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b212c0ca31
We moved away from SHA1_HEADER to a preprocessor if chain, but didn't update the comment discussing the platform defines. Update this comment so it reflects the current state of our codebase. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
102 lines
2.9 KiB
C
102 lines
2.9 KiB
C
#ifndef HASH_H
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#define HASH_H
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#include "git-compat-util.h"
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#if defined(SHA1_PPC)
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#include "ppc/sha1.h"
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#elif defined(SHA1_APPLE)
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#include <CommonCrypto/CommonDigest.h>
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#elif defined(SHA1_OPENSSL)
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#include <openssl/sha.h>
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#elif defined(SHA1_DC)
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#include "sha1dc_git.h"
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#else /* SHA1_BLK */
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#include "block-sha1/sha1.h"
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#endif
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#ifndef platform_SHA_CTX
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/*
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* platform's underlying implementation of SHA-1; could be OpenSSL,
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* blk_SHA, Apple CommonCrypto, etc... Note that the relevant
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* SHA-1 header may have already defined platform_SHA_CTX for our
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* own implementations like block-sha1 and ppc-sha1, so we list
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* the default for OpenSSL compatible SHA-1 implementations here.
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*/
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#define platform_SHA_CTX SHA_CTX
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#define platform_SHA1_Init SHA1_Init
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#define platform_SHA1_Update SHA1_Update
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#define platform_SHA1_Final SHA1_Final
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#endif
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#define git_SHA_CTX platform_SHA_CTX
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#define git_SHA1_Init platform_SHA1_Init
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#define git_SHA1_Update platform_SHA1_Update
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#define git_SHA1_Final platform_SHA1_Final
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#ifdef SHA1_MAX_BLOCK_SIZE
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#include "compat/sha1-chunked.h"
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#undef git_SHA1_Update
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#define git_SHA1_Update git_SHA1_Update_Chunked
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#endif
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/*
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* Note that these constants are suitable for indexing the hash_algos array and
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* comparing against each other, but are otherwise arbitrary, so they should not
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* be exposed to the user or serialized to disk. To know whether a
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* git_hash_algo struct points to some usable hash function, test the format_id
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* field for being non-zero. Use the name field for user-visible situations and
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* the format_id field for fixed-length fields on disk.
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*/
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/* An unknown hash function. */
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#define GIT_HASH_UNKNOWN 0
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/* SHA-1 */
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#define GIT_HASH_SHA1 1
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/* Number of algorithms supported (including unknown). */
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#define GIT_HASH_NALGOS (GIT_HASH_SHA1 + 1)
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/* A suitably aligned type for stack allocations of hash contexts. */
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union git_hash_ctx {
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git_SHA_CTX sha1;
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};
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typedef union git_hash_ctx git_hash_ctx;
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typedef void (*git_hash_init_fn)(git_hash_ctx *ctx);
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typedef void (*git_hash_update_fn)(git_hash_ctx *ctx, const void *in, size_t len);
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typedef void (*git_hash_final_fn)(unsigned char *hash, git_hash_ctx *ctx);
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struct git_hash_algo {
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/*
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* The name of the algorithm, as appears in the config file and in
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* messages.
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*/
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const char *name;
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/* A four-byte version identifier, used in pack indices. */
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uint32_t format_id;
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/* The length of the hash in binary. */
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size_t rawsz;
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/* The length of the hash in hex characters. */
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size_t hexsz;
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/* The hash initialization function. */
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git_hash_init_fn init_fn;
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/* The hash update function. */
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git_hash_update_fn update_fn;
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/* The hash finalization function. */
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git_hash_final_fn final_fn;
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/* The OID of the empty tree. */
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const struct object_id *empty_tree;
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/* The OID of the empty blob. */
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const struct object_id *empty_blob;
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};
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extern const struct git_hash_algo hash_algos[GIT_HASH_NALGOS];
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#endif
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