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/ecp.c b/library/ecp.c
index ecea591..db36191 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -1046,25 +1046,29 @@
#define INC_MUL_COUNT
#endif
-#define MOD_MUL( N ) do { MBEDTLS_MPI_CHK( ecp_modp( &N, grp ) ); INC_MUL_COUNT } \
- while( 0 )
+#define MOD_MUL( N ) \
+ do \
+ { \
+ MBEDTLS_MPI_CHK( ecp_modp( &(N), grp ) ); \
+ INC_MUL_COUNT \
+ } while( 0 )
/*
* Reduce a mbedtls_mpi mod p in-place, to use after mbedtls_mpi_sub_mpi
* N->s < 0 is a very fast test, which fails only if N is 0
*/
-#define MOD_SUB( N ) \
- while( N.s < 0 && mbedtls_mpi_cmp_int( &N, 0 ) != 0 ) \
- MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &N, &N, &grp->P ) )
+#define MOD_SUB( N ) \
+ while( (N).s < 0 && mbedtls_mpi_cmp_int( &(N), 0 ) != 0 ) \
+ MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &(N), &(N), &grp->P ) )
/*
* Reduce a mbedtls_mpi mod p in-place, to use after mbedtls_mpi_add_mpi and mbedtls_mpi_mul_int.
* We known P, N and the result are positive, so sub_abs is correct, and
* a bit faster.
*/
-#define MOD_ADD( N ) \
- while( mbedtls_mpi_cmp_mpi( &N, &grp->P ) >= 0 ) \
- MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( &N, &N, &grp->P ) )
+#define MOD_ADD( N ) \
+ while( mbedtls_mpi_cmp_mpi( &(N), &grp->P ) >= 0 ) \
+ MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( &(N), &(N), &grp->P ) )
#if defined(ECP_SHORTWEIERSTRASS)
/*