module Digest::Instance - RDoc Documentation

# module Digest::Instance

This module provides instance methods for a digest implementation object to calculate message digest values.

### Public Instance Methods

digest_obj << string → digest_obj click to toggle source

Updates the digest using a given string and returns self.

The update() method and the left-shift operator are overridden by each implementation subclass. (One should be an alias for the other)

    static VALUE
    rb_digest_instance_update(VALUE self, VALUE str)
    {
        rb_digest_instance_method_unimpl(self, "update");

        UNREACHABLE;
    }

digest_obj == another_digest_obj → boolean click to toggle source
digest_obj == string → boolean

If a string is given, checks whether it is equal to the hex-encoded hash value of the digest object. If another digest instance is given, checks whether they have the same hash value. Otherwise returns false.

    static VALUE
    rb_digest_instance_equal(VALUE self, VALUE other)
    {
        VALUE str1, str2;

        if (rb_obj_is_kind_of(other, rb_mDigest_Instance) == Qtrue) {
            str1 = rb_digest_instance_digest(0, 0, self);
            str2 = rb_digest_instance_digest(0, 0, other);
        } else {
            str1 = rb_digest_instance_to_s(self);
            str2 = rb_check_string_type(other);
            if (NIL_P(str2)) return Qfalse;
        }

        /* never blindly assume that subclass methods return strings */
        StringValue(str1);
        StringValue(str2);

        if (RSTRING_LEN(str1) == RSTRING_LEN(str2) &&
            rb_str_cmp(str1, str2) == 0) {
            return Qtrue;
        }
        return Qfalse;
    }

base64digest(str = nil) click to toggle source

If none is given, returns the resulting hash value of the digest in a base64 encoded form, keeping the digest's state.

If a `string` is given, returns the hash value for the given `string` in a base64 encoded form, resetting the digest to the initial state before and after the process.

In either case, the return value is properly padded with '=' and contains no line feeds.

    # File ext/digest/lib/digest.rb, line 67
    def base64digest(str = nil)
      [str ? digest(str) : digest].pack('m0')
    end

base64digest!() click to toggle source

Returns the resulting hash value and resets the digest to the initial state.

    # File ext/digest/lib/digest.rb, line 73
    def base64digest!
      [digest!].pack('m0')
    end

block_length → integer click to toggle source

Returns the block length of the digest.

This method is overridden by each implementation subclass.

    static VALUE
    rb_digest_instance_block_length(VALUE self)
    {
        rb_digest_instance_method_unimpl(self, "block_length");

        UNREACHABLE;
    }

bubblebabble → hash_string click to toggle source

Returns the resulting hash value in a Bubblebabble encoded form.

    static VALUE
    rb_digest_instance_bubblebabble(VALUE self)
    {
        return bubblebabble_str_new(rb_funcall(self, id_digest, 0));
    }

digest → string click to toggle source
digest(string) → string

If none is given, returns the resulting hash value of the digest, keeping the digest's state.

If a string is given, returns the hash value for the given string, resetting the digest to the initial state before and after the process.

    static VALUE
    rb_digest_instance_digest(int argc, VALUE *argv, VALUE self)
    {
        VALUE str, value;

        if (rb_scan_args(argc, argv, "01", &str) > 0) {
            rb_funcall(self, id_reset, 0);
            rb_funcall(self, id_update, 1, str);
            value = rb_funcall(self, id_finish, 0);
            rb_funcall(self, id_reset, 0);
        } else {
            value = rb_funcall(rb_obj_clone(self), id_finish, 0);
        }

        return value;
    }

digest! → string click to toggle source

Returns the resulting hash value and resets the digest to the initial state.

    static VALUE
    rb_digest_instance_digest_bang(VALUE self)
    {
        VALUE value = rb_funcall(self, id_finish, 0);
        rb_funcall(self, id_reset, 0);

        return value;
    }

digest_length → integer click to toggle source

Returns the length of the hash value of the digest.

This method should be overridden by each implementation subclass. If not, digest_obj.digest().length() is returned.

    static VALUE
    rb_digest_instance_digest_length(VALUE self)
    {
        /* subclasses really should redefine this method */
        VALUE digest = rb_digest_instance_digest(0, 0, self);

        /* never blindly assume that #digest() returns a string */
        StringValue(digest);
        return INT2NUM(RSTRING_LEN(digest));
    }

file(name) click to toggle source

Updates the digest with the contents of a given file name and returns self.

    # File ext/digest/lib/digest.rb, line 48
    def file(name)
      File.open(name, "rb") {|f|
        buf = ""
        while f.read(16384, buf)
          update buf
        end
      }
      self
    end

hexdigest → string click to toggle source
hexdigest(string) → string

If none is given, returns the resulting hash value of the digest in a hex-encoded form, keeping the digest's state.

If a string is given, returns the hash value for the given string in a hex-encoded form, resetting the digest to the initial state before and after the process.

    static VALUE
    rb_digest_instance_hexdigest(int argc, VALUE *argv, VALUE self)
    {
        VALUE str, value;

        if (rb_scan_args(argc, argv, "01", &str) > 0) {
            rb_funcall(self, id_reset, 0);
            rb_funcall(self, id_update, 1, str);
            value = rb_funcall(self, id_finish, 0);
            rb_funcall(self, id_reset, 0);
        } else {
            value = rb_funcall(rb_obj_clone(self), id_finish, 0);
        }

        return hexencode_str_new(value);
    }

hexdigest! → string click to toggle source

Returns the resulting hash value in a hex-encoded form and resets the digest to the initial state.

    static VALUE
    rb_digest_instance_hexdigest_bang(VALUE self)
    {
        VALUE value = rb_funcall(self, id_finish, 0);
        rb_funcall(self, id_reset, 0);

        return hexencode_str_new(value);
    }

inspect → string click to toggle source

Creates a printable version of the digest object.

    static VALUE
    rb_digest_instance_inspect(VALUE self)
    {
        VALUE str;
        size_t digest_len = 32;     /* about this size at least */
        const char *cname;

        cname = rb_obj_classname(self);

        /* #<Digest::ClassName: xxxxx...xxxx> */
        str = rb_str_buf_new(2 + strlen(cname) + 2 + digest_len * 2 + 1);
        rb_str_buf_cat2(str, "#<");
        rb_str_buf_cat2(str, cname);
        rb_str_buf_cat2(str, ": ");
        rb_str_buf_append(str, rb_digest_instance_hexdigest(0, 0, self));
        rb_str_buf_cat2(str, ">");
        return str;
    }

length → integer click to toggle source

Returns digest_obj.digest_length().

    static VALUE
    rb_digest_instance_length(VALUE self)
    {
        return rb_funcall(self, id_digest_length, 0);
    }

new → another_digest_obj click to toggle source

Returns a new, initialized copy of the digest object. Equivalent to digest_obj.clone().reset().

    static VALUE
    rb_digest_instance_new(VALUE self)
    {
        VALUE clone = rb_obj_clone(self);
        rb_funcall(clone, id_reset, 0);
        return clone;
    }

reset → digest_obj click to toggle source

Resets the digest to the initial state and returns self.

This method is overridden by each implementation subclass.

    static VALUE
    rb_digest_instance_reset(VALUE self)
    {
        rb_digest_instance_method_unimpl(self, "reset");

        UNREACHABLE;
    }

size → integer click to toggle source

Returns digest_obj.digest_length().

    static VALUE
    rb_digest_instance_length(VALUE self)
    {
        return rb_funcall(self, id_digest_length, 0);
    }

to_s → string click to toggle source

Returns digest_obj.hexdigest().

    static VALUE
    rb_digest_instance_to_s(VALUE self)
    {
        return rb_funcall(self, id_hexdigest, 0);
    }

update(string) → digest_obj click to toggle source

Updates the digest using a given string and returns self.

The update() method and the left-shift operator are overridden by each implementation subclass. (One should be an alias for the other)

    static VALUE
    rb_digest_instance_update(VALUE self, VALUE str)
    {
        rb_digest_instance_method_unimpl(self, "update");

        UNREACHABLE;
    }

### Private Instance Methods

instance_eval { finish } → digest_obj click to toggle source

Finishes the digest and returns the resulting hash value.

This method is overridden by each implementation subclass and often made private, because some of those subclasses may leave internal data uninitialized. Do not call this method from outside. Use digest!() instead, which ensures that internal data be reset for security reasons.

    static VALUE
    rb_digest_instance_finish(VALUE self)
    {
        rb_digest_instance_method_unimpl(self, "finish");

        UNREACHABLE;
    }