add crc methods

CHANGELOG.md

@@ -1,3 +1,8 @@
+## Unreleased ##
+
+### enhancements
+  * add crc methods
+
 ## 0.7.0 (October 25, 2012) ##
 
 ### enhancements

README.md

@@ -21,6 +21,8 @@ CityHash.hash64(text, seed1)        # => 9154302171269876511
 CityHash.hash64(text, seed1, seed2) # => 4854399283587686019
 CityHash.hash128(text)              # => 124124989950401219618153994964897029896
 CityHash.hash128(text, seed1)       # => 101668641288246442316643001405184598611
+CityHash.hash128crc(text)           # => 124124989950401219618153994964897029896
+CityHash.hash128crc(text, seed1)    # => 101668641288246442316643001405184598611
 ```
 
 ### Contributing to cityhash

ext/cityhash/citycrc.h

@@ -0,0 +1,43 @@
+// Copyright (c) 2011 Google, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+// CityHash, by Geoff Pike and Jyrki Alakuijala
+//
+// This file declares the subset of the CityHash functions that require
+// _mm_crc32_u64().  See the CityHash README for details.
+//
+// Functions in the CityHash family are not suitable for cryptography.
+
+#ifndef CITY_HASH_CRC_H_
+#define CITY_HASH_CRC_H_
+
+#include <city.h>
+
+// Hash function for a byte array.
+uint128 CityHashCrc128(const char *s, size_t len);
+
+// Hash function for a byte array.  For convenience, a 128-bit seed is also
+// hashed into the result.
+uint128 CityHashCrc128WithSeed(const char *s, size_t len, uint128 seed);
+
+// Hash function for a byte array.  Sets result[0] ... result[3].
+void CityHashCrc256(const char *s, size_t len, uint64 *result);
+
+#endif  // CITY_HASH_CRC_H_

ext/cityhash/cityhash.cc

@@ -1,6 +1,10 @@
 #include <ruby.h>
 #include "city.h"
 
+#ifdef __SSE4_2__
+#include "citycrc.h"
+#endif
+
 // Use this typedef to make the compiler happy when
 // calling rb_define_method()
 typedef VALUE (ruby_method)(...);
@@ -38,6 +42,21 @@ extern "C" VALUE cityhash_hash128_with_seed(VALUE mod, VALUE input, VALUE seed_s
   return rb_str_new((char *)&hash, sizeof(hash));
 }
 
+#ifdef __SSE4_2__
+extern "C" VALUE cityhash_hashcrc128(VALUE mod, VALUE input)
+{
+  uint128 hash = CityHashCrc128(StringValuePtr(input), RSTRING_LEN(input));
+  return rb_str_new((char *)&hash, sizeof(hash));
+}
+
+extern "C" VALUE cityhash_hashcrc128_with_seed(VALUE mod, VALUE input, VALUE seed_string)
+{
+  uint128 seed = *(uint128 *)StringValuePtr(seed_string);
+  uint128 hash = CityHashCrc128WithSeed(StringValuePtr(input), RSTRING_LEN(input), seed);
+  return rb_str_new((char *)&hash, sizeof(hash));
+}
+#endif
+
 extern "C" void Init_cityhash()
 {
   VALUE mCityHash = rb_define_module("CityHash");
@@ -51,4 +70,9 @@ extern "C" void Init_cityhash()
 
   rb_define_singleton_method(mInternal, "hash128", (ruby_method*) &cityhash_hash128, 1);
   rb_define_singleton_method(mInternal, "hash128_with_seed", (ruby_method*) &cityhash_hash128_with_seed, 2);
+
+#ifdef __SSE4_2__
+  rb_define_singleton_method(mInternal, "hash128crc", (ruby_method*) &cityhash_hashcrc128, 1);
+  rb_define_singleton_method(mInternal, "hash128crc_with_seed", (ruby_method*) &cityhash_hashcrc128_with_seed, 2);
+#endif
 }

ext/cityhash/extconf.rb

@@ -1,6 +1,6 @@
 require 'mkmf'
 
-%w{g O3 Wall}.each do |flag|
+%w{g O3 Wall msse4.2}.each do |flag|
   flag = "-#{flag}"
   $CPPFLAGS += " #{flag}" unless $CPPFLAGS.split.include? flag
 end

lib/cityhash.rb

@@ -16,12 +16,32 @@ def self.hash64(input, seed1=nil, seed2=nil)
   end
 
   def self.hash128(input, seed=nil)
-    if seed
-      seed = [seed & LOW64_MASK, seed & HIGH64_MASK >> 64].pack('QQ')
-      digest = Internal.hash128_with_seed(input, seed)
+    digest = if seed
+      Internal.hash128_with_seed(input, packed_seed(seed))
     else
-      digest = Internal.hash128(input)
+      Internal.hash128(input)
     end
+
+    unpacked_digest(digest)
+  end
+
+  def self.hash128crc(input, seed=nil)
+    digest = if seed
+      Internal.hash128crc_with_seed(input, packed_seed(seed))
+    else
+      Internal.hash128crc(input)
+    end
+
+    unpacked_digest(digest)
+  end
+
+  private
+
+  def self.packed_seed(seed)
+    [seed & LOW64_MASK, seed & HIGH64_MASK >> 64].pack('QQ')
+  end
+
+  def self.unpacked_digest(digest)
     [0..7, 8..15].map { |r| digest[r].unpack('Q').first.to_s }.join.to_i
   end
 end

test/cityhash_test.rb

@@ -25,4 +25,13 @@
     seed = (123 << 64) | 123
     assert_equal 1834994000056895780313918994795281207519, CityHash.hash128("test", seed)
   end
+
+  it "returns 128bit crc hash" do
+    assert_equal 124124989950401219618153994964897029896, CityHash.hash128crc("test")
+  end
+
+  it "returns 128bit crc hash with seed" do
+    seed = (123 << 64) | 123
+    assert_equal 1834994000056895780313918994795281207519, CityHash.hash128crc("test", seed)
+  end
 end