Optimise unneccesary cf table accesses away

Also fix missed bare access of base_64_dec_map

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
This commit is contained in:
Paul Elliott 2021-03-01 18:33:09 +00:00
parent 86cb928e54
commit 6a66737433

View file

@ -238,6 +238,7 @@ int mbedtls_base64_decode( unsigned char *dst, size_t dlen, size_t *olen,
size_t i, n;
uint32_t j, x;
unsigned char *p;
unsigned char dec_map_lookup;
/* First pass: check for validity and get output length */
for( i = n = j = 0; i < slen; i++ )
@ -268,11 +269,12 @@ int mbedtls_base64_decode( unsigned char *dst, size_t dlen, size_t *olen,
if( src[i] == '=' && ++j > 2 )
return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER );
if( src[i] > 127 ||
mbedtls_base64_table_lookup( base64_dec_map, sizeof( base64_dec_map ), src[i] ) == 127 )
dec_map_lookup = mbedtls_base64_table_lookup( base64_dec_map, sizeof( base64_dec_map ), src[i] );
if( src[i] > 127 || dec_map_lookup == 127 )
return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER );
if( base64_dec_map[src[i]] < 64 && j != 0 )
if( dec_map_lookup < 64 && j != 0 )
return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER );
n++;
@ -302,9 +304,10 @@ int mbedtls_base64_decode( unsigned char *dst, size_t dlen, size_t *olen,
if( *src == '\r' || *src == '\n' || *src == ' ' )
continue;
j -= ( mbedtls_base64_table_lookup(base64_dec_map, sizeof( base64_dec_map ), *src ) == 64 );
x = ( x << 6 ) |
( mbedtls_base64_table_lookup( base64_dec_map, sizeof( base64_dec_map ), *src ) & 0x3F );
dec_map_lookup = mbedtls_base64_table_lookup(base64_dec_map, sizeof( base64_dec_map ), *src );
j -= ( dec_map_lookup == 64 );
x = ( x << 6 ) | ( dec_map_lookup & 0x3F );
if( ++n == 4 )
{