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Crypto: Make AES call malloc much less often

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ByteBuffer::slice_view() allocates a new ByteBuffer object,
which as a RefPtr and everything.

Nowadays it should probably return a Bytes / Span<u8>, but AES was only
using slice_view() to extract the pointer again.  So just add ady a
range check at the top, and do pointer arithmetic to do the same thing
faster.

Reduces time to run `disasm /bin/id` by a bit under 40%,
from ~8.3s to ~5s (min-of-3 runs).
This commit is contained in:
Nico Weber 2020-08-11 09:30:04 -04:00 • committed by Andreas Kling
parent faab8a82cb
commit 8d3d0054ed
1 changed files with 9 additions and 8 deletions
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17
Libraries/LibCrypto/Cipher/AES.cpp
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@ -67,6 +67,7 @@ void AESCipherKey::expand_encrypt_key(const ByteBuffer& user_key, size_t bits)
ASSERT(!user_key.is_null());
ASSERT(is_valid_key_size(bits));
ASSERT(user_key.size() >= bits / 8);
round_key = round_keys();
@ -78,10 +79,10 @@ void AESCipherKey::expand_encrypt_key(const ByteBuffer& user_key, size_t bits)
m_rounds = 14;
}
round_key[0] = get_key(user_key.slice_view(0, 4).data());
round_key[1] = get_key(user_key.slice_view(4, 4).data());
round_key[2] = get_key(user_key.slice_view(8, 4).data());
round_key[3] = get_key(user_key.slice_view(12, 4).data());
round_key[0] = get_key(user_key.data());
round_key[1] = get_key(user_key.data() + 4);
round_key[2] = get_key(user_key.data() + 8);
round_key[3] = get_key(user_key.data() + 12);
if (bits == 128) {
for (;;) {
temp = round_key[3];
@ -103,8 +104,8 @@ void AESCipherKey::expand_encrypt_key(const ByteBuffer& user_key, size_t bits)
return;
}
round_key[4] = get_key(user_key.slice_view(16, 4).data());
round_key[5] = get_key(user_key.slice_view(20, 4).data());
round_key[4] = get_key(user_key.data() + 16);
round_key[5] = get_key(user_key.data() + 20);
if (bits == 192) {
for (;;) {
temp = round_key[5];
@ -131,8 +132,8 @@ void AESCipherKey::expand_encrypt_key(const ByteBuffer& user_key, size_t bits)
return;
}
round_key[6] = get_key(user_key.slice_view(24, 4).data());
round_key[7] = get_key(user_key.slice_view(28, 4).data());
round_key[6] = get_key(user_key.data() + 24);
round_key[7] = get_key(user_key.data() + 28);
if (true) { // bits == 256
for (;;) {
temp = round_key[7];