git/sha256/gcrypt.h
brian m. carlson 27dc04c545 sha256: add an SHA-256 implementation using libgcrypt
Generally, one gets better performance out of cryptographic routines
written in assembly than C, and this is also true for SHA-256.  In
addition, most Linux distributions cannot distribute Git linked against
OpenSSL for licensing reasons.

Most systems with GnuPG will also have libgcrypt, since it is a
dependency of GnuPG.  libgcrypt is also faster than the SHA1DC
implementation for messages of a few KiB and larger.

For comparison, on a Core i7-6600U, this implementation processes 16 KiB
chunks at 355 MiB/s while SHA1DC processes equivalent chunks at 337
MiB/s.

In addition, libgcrypt is licensed under the LGPL 2.1, which is
compatible with the GPL.  Add an implementation of SHA-256 that uses
libgcrypt.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-14 16:54:53 +09:00

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727 B
C

#ifndef SHA256_GCRYPT_H
#define SHA256_GCRYPT_H
#include <gcrypt.h>
#define SHA256_DIGEST_SIZE 32
typedef gcry_md_hd_t gcrypt_SHA256_CTX;
inline void gcrypt_SHA256_Init(gcrypt_SHA256_CTX *ctx)
{
gcry_md_open(ctx, GCRY_MD_SHA256, 0);
}
inline void gcrypt_SHA256_Update(gcrypt_SHA256_CTX *ctx, const void *data, size_t len)
{
gcry_md_write(*ctx, data, len);
}
inline void gcrypt_SHA256_Final(unsigned char *digest, gcrypt_SHA256_CTX *ctx)
{
memcpy(digest, gcry_md_read(*ctx, GCRY_MD_SHA256), SHA256_DIGEST_SIZE);
}
#define platform_SHA256_CTX gcrypt_SHA256_CTX
#define platform_SHA256_Init gcrypt_SHA256_Init
#define platform_SHA256_Update gcrypt_SHA256_Update
#define platform_SHA256_Final gcrypt_SHA256_Final
#endif