lib/got_lib_hash.h

   1 /*
   2  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #define GOT_SHA1_STRING_ZERO "0000000000000000000000000000000000000000"
  18 #define GOT_SHA256_STRING_ZERO "0000000000000000000000000000000000000000000000000000000000000000"
  19
  20 #define GOT_HASH_DIGEST_MAXLEN SHA256_DIGEST_LENGTH
  21
  22 int got_parse_xdigit(uint8_t *, const char *);
  23
  24 char *got_sha1_digest_to_str(const uint8_t *, char *, size_t);
  25 char *got_sha256_digest_to_str(const uint8_t *, char *, size_t);
  26
  27 int got_parse_hash_digest(uint8_t *, const char *, enum got_hash_algorithm);
  28
  29 /*
  30  * Write the string representation fo an object ID in the given buffer.
  31  * This buffer must be at least GOT_OBJECT_ID_HEX_MAXLEN bytes in size.
  32  * The output depneds on the hash function used by the repository format.
  33  */
  34 char *got_object_id_hex(struct got_object_id *, char *, size_t);
  35
  36 int got_parse_object_id(struct got_object_id *, const char *,
  37     enum got_hash_algorithm);
  38
  39 static inline int
  40 got_hash_digest_length(enum got_hash_algorithm algo)
  41 {
  42         switch (algo) {
  43         case GOT_HASH_SHA1:
  44                 return SHA1_DIGEST_LENGTH;
  45         case GOT_HASH_SHA256:
  46                 return SHA256_DIGEST_LENGTH;
  47         default:
  48                 return 0;
  49         }
  50 }
  51
  52 static inline int
  53 got_hash_digest_string_length(enum got_hash_algorithm algo)
  54 {
  55         switch (algo) {
  56         case GOT_HASH_SHA1:
  57                 return SHA1_DIGEST_STRING_LENGTH;
  58         case GOT_HASH_SHA256:
  59                 return SHA256_DIGEST_STRING_LENGTH;
  60         default:
  61                 return 0;
  62         }
  63 }
  64
  65 struct got_hash {
  66         SHA1_CTX                 sha1_ctx;
  67         SHA2_CTX                 sha256_ctx;
  68         enum got_hash_algorithm  algo;
  69 };
  70
  71 /*
  72  * These functions allow to compute and check hashes.
  73  * The hash function used is specified during got_hash_init.
  74  * Data can be added with got_hash_update and, once done, the checksum
  75  * saved in a buffer long at least GOT_HASH_DIGEST_MAXLEN bytes with
  76  * got_hash_final or in an got_object_id with got_hash_final_object_id.
  77  */
  78 void    got_hash_init(struct got_hash *, enum got_hash_algorithm);
  79 void    got_hash_update(struct got_hash *, const void *, size_t);
  80 void    got_hash_final(struct got_hash *, uint8_t *);
  81 void    got_hash_final_object_id(struct got_hash *, struct got_object_id *);
  82
  83 /*
  84  * Compare two hash digest; similar to memcmp().
  85  */
  86 int     got_hash_cmp(enum got_hash_algorithm, uint8_t *, uint8_t *);