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Add a function for adding the full hexadecimal hash value of an object
ID to a strbuf. It's thread-safe and slightly more efficient than using
strbuf_addstr() with oid_to_hex() because it doesn't have to determine
the length of the string or copy it from the intermediate static buffer.
Add and apply a semantic patch to use it throughout the code base.
I get a tiny speedup for git log showing a single hash per commit:
Benchmark 1: ./git_main log --format=%H
Time (mean ± σ): 91.2 ms ± 0.7 ms [User: 51.9 ms, System: 38.6 ms]
Range (min … max): 89.8 ms … 92.6 ms 31 runs
Benchmark 2: ./git log --format=%H
Time (mean ± σ): 90.5 ms ± 0.7 ms [User: 51.0 ms, System: 38.8 ms]
Range (min … max): 89.2 ms … 92.3 ms 32 runs
Summary
./git log --format=%H ran
1.01 ± 0.01 times faster than ./git_main log --format=%H
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
78 lines
3.1 KiB
C
78 lines
3.1 KiB
C
#ifndef HEX_H
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#define HEX_H
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#include "hash.h"
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#include "hex-ll.h"
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/*
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* Try to read a hash (specified by the_hash_algo) in hexadecimal
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* format from the 40 (or whatever length the hash algorithm uses)
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* characters starting at hex. Write the 20-byte (or the length of
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* the hash) result to hash in binary form.
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* Return 0 on success. Reading stops if a NUL is encountered in the
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* input, so it is safe to pass this function an arbitrary
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* null-terminated string.
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*/
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int get_oid_hex_algop(const char *hex, struct object_id *oid, const struct git_hash_algo *algop);
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/*
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* Convert a binary hash in "unsigned char []" or an object name in
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* "struct object_id *" to its hex equivalent. The `_r` variant is reentrant,
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* and writes the NUL-terminated output to the buffer `out`, which must be at
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* least `GIT_MAX_HEXSZ + 1` bytes, and returns a pointer to out for
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* convenience.
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*
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* The non-`_r` variant returns a static buffer, but uses a ring of 4
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* buffers, making it safe to make multiple calls for a single statement, like:
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*
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* printf("%s -> %s", hash_to_hex(one), hash_to_hex(two));
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* printf("%s -> %s", oid_to_hex(one), oid_to_hex(two));
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*/
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char *hash_to_hex_algop_r(char *buffer, const unsigned char *hash, const struct git_hash_algo *);
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char *oid_to_hex_r(char *out, const struct object_id *oid);
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char *hash_to_hex_algop(const unsigned char *hash, const struct git_hash_algo *); /* static buffer result! */
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char *oid_to_hex(const struct object_id *oid); /* same static buffer */
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struct strbuf;
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/* Apply oid_to_hex_r() to a strbuf to append the hexadecimal hash. */
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void strbuf_add_oid_hex(struct strbuf *sb, const struct object_id *oid);
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/*
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* Parse a 40-character hexadecimal object ID starting from hex, updating the
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* pointer specified by end when parsing stops. The resulting object ID is
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* stored in oid. Returns 0 on success. Parsing will stop on the first NUL or
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* other invalid character. end is only updated on success; otherwise, it is
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* unmodified.
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*/
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#define parse_oid_hex_algop(hex, oid, end, algo) \
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parse_oid_hex_algop_impl((hex), (oid), CONST_OUTPARAM((hex), (end)), (algo))
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int parse_oid_hex_algop_impl(const char *hex, struct object_id *oid, const char **end,
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const struct git_hash_algo *algo);
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/*
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* These functions work like get_oid_hex and parse_oid_hex, but they will parse
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* a hex value for any algorithm. The algorithm is detected based on the length
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* and the algorithm in use is returned. If this is not a hex object ID in any
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* algorithm, returns GIT_HASH_UNKNOWN.
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*/
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int get_oid_hex_any(const char *hex, struct object_id *oid);
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int parse_oid_hex_any(const char *hex, struct object_id *oid, const char **end);
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#ifdef USE_THE_REPOSITORY_VARIABLE
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/* Like get_oid_hex_algop, but for `the_hash_algo`. */
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int get_hash_hex(const char *hex, unsigned char *hash);
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int get_oid_hex(const char *hex, struct object_id *oid);
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/* Like parse_oid_hex_algop, but uses `the_hash_algo`. */
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int parse_oid_hex(const char *hex, struct object_id *oid, const char **end);
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/*
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* Same as `hash_to_hex_algop()`, but uses `the_hash_algo`.
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*/
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char *hash_to_hex(const unsigned char *hash);
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#endif /* USE_THE_REPOSITORY_VARIABLE */
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#endif /* HEX_H */
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