[FFmpeg-devel] [PATCH] add several "const" in aes.c/aes.h

[Reimar Döffinger]

Hello,
attached patch adds "const" in aes.c/aes.h where it is possible without
generating additional warnings.
I stumbled over this while investigating how ugly it would be to use the
same API for all encryption/decryption functions.

Greetings,
Reimar D?ffinger
-------------- next part --------------
Index: libavutil/aes.c
===================================================================
--- libavutil/aes.c	(revision 16844)
+++ libavutil/aes.c	(working copy)
@@ -47,12 +47,12 @@
 static uint32_t dec_multbl[4][256];
 #endif
 
-static inline void addkey(uint64_t dst[2], uint64_t src[2], uint64_t round_key[2]){
+static inline void addkey(uint64_t dst[2], const uint64_t src[2], const uint64_t round_key[2]){
     dst[0] = src[0] ^ round_key[0];
     dst[1] = src[1] ^ round_key[1];
 }
 
-static void subshift(uint8_t s0[2][16], int s, uint8_t *box){
+static void subshift(uint8_t s0[2][16], int s, const uint8_t *box){
     uint8_t (*s1)[16]= s0[0] - s;
     uint8_t (*s3)[16]= s0[0] + s;
     s0[0][0]=box[s0[1][ 0]]; s0[0][ 4]=box[s0[1][ 4]]; s0[0][ 8]=box[s0[1][ 8]]; s0[0][12]=box[s0[1][12]];
@@ -77,7 +77,7 @@
     ((uint32_t *)(state))[3] = mix_core(multbl, state[1][3][0], state[1][s1-1][1], state[1][1][2], state[1][s3-1][3]);
 }
 
-static inline void crypt(AVAES *a, int s, uint8_t *sbox, uint32_t *multbl){
+static inline void crypt(AVAES *a, int s, const uint8_t *sbox, const uint32_t *multbl){
     int r;
 
     for(r=a->rounds-1; r>0; r--){
@@ -87,7 +87,7 @@
     subshift(a->state[0][0], s, sbox);
 }
 
-void av_aes_crypt(AVAES *a, uint8_t *dst, uint8_t *src, int count, uint8_t *iv, int decrypt){
+void av_aes_crypt(AVAES *a, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt){
     while(count--){
         addkey(a->state[1], src, a->round_key[a->rounds]);
         if(decrypt) {
@@ -108,7 +108,7 @@
     }
 }
 
-static void init_multbl2(uint8_t tbl[1024], int c[4], uint8_t *log8, uint8_t *alog8, uint8_t *sbox){
+static void init_multbl2(uint8_t tbl[1024], const int c[4], const uint8_t *log8, const uint8_t *alog8, const uint8_t *sbox){
     int i, j;
     for(i=0; i<1024; i++){
         int x= sbox[i>>2];
@@ -146,8 +146,8 @@
             inv_sbox[j]= i;
             sbox    [i]= j;
         }
-        init_multbl2(dec_multbl[0], (int[4]){0xe, 0x9, 0xd, 0xb}, log8, alog8, inv_sbox);
-        init_multbl2(enc_multbl[0], (int[4]){0x2, 0x1, 0x1, 0x3}, log8, alog8, sbox);
+        init_multbl2(dec_multbl[0], (const int[4]){0xe, 0x9, 0xd, 0xb}, log8, alog8, inv_sbox);
+        init_multbl2(enc_multbl[0], (const int[4]){0x2, 0x1, 0x1, 0x3}, log8, alog8, sbox);
     }
 
     if(key_bits!=128 && key_bits!=192 && key_bits!=256)
Index: libavutil/aes.h
===================================================================
--- libavutil/aes.h	(revision 16844)
+++ libavutil/aes.h	(working copy)
@@ -42,6 +42,6 @@
  * @param iv initialization vector for CBC mode, if NULL then ECB will be used
  * @param decrypt 0 for encryption, 1 for decryption
  */
-void av_aes_crypt(struct AVAES *a, uint8_t *dst, uint8_t *src, int count, uint8_t *iv, int decrypt);
+void av_aes_crypt(struct AVAES *a, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt);
 
 #endif /* AVUTIL_AES_H */