Small ffi fixes

Constify arg to botan_pk_op_decrypt, and correct comment on
botan_mp_is_positive, which returns true even for zero.

Considered changing botan_mp_is_positive to match the comment, and
return false for zero, but we already test that botan_mp_is_positive(0) == 1,
so I left it as is and fixed the comment.

2 files changed, 6 insertions, 4 deletions

diff --git a/src/lib/ffi/ffi.cpp b/src/lib/ffi/ffi.cpp
index b4f0412d6..7cf69efb3 100644
--- a/src/lib/ffi/ffi.cpp
+++ b/src/lib/ffi/ffi.cpp
@@ -1888,7 +1888,7 @@ int botan_pk_op_decrypt_destroy(botan_pk_op_decrypt_t op)
 
 int botan_pk_op_decrypt(botan_pk_op_decrypt_t op,
                         uint8_t out[], size_t* out_len,
-                        uint8_t ciphertext[], size_t ciphertext_len)
+                        const uint8_t ciphertext[], size_t ciphertext_len)
    {
    return BOTAN_FFI_DO(Botan::PK_Decryptor, op, o, {
       return write_vec_output(out, out_len, o.decrypt(ciphertext, ciphertext_len));
diff --git a/src/lib/ffi/ffi.h b/src/lib/ffi/ffi.h
index 76cdaa145..59e767385 100644
--- a/src/lib/ffi/ffi.h
+++ b/src/lib/ffi/ffi.h
@@ -529,12 +529,14 @@ BOTAN_DLL int botan_mp_from_bin(const botan_mp_t mp, const uint8_t vec[], size_t
 BOTAN_DLL int botan_mp_to_uint32(const botan_mp_t mp, uint32_t* val);
 
 /**
-* Return true iff mp is greater than 0
+* This function is not well named. Returns 1 iff mp is greater than
+* *or equal to* zero. Use botan_mp_is_negative to detect negative
+* numbers, botan_mp_is_zero to check for zero.
 */
 BOTAN_DLL int botan_mp_is_positive(const botan_mp_t mp);
 
 /**
-* Return true iff mp is less than 0
+* Return 1 iff mp is less than 0
 */
 BOTAN_DLL int botan_mp_is_negative(const botan_mp_t mp);
 
@@ -812,7 +814,7 @@ BOTAN_DLL int botan_pk_op_decrypt_destroy(botan_pk_op_decrypt_t op);
 
 BOTAN_DLL int botan_pk_op_decrypt(botan_pk_op_decrypt_t op,
                                   uint8_t out[], size_t* out_len,
-                                  uint8_t ciphertext[], size_t ciphertext_len);
+                                  const uint8_t ciphertext[], size_t ciphertext_len);
 
 /*
 * Signature Generation