From 01d15ca3b256246e91d27aa1bfd933035017a82c Mon Sep 17 00:00:00 2001
From: Harshavardhana <harsha@harshavardhana.net>
Date: Fri, 23 Jan 2015 19:33:37 -0800
Subject: [PATCH] Implement crc32c for Darwin, update documentation

---
 BUILDDEPS.md                                  |  5 ++-
 Makefile                                      |  7 ----
 README.md                                     |  2 +-
 pkg/utils/checksum/crc32c/crc32c_darwin.go    | 35 +++++++++++++++++++
 .../crc32c/{crc32c.go => crc32c_linux.go}     |  0
 .../{crc32c_amd64.S => crc32c_linux_amd64.S}  |  0
 6 files changed, 38 insertions(+), 11 deletions(-)
 create mode 100644 pkg/utils/checksum/crc32c/crc32c_darwin.go
 rename pkg/utils/checksum/crc32c/{crc32c.go => crc32c_linux.go} (100%)
 rename pkg/utils/checksum/crc32c/{crc32c_amd64.S => crc32c_linux_amd64.S} (100%)

diff --git a/BUILDDEPS.md b/BUILDDEPS.md
index b243ae355..1935aec57 100644
--- a/BUILDDEPS.md
+++ b/BUILDDEPS.md
@@ -50,9 +50,9 @@ This installation document assumes Mac OSX Yosemite 10.10 or later on x86-64 pla
 $ ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
 ```
 
-##### Install Git and GCC
+##### Install Git
 ```sh
-$ brew install git gcc
+$ brew install git
 ```
 
 ##### Install YASM
@@ -64,7 +64,6 @@ $ brew install yasm
 ```
 
 ##### Install Go 1.4+
-
 On MacOSX ``brew.sh`` is the best way to install golang
 
 For example:
diff --git a/Makefile b/Makefile
index 80ab9e08c..524d83516 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,6 @@
 #GOPATH := $(CURDIR)/tmp/gopath
 MAKE_OPTIONS := -s
 ARCH := $(shell uname -s)
-GCCVERSIONGTEQ4 := $(shell expr `gcc -dumpversion | cut -f1 -d.` \>= 4)
 
 all: getdeps install
 
@@ -20,13 +19,7 @@ build-utils:
 	@godep go test -race -coverprofile=cover.out github.com/minio-io/minio/pkg/utils/crypto/sha1
 	@godep go test -race -coverprofile=cover.out github.com/minio-io/minio/pkg/utils/crypto/sha256
 	@godep go test -race -coverprofile=cover.out github.com/minio-io/minio/pkg/utils/crypto/sha512
-ifeq ($(ARCH), Darwin)
-ifeq ($(GCCVERSIONGTEQ4), "1")
 	@godep go test -race -coverprofile=cover.out github.com/minio-io/minio/pkg/utils/checksum/crc32c
-endif
-else
-	@godep go test -race -coverprofile=cover.out github.com/minio-io/minio/pkg/utils/checksum/crc32c
-endif
 
 #build-os:
 #	@godep go test -race -coverprofile=cover.out github.com/minio-io/minio/pkg/os/scsi
diff --git a/README.md b/README.md
index 903ae6d20..4ec628572 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,7 @@ Minio's design is inspired by Amazon's S3 for its API and Facebook's Haystack fo
 | ------------- | ------------- |
 | Linux  | Yes  |
 | Windows | Not yet |
-| Mac OSX | Yes(with GCC) |
+| Mac OSX | Yes |
 
 ### Supported architectures
 
diff --git a/pkg/utils/checksum/crc32c/crc32c_darwin.go b/pkg/utils/checksum/crc32c/crc32c_darwin.go
new file mode 100644
index 000000000..a1e706e92
--- /dev/null
+++ b/pkg/utils/checksum/crc32c/crc32c_darwin.go
@@ -0,0 +1,35 @@
+/*
+ * Mini 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.
+ */
+
+// +build amd64
+
+package crc32c
+
+import (
+	"errors"
+        "hash/crc32"
+)
+
+var castanagoliTable = crc32.MakeTable(crc32.Castagnoli)
+
+func Crc32c(buffer []byte) (uint32, error) {
+        crc := crc32.New(castanagoliTable)
+        if len(buffer) <= 0 {
+           return 0, errors.New("input buffer cannot be null")
+        }
+        crc.Write(buffer)
+	return crc.Sum32(), nil
+}
diff --git a/pkg/utils/checksum/crc32c/crc32c.go b/pkg/utils/checksum/crc32c/crc32c_linux.go
similarity index 100%
rename from pkg/utils/checksum/crc32c/crc32c.go
rename to pkg/utils/checksum/crc32c/crc32c_linux.go
diff --git a/pkg/utils/checksum/crc32c/crc32c_amd64.S b/pkg/utils/checksum/crc32c/crc32c_linux_amd64.S
similarity index 100%
rename from pkg/utils/checksum/crc32c/crc32c_amd64.S
rename to pkg/utils/checksum/crc32c/crc32c_linux_amd64.S