1 files changed, 45 insertions, 0 deletions
diff --git a/thirdparty/mbedtls/library/common.h b/thirdparty/mbedtls/library/common.h
index c06472418d..1663d50226 100644
--- a/thirdparty/mbedtls/library/common.h
+++ b/thirdparty/mbedtls/library/common.h
@@ -29,8 +29,15 @@
 #include "mbedtls/config.h"
 #endif
 
+#include <stddef.h>
 #include <stdint.h>
 
+/* Define `inline` on some non-C99-compliant compilers. */
+#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
+    !defined(inline) && !defined(__cplusplus)
+#define inline __inline
+#endif
+
 /** Helper to define a function as static except when building invasive tests.
  *
  * If a function is only used inside its own source file and should be
@@ -52,6 +59,44 @@
 #define MBEDTLS_STATIC_TESTABLE static
 #endif
 
+/** Return an offset into a buffer.
+ *
+ * This is just the addition of an offset to a pointer, except that this
+ * function also accepts an offset of 0 into a buffer whose pointer is null.
+ * (`p + n` has undefined behavior when `p` is null, even when `n == 0`.
+ * A null pointer is a valid buffer pointer when the size is 0, for example
+ * as the result of `malloc(0)` on some platforms.)
+ *
+ * \param p     Pointer to a buffer of at least n bytes.
+ *              This may be \p NULL if \p n is zero.
+ * \param n     An offset in bytes.
+ * \return      Pointer to offset \p n in the buffer \p p.
+ *              Note that this is only a valid pointer if the size of the
+ *              buffer is at least \p n + 1.
+ */
+static inline unsigned char *mbedtls_buffer_offset(
+    unsigned char *p, size_t n )
+{
+    return( p == NULL ? NULL : p + n );
+}
+
+/** Return an offset into a read-only buffer.
+ *
+ * Similar to mbedtls_buffer_offset(), but for const pointers.
+ *
+ * \param p     Pointer to a buffer of at least n bytes.
+ *              This may be \p NULL if \p n is zero.
+ * \param n     An offset in bytes.
+ * \return      Pointer to offset \p n in the buffer \p p.
+ *              Note that this is only a valid pointer if the size of the
+ *              buffer is at least \p n + 1.
+ */
+static inline const unsigned char *mbedtls_buffer_offset_const(
+    const unsigned char *p, size_t n )
+{
+    return( p == NULL ? NULL : p + n );
+}
+
 /** Byte Reading Macros
  *
  * Given a multi-byte integer \p x, MBEDTLS_BYTE_n retrieves the n-th