Class: Phylax::Digest

Inherits:
Object
  • Object
show all
Defined in:
lib/phylax.rb,
ext/phylax/phylax.c

Overview

Streaming message digest (SHA-256/384/512).

d = Phylax::Digest.new(:sha256)
d << "chunk one" << "chunk two"
d.hexdigest            # non-destructive; you may keep updating

Constant Summary collapse

SIZES =

Bytes in the final digest, keyed by algorithm symbol.

{ sha256: 32, sha384: 48, sha512: 64 }.freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name) ⇒ Digest

Returns a new instance of Digest.



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# File 'lib/phylax.rb', line 117

def initialize(name)
  idx = HASHES.fetch(name) { raise ArgumentError, "unknown hash #{name.inspect}" }
  @name = name
  _init(idx)
end

Instance Attribute Details

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/phylax.rb', line 115

def name
  @name
end

Class Method Details

.digest(name, data) ⇒ Object

Convenience: hash data in one call.



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# File 'lib/phylax.rb', line 138

def self.digest(name, data)
  new(name).update(data).digest
end

.hexdigest(name, data) ⇒ Object 



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# File 'lib/phylax.rb', line 142

def self.hexdigest(name, data)
  digest(name, data).unpack1("H*")
end

Instance Method Details

#<<(data) ⇒ Object 



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# File 'lib/phylax.rb', line 123

def <<(data)
  update(data)
end

#_init(vidx) ⇒ Object

Phylax::Digest#_init(idx) — (re)create the underlying hash object.



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# File 'ext/phylax/phylax.c', line 427

static VALUE
digest_init(VALUE self, VALUE vidx)
{
    digest_t *d = digest_get(self);
    int i = alg_index(vidx);
    NTSTATUS st;

    if (d->h) { BCryptDestroyHash(d->h); d->h = NULL; }
    st = BCryptCreateHash(g_hash[i], &d->h, NULL, 0, NULL, 0, 0);
    if (!NT_SUCCESS(st))
        raise_nt("BCryptCreateHash", st);
    d->idx = i;
    return self;
}

#digest ⇒ Object

Non-destructive: duplicate the running state and finish the copy, leaving the original open for further #update (matches Ruby stdlib Digest semantics).



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# File 'ext/phylax/phylax.c', line 460

static VALUE
digest_digest(VALUE self)
{
    digest_t *d = digest_get(self);
    BCRYPT_HASH_HANDLE dup = NULL;
    PUCHAR obj;
    ULONG objlen;
    NTSTATUS st;
    VALUE out;

    if (!d->h) rb_raise(eError, "phylax: digest not initialized");

    /* Allocate the Ruby output first so the malloc below is the last resource
     * acquired; an rb_str_new (OOM) raise then leaks nothing. */
    out = rb_str_new(NULL, g_dlen[d->idx]);
    rb_enc_associate(out, rb_ascii8bit_encoding());

    objlen = g_objlen_hash[d->idx];
    obj = (PUCHAR)malloc(objlen ? objlen : 1);
    if (!obj) rb_raise(rb_eNoMemError, "phylax: out of memory");

    st = BCryptDuplicateHash(d->h, &dup, obj, objlen, 0);
    if (NT_SUCCESS(st))
        st = BCryptFinishHash(dup, (PUCHAR)RSTRING_PTR(out), g_dlen[d->idx], 0);
    if (dup) BCryptDestroyHash(dup);
    free(obj);
    if (!NT_SUCCESS(st))
        raise_nt("BCryptDuplicateHash", st);

    return out;
}

#digest_length ⇒ Object 



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# File 'ext/phylax/phylax.c', line 492

static VALUE
digest_size(VALUE self)
{
    digest_t *d = digest_get(self);
    if (d->idx < 0) rb_raise(eError, "phylax: digest not initialized");
    return UINT2NUM(g_dlen[d->idx]);
}

#hexdigest ⇒ Object 



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# File 'lib/phylax.rb', line 133

def hexdigest
  digest.unpack1("H*")
end

#inspect ⇒ Object 



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# File 'lib/phylax.rb', line 151

def inspect
  "#<Phylax::Digest #{@name}>"
end

#reset ⇒ Object

Discard any fed data and start over.



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# File 'lib/phylax.rb', line 128

def reset
  _init(HASHES.fetch(@name))
  self
end

#size ⇒ Object Also known as: length 



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# File 'lib/phylax.rb', line 146

def size
  digest_length
end

#update(data) ⇒ Object 



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# File 'ext/phylax/phylax.c', line 442

static VALUE
digest_update(VALUE self, VALUE data)
{
    digest_t *d = digest_get(self);
    PUCHAR pin;
    ULONG nin;
    NTSTATUS st;

    if (!d->h) rb_raise(eError, "phylax: digest not initialized");
    nin = str_bytes(&data, &pin);
    st = BCryptHashData(d->h, pin, nin, 0);
    if (!NT_SUCCESS(st))
        raise_nt("BCryptHashData", st);
    return self;
}