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Use aligned 64bit mask to improve performance (#52)

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This commit is contained in:
Tom Atkinson
2016-10-14 17:52:16 +02:00
committed by GitHub
parent 476effed77
commit e91cf2a790
1 changed files with 73 additions and 29 deletions
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src/bufferutil.cc
+73 -29
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@@ -65,21 +65,42 @@ protected:
{
Nan::HandleScope scope;
Local<Object> buffer_obj = info[0]->ToObject();
size_t length = Buffer::Length(buffer_obj);
Local<Object> mask_obj = info[1]->ToObject();
unsigned int *mask = (unsigned int*)Buffer::Data(mask_obj);
unsigned int* from = (unsigned int*)Buffer::Data(buffer_obj);
size_t len32 = length / 4;
unsigned int i;
for (i = 0; i < len32; ++i) *(from + i) ^= *mask;
from += i;
switch (length % 4) {
case 3: *((unsigned char*)from+2) = *((unsigned char*)from+2) ^ ((unsigned char*)mask)[2];
case 2: *((unsigned char*)from+1) = *((unsigned char*)from+1) ^ ((unsigned char*)mask)[1];
case 1: *((unsigned char*)from ) = *((unsigned char*)from ) ^ ((unsigned char*)mask)[0];
case 0:;
}
char* mask = Buffer::Data(mask_obj);
char* from = Buffer::Data(buffer_obj);
size_t length = Buffer::Length(buffer_obj);
info.GetReturnValue().Set(Nan::True());
/* Alignment preamble */
size_t index;
for (index = 0; index < length && (reinterpret_cast<size_t>(from) & 0x07); index++)
*from++ ^= mask[index % 4];
length -= index;
if (!length)
return;
/* Realign mask and convert to 64 bit */
char maskAlignedArray[8];
for (size_t i = 0; i < 8; i++, index++)
maskAlignedArray[i] = mask[index % 4];
/* Apply 64 bit mask in 8 byte chunks */
size_t loop = length / 8;
uint64_t* pSource8;
uint64_t* pMask8 = reinterpret_cast<uint64_t*>(maskAlignedArray);
while (loop--) {
pSource8 = reinterpret_cast<uint64_t*>(from);
*pSource8 ^= *pMask8;
from += 8;
}
/* Apply mask to remaining data */
char* pmaskAlignedArray = maskAlignedArray;
length &= 0x7;
while (length--)
*from++ ^= *pmaskAlignedArray++;
}
static NAN_METHOD(Mask)
@@ -87,24 +108,47 @@ protected:
Nan::HandleScope scope;
Local<Object> buffer_obj = info[0]->ToObject();
Local<Object> mask_obj = info[1]->ToObject();
unsigned int *mask = (unsigned int*)Buffer::Data(mask_obj);
Local<Object> output_obj = info[2]->ToObject();
unsigned int dataOffset = info[3]->Int32Value();
unsigned int length = info[4]->Int32Value();
unsigned int* to = (unsigned int*)(Buffer::Data(output_obj) + dataOffset);
unsigned int* from = (unsigned int*)Buffer::Data(buffer_obj);
unsigned int len32 = length / 4;
unsigned int i;
for (i = 0; i < len32; ++i) *(to + i) = *(from + i) ^ *mask;
to += i;
from += i;
switch (length % 4) {
case 3: *((unsigned char*)to+2) = *((unsigned char*)from+2) ^ *((unsigned char*)mask+2);
case 2: *((unsigned char*)to+1) = *((unsigned char*)from+1) ^ *((unsigned char*)mask+1);
case 1: *((unsigned char*)to ) = *((unsigned char*)from ) ^ *((unsigned char*)mask);
case 0:;
}
size_t dataOffset = info[3]->Int32Value();
size_t length = info[4]->Int32Value();
char* mask = Buffer::Data(mask_obj);
char* from = Buffer::Data(buffer_obj);
char* to = Buffer::Data(output_obj) + dataOffset;
info.GetReturnValue().Set(Nan::True());
/* Alignment preamble */
size_t index;
for (index = 0; index < length && (reinterpret_cast<size_t>(from) & 0x07); index++)
*to++ ^= mask[index % 4];
length -= index;
if (!length)
return;
/* Realign mask and convert to 64 bit */
char maskAlignedArray[8];
for (size_t i = 0; i < 8; i++, index++)
maskAlignedArray[i] = mask[index % 4];
/* Apply 64 bit mask in 8 byte chunks */
size_t loop = length / 8;
uint64_t* pFrom8;
uint64_t* pTo8;
uint64_t* pMask8 = reinterpret_cast<uint64_t*>(maskAlignedArray);
while (loop--) {
pFrom8 = reinterpret_cast<uint64_t*>(from);
pTo8 = reinterpret_cast<uint64_t*>(to);
*pTo8 = *pFrom8 ^ *pMask8;
from += 8;
to += 8;
}
/* Apply mask to remaining data */
char* pmaskAlignedArray = maskAlignedArray;
length &= 0x7;
while (length--)
*to++ = *from++ ^ *pmaskAlignedArray++;
}
};