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Diffstat (limited to 'vendor/github.com/klauspost/crc32/crc32.go')
| -rw-r--r-- | vendor/github.com/klauspost/crc32/crc32.go | 207 |
1 files changed, 0 insertions, 207 deletions
diff --git a/vendor/github.com/klauspost/crc32/crc32.go b/vendor/github.com/klauspost/crc32/crc32.go deleted file mode 100644 index 8aa91b17e9..0000000000 --- a/vendor/github.com/klauspost/crc32/crc32.go +++ /dev/null @@ -1,207 +0,0 @@ -// 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. - -// Package crc32 implements the 32-bit cyclic redundancy check, or CRC-32, -// checksum. See http://en.wikipedia.org/wiki/Cyclic_redundancy_check for -// information. -// -// Polynomials are represented in LSB-first form also known as reversed representation. -// -// See http://en.wikipedia.org/wiki/Mathematics_of_cyclic_redundancy_checks#Reversed_representations_and_reciprocal_polynomials -// for information. -package crc32 - -import ( - "hash" - "sync" -) - -// The size of a CRC-32 checksum in bytes. -const Size = 4 - -// Predefined polynomials. -const ( - // IEEE is by far and away the most common CRC-32 polynomial. - // Used by ethernet (IEEE 802.3), v.42, fddi, gzip, zip, png, ... - IEEE = 0xedb88320 - - // Castagnoli's polynomial, used in iSCSI. - // Has better error detection characteristics than IEEE. - // http://dx.doi.org/10.1109/26.231911 - Castagnoli = 0x82f63b78 - - // Koopman's polynomial. - // Also has better error detection characteristics than IEEE. - // http://dx.doi.org/10.1109/DSN.2002.1028931 - Koopman = 0xeb31d82e -) - -// Table is a 256-word table representing the polynomial for efficient processing. -type Table [256]uint32 - -// This file makes use of functions implemented in architecture-specific files. -// The interface that they implement is as follows: -// -// // archAvailableIEEE reports whether an architecture-specific CRC32-IEEE -// // algorithm is available. -// archAvailableIEEE() bool -// -// // archInitIEEE initializes the architecture-specific CRC3-IEEE algorithm. -// // It can only be called if archAvailableIEEE() returns true. -// archInitIEEE() -// -// // archUpdateIEEE updates the given CRC32-IEEE. It can only be called if -// // archInitIEEE() was previously called. -// archUpdateIEEE(crc uint32, p []byte) uint32 -// -// // archAvailableCastagnoli reports whether an architecture-specific -// // CRC32-C algorithm is available. -// archAvailableCastagnoli() bool -// -// // archInitCastagnoli initializes the architecture-specific CRC32-C -// // algorithm. It can only be called if archAvailableCastagnoli() returns -// // true. -// archInitCastagnoli() -// -// // archUpdateCastagnoli updates the given CRC32-C. It can only be called -// // if archInitCastagnoli() was previously called. -// archUpdateCastagnoli(crc uint32, p []byte) uint32 - -// castagnoliTable points to a lazily initialized Table for the Castagnoli -// polynomial. MakeTable will always return this value when asked to make a -// Castagnoli table so we can compare against it to find when the caller is -// using this polynomial. -var castagnoliTable *Table -var castagnoliTable8 *slicing8Table -var castagnoliArchImpl bool -var updateCastagnoli func(crc uint32, p []byte) uint32 -var castagnoliOnce sync.Once - -func castagnoliInit() { - castagnoliTable = simpleMakeTable(Castagnoli) - castagnoliArchImpl = archAvailableCastagnoli() - - if castagnoliArchImpl { - archInitCastagnoli() - updateCastagnoli = archUpdateCastagnoli - } else { - // Initialize the slicing-by-8 table. - castagnoliTable8 = slicingMakeTable(Castagnoli) - updateCastagnoli = func(crc uint32, p []byte) uint32 { - return slicingUpdate(crc, castagnoliTable8, p) - } - } -} - -// IEEETable is the table for the IEEE polynomial. -var IEEETable = simpleMakeTable(IEEE) - -// ieeeTable8 is the slicing8Table for IEEE -var ieeeTable8 *slicing8Table -var ieeeArchImpl bool -var updateIEEE func(crc uint32, p []byte) uint32 -var ieeeOnce sync.Once - -func ieeeInit() { - ieeeArchImpl = archAvailableIEEE() - - if ieeeArchImpl { - archInitIEEE() - updateIEEE = archUpdateIEEE - } else { - // Initialize the slicing-by-8 table. - ieeeTable8 = slicingMakeTable(IEEE) - updateIEEE = func(crc uint32, p []byte) uint32 { - return slicingUpdate(crc, ieeeTable8, p) - } - } -} - -// MakeTable returns a Table constructed from the specified polynomial. -// The contents of this Table must not be modified. -func MakeTable(poly uint32) *Table { - switch poly { - case IEEE: - ieeeOnce.Do(ieeeInit) - return IEEETable - case Castagnoli: - castagnoliOnce.Do(castagnoliInit) - return castagnoliTable - } - return simpleMakeTable(poly) -} - -// digest represents the partial evaluation of a checksum. -type digest struct { - crc uint32 - tab *Table -} - -// New creates a new hash.Hash32 computing the CRC-32 checksum -// using the polynomial represented by the Table. -// Its Sum method will lay the value out in big-endian byte order. -func New(tab *Table) hash.Hash32 { - if tab == IEEETable { - ieeeOnce.Do(ieeeInit) - } - return &digest{0, tab} -} - -// NewIEEE creates a new hash.Hash32 computing the CRC-32 checksum -// using the IEEE polynomial. -// Its Sum method will lay the value out in big-endian byte order. -func NewIEEE() hash.Hash32 { return New(IEEETable) } - -func (d *digest) Size() int { return Size } - -func (d *digest) BlockSize() int { return 1 } - -func (d *digest) Reset() { d.crc = 0 } - -// Update returns the result of adding the bytes in p to the crc. -func Update(crc uint32, tab *Table, p []byte) uint32 { - switch tab { - case castagnoliTable: - return updateCastagnoli(crc, p) - case IEEETable: - // Unfortunately, because IEEETable is exported, IEEE may be used without a - // call to MakeTable. We have to make sure it gets initialized in that case. - ieeeOnce.Do(ieeeInit) - return updateIEEE(crc, p) - default: - return simpleUpdate(crc, tab, p) - } -} - -func (d *digest) Write(p []byte) (n int, err error) { - switch d.tab { - case castagnoliTable: - d.crc = updateCastagnoli(d.crc, p) - case IEEETable: - // We only create digest objects through New() which takes care of - // initialization in this case. - d.crc = updateIEEE(d.crc, p) - default: - d.crc = simpleUpdate(d.crc, d.tab, p) - } - return len(p), nil -} - -func (d *digest) Sum32() uint32 { return d.crc } - -func (d *digest) Sum(in []byte) []byte { - s := d.Sum32() - return append(in, byte(s>>24), byte(s>>16), byte(s>>8), byte(s)) -} - -// Checksum returns the CRC-32 checksum of data -// using the polynomial represented by the Table. -func Checksum(data []byte, tab *Table) uint32 { return Update(0, tab, data) } - -// ChecksumIEEE returns the CRC-32 checksum of data -// using the IEEE polynomial. -func ChecksumIEEE(data []byte) uint32 { - ieeeOnce.Do(ieeeInit) - return updateIEEE(0, data) -} |