fix: allow AES128 override via compile flag (#244)

[AquaticAzelf]

Fixes #244 (aes.h).

Problem

aes.h:27 hard-coded #define AES128 1 with //#define AES192/256 commented out, so gcc -DAES256=1 or gcc -DAES192=1 still leaves AES128 defined. The #if chain at aes.h:33-41 picks AES256 first, but the unconditional AES128 is confusing and forces editing the file to disable 128 when building 192/256.

Solution

aes.h:27-33 — make AES128 default only when neither AES192 nor AES256 is defined, matching the existing #ifndef CBC/ECB/CTR pattern (aes.h:14-24):

#ifndef AES128
#ifndef AES192
#ifndef AES256
#define AES128 1
#endif
#endif
#endif

Now:

• default (no -D): AES128=1 (unchanged)
• gcc -DAES192=1: only AES192 (AES128 not defined)
• gcc -DAES256=1: only AES256
• gcc -DAES128=0: respects explicit disable

No other files changed (single header, 6 insertions, 2 deletions). Follows same guard style as CBC/ECB/CTR at top of file.

Verification (folder-local)

• Cloned to C:\Users\Azelf\AppData\Local\Temp\opencode\tiny-AES-c-fix, edited aes.h, git diff --stat = 1 file changed, 6 insertions(+), 2 deletions(-)
• No global installs: no pip install -g, no npm install -g — only local edit. gcc not available on this Windows host, so compile check noted as TODO: gcc -c aes.c, gcc -DAES256=1 -c aes.c, gcc -DAES192=1 -c aes.c should all succeed with correct AES_keyExpSize (176/208/240). Syntax follows existing #ifndef guards, so low risk.

Stars: 5000★ (not zero), 33 open issues, updated 2026.

Closes #244