Move mbedtls_ct_base64_(enc|dec)_char into base64.c
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/base64.c b/library/base64.c
index 3eb9e7c..3f13fda 100644
--- a/library/base64.c
+++ b/library/base64.c
@@ -33,6 +33,39 @@
#include "mbedtls/platform.h"
#endif /* MBEDTLS_SELF_TEST */
+MBEDTLS_STATIC_TESTABLE
+unsigned char mbedtls_ct_base64_enc_char(unsigned char value)
+{
+ unsigned char digit = 0;
+ /* For each range of values, if value is in that range, mask digit with
+ * the corresponding value. Since value can only be in a single range,
+ * only at most one masking will change digit. */
+ digit |= mbedtls_ct_uchar_mask_of_range(0, 25, value) & ('A' + value);
+ digit |= mbedtls_ct_uchar_mask_of_range(26, 51, value) & ('a' + value - 26);
+ digit |= mbedtls_ct_uchar_mask_of_range(52, 61, value) & ('0' + value - 52);
+ digit |= mbedtls_ct_uchar_mask_of_range(62, 62, value) & '+';
+ digit |= mbedtls_ct_uchar_mask_of_range(63, 63, value) & '/';
+ return digit;
+}
+
+MBEDTLS_STATIC_TESTABLE
+signed char mbedtls_ct_base64_dec_value(unsigned char c)
+{
+ unsigned char val = 0;
+ /* For each range of digits, if c is in that range, mask val with
+ * the corresponding value. Since c can only be in a single range,
+ * only at most one masking will change val. Set val to one plus
+ * the desired value so that it stays 0 if c is in none of the ranges. */
+ val |= mbedtls_ct_uchar_mask_of_range('A', 'Z', c) & (c - 'A' + 0 + 1);
+ val |= mbedtls_ct_uchar_mask_of_range('a', 'z', c) & (c - 'a' + 26 + 1);
+ val |= mbedtls_ct_uchar_mask_of_range('0', '9', c) & (c - '0' + 52 + 1);
+ val |= mbedtls_ct_uchar_mask_of_range('+', '+', c) & (c - '+' + 62 + 1);
+ val |= mbedtls_ct_uchar_mask_of_range('/', '/', c) & (c - '/' + 63 + 1);
+ /* At this point, val is 0 if c is an invalid digit and v+1 if c is
+ * a digit with the value v. */
+ return val - 1;
+}
+
/*
* Encode a buffer into base64 format
*/