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#define NAPI_VERSION 1
#include <assert.h>
#include <node_api.h>
napi_value Mask(napi_env env, napi_callback_info info) {
napi_status status;
size_t argc = 5;
napi_value argv[5];
status = napi_get_cb_info(env, info, &argc, argv, NULL, NULL);
assert(status == napi_ok);
uint8_t *source;
uint8_t *mask;
uint8_t *destination;
uint32_t offset;
uint32_t length;
status = napi_get_buffer_info(env, argv[0], (void **)&source, NULL);
assert(status == napi_ok);
status = napi_get_buffer_info(env, argv[1], (void **)&mask, NULL);
assert(status == napi_ok);
status = napi_get_buffer_info(env, argv[2], (void **)&destination, NULL);
assert(status == napi_ok);
status = napi_get_value_uint32(env, argv[3], &offset);
assert(status == napi_ok);
status = napi_get_value_uint32(env, argv[4], &length);
assert(status == napi_ok);
destination += offset;
uint32_t index = 0;
//
// Alignment preamble.
//
while (index < length && ((size_t)source % 8)) {
*destination++ = *source++ ^ mask[index % 4];
index++;
}
length -= index;
if (!length)
return NULL;
//
// Realign mask and convert to 64 bit.
//
uint8_t maskAlignedArray[8];
for (uint8_t i = 0; i < 8; i++, index++) {
maskAlignedArray[i] = mask[index % 4];
}
//
// Apply 64 bit mask in 8 byte chunks.
//
uint32_t loop = length / 8;
uint64_t *pMask8 = (uint64_t *)maskAlignedArray;
while (loop--) {
uint64_t *pFrom8 = (uint64_t *)source;
uint64_t *pTo8 = (uint64_t *)destination;
*pTo8 = *pFrom8 ^ *pMask8;
source += 8;
destination += 8;
}
//
// Apply mask to remaining data.
//
uint8_t *pmaskAlignedArray = maskAlignedArray;
length %= 8;
while (length--) {
*destination++ = *source++ ^ *pmaskAlignedArray++;
}
return NULL;
}
napi_value Unmask(napi_env env, napi_callback_info info) {
napi_status status;
size_t argc = 2;
napi_value argv[2];
status = napi_get_cb_info(env, info, &argc, argv, NULL, NULL);
assert(status == napi_ok);
uint8_t *source;
size_t length;
uint8_t *mask;
status = napi_get_buffer_info(env, argv[0], (void **)&source, &length);
assert(status == napi_ok);
status = napi_get_buffer_info(env, argv[1], (void **)&mask, NULL);
assert(status == napi_ok);
uint32_t index = 0;
//
// Alignment preamble.
//
while (index < length && ((size_t)source % 8)) {
*source++ ^= mask[index % 4];
index++;
}
length -= index;
if (!length)
return NULL;
//
// Realign mask and convert to 64 bit.
//
uint8_t maskAlignedArray[8];
for (uint8_t i = 0; i < 8; i++, index++) {
maskAlignedArray[i] = mask[index % 4];
}
//
// Apply 64 bit mask in 8 byte chunks.
//
uint32_t loop = length / 8;
uint64_t *pMask8 = (uint64_t *)maskAlignedArray;
while (loop--) {
uint64_t *pSource8 = (uint64_t *)source;
*pSource8 ^= *pMask8;
source += 8;
}
//
// Apply mask to remaining data.
//
uint8_t *pmaskAlignedArray = maskAlignedArray;
length %= 8;
while (length--) {
*source++ ^= *pmaskAlignedArray++;
}
return NULL;
}
napi_value Init(napi_env env, napi_value exports) {
napi_status status;
napi_value mask;
napi_value unmask;
status = napi_create_function(env, NULL, 0, Mask, NULL, &mask);
assert(status == napi_ok);
status = napi_create_function(env, NULL, 0, Unmask, NULL, &unmask);
assert(status == napi_ok);
status = napi_set_named_property(env, exports, "mask", mask);
assert(status == napi_ok);
status = napi_set_named_property(env, exports, "unmask", unmask);
assert(status == napi_ok);
return exports;
}
NAPI_MODULE(NODE_GYP_MODULE_NAME, Init)
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