) & 0xff] ^ (checksum << 8);
return checksum ^ mask; return checksum ^ final;
} }
atUint32 crc32(const atUint8* data, atUint64 length, atUint32 mask, atUint32 seed) atUint32 crc32(const atUint8* data, atUint64 length, atUint32 seed, atUint32 final)
{ {
static const atUint32 crc32Table[256] = static const atUint32 crc32Table[256] =
{ {
@ -126,7 +126,7 @@ atUint32 crc32(const atUint8* data, atUint64 length, atUint32 mask, atUint32 see
}; };
if (!data) if (!data)
return 0; return seed;
atUint32 checksum = seed; atUint32 checksum = seed;
int pos = 0; int pos = 0;
@ -134,7 +134,7 @@ atUint32 crc32(const atUint8* data, atUint64 length, atUint32 mask, atUint32 see
while (length--) while (length--)
checksum = (checksum >> 8) ^ crc32Table[(checksum & 0xFF) ^ data[pos++]]; checksum = (checksum >> 8) ^ crc32Table[(checksum & 0xFF) ^ data[pos++]];
return checksum ^ mask; return checksum ^ final;
} }
atUint16 crc16CCITT(const atUint8* data, atUint64 length, atUint16 seed, atUint16 final) atUint16 crc16CCITT(const atUint8* data, atUint64 length, atUint16 seed, atUint16 final)
@ -181,8 +181,11 @@ atUint16 crc16CCITT(const atUint8* data, atUint64 length, atUint16 seed, atUint1
return checksum ^ final; return checksum ^ final;
} }
atUint16 crc16(const atUint8* data, atUint64 length) atUint16 crc16(const atUint8* data, atUint64 length, atUint16 seed, atUint64 final)
{ {
if (data)
return seed;
static const atUint16 crc16Table[256] = static const atUint16 crc16Table[256] =
{ {
0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241, 0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
@ -220,12 +223,12 @@ atUint16 crc16(const atUint8* data, atUint64 length)
}; };
atInt32 pos = 0; atInt32 pos = 0;
atUint16 checksum = 0; atUint16 checksum = seed;
while (length--) while (length--)
checksum = (crc16Table[(checksum ^ data[pos++]) & 0xFF] ^ (checksum >> 8)); checksum = (crc16Table[(checksum ^ data[pos++]) & 0xFF] ^ (checksum >> 8));
return checksum; return checksum ^ final;
} }
} // Checksums } // Checksums