initial import

Author: jmoiron

LICENSE

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+Simplified BSD License
+
+Copyright (c) 2016, Datadog <info@datadoghq.com>
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright notice,
+      this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright notice,
+      this list of conditions and the following disclaimer in the documentation
+      and/or other materials provided with the distribution.
+    * Neither the name of the copyright holder nor the names of its contributors
+      may be used to endorse or promote products derived from this software
+      without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

adler32.go

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+// Pulled from https://github.com/youtube/vitess 229422035ca0c716ad0c1397ea1351fe62b0d35a
+// Copyright 2012, Google Inc. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package czlib
+
+// #cgo pkg-config: zlib
+
+/*
+
+#include "zlib.h"
+*/
+import "C"
+
+import (
+	"hash"
+	"unsafe"
+)
+
+type adler32Hash struct {
+	adler C.uLong
+}
+
+// an empty buffer has an adler32 of '1' by default, so start with that
+// (the go hash/adler32 does the same)
+func newAdler32() hash.Hash32 {
+	a := &adler32Hash{}
+	a.Reset()
+	return a
+}
+
+// Write implements an io.Writer interface
+func (a *adler32Hash) Write(p []byte) (n int, err error) {
+	if len(p) > 0 {
+		a.adler = C.adler32(a.adler, (*C.Bytef)(unsafe.Pointer(&p[0])), (C.uInt)(len(p)))
+	}
+	return len(p), nil
+}
+
+// Sum implements a hash.Hash interface
+func (a *adler32Hash) Sum(b []byte) []byte {
+	s := a.Sum32()
+	b = append(b, byte(s>>24))
+	b = append(b, byte(s>>16))
+	b = append(b, byte(s>>8))
+	b = append(b, byte(s))
+	return b
+}
+
+// Reset resets the hash to default value
+func (a *adler32Hash) Reset() {
+	a.adler = C.adler32(0, (*C.Bytef)(unsafe.Pointer(nil)), 0)
+}
+
+// Size returns the (fixed) size of the hash
+func (a *adler32Hash) Size() int {
+	return 4
+}
+
+// BlockSize returns the (fixed) block size
+func (a *adler32Hash) BlockSize() int {
+	return 1
+}
+
+// Sum32 implements a hash.Hash32 interface
+func (a *adler32Hash) Sum32() uint32 {
+	return uint32(a.adler)
+}
+
+// helper method for partial checksums. From the zlib.h header:
+//
+//   Combine two Adler-32 checksums into one.  For two sequences of bytes, seq1
+// and seq2 with lengths len1 and len2, Adler-32 checksums were calculated for
+// each, adler1 and adler2.  adler32_combine() returns the Adler-32 checksum of
+// seq1 and seq2 concatenated, requiring only adler1, adler2, and len2.
+func adler32Combine(adler1, adler2 uint32, len2 int) uint32 {
+	return uint32(C.adler32_combine(C.uLong(adler1), C.uLong(adler2), C.z_off_t(len2)))
+}

crc32.go

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+// Pulled from https://github.com/youtube/vitess 229422035ca0c716ad0c1397ea1351fe62b0d35a
+// Copyright 2012, Google Inc. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package czlib
+
+/*
+#include "zlib.h"
+*/
+import "C"
+
+import (
+	"hash"
+	"unsafe"
+)
+
+type crc32Hash struct {
+	crc C.uLong
+}
+
+// an empty buffer has an crc32 of '1' by default, so start with that
+// (the go hash/crc32 does the same)
+func newCrc32() hash.Hash32 {
+	c := &crc32Hash{}
+	c.Reset()
+	return c
+}
+
+// Write implements an io.Writer interface
+func (a *crc32Hash) Write(p []byte) (n int, err error) {
+	if len(p) > 0 {
+		a.crc = C.crc32(a.crc, (*C.Bytef)(unsafe.Pointer(&p[0])), (C.uInt)(len(p)))
+	}
+	return len(p), nil
+}
+
+// Sum implements a hash.Hash interface
+func (a *crc32Hash) Sum(b []byte) []byte {
+	s := a.Sum32()
+	b = append(b, byte(s>>24))
+	b = append(b, byte(s>>16))
+	b = append(b, byte(s>>8))
+	b = append(b, byte(s))
+	return b
+}
+
+// Reset resets the hash to default value
+func (a *crc32Hash) Reset() {
+	a.crc = C.crc32(0, (*C.Bytef)(unsafe.Pointer(nil)), 0)
+}
+
+// Size returns the (fixed) size of the hash
+func (a *crc32Hash) Size() int {
+	return 4
+}
+
+// BlockSize returns the (fixed) block size of the hash
+func (a *crc32Hash) BlockSize() int {
+	return 1
+}
+
+// Sum32 implements a hash.Hash32 interface
+func (a *crc32Hash) Sum32() uint32 {
+	return uint32(a.crc)
+}
+
+// helper method for partial checksums. From the zlib.h header:
+//
+//   Combine two CRC-32 checksums into one.  For two sequences of bytes, seq1
+// and seq2 with lengths len1 and len2, CRC-32 checksums were calculated for
+// each, crc1 and crc2.  crc32_combine() returns the CRC-32 checksum of
+// seq1 and seq2 concatenated, requiring only crc1, crc2, and len2.
+func crc32Combine(crc1, crc2 uint32, len2 int) uint32 {
+	return uint32(C.crc32_combine(C.uLong(crc1), C.uLong(crc2), C.z_off_t(len2)))
+}

czlib.go

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+// Copyright 2016, Datadog Inc.  All rights reserved.
+
+package czlib
+
+import (
+	"compress/flate"
+	"compress/zlib"
+)
+
+// Constants copied from the flate package, so that code that imports czlib
+// does not also have to import "compress/flate".
+const (
+	NoCompression      = flate.NoCompression
+	BestSpeed          = flate.BestSpeed
+	BestCompression    = flate.BestCompression
+	DefaultCompression = flate.DefaultCompression
+)
+
+var (
+	// ErrChecksum is returned when reading ZLIB data that has an invalid checksum.
+	ErrChecksum = zlib.ErrChecksum
+	// ErrDictionary is returned when reading ZLIB data that has an invalid dictionary.
+	ErrDictionary = zlib.ErrDictionary
+	// ErrHeader is returned when reading ZLIB data that has an invalid header.
+	ErrHeader = zlib.ErrHeader
+)