hex.h

   1 #ifndef HEX_H
   2 #define HEX_H
   3
   4 #include "hash.h"
   5
   6 extern const signed char hexval_table[256];
   7 static inline unsigned int hexval(unsigned char c)
   8 {
   9         return hexval_table[c];
  10 }
  11
  12 /*
  13  * Convert two consecutive hexadecimal digits into a char.  Return a
  14  * negative value on error.  Don't run over the end of short strings.
  15  */
  16 static inline int hex2chr(const char *s)
  17 {
  18         unsigned int val = hexval(s[0]);
  19         return (val & ~0xf) ? val : (val << 4) | hexval(s[1]);
  20 }
  21
  22 /*
  23  * Try to read a SHA1 in hexadecimal format from the 40 characters
  24  * starting at hex.  Write the 20-byte result to sha1 in binary form.
  25  * Return 0 on success.  Reading stops if a NUL is encountered in the
  26  * input, so it is safe to pass this function an arbitrary
  27  * null-terminated string.
  28  */
  29 int get_sha1_hex(const char *hex, unsigned char *sha1);
  30 int get_oid_hex(const char *hex, struct object_id *sha1);
  31
  32 /* Like get_oid_hex, but for an arbitrary hash algorithm. */
  33 int get_oid_hex_algop(const char *hex, struct object_id *oid, const struct git_hash_algo *algop);
  34
  35 /*
  36  * Read `len` pairs of hexadecimal digits from `hex` and write the
  37  * values to `binary` as `len` bytes. Return 0 on success, or -1 if
  38  * the input does not consist of hex digits).
  39  */
  40 int hex_to_bytes(unsigned char *binary, const char *hex, size_t len);
  41
  42 /*
  43  * Convert a binary hash in "unsigned char []" or an object name in
  44  * "struct object_id *" to its hex equivalent. The `_r` variant is reentrant,
  45  * and writes the NUL-terminated output to the buffer `out`, which must be at
  46  * least `GIT_MAX_HEXSZ + 1` bytes, and returns a pointer to out for
  47  * convenience.
  48  *
  49  * The non-`_r` variant returns a static buffer, but uses a ring of 4
  50  * buffers, making it safe to make multiple calls for a single statement, like:
  51  *
  52  *   printf("%s -> %s", hash_to_hex(one), hash_to_hex(two));
  53  *   printf("%s -> %s", oid_to_hex(one), oid_to_hex(two));
  54  */
  55 char *hash_to_hex_algop_r(char *buffer, const unsigned char *hash, const struct git_hash_algo *);
  56 char *oid_to_hex_r(char *out, const struct object_id *oid);
  57 char *hash_to_hex_algop(const unsigned char *hash, const struct git_hash_algo *);       /* static buffer result! */
  58 char *hash_to_hex(const unsigned char *hash);                                           /* same static buffer */
  59 char *oid_to_hex(const struct object_id *oid);                                          /* same static buffer */
  60
  61 /*
  62  * Parse a 40-character hexadecimal object ID starting from hex, updating the
  63  * pointer specified by end when parsing stops.  The resulting object ID is
  64  * stored in oid.  Returns 0 on success.  Parsing will stop on the first NUL or
  65  * other invalid character.  end is only updated on success; otherwise, it is
  66  * unmodified.
  67  */
  68 int parse_oid_hex(const char *hex, struct object_id *oid, const char **end);
  69
  70 /* Like parse_oid_hex, but for an arbitrary hash algorithm. */
  71 int parse_oid_hex_algop(const char *hex, struct object_id *oid, const char **end,
  72                         const struct git_hash_algo *algo);
  73
  74
  75 /*
  76  * These functions work like get_oid_hex and parse_oid_hex, but they will parse
  77  * a hex value for any algorithm. The algorithm is detected based on the length
  78  * and the algorithm in use is returned. If this is not a hex object ID in any
  79  * algorithm, returns GIT_HASH_UNKNOWN.
  80  */
  81 int get_oid_hex_any(const char *hex, struct object_id *oid);
  82 int parse_oid_hex_any(const char *hex, struct object_id *oid, const char **end);
  83
  84 #endif