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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"),
            Data_Wrap_Struct(0, 0, 0, (void *)&sha1));
Methods
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Instance Public methods

digest_base << string → digest_base

Update the digest using given string and return self.

Alias for: update

digest_base.block_length → Integer

Return the block length of the digest in bytes.

Source: show 

static VALUE
rb_digest_base_block_length(VALUE self)
{
    rb_digest_metadata_t *algo;

    algo = get_digest_obj_metadata(self);

    return SIZET2NUM(algo->block_len);
}

digest_base.digest_length → Integer

Return the length of the hash value in bytes.

Source: show 

static VALUE
rb_digest_base_digest_length(VALUE self)
{
    rb_digest_metadata_t *algo;

    algo = get_digest_obj_metadata(self);

    return SIZET2NUM(algo->digest_len);
}

digest_base.reset → digest_base

Reset the digest to its initial state and return self.

Source: show 

static VALUE
rb_digest_base_reset(VALUE self)
{
    rb_digest_metadata_t *algo;
    void *pctx;

    algo = get_digest_obj_metadata(self);

    TypedData_Get_Struct(self, void, &digest_type, pctx);

    algo_init(algo, pctx);

    return self;
}

digest_base.update(string) → digest_base

Update the digest using given string and return self.

Also aliased as: <<

Source: show 

static VALUE
rb_digest_base_update(VALUE self, VALUE str)
{
    rb_digest_metadata_t *algo;
    void *pctx;

    algo = get_digest_obj_metadata(self);

    TypedData_Get_Struct(self, void, &digest_type, pctx);

    StringValue(str);
    algo->update_func(pctx, (unsigned char *)RSTRING_PTR(str), RSTRING_LEN(str));
    RB_GC_GUARD(str);

    return self;
}