1 files changed, 159 insertions, 0 deletions
diff --git a/libgo/go/crypto/sha256/sha256.go b/libgo/go/crypto/sha256/sha256.go
new file mode 100644
index 0000000000..57a8ffa0d7
--- /dev/null
+++ b/libgo/go/crypto/sha256/sha256.go
@@ -0,0 +1,159 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This package implements the SHA224 and SHA256 hash algorithms as defined in FIPS 180-2.
+package sha256
+
+import (
+	"hash"
+	"os"
+)
+
+// The size of a SHA256 checksum in bytes.
+const Size = 32
+
+// The size of a SHA224 checksum in bytes.
+const Size224 = 28
+
+const (
+	_Chunk     = 64
+	_Init0     = 0x6A09E667
+	_Init1     = 0xBB67AE85
+	_Init2     = 0x3C6EF372
+	_Init3     = 0xA54FF53A
+	_Init4     = 0x510E527F
+	_Init5     = 0x9B05688C
+	_Init6     = 0x1F83D9AB
+	_Init7     = 0x5BE0CD19
+	_Init0_224 = 0xC1059ED8
+	_Init1_224 = 0x367CD507
+	_Init2_224 = 0x3070DD17
+	_Init3_224 = 0xF70E5939
+	_Init4_224 = 0xFFC00B31
+	_Init5_224 = 0x68581511
+	_Init6_224 = 0x64F98FA7
+	_Init7_224 = 0xBEFA4FA4
+)
+
+// digest represents the partial evaluation of a checksum.
+type digest struct {
+	h     [8]uint32
+	x     [_Chunk]byte
+	nx    int
+	len   uint64
+	is224 bool // mark if this digest is SHA-224
+}
+
+func (d *digest) Reset() {
+	if !d.is224 {
+		d.h[0] = _Init0
+		d.h[1] = _Init1
+		d.h[2] = _Init2
+		d.h[3] = _Init3
+		d.h[4] = _Init4
+		d.h[5] = _Init5
+		d.h[6] = _Init6
+		d.h[7] = _Init7
+	} else {
+		d.h[0] = _Init0_224
+		d.h[1] = _Init1_224
+		d.h[2] = _Init2_224
+		d.h[3] = _Init3_224
+		d.h[4] = _Init4_224
+		d.h[5] = _Init5_224
+		d.h[6] = _Init6_224
+		d.h[7] = _Init7_224
+	}
+	d.nx = 0
+	d.len = 0
+}
+
+// New returns a new hash.Hash computing the SHA256 checksum.
+func New() hash.Hash {
+	d := new(digest)
+	d.Reset()
+	return d
+}
+
+// New224 returns a new hash.Hash computing the SHA224 checksum.
+func New224() hash.Hash {
+	d := new(digest)
+	d.is224 = true
+	d.Reset()
+	return d
+}
+
+func (d *digest) Size() int {
+	if !d.is224 {
+		return Size
+	}
+	return Size224
+}
+
+func (d *digest) Write(p []byte) (nn int, err os.Error) {
+	nn = len(p)
+	d.len += uint64(nn)
+	if d.nx > 0 {
+		n := len(p)
+		if n > _Chunk-d.nx {
+			n = _Chunk - d.nx
+		}
+		for i := 0; i < n; i++ {
+			d.x[d.nx+i] = p[i]
+		}
+		d.nx += n
+		if d.nx == _Chunk {
+			_Block(d, d.x[0:])
+			d.nx = 0
+		}
+		p = p[n:]
+	}
+	n := _Block(d, p)
+	p = p[n:]
+	if len(p) > 0 {
+		d.nx = copy(d.x[:], p)
+	}
+	return
+}
+
+func (d0 *digest) Sum() []byte {
+	// Make a copy of d0 so that caller can keep writing and summing.
+	d := new(digest)
+	*d = *d0
+
+	// Padding.  Add a 1 bit and 0 bits until 56 bytes mod 64.
+	len := d.len
+	var tmp [64]byte
+	tmp[0] = 0x80
+	if len%64 < 56 {
+		d.Write(tmp[0 : 56-len%64])
+	} else {
+		d.Write(tmp[0 : 64+56-len%64])
+	}
+
+	// Length in bits.
+	len <<= 3
+	for i := uint(0); i < 8; i++ {
+		tmp[i] = byte(len >> (56 - 8*i))
+	}
+	d.Write(tmp[0:8])
+
+	if d.nx != 0 {
+		panic("d.nx != 0")
+	}
+
+	p := make([]byte, 32)
+	j := 0
+	for _, s := range d.h {
+		p[j+0] = byte(s >> 24)
+		p[j+1] = byte(s >> 16)
+		p[j+2] = byte(s >> 8)
+		p[j+3] = byte(s >> 0)
+		j += 4
+	}
+	if d.is224 {
+		return p[0:28]
+	}
+	return p
+}