Make mbedtls_cf_size_mask_lt function static
The mbedtls_cf_size_mask_lt is solely used as an auxiliary function
for mbedtls_cf_size_mask_ge.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
diff --git a/library/constant_time.c b/library/constant_time.c
index 9663612..e0eadac 100644
--- a/library/constant_time.c
+++ b/library/constant_time.c
@@ -103,8 +103,20 @@
#endif /* MBEDTLS_BIGNUM_C */
-size_t mbedtls_cf_size_mask_lt( size_t x,
- size_t y )
+/** Constant-flow mask generation for "less than" comparison:
+ * - if \p x < \p y, return all-bits 1, that is (size_t) -1
+ * - otherwise, return all bits 0, that is 0
+ *
+ * This function can be used to write constant-time code by replacing branches
+ * with bit operations using masks.
+ *
+ * \param x The first value to analyze.
+ * \param y The second value to analyze.
+ *
+ * \return All-bits-one if \p x is less than \p y, otherwise zero.
+ */
+static size_t mbedtls_cf_size_mask_lt( size_t x,
+ size_t y )
{
/* This has the most significant bit set if and only if x < y */
const size_t sub = x - y;
diff --git a/library/constant_time.h b/library/constant_time.h
index 3c7502f..336a151 100644
--- a/library/constant_time.h
+++ b/library/constant_time.h
@@ -104,24 +104,6 @@
#endif /* MBEDTLS_BIGNUM_C */
-/** Constant-flow mask generation for "less than" comparison:
- * - if \p x < \p y, return all-bits 1, that is (size_t) -1
- * - otherwise, return all bits 0, that is 0
- *
- * This function can be used to write constant-time code by replacing branches
- * with bit operations using masks.
- *
- * This function is implemented without using comparison operators, as those
- * might be translated to branches by some compilers on some platforms.
- *
- * \param x The first value to analyze.
- * \param y The second value to analyze.
- *
- * \return All-bits-one if \p x is less than \p y, otherwise zero.
- */
-size_t mbedtls_cf_size_mask_lt( size_t x,
- size_t y );
-
/** Constant-flow mask generation for "greater or equal" comparison:
* - if \p x >= \p y, return all-bits 1, that is (size_t) -1
* - otherwise, return all bits 0, that is 0