*: Simpler conversion to bytes

According to the cython documentation, indexing a C string returns a
copy as bytes.  Therefore, calling `bytes()` explicitely makes an extra,
unnecessary copy.

Author: Synss

src/mbedtls/_md.pyx

@@ -119,7 +119,7 @@ cdef class MDBase:
             raise MemoryError()
         try:
             check_error(self._finish(output))
-            return bytes(output[:self.digest_size])
+            return output[:self.digest_size]
         finally:
             free(output)
 

src/mbedtls/_random.pyx

@@ -42,7 +42,7 @@ cdef class _Entropy:
             raise MemoryError()
         try:
             check_error(_rnd.mbedtls_entropy_func(&self._ctx, output, length))
-            return bytes(output[:length])
+            return output[:length]
         finally:
             free(output)
 
@@ -90,7 +90,7 @@ cdef class Random:
             check_error(
                 _rnd.mbedtls_ctr_drbg_random(&self._ctx, output, length)
             )
-            ret = bytes(output[:length])
+            ret = output[:length]
             _plt.mbedtls_platform_zeroize(output, length)
             return ret
         finally:

src/mbedtls/cipher/_cipher.pyx

@@ -279,7 +279,7 @@ cdef class Cipher(_CipherBase):
                 &self._dec_ctx,
                 &iv[0] if iv.size else NULL, iv.size,
                 &input[0], input.size, output, &olen))
-            return bytes(output[:olen])
+            return output[:olen]
         finally:
             free(output)
 
@@ -325,7 +325,7 @@ cdef class AEADCipher(_CipherBase):
                 &iv[0], iv.size, pad, ad.size,
                 &input[0], input.size, output, &olen,
                 tag, sizeof(tag)))
-            return bytes(output[:olen]), bytes(tag[:16])
+            return output[:olen], tag[:16]
         finally:
             free(output)
 
@@ -354,7 +354,7 @@ cdef class AEADCipher(_CipherBase):
                 &iv[0], iv.size, pad, ad.size,
                 &input[0], input.size, output, &olen,
                 &tag[0], tag.size))
-            return bytes(output[:olen])
+            return output[:olen]
         finally:
             free(output)
 

src/mbedtls/hkdf.pyx

@@ -59,7 +59,7 @@ def hkdf(
             0 if info is None else info.size,
             okm, length
         ))
-        return bytes(okm[:length])
+        return okm[:length]
     finally:
         free(okm)
 
@@ -103,7 +103,7 @@ def extract(
             &key[0], key.size,
             prk
         ))
-        return bytes(prk[:hmac.digest_size])
+        return prk[:hmac.digest_size]
     finally:
         free(prk)
 
@@ -148,6 +148,6 @@ def expand(
             0 if info is None else info.size,
             okm, length
         ))
-        return bytes(okm[:length])
+        return okm[:length]
     finally:
         free(okm)

src/mbedtls/mpi.pyx

@@ -103,7 +103,7 @@ cdef class MPI:
         try:
             check_error(_mpi.mbedtls_mpi_write_binary(
                 &self._ctx, output, length))
-            return bytes(output[:length])[::-1 if byteorder == "little" else 1]
+            return output[:length][::-1 if byteorder == "little" else 1]
         except Exception as exc:
             raise OverflowError from exc
         finally:

src/mbedtls/pk.pyx

@@ -299,7 +299,7 @@ cdef class CipherBase:
                 &output[0], &sig_len,
                 &_rnd.mbedtls_ctr_drbg_random, &__rng._ctx))
             assert sig_len != 0
-            return bytes(output[:sig_len])
+            return output[:sig_len]
         finally:
             free(output)
 
@@ -348,7 +348,7 @@ cdef class CipherBase:
                 &self._ctx, &message[0], message.size,
                 output, &olen, self.key_size,
                 &_rnd.mbedtls_ctr_drbg_random, &__rng._ctx))
-            return bytes(output[:olen])
+            return output[:olen]
         finally:
             free(output)
 
@@ -371,7 +371,7 @@ cdef class CipherBase:
                 &self._ctx, &message[0], message.size,
                 output, &olen, self.key_size,
                 &_rnd.mbedtls_ctr_drbg_random, &__rng._ctx))
-            return bytes(output[:olen])
+            return output[:olen]
         finally:
             free(output)
 
@@ -396,7 +396,7 @@ cdef class CipherBase:
         try:
             olen = check_error(
                 _pk.mbedtls_pk_write_key_der(&self._ctx, output, osize))
-            return bytes(output[osize - olen:osize])
+            return output[osize - olen:osize]
         finally:
             free(output)
 
@@ -412,7 +412,7 @@ cdef class CipherBase:
         try:
             check_error(
                 _pk.mbedtls_pk_write_key_pem(&self._ctx, output, osize))
-            return bytes(output[0:osize]).decode("ascii")
+            return output[0:osize].decode("ascii")
         finally:
             free(output)
 
@@ -443,7 +443,7 @@ cdef class CipherBase:
         try:
             olen = check_error(
                 _pk.mbedtls_pk_write_pubkey_der(&self._ctx, output, osize))
-            return bytes(output[osize - olen:osize])
+            return output[osize - olen:osize]
         finally:
             free(output)
 
@@ -459,7 +459,7 @@ cdef class CipherBase:
         try:
             check_error(
                 _pk.mbedtls_pk_write_pubkey_pem(&self._ctx, output, osize))
-            return bytes(output[0:osize]).decode("ascii")
+            return output[0:osize].decode("ascii")
         finally:
             free(output)
 
@@ -845,7 +845,7 @@ cdef class DHServer(DHBase):
                 &self._ctx, self.key_size, &output[0], &olen,
                 &_rnd.mbedtls_ctr_drbg_random, &__rng._ctx))
             assert olen != 0
-            return bytes(output[:olen])
+            return output[:olen]
         finally:
             free(output)
 
@@ -1039,7 +1039,7 @@ cdef class ECDHServer(ECDHBase):
                 &self._ctx, &olen, &output[0], _mpi.MBEDTLS_MPI_MAX_SIZE,
                 &_rnd.mbedtls_ctr_drbg_random, &__rng._ctx))
             assert olen != 0
-            return bytes(output[:olen])
+            return output[:olen]
         finally:
             free(output)
 
@@ -1076,7 +1076,7 @@ cdef class ECDHClient(ECDHBase):
                 &self._ctx, &olen, &output[0], _mpi.MBEDTLS_MPI_MAX_SIZE,
                 &_rnd.mbedtls_ctr_drbg_random, &__rng._ctx))
             assert olen != 0
-            return bytes(output[:olen])
+            return output[:olen]
         finally:
             free(output)
 

src/mbedtls/x509.pyx

@@ -157,7 +157,7 @@ cdef class CRT(Certificate):
         try:
             written = check_error(x509.mbedtls_x509_crt_info(
                 &output[0], osize, prefix, &self._ctx))
-            return bytes(output[:written]).decode("utf8")
+            return output[:written].decode("utf8")
         finally:
             free(output)
 
@@ -239,7 +239,7 @@ cdef class CRT(Certificate):
         try:
             written = x509.mbedtls_x509_dn_gets(
                 &c_buf[0], osize, &self._ctx.issuer)
-            return bytes(c_buf[:written]).decode("utf8")
+            return c_buf[:written].decode("utf8")
         finally:
             free(c_buf)
 
@@ -284,7 +284,7 @@ cdef class CRT(Certificate):
         try:
             written = x509.mbedtls_x509_dn_gets(
                 &c_buf[0], osize, &self._ctx.subject)
-            return bytes(c_buf[:written]).decode("utf8")
+            return c_buf[:written].decode("utf8")
         finally:
             free(c_buf)
 
@@ -511,7 +511,7 @@ cdef class _CRTWriter:
         try:
             written = check_error(x509.mbedtls_x509write_crt_der(
                 &self._ctx, &output[0], osize, NULL, NULL))
-            return bytes(output[osize - written:osize])
+            return output[osize - written:osize]
         finally:
             free(output)
 
@@ -665,7 +665,7 @@ cdef class CSR(Certificate):
         try:
             written = check_error(x509.mbedtls_x509_csr_info(
                 &output[0], osize, prefix, &self._ctx))
-            return bytes(output[:written]).decode("utf8")
+            return output[:written].decode("utf8")
         finally:
             free(output)
 
@@ -705,7 +705,7 @@ cdef class CSR(Certificate):
         try:
             written = x509.mbedtls_x509_dn_gets(
                 &c_buf[0], osize, &self._ctx.subject)
-            return bytes(c_buf[:written]).decode("utf8")
+            return c_buf[:written].decode("utf8")
         finally:
             free(c_buf)
 
@@ -841,7 +841,7 @@ cdef class _CSRWriter:
         try:
             written = check_error(x509.mbedtls_x509write_csr_der(
                 &self._ctx, &output[0], osize, NULL, NULL))
-            return bytes(output[osize - written:osize])
+            return output[osize - written:osize]
         finally:
             free(output)
 
@@ -891,7 +891,7 @@ cdef class CRL(Certificate):
         try:
             written = check_error(x509.mbedtls_x509_crl_info(
                 &output[0], osize, prefix, &self._ctx))
-            return bytes(output[:written]).decode("utf8")
+            return output[:written].decode("utf8")
         finally:
             free(output)
 
@@ -948,7 +948,7 @@ cdef class CRL(Certificate):
         try:
             written = x509.mbedtls_x509_dn_gets(
                 &c_buf[0], osize, &self._ctx.issuer)
-            return bytes(c_buf[:written]).decode("utf8")
+            return c_buf[:written].decode("utf8")
         finally:
             free(c_buf)