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fix: optimize decompress double

This commit is contained in:
dapan1121 2023-04-18 13:44:41 +08:00
parent 5becc19c3c
commit ed34b401ee
1 changed files with 12 additions and 15 deletions
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27
source/util/src/tcompression.c
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@ -912,11 +912,11 @@ int32_t tsCompressDoubleImp(const char *const input, const int32_t nelements, ch
return opos;
}
uint64_t decodeDoubleValue(const char *const input, int32_t *const ipos, uint8_t flag) {
FORCE_INLINE uint64_t decodeDoubleValue(const char *const input, int32_t *const ipos, uint8_t flag) {
uint64_t diff = 0ul;
int32_t nbytes = (flag & INT8MASK(3)) + 1;
int32_t nbytes = (flag & 0x7) + 1;
for (int32_t i = 0; i < nbytes; i++) {
diff = diff | ((INT64MASK(8) & input[(*ipos)++]) << BITS_PER_BYTE * i);
diff |= ((0xffff & input[(*ipos)++]) << BITS_PER_BYTE * i);
}
int32_t shift_width = (LONG_BYTES * BITS_PER_BYTE - nbytes * BITS_PER_BYTE) * (flag >> 3);
diff <<= shift_width;
@ -936,25 +936,22 @@ int32_t tsDecompressDoubleImp(const char *const input, const int32_t nelements,
uint8_t flags = 0;
int32_t ipos = 1;
int32_t opos = 0;
uint64_t prev_value = 0;
uint64_t diff = 0;
union {
uint64_t bits;
double real;
} curr;
curr.bits = 0;
for (int32_t i = 0; i < nelements; i++) {
if ((i & 0x01) == 0) {
flags = input[ipos++];
}
uint8_t flag = flags & INT8MASK(4);
diff = decodeDoubleValue(input, &ipos, flags & 0x0f);
flags >>= 4;
uint64_t diff = decodeDoubleValue(input, &ipos, flag);
union {
uint64_t bits;
double real;
} curr;
uint64_t predicted = prev_value;
curr.bits = predicted ^ diff;
prev_value = curr.bits;
curr.bits ^= diff;
ostream[opos++] = curr.real;
}