stupidgcm: introduce stupidAEADCommon and use for both chacha & gcm

Nice deduplication and brings the GCM decrypt speed up to par.

internal/speed$ benchstat old new
name                old time/op   new time/op   delta
StupidGCM-4          4.71µs ± 0%   4.66µs ± 0%   -0.99%  (p=0.008 n=5+5)
StupidGCMDecrypt-4   5.77µs ± 1%   4.51µs ± 0%  -21.80%  (p=0.008 n=5+5)

name                old speed     new speed     delta
StupidGCM-4         870MB/s ± 0%  879MB/s ± 0%   +1.01%  (p=0.008 n=5+5)
StupidGCMDecrypt-4  710MB/s ± 1%  908MB/s ± 0%  +27.87%  (p=0.008 n=5+5)

1 files changed, 0 insertions, 32 deletions

diff --git a/internal/stupidgcm/chacha.h b/internal/stupidgcm/chacha.h
deleted file mode 100644
index a5eac04..0000000
--- a/internal/stupidgcm/chacha.h
+++ /dev/null
@@ -1,32 +0,0 @@
-enum aeadType {
-    aeadTypeChacha = 1,
-    aeadTypeGcm = 2,
-};
-
-int aead_seal(
-    const enum aeadType cipherId,
-    const unsigned char* const plaintext,
-    const int plaintextLen,
-    const unsigned char* const authData,
-    const int authDataLen,
-    const unsigned char* const key,
-    const int keyLen,
-    const unsigned char* const iv,
-    const int ivLen,
-    unsigned char* const ciphertext,
-    const int ciphertextBufLen);
-
-int aead_open(
-    const enum aeadType cipherId,
-    const unsigned char* const ciphertext,
-    const int ciphertextLen,
-    const unsigned char* const authData,
-    const int authDataLen,
-    unsigned char* const tag,
-    const int tagLen,
-    const unsigned char* const key,
-    const int keyLen,
-    const unsigned char* const iv,
-    const int ivLen,
-    unsigned char* const plaintext,
-    const int plaintextBufLen);