From f1410731db23db880a556f4cb951933be8d0fb79 Mon Sep 17 00:00:00 2001
From: Harshavardhana <harsha@minio.io>
Date: Wed, 24 Jun 2015 14:16:28 -0700
Subject: [PATCH] Add windows code for sha1 and crc32c

---
 pkg/utils/checksum/crc32c/crc32c_windows.go |  51 ++++++
 pkg/utils/crypto/sha1/sha1_windows.go       | 167 ++++++++++++++++++++
 2 files changed, 218 insertions(+)
 create mode 100644 pkg/utils/checksum/crc32c/crc32c_windows.go
 create mode 100644 pkg/utils/crypto/sha1/sha1_windows.go

diff --git a/pkg/utils/checksum/crc32c/crc32c_windows.go b/pkg/utils/checksum/crc32c/crc32c_windows.go
new file mode 100644
index 000000000..f657d003c
--- /dev/null
+++ b/pkg/utils/checksum/crc32c/crc32c_windows.go
@@ -0,0 +1,51 @@
+/*
+ * Minimalist Object Storage, (C) 2014 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package crc32c
+
+import (
+	"hash/crc32"
+	"io"
+)
+
+var castanagoliTable = crc32.MakeTable(crc32.Castagnoli)
+
+/// Convenience functions
+
+// Sum32 - single caller crc helper
+func Sum32(buffer []byte) uint32 {
+	crc := crc32.New(castanagoliTable)
+	crc.Reset()
+	crc.Write(buffer)
+	return crc.Sum32()
+}
+
+// Sum - io.Reader based crc helper
+func Sum(reader io.Reader) (uint32, error) {
+	h := crc32.New(castanagoliTable)
+	var err error
+	for err == nil {
+		length := 0
+		byteBuffer := make([]byte, 1024*1024)
+		length, err = reader.Read(byteBuffer)
+		byteBuffer = byteBuffer[0:length]
+		h.Write(byteBuffer)
+	}
+	if err != io.EOF {
+		return 0, err
+	}
+	return h.Sum32(), nil
+}
diff --git a/pkg/utils/crypto/sha1/sha1_windows.go b/pkg/utils/crypto/sha1/sha1_windows.go
new file mode 100644
index 000000000..05a9cb333
--- /dev/null
+++ b/pkg/utils/crypto/sha1/sha1_windows.go
@@ -0,0 +1,167 @@
+// 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 of
+// Golang project:
+//    https://github.com/golang/go/blob/master/LICENSE
+
+// Using this part of Minio codebase under the license
+// Apache License Version 2.0 with modifications
+
+// Package sha1 implements the SHA1 hash algorithm as defined in RFC 3174.
+package sha1
+
+import (
+	"hash"
+	"io"
+
+	"github.com/minio/minio/pkg/utils/cpu"
+)
+
+// The size of a SHA1 checksum in bytes.
+const Size = 20
+
+// The blocksize of SHA1 in bytes.
+const BlockSize = 64
+
+const (
+	chunk = 64
+	init0 = 0x67452301
+	init1 = 0xEFCDAB89
+	init2 = 0x98BADCFE
+	init3 = 0x10325476
+	init4 = 0xC3D2E1F0
+)
+
+// digest represents the partial evaluation of a checksum.
+type digest struct {
+	h   [5]uint32
+	x   [chunk]byte
+	nx  int
+	len uint64
+}
+
+// Reset digest
+func (d *digest) Reset() {
+	d.h[0] = init0
+	d.h[1] = init1
+	d.h[2] = init2
+	d.h[3] = init3
+	d.h[4] = init4
+	d.nx = 0
+	d.len = 0
+}
+
+// New returns a new hash.Hash computing the SHA1 checksum.
+func New() hash.Hash {
+	d := new(digest)
+	d.Reset()
+	return d
+}
+
+func block(dig *digest, p []byte) {
+	switch true {
+	case cpu.HasSSE41() == true:
+		blockSSE3(dig, p)
+	default:
+		blockGeneric(dig, p)
+	}
+}
+
+// Return output size
+func (d *digest) Size() int { return Size }
+
+// Return checksum blocksize
+func (d *digest) BlockSize() int { return BlockSize }
+
+// Write to digest
+func (d *digest) Write(p []byte) (nn int, err error) {
+	nn = len(p)
+	d.len += uint64(nn)
+	if d.nx > 0 {
+		n := copy(d.x[d.nx:], p)
+		d.nx += n
+		if d.nx == chunk {
+			block(d, d.x[:])
+			d.nx = 0
+		}
+		p = p[n:]
+	}
+	if len(p) >= chunk {
+		n := len(p) &^ (chunk - 1)
+		block(d, p[:n])
+		p = p[n:]
+	}
+	if len(p) > 0 {
+		d.nx = copy(d.x[:], p)
+	}
+	return
+}
+
+// Return checksum bytes
+func (d *digest) Sum(in []byte) []byte {
+	// Make a copy of d0 so that caller can keep writing and summing.
+	d0 := *d
+	hash := d0.checkSum()
+	return append(in, hash[:]...)
+}
+
+// Intermediate checksum function
+func (d *digest) checkSum() [Size]byte {
+	len := d.len
+	// Padding.  Add a 1 bit and 0 bits until 56 bytes mod 64.
+	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")
+	}
+
+	var digest [Size]byte
+	for i, s := range d.h {
+		digest[i*4] = byte(s >> 24)
+		digest[i*4+1] = byte(s >> 16)
+		digest[i*4+2] = byte(s >> 8)
+		digest[i*4+3] = byte(s)
+	}
+
+	return digest
+}
+
+/// Convenience functions
+
+// Sum1 - single caller sha1 helper
+func Sum1(data []byte) [Size]byte {
+	var d digest
+	d.Reset()
+	d.Write(data)
+	return d.checkSum()
+}
+
+// Sum - io.Reader based streaming sha1 helper
+func Sum(reader io.Reader) ([]byte, error) {
+	h := New()
+	var err error
+	for err == nil {
+		length := 0
+		byteBuffer := make([]byte, 1024*1024)
+		length, err = reader.Read(byteBuffer)
+		byteBuffer = byteBuffer[0:length]
+		h.Write(byteBuffer)
+	}
+	if err != io.EOF {
+		return nil, err
+	}
+	return h.Sum(nil), nil
+}