Doc: write documentation for many macros and functions
As of this commit, all #identifier links in the documentation are resolved.
diff --git a/include/psa/crypto_sizes.h b/include/psa/crypto_sizes.h
index 574d3e5..ab5b17e 100644
--- a/include/psa/crypto_sizes.h
+++ b/include/psa/crypto_sizes.h
@@ -237,17 +237,69 @@
* sensible size or 0.
* If the parameters are not valid, the
* return value is unspecified.
- *
*/
#define PSA_ASYMMETRIC_SIGN_OUTPUT_SIZE(key_type, key_bits, alg) \
(PSA_KEY_TYPE_IS_RSA(key_type) ? ((void)alg, PSA_BITS_TO_BYTES(key_bits)) : \
PSA_KEY_TYPE_IS_ECC(key_type) ? PSA_ECDSA_SIGNATURE_SIZE(key_bits) : \
((void)alg, 0))
+/** Safe output buffer size for psa_asymmetric_encrypt().
+ *
+ * This macro returns a safe buffer size for a ciphertext produced using
+ * a key of the specified type and size, with the specified algorithm.
+ * Note that the actual size of the ciphertext may be smaller, depending
+ * on the algorithm.
+ *
+ * \warning This function may call its arguments multiple times or
+ * zero times, so you should not pass arguments that contain
+ * side effects.
+ *
+ * \param key_type An asymmetric key type (this may indifferently be a
+ * key pair type or a public key type).
+ * \param key_bits The size of the key in bits.
+ * \param alg The signature algorithm.
+ *
+ * \return If the parameters are valid and supported, return
+ * a buffer size in bytes that guarantees that
+ * psa_asymmetric_encrypt() will not fail with
+ * #PSA_ERROR_BUFFER_TOO_SMALL.
+ * If the parameters are a valid combination that is not supported
+ * by the implementation, this macro either shall return either a
+ * sensible size or 0.
+ * If the parameters are not valid, the
+ * return value is unspecified.
+ */
#define PSA_ASYMMETRIC_ENCRYPT_OUTPUT_SIZE(key_type, key_bits, alg) \
(PSA_KEY_TYPE_IS_RSA(key_type) ? \
((void)alg, PSA_BITS_TO_BYTES(key_bits)) : \
0)
+
+/** Safe output buffer size for psa_asymmetric_decrypt().
+ *
+ * This macro returns a safe buffer size for a ciphertext produced using
+ * a key of the specified type and size, with the specified algorithm.
+ * Note that the actual size of the ciphertext may be smaller, depending
+ * on the algorithm.
+ *
+ * \warning This function may call its arguments multiple times or
+ * zero times, so you should not pass arguments that contain
+ * side effects.
+ *
+ * \param key_type An asymmetric key type (this may indifferently be a
+ * key pair type or a public key type).
+ * \param key_bits The size of the key in bits.
+ * \param alg The signature algorithm.
+ *
+ * \return If the parameters are valid and supported, return
+ * a buffer size in bytes that guarantees that
+ * psa_asymmetric_decrypt() will not fail with
+ * #PSA_ERROR_BUFFER_TOO_SMALL.
+ * If the parameters are a valid combination that is not supported
+ * by the implementation, this macro either shall return either a
+ * sensible size or 0.
+ * If the parameters are not valid, the
+ * return value is unspecified.
+ */
#define PSA_ASYMMETRIC_DECRYPT_OUTPUT_SIZE(key_type, key_bits, alg) \
(PSA_KEY_TYPE_IS_RSA(key_type) ? \
PSA_BITS_TO_BYTES(key_bits) - PSA_RSA_MINIMUM_PADDING_SIZE(alg) : \