git/sha256/gcrypt.h
brian m. carlson 768e30ea27 hash: implement and use a context cloning function
For all of our SHA-1 implementations and most of our SHA-256
implementations, the hash context we use is a real struct.  For these
implementations, it's possible to copy a hash context by making a copy
of the struct.

However, for our libgcrypt implementation, our hash context is a
pointer.  Consequently, copying it does not lead to an independent hash
context like we intended.

Fortunately, however, libgcrypt provides us with a handy function to
copy hash contexts.  Let's add a cloning function to the hash algorithm
API, and use it in the one place we need to make a hash context copy.
With this change, our libgcrypt SHA-256 implementation is fully
functional with all of our other hash implementations.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-24 09:33:21 -08:00

37 lines
894 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);
}
inline void gcrypt_SHA256_Clone(gcrypt_SHA256_CTX *dst, const gcrypt_SHA256_CTX *src)
{
gcry_md_copy(dst, *src);
}
#define platform_SHA256_CTX gcrypt_SHA256_CTX
#define platform_SHA256_Init gcrypt_SHA256_Init
#define platform_SHA256_Clone gcrypt_SHA256_Clone
#define platform_SHA256_Update gcrypt_SHA256_Update
#define platform_SHA256_Final gcrypt_SHA256_Final
#endif