class Digest::Base

This abstract class provides a common interface to message digest implementation classes written in C.

Write a Digest subclass in C

Digest::Base provides a common interface to message digest classes written in C. These classes must provide a struct of type rb_digest_metadata_t: typedef int (rb_digest_hash_init_func_t)(void ); typedef void (rb_digest_hash_update_func_t)(void , unsigned char , size_t); typedef int (rb_digest_hash_finish_func_t)(void , unsigned char );

typedef struct {
  int api_version;
  size_t digest_len;
  size_t block_len;
  size_t ctx_size;
  rb_digest_hash_init_func_t init_func;
  rb_digest_hash_update_func_t update_func;
  rb_digest_hash_finish_func_t finish_func;
} rb_digest_metadata_t;

This structure must be set as an instance variable named metadata (without the +@+ in front of the name). By example: static const rb_digest_metadata_t sha1 = { RUBY_DIGEST_API_VERSION, SHA1_DIGEST_LENGTH, SHA1_BLOCK_LENGTH, sizeof(SHA1_CTX), (rb_digest_hash_init_func_t)SHA1_Init, (rb_digest_hash_update_func_t)SHA1_Update, (rb_digest_hash_finish_func_t)SHA1_Finish, };

rb_ivar_set(cDigest_SHA1, rb_intern("metadata"),
            rb_digest_make_metadata(&sha1));