#ifndef HASH_H
#define HASH_H
+#include "git-compat-util.h"
+
#if defined(SHA1_PPC)
#include "ppc/sha1.h"
#elif defined(SHA1_APPLE)
#include "block-sha1/sha1.h"
#endif
+#ifndef platform_SHA_CTX
+/*
+ * platform's underlying implementation of SHA-1; could be OpenSSL,
+ * blk_SHA, Apple CommonCrypto, etc... Note that the relevant
+ * SHA-1 header may have already defined platform_SHA_CTX for our
+ * own implementations like block-sha1 and ppc-sha1, so we list
+ * the default for OpenSSL compatible SHA-1 implementations here.
+ */
+#define platform_SHA_CTX SHA_CTX
+#define platform_SHA1_Init SHA1_Init
+#define platform_SHA1_Update SHA1_Update
+#define platform_SHA1_Final SHA1_Final
+#endif
+
+#define git_SHA_CTX platform_SHA_CTX
+#define git_SHA1_Init platform_SHA1_Init
+#define git_SHA1_Update platform_SHA1_Update
+#define git_SHA1_Final platform_SHA1_Final
+
+#ifdef SHA1_MAX_BLOCK_SIZE
+#include "compat/sha1-chunked.h"
+#undef git_SHA1_Update
+#define git_SHA1_Update git_SHA1_Update_Chunked
+#endif
+
+/*
+ * Note that these constants are suitable for indexing the hash_algos array and
+ * comparing against each other, but are otherwise arbitrary, so they should not
+ * be exposed to the user or serialized to disk. To know whether a
+ * git_hash_algo struct points to some usable hash function, test the format_id
+ * field for being non-zero. Use the name field for user-visible situations and
+ * the format_id field for fixed-length fields on disk.
+ */
+/* An unknown hash function. */
+#define GIT_HASH_UNKNOWN 0
+/* SHA-1 */
+#define GIT_HASH_SHA1 1
+/* Number of algorithms supported (including unknown). */
+#define GIT_HASH_NALGOS (GIT_HASH_SHA1 + 1)
+
+/* A suitably aligned type for stack allocations of hash contexts. */
+union git_hash_ctx {
+ git_SHA_CTX sha1;
+};
+typedef union git_hash_ctx git_hash_ctx;
+
+typedef void (*git_hash_init_fn)(git_hash_ctx *ctx);
+typedef void (*git_hash_update_fn)(git_hash_ctx *ctx, const void *in, size_t len);
+typedef void (*git_hash_final_fn)(unsigned char *hash, git_hash_ctx *ctx);
+
+struct git_hash_algo {
+ /*
+ * The name of the algorithm, as appears in the config file and in
+ * messages.
+ */
+ const char *name;
+
+ /* A four-byte version identifier, used in pack indices. */
+ uint32_t format_id;
+
+ /* The length of the hash in binary. */
+ size_t rawsz;
+
+ /* The length of the hash in hex characters. */
+ size_t hexsz;
+
+ /* The hash initialization function. */
+ git_hash_init_fn init_fn;
+
+ /* The hash update function. */
+ git_hash_update_fn update_fn;
+
+ /* The hash finalization function. */
+ git_hash_final_fn final_fn;
+
+ /* The OID of the empty tree. */
+ const struct object_id *empty_tree;
+
+ /* The OID of the empty blob. */
+ const struct object_id *empty_blob;
+};
+extern const struct git_hash_algo hash_algos[GIT_HASH_NALGOS];
+
#endif