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The naming convention around get_sha1_hex() and its friends is awkward these days, after "struct object_id" was introduced. There are three public functions around this area: * get_sha1_hex() - use the implied the_hash_algo, fill uchar * * get_oid_hex() - use the implied the_hash_algo, fill oid * * get_oid_hex_algop() - use the passed algop, fill oid * Between the latter two, the "_algop" suffix signals whether the the_hash_algo is used as the implied algorithm or the caller should pass an algorithm explicitly. That is very much understandable and is a good convention. Between the former two, however, the "SHA1" vs "OID" in the names differentiate in what type of variable the result is stored. We could argue that it makes sense to use "SHA1" to mean "flat byte buffer" to honor the historical practice in the days before "struct object_id" was invented, but the natural fourth friend of the above group would take an algop and fill a flat byte buffer, and it would be strange to name it get_sha1_hex_algop(). Do we use the passed in algo, or are we limited to SHA-1 ;-)? In fact, such a function exists, albeit as a private helper function used by the implementation of these functions, and is named a lot more sensibly: get_hash_hex_algop(). Correct the misnomer of get_sha1_hex() and use "hash", instead of "sha1", as "flat byte buffer that stores binary (as opposed to hexadecimal) representation of the hash". The four (2x2) friends now become: * get_hash_hex() - use the implied the_hash_algo, fill uchar * * get_oid_hex() - use the implied the_hash_algo, fill oid * * get_hash_hex_algop() - use the passed algop, fill uchar * * get_oid_hex_algop() - use the passed algop, fill oid * As there are only two remaining calls to get_sha1_hex() in the codebase right now, the blast radious of this change is fairly small. Signed-off-by: Junio C Hamano <gitster@pobox.com>
87 lines
3.4 KiB
C
87 lines
3.4 KiB
C
#ifndef HEX_H
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#define HEX_H
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#include "hash-ll.h"
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extern const signed char hexval_table[256];
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static inline unsigned int hexval(unsigned char c)
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{
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return hexval_table[c];
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}
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/*
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* Convert two consecutive hexadecimal digits into a char. Return a
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* negative value on error. Don't run over the end of short strings.
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*/
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static inline int hex2chr(const char *s)
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{
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unsigned int val = hexval(s[0]);
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return (val & ~0xf) ? val : (val << 4) | hexval(s[1]);
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}
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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_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 get_oid_hex, but for an arbitrary hash algorithm. */
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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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* Read `len` pairs of hexadecimal digits from `hex` and write the
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* values to `binary` as `len` bytes. Return 0 on success, or -1 if
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* the input does not consist of hex digits).
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*/
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int hex_to_bytes(unsigned char *binary, const char *hex, size_t len);
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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 *hash_to_hex(const unsigned char *hash); /* same static buffer */
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char *oid_to_hex(const struct object_id *oid); /* same static buffer */
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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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int parse_oid_hex(const char *hex, struct object_id *oid, const char **end);
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/* Like parse_oid_hex, but for an arbitrary hash algorithm. */
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int parse_oid_hex_algop(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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#endif
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