X-Git-Url: http://git.osdn.net/view?p=bytom%2Fvapor.git;a=blobdiff_plain;f=vendor%2Fgithub.com%2Fgolang%2Fsnappy%2Fencode_other.go;fp=vendor%2Fgithub.com%2Fgolang%2Fsnappy%2Fencode_other.go;h=0000000000000000000000000000000000000000;hp=dbcae905e6e047ba3c00f68057f5bf8541e981fa;hb=d09b7a78d44dc259725902b8141cdba0d716b121;hpb=ee01d543fdfe1fd0a4d548965c66f7923ea7b062

diff --git a/vendor/github.com/golang/snappy/encode_other.go b/vendor/github.com/golang/snappy/encode_other.go
deleted file mode 100644
index dbcae905..00000000
--- a/vendor/github.com/golang/snappy/encode_other.go
+++ /dev/null
@@ -1,238 +0,0 @@
-// Copyright 2016 The Snappy-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.
-
-// +build !amd64 appengine !gc noasm
-
-package snappy
-
-func load32(b []byte, i int) uint32 {
-	b = b[i : i+4 : len(b)] // Help the compiler eliminate bounds checks on the next line.
-	return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
-}
-
-func load64(b []byte, i int) uint64 {
-	b = b[i : i+8 : len(b)] // Help the compiler eliminate bounds checks on the next line.
-	return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
-		uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
-}
-
-// emitLiteral writes a literal chunk and returns the number of bytes written.
-//
-// It assumes that:
-//	dst is long enough to hold the encoded bytes
-//	1 <= len(lit) && len(lit) <= 65536
-func emitLiteral(dst, lit []byte) int {
-	i, n := 0, uint(len(lit)-1)
-	switch {
-	case n < 60:
-		dst[0] = uint8(n)<<2 | tagLiteral
-		i = 1
-	case n < 1<<8:
-		dst[0] = 60<<2 | tagLiteral
-		dst[1] = uint8(n)
-		i = 2
-	default:
-		dst[0] = 61<<2 | tagLiteral
-		dst[1] = uint8(n)
-		dst[2] = uint8(n >> 8)
-		i = 3
-	}
-	return i + copy(dst[i:], lit)
-}
-
-// emitCopy writes a copy chunk and returns the number of bytes written.
-//
-// It assumes that:
-//	dst is long enough to hold the encoded bytes
-//	1 <= offset && offset <= 65535
-//	4 <= length && length <= 65535
-func emitCopy(dst []byte, offset, length int) int {
-	i := 0
-	// The maximum length for a single tagCopy1 or tagCopy2 op is 64 bytes. The
-	// threshold for this loop is a little higher (at 68 = 64 + 4), and the
-	// length emitted down below is is a little lower (at 60 = 64 - 4), because
-	// it's shorter to encode a length 67 copy as a length 60 tagCopy2 followed
-	// by a length 7 tagCopy1 (which encodes as 3+2 bytes) than to encode it as
-	// a length 64 tagCopy2 followed by a length 3 tagCopy2 (which encodes as
-	// 3+3 bytes). The magic 4 in the 64±4 is because the minimum length for a
-	// tagCopy1 op is 4 bytes, which is why a length 3 copy has to be an
-	// encodes-as-3-bytes tagCopy2 instead of an encodes-as-2-bytes tagCopy1.
-	for length >= 68 {
-		// Emit a length 64 copy, encoded as 3 bytes.
-		dst[i+0] = 63<<2 | tagCopy2
-		dst[i+1] = uint8(offset)
-		dst[i+2] = uint8(offset >> 8)
-		i += 3
-		length -= 64
-	}
-	if length > 64 {
-		// Emit a length 60 copy, encoded as 3 bytes.
-		dst[i+0] = 59<<2 | tagCopy2
-		dst[i+1] = uint8(offset)
-		dst[i+2] = uint8(offset >> 8)
-		i += 3
-		length -= 60
-	}
-	if length >= 12 || offset >= 2048 {
-		// Emit the remaining copy, encoded as 3 bytes.
-		dst[i+0] = uint8(length-1)<<2 | tagCopy2
-		dst[i+1] = uint8(offset)
-		dst[i+2] = uint8(offset >> 8)
-		return i + 3
-	}
-	// Emit the remaining copy, encoded as 2 bytes.
-	dst[i+0] = uint8(offset>>8)<<5 | uint8(length-4)<<2 | tagCopy1
-	dst[i+1] = uint8(offset)
-	return i + 2
-}
-
-// extendMatch returns the largest k such that k <= len(src) and that
-// src[i:i+k-j] and src[j:k] have the same contents.
-//
-// It assumes that:
-//	0 <= i && i < j && j <= len(src)
-func extendMatch(src []byte, i, j int) int {
-	for ; j < len(src) && src[i] == src[j]; i, j = i+1, j+1 {
-	}
-	return j
-}
-
-func hash(u, shift uint32) uint32 {
-	return (u * 0x1e35a7bd) >> shift
-}
-
-// encodeBlock encodes a non-empty src to a guaranteed-large-enough dst. It
-// assumes that the varint-encoded length of the decompressed bytes has already
-// been written.
-//
-// It also assumes that:
-//	len(dst) >= MaxEncodedLen(len(src)) &&
-// 	minNonLiteralBlockSize <= len(src) && len(src) <= maxBlockSize
-func encodeBlock(dst, src []byte) (d int) {
-	// Initialize the hash table. Its size ranges from 1<<8 to 1<<14 inclusive.
-	// The table element type is uint16, as s < sLimit and sLimit < len(src)
-	// and len(src) <= maxBlockSize and maxBlockSize == 65536.
-	const (
-		maxTableSize = 1 << 14
-		// tableMask is redundant, but helps the compiler eliminate bounds
-		// checks.
-		tableMask = maxTableSize - 1
-	)
-	shift := uint32(32 - 8)
-	for tableSize := 1 << 8; tableSize < maxTableSize && tableSize < len(src); tableSize *= 2 {
-		shift--
-	}
-	// In Go, all array elements are zero-initialized, so there is no advantage
-	// to a smaller tableSize per se. However, it matches the C++ algorithm,
-	// and in the asm versions of this code, we can get away with zeroing only
-	// the first tableSize elements.
-	var table [maxTableSize]uint16
-
-	// sLimit is when to stop looking for offset/length copies. The inputMargin
-	// lets us use a fast path for emitLiteral in the main loop, while we are
-	// looking for copies.
-	sLimit := len(src) - inputMargin
-
-	// nextEmit is where in src the next emitLiteral should start from.
-	nextEmit := 0
-
-	// The encoded form must start with a literal, as there are no previous
-	// bytes to copy, so we start looking for hash matches at s == 1.
-	s := 1
-	nextHash := hash(load32(src, s), shift)
-
-	for {
-		// Copied from the C++ snappy implementation:
-		//
-		// Heuristic match skipping: If 32 bytes are scanned with no matches
-		// found, start looking only at every other byte. If 32 more bytes are
-		// scanned (or skipped), look at every third byte, etc.. When a match
-		// is found, immediately go back to looking at every byte. This is a
-		// small loss (~5% performance, ~0.1% density) for compressible data
-		// due to more bookkeeping, but for non-compressible data (such as
-		// JPEG) it's a huge win since the compressor quickly "realizes" the
-		// data is incompressible and doesn't bother looking for matches
-		// everywhere.
-		//
-		// The "skip" variable keeps track of how many bytes there are since
-		// the last match; dividing it by 32 (ie. right-shifting by five) gives
-		// the number of bytes to move ahead for each iteration.
-		skip := 32
-
-		nextS := s
-		candidate := 0
-		for {
-			s = nextS
-			bytesBetweenHashLookups := skip >> 5
-			nextS = s + bytesBetweenHashLookups
-			skip += bytesBetweenHashLookups
-			if nextS > sLimit {
-				goto emitRemainder
-			}
-			candidate = int(table[nextHash&tableMask])
-			table[nextHash&tableMask] = uint16(s)
-			nextHash = hash(load32(src, nextS), shift)
-			if load32(src, s) == load32(src, candidate) {
-				break
-			}
-		}
-
-		// A 4-byte match has been found. We'll later see if more than 4 bytes
-		// match. But, prior to the match, src[nextEmit:s] are unmatched. Emit
-		// them as literal bytes.
-		d += emitLiteral(dst[d:], src[nextEmit:s])
-
-		// Call emitCopy, and then see if another emitCopy could be our next
-		// move. Repeat until we find no match for the input immediately after
-		// what was consumed by the last emitCopy call.
-		//
-		// If we exit this loop normally then we need to call emitLiteral next,
-		// though we don't yet know how big the literal will be. We handle that
-		// by proceeding to the next iteration of the main loop. We also can
-		// exit this loop via goto if we get close to exhausting the input.
-		for {
-			// Invariant: we have a 4-byte match at s, and no need to emit any
-			// literal bytes prior to s.
-			base := s
-
-			// Extend the 4-byte match as long as possible.
-			//
-			// This is an inlined version of:
-			//	s = extendMatch(src, candidate+4, s+4)
-			s += 4
-			for i := candidate + 4; s < len(src) && src[i] == src[s]; i, s = i+1, s+1 {
-			}
-
-			d += emitCopy(dst[d:], base-candidate, s-base)
-			nextEmit = s
-			if s >= sLimit {
-				goto emitRemainder
-			}
-
-			// We could immediately start working at s now, but to improve
-			// compression we first update the hash table at s-1 and at s. If
-			// another emitCopy is not our next move, also calculate nextHash
-			// at s+1. At least on GOARCH=amd64, these three hash calculations
-			// are faster as one load64 call (with some shifts) instead of
-			// three load32 calls.
-			x := load64(src, s-1)
-			prevHash := hash(uint32(x>>0), shift)
-			table[prevHash&tableMask] = uint16(s - 1)
-			currHash := hash(uint32(x>>8), shift)
-			candidate = int(table[currHash&tableMask])
-			table[currHash&tableMask] = uint16(s)
-			if uint32(x>>8) != load32(src, candidate) {
-				nextHash = hash(uint32(x>>16), shift)
-				s++
-				break
-			}
-		}
-	}
-
-emitRemainder:
-	if nextEmit < len(src) {
-		d += emitLiteral(dst[d:], src[nextEmit:])
-	}
-	return d
-}