#ifndef HASH_H
#define HASH_H
+#include "git-compat-util.h"
+#include "repository.h"
+
+#if defined(SHA1_PPC)
+#include "ppc/sha1.h"
+#elif defined(SHA1_APPLE)
+#include <CommonCrypto/CommonDigest.h>
+#elif defined(SHA1_OPENSSL)
+#include <openssl/sha.h>
+#elif defined(SHA1_DC)
+#include "sha1dc_git.h"
+#else /* SHA1_BLK */
+#include "block-sha1/sha1.h"
+#endif
+
+#if defined(SHA256_GCRYPT)
+#define SHA256_NEEDS_CLONE_HELPER
+#include "sha256/gcrypt.h"
+#elif defined(SHA256_OPENSSL)
+#include <openssl/sha.h>
+#else
+#include "sha256/block/sha256.h"
+#endif
+
+#ifndef platform_SHA_CTX
/*
- * These are some simple generic hash table helper functions.
- * Not necessarily suitable for all users, but good for things
- * where you want to just keep track of a list of things, and
- * have a good hash to use on them.
- *
- * It keeps the hash table at roughly 50-75% free, so the memory
- * cost of the hash table itself is roughly
- *
- * 3 * 2*sizeof(void *) * nr_of_objects
- *
- * bytes.
- *
- * FIXME: on 64-bit architectures, we waste memory. It would be
- * good to have just 32-bit pointers, requiring a special allocator
- * for hashed entries or something.
+ * 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.
*/
-struct hash_table_entry {
- unsigned int hash;
- void *ptr;
+#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
+
+#ifndef platform_SHA256_CTX
+#define platform_SHA256_CTX SHA256_CTX
+#define platform_SHA256_Init SHA256_Init
+#define platform_SHA256_Update SHA256_Update
+#define platform_SHA256_Final SHA256_Final
+#endif
+
+#define git_SHA256_CTX platform_SHA256_CTX
+#define git_SHA256_Init platform_SHA256_Init
+#define git_SHA256_Update platform_SHA256_Update
+#define git_SHA256_Final platform_SHA256_Final
+
+#ifdef platform_SHA256_Clone
+#define git_SHA256_Clone platform_SHA256_Clone
+#endif
+
+#ifdef SHA1_MAX_BLOCK_SIZE
+#include "compat/sha1-chunked.h"
+#undef git_SHA1_Update
+#define git_SHA1_Update git_SHA1_Update_Chunked
+#endif
+
+static inline void git_SHA1_Clone(git_SHA_CTX *dst, const git_SHA_CTX *src)
+{
+ memcpy(dst, src, sizeof(*dst));
+}
+
+#ifndef SHA256_NEEDS_CLONE_HELPER
+static inline void git_SHA256_Clone(git_SHA256_CTX *dst, const git_SHA256_CTX *src)
+{
+ memcpy(dst, src, sizeof(*dst));
+}
+#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
+/* SHA-256 */
+#define GIT_HASH_SHA256 2
+/* Number of algorithms supported (including unknown). */
+#define GIT_HASH_NALGOS (GIT_HASH_SHA256 + 1)
+
+/* A suitably aligned type for stack allocations of hash contexts. */
+union git_hash_ctx {
+ git_SHA_CTX sha1;
+ git_SHA256_CTX sha256;
+};
+typedef union git_hash_ctx git_hash_ctx;
+
+typedef void (*git_hash_init_fn)(git_hash_ctx *ctx);
+typedef void (*git_hash_clone_fn)(git_hash_ctx *dst, const git_hash_ctx *src);
+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 block size of the hash. */
+ size_t blksz;
+
+ /* The hash initialization function. */
+ git_hash_init_fn init_fn;
+
+ /* The hash context cloning function. */
+ git_hash_clone_fn clone_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];
+
+/*
+ * Return a GIT_HASH_* constant based on the name. Returns GIT_HASH_UNKNOWN if
+ * the name doesn't match a known algorithm.
+ */
+int hash_algo_by_name(const char *name);
+/* Identical, except based on the format ID. */
+int hash_algo_by_id(uint32_t format_id);
+/* Identical, except based on the length. */
+int hash_algo_by_length(int len);
+/* Identical, except for a pointer to struct git_hash_algo. */
+static inline int hash_algo_by_ptr(const struct git_hash_algo *p)
+{
+ return p - hash_algos;
+}
+
+/* The length in bytes and in hex digits of an object name (SHA-1 value). */
+#define GIT_SHA1_RAWSZ 20
+#define GIT_SHA1_HEXSZ (2 * GIT_SHA1_RAWSZ)
+/* The block size of SHA-1. */
+#define GIT_SHA1_BLKSZ 64
+
+/* The length in bytes and in hex digits of an object name (SHA-256 value). */
+#define GIT_SHA256_RAWSZ 32
+#define GIT_SHA256_HEXSZ (2 * GIT_SHA256_RAWSZ)
+/* The block size of SHA-256. */
+#define GIT_SHA256_BLKSZ 64
-struct hash_table {
- unsigned int size, nr;
- struct hash_table_entry *array;
+/* The length in byte and in hex digits of the largest possible hash value. */
+#define GIT_MAX_RAWSZ GIT_SHA256_RAWSZ
+#define GIT_MAX_HEXSZ GIT_SHA256_HEXSZ
+/* The largest possible block size for any supported hash. */
+#define GIT_MAX_BLKSZ GIT_SHA256_BLKSZ
+
+struct object_id {
+ unsigned char hash[GIT_MAX_RAWSZ];
};
-extern void *lookup_hash(unsigned int hash, const struct hash_table *table);
-extern void **insert_hash(unsigned int hash, void *ptr, struct hash_table *table);
-extern int for_each_hash(const struct hash_table *table, int (*fn)(void *, void *), void *data);
-extern void free_hash(struct hash_table *table);
+#define the_hash_algo the_repository->hash_algo
+
+extern const struct object_id null_oid;
+
+static inline int hashcmp(const unsigned char *sha1, const unsigned char *sha2)
+{
+ /*
+ * Teach the compiler that there are only two possibilities of hash size
+ * here, so that it can optimize for this case as much as possible.
+ */
+ if (the_hash_algo->rawsz == GIT_MAX_RAWSZ)
+ return memcmp(sha1, sha2, GIT_MAX_RAWSZ);
+ return memcmp(sha1, sha2, GIT_SHA1_RAWSZ);
+}
+
+static inline int oidcmp(const struct object_id *oid1, const struct object_id *oid2)
+{
+ return hashcmp(oid1->hash, oid2->hash);
+}
+
+static inline int hasheq(const unsigned char *sha1, const unsigned char *sha2)
+{
+ /*
+ * We write this here instead of deferring to hashcmp so that the
+ * compiler can properly inline it and avoid calling memcmp.
+ */
+ if (the_hash_algo->rawsz == GIT_MAX_RAWSZ)
+ return !memcmp(sha1, sha2, GIT_MAX_RAWSZ);
+ return !memcmp(sha1, sha2, GIT_SHA1_RAWSZ);
+}
+
+static inline int oideq(const struct object_id *oid1, const struct object_id *oid2)
+{
+ return hasheq(oid1->hash, oid2->hash);
+}
+
+static inline int is_null_oid(const struct object_id *oid)
+{
+ return oideq(oid, &null_oid);
+}
+
+static inline void hashcpy(unsigned char *sha_dst, const unsigned char *sha_src)
+{
+ memcpy(sha_dst, sha_src, the_hash_algo->rawsz);
+}
+
+static inline void oidcpy(struct object_id *dst, const struct object_id *src)
+{
+ memcpy(dst->hash, src->hash, GIT_MAX_RAWSZ);
+}
-static inline void init_hash(struct hash_table *table)
+static inline struct object_id *oiddup(const struct object_id *src)
{
- table->size = 0;
- table->nr = 0;
- table->array = NULL;
+ struct object_id *dst = xmalloc(sizeof(struct object_id));
+ oidcpy(dst, src);
+ return dst;
}
+static inline void hashclr(unsigned char *hash)
+{
+ memset(hash, 0, the_hash_algo->rawsz);
+}
+
+static inline void oidclr(struct object_id *oid)
+{
+ memset(oid->hash, 0, GIT_MAX_RAWSZ);
+}
+
+static inline void oidread(struct object_id *oid, const unsigned char *hash)
+{
+ memcpy(oid->hash, hash, the_hash_algo->rawsz);
+}
+
+static inline int is_empty_blob_sha1(const unsigned char *sha1)
+{
+ return hasheq(sha1, the_hash_algo->empty_blob->hash);
+}
+
+static inline int is_empty_blob_oid(const struct object_id *oid)
+{
+ return oideq(oid, the_hash_algo->empty_blob);
+}
+
+static inline int is_empty_tree_sha1(const unsigned char *sha1)
+{
+ return hasheq(sha1, the_hash_algo->empty_tree->hash);
+}
+
+static inline int is_empty_tree_oid(const struct object_id *oid)
+{
+ return oideq(oid, the_hash_algo->empty_tree);
+}
+
+const char *empty_tree_oid_hex(void);
+const char *empty_blob_oid_hex(void);
+
#endif
projects / platform / upstream / git.git / blobdiff