Improve macro hygiene
This commit improves hygiene and formatting of macro definitions
throughout the library. Specifically:
- It adds brackets around parameters to avoid unintended
interpretation of arguments, e.g. due to operator precedence.
- It adds uses of the `do { ... } while( 0 )` idiom for macros that
can be used as commands.
diff --git a/library/ccm.c b/library/ccm.c
index 01e58b0..c6211ee 100644
--- a/library/ccm.c
+++ b/library/ccm.c
@@ -134,11 +134,17 @@
* This avoids allocating one more 16 bytes buffer while allowing src == dst.
*/
#define CTR_CRYPT( dst, src, len ) \
- if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctr, 16, b, &olen ) ) != 0 ) \
- return( ret ); \
- \
- for( i = 0; i < len; i++ ) \
- dst[i] = src[i] ^ b[i];
+ do \
+ { \
+ if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctr, \
+ 16, b, &olen ) ) != 0 ) \
+ { \
+ return( ret ); \
+ } \
+ \
+ for( i = 0; i < (len); i++ ) \
+ (dst)[i] = (src)[i] ^ b[i]; \
+ } while( 0 )
/*
* Authenticated encryption or decryption