mirror of https://github.com/dnomd343/md5sum.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
60 lines
1.5 KiB
60 lines
1.5 KiB
#include <cstring>
|
|
|
|
#include "md5.h"
|
|
|
|
namespace md5 {
|
|
|
|
static constexpr unsigned char Padding[64] { 0x80, /* 0x00, ... */ };
|
|
|
|
const void* MD5::UpdateImpl(const void *data, uint64_t len) {
|
|
auto *block = static_cast<const uint32_t *>(data);
|
|
auto *limit = block + ((len &= ~0b111111ULL) >> 2);
|
|
|
|
auto A = ctx_.A;
|
|
auto B = ctx_.B;
|
|
auto C = ctx_.C;
|
|
auto D = ctx_.D;
|
|
|
|
while (block < limit) {
|
|
auto A_ = A;
|
|
auto B_ = B;
|
|
auto C_ = C;
|
|
auto D_ = D;
|
|
MD5_UPDATE
|
|
A += A_;
|
|
B += B_;
|
|
C += C_;
|
|
D += D_;
|
|
block += 16; // move to next block
|
|
}
|
|
|
|
ctx_.A = A;
|
|
ctx_.B = B;
|
|
ctx_.C = C;
|
|
ctx_.D = D;
|
|
ctx_.size += len;
|
|
return static_cast<const void *>(limit);
|
|
}
|
|
|
|
void MD5::FinalImpl(const void *data, uint64_t len) {
|
|
if (len >= 120) { // len -> [64 + 56, INF)
|
|
data = UpdateImpl(data, len);
|
|
len &= 0b111111; // len -> [0, 64)
|
|
}
|
|
|
|
unsigned char buffer[128]; // 2 blocks
|
|
std::memcpy(buffer, data, len);
|
|
uint64_t total = (ctx_.size + len) << 3; // total number in bit
|
|
|
|
if (len < 56) { // len -> [0, 56)
|
|
std::memcpy(buffer + len, Padding, 56 - len);
|
|
std::memcpy(buffer + 56, &total, 8);
|
|
UpdateImpl(buffer, 64); // update 1 block
|
|
} else { // len -> [56, 64 + 56)
|
|
std::memcpy(buffer + len, Padding, 120 - len);
|
|
std::memcpy(buffer + 120, &total, 8);
|
|
UpdateImpl(buffer, 128); // update 2 blocks
|
|
}
|
|
}
|
|
|
|
} // namespace md5
|
|
|