jochen
be92762969
The live tests reached one shared bus and assert, read and remove the mesh's own objects by their fixed names, so packages run in parallel deleted what each other read and the suite passed only one package at a time; a red suite read as noise. internal/testbus starts a server per test, linked in at the nats-server release go.mod pins, and a test holds that pin to the catalogue's bus image and to the facts snapshot's bus when there is one, so the tests never run a bus the mesh does not. The waiter test read a timing (the most connections held at one look) and now reads the state it means (the fewest held across the wait). make check runs the packages in parallel under the race detector, with a timeout.
741 lines
18 KiB
Go
741 lines
18 KiB
Go
//go:build (!amd64 && !arm64) || appengine || !gc || noasm
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package s2
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import (
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"bytes"
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"math/bits"
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)
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const hasAsm = false
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// encodeBlock encodes a non-empty src to a guaranteed-large-enough dst. It
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// assumes that the varint-encoded length of the decompressed bytes has already
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// been written.
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//
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// It also assumes that:
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//
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// len(dst) >= MaxEncodedLen(len(src))
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func encodeBlock(dst, src []byte) (d int) {
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if len(src) < minNonLiteralBlockSize {
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return 0
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}
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if len(src) <= 64<<10 {
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return encodeBlockGo64K(dst, src)
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}
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return encodeBlockGo(dst, src)
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}
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// encodeBlockBetter encodes a non-empty src to a guaranteed-large-enough dst. It
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// assumes that the varint-encoded length of the decompressed bytes has already
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// been written.
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//
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// It also assumes that:
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//
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// len(dst) >= MaxEncodedLen(len(src))
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func encodeBlockBetter(dst, src []byte) (d int) {
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if len(src) <= 64<<10 {
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return encodeBlockBetterGo64K(dst, src)
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}
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return encodeBlockBetterGo(dst, src)
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}
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// encodeBlockBetter encodes a non-empty src to a guaranteed-large-enough dst. It
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// assumes that the varint-encoded length of the decompressed bytes has already
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// been written.
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//
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// It also assumes that:
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//
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// len(dst) >= MaxEncodedLen(len(src))
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func encodeBlockBetterSnappy(dst, src []byte) (d int) {
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if len(src) <= 64<<10 {
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return encodeBlockBetterSnappyGo64K(dst, src)
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}
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return encodeBlockBetterSnappyGo(dst, src)
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}
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// encodeBlock encodes a non-empty src to a guaranteed-large-enough dst. It
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// assumes that the varint-encoded length of the decompressed bytes has already
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// been written.
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//
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// It also assumes that:
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//
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// len(dst) >= MaxEncodedLen(len(src))
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func encodeBlockSnappy(dst, src []byte) (d int) {
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if len(src) < minNonLiteralBlockSize {
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return 0
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}
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if len(src) <= 64<<10 {
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return encodeBlockSnappyGo64K(dst, src)
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}
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return encodeBlockSnappyGo(dst, src)
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}
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// emitLiteral writes a literal chunk and returns the number of bytes written.
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//
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// It assumes that:
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//
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// dst is long enough to hold the encoded bytes
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// 0 <= len(lit) && len(lit) <= math.MaxUint32
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func emitLiteral(dst, lit []byte) int {
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if len(lit) == 0 {
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return 0
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}
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const num = 63<<2 | tagLiteral
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i, n := 0, uint(len(lit)-1)
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switch {
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case n < 60:
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dst[0] = uint8(n)<<2 | tagLiteral
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i = 1
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case n < 1<<8:
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dst[1] = uint8(n)
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dst[0] = 60<<2 | tagLiteral
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i = 2
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case n < 1<<16:
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dst[2] = uint8(n >> 8)
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dst[1] = uint8(n)
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dst[0] = 61<<2 | tagLiteral
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i = 3
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case n < 1<<24:
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dst[3] = uint8(n >> 16)
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dst[2] = uint8(n >> 8)
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dst[1] = uint8(n)
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dst[0] = 62<<2 | tagLiteral
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i = 4
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default:
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dst[4] = uint8(n >> 24)
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dst[3] = uint8(n >> 16)
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dst[2] = uint8(n >> 8)
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dst[1] = uint8(n)
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dst[0] = 63<<2 | tagLiteral
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i = 5
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}
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return i + copy(dst[i:], lit)
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}
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// emitRepeat writes a repeat chunk and returns the number of bytes written.
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// Length must be at least 4 and < 1<<24
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func emitRepeat(dst []byte, offset, length int) int {
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// Repeat offset, make length cheaper
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length -= 4
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if length <= 4 {
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dst[0] = uint8(length)<<2 | tagCopy1
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dst[1] = 0
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return 2
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}
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if length < 8 && offset < 2048 {
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// Encode WITH offset
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dst[1] = uint8(offset)
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dst[0] = uint8(offset>>8)<<5 | uint8(length)<<2 | tagCopy1
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return 2
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}
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if length < (1<<8)+4 {
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length -= 4
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dst[2] = uint8(length)
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dst[1] = 0
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dst[0] = 5<<2 | tagCopy1
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return 3
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}
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if length < (1<<16)+(1<<8) {
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length -= 1 << 8
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dst[3] = uint8(length >> 8)
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dst[2] = uint8(length >> 0)
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dst[1] = 0
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dst[0] = 6<<2 | tagCopy1
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return 4
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}
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const maxRepeat = (1 << 24) - 1
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length -= 1 << 16
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left := 0
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if length > maxRepeat {
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left = length - maxRepeat + 4
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length = maxRepeat - 4
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}
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dst[4] = uint8(length >> 16)
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dst[3] = uint8(length >> 8)
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dst[2] = uint8(length >> 0)
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dst[1] = 0
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dst[0] = 7<<2 | tagCopy1
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if left > 0 {
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return 5 + emitRepeat(dst[5:], offset, left)
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}
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return 5
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}
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// emitCopy writes a copy chunk and returns the number of bytes written.
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//
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// It assumes that:
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//
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// dst is long enough to hold the encoded bytes
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// 1 <= offset && offset <= math.MaxUint32
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// 4 <= length && length <= 1 << 24
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func emitCopy(dst []byte, offset, length int) int {
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if offset >= 65536 {
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i := 0
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if length > 64 {
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// Emit a length 64 copy, encoded as 5 bytes.
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dst[4] = uint8(offset >> 24)
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dst[3] = uint8(offset >> 16)
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dst[2] = uint8(offset >> 8)
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dst[1] = uint8(offset)
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dst[0] = 63<<2 | tagCopy4
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length -= 64
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if length >= 4 {
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// Emit remaining as repeats
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return 5 + emitRepeat(dst[5:], offset, length)
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}
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i = 5
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}
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if length == 0 {
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return i
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}
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// Emit a copy, offset encoded as 4 bytes.
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dst[i+0] = uint8(length-1)<<2 | tagCopy4
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dst[i+1] = uint8(offset)
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dst[i+2] = uint8(offset >> 8)
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dst[i+3] = uint8(offset >> 16)
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dst[i+4] = uint8(offset >> 24)
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return i + 5
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}
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// Offset no more than 2 bytes.
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if length > 64 {
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off := 3
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if offset < 2048 {
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// emit 8 bytes as tagCopy1, rest as repeats.
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dst[1] = uint8(offset)
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dst[0] = uint8(offset>>8)<<5 | uint8(8-4)<<2 | tagCopy1
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length -= 8
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off = 2
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} else {
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// Emit a length 60 copy, encoded as 3 bytes.
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// Emit remaining as repeat value (minimum 4 bytes).
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dst[2] = uint8(offset >> 8)
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dst[1] = uint8(offset)
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dst[0] = 59<<2 | tagCopy2
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length -= 60
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}
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// Emit remaining as repeats, at least 4 bytes remain.
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return off + emitRepeat(dst[off:], offset, length)
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}
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if length >= 12 || offset >= 2048 {
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// Emit the remaining copy, encoded as 3 bytes.
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dst[2] = uint8(offset >> 8)
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dst[1] = uint8(offset)
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dst[0] = uint8(length-1)<<2 | tagCopy2
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return 3
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}
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// Emit the remaining copy, encoded as 2 bytes.
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dst[1] = uint8(offset)
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dst[0] = uint8(offset>>8)<<5 | uint8(length-4)<<2 | tagCopy1
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return 2
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}
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// emitCopyNoRepeat writes a copy chunk and returns the number of bytes written.
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//
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// It assumes that:
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//
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// dst is long enough to hold the encoded bytes
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// 1 <= offset && offset <= math.MaxUint32
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// 4 <= length && length <= 1 << 24
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func emitCopyNoRepeat(dst []byte, offset, length int) int {
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if offset >= 65536 {
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i := 0
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if length > 64 {
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// Emit a length 64 copy, encoded as 5 bytes.
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dst[4] = uint8(offset >> 24)
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dst[3] = uint8(offset >> 16)
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dst[2] = uint8(offset >> 8)
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dst[1] = uint8(offset)
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dst[0] = 63<<2 | tagCopy4
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length -= 64
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if length >= 4 {
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// Emit remaining as repeats
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return 5 + emitCopyNoRepeat(dst[5:], offset, length)
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}
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i = 5
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}
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if length == 0 {
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return i
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}
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// Emit a copy, offset encoded as 4 bytes.
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dst[i+0] = uint8(length-1)<<2 | tagCopy4
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dst[i+1] = uint8(offset)
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dst[i+2] = uint8(offset >> 8)
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dst[i+3] = uint8(offset >> 16)
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dst[i+4] = uint8(offset >> 24)
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return i + 5
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}
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// Offset no more than 2 bytes.
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if length > 64 {
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// Emit a length 60 copy, encoded as 3 bytes.
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// Emit remaining as repeat value (minimum 4 bytes).
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dst[2] = uint8(offset >> 8)
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dst[1] = uint8(offset)
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dst[0] = 59<<2 | tagCopy2
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length -= 60
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// Emit remaining as repeats, at least 4 bytes remain.
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return 3 + emitCopyNoRepeat(dst[3:], offset, length)
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}
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if length >= 12 || offset >= 2048 {
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// Emit the remaining copy, encoded as 3 bytes.
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dst[2] = uint8(offset >> 8)
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dst[1] = uint8(offset)
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dst[0] = uint8(length-1)<<2 | tagCopy2
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return 3
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}
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// Emit the remaining copy, encoded as 2 bytes.
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dst[1] = uint8(offset)
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dst[0] = uint8(offset>>8)<<5 | uint8(length-4)<<2 | tagCopy1
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return 2
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}
|
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// matchLen returns how many bytes match in a and b
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//
|
|
// It assumes that:
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//
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// len(a) <= len(b)
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func matchLen(a []byte, b []byte) int {
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b = b[:len(a)]
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var checked int
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if len(a) > 4 {
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// Try 4 bytes first
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if diff := load32(a, 0) ^ load32(b, 0); diff != 0 {
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return bits.TrailingZeros32(diff) >> 3
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}
|
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// Switch to 8 byte matching.
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checked = 4
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a = a[4:]
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b = b[4:]
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for len(a) >= 8 {
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b = b[:len(a)]
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if diff := load64(a, 0) ^ load64(b, 0); diff != 0 {
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return checked + (bits.TrailingZeros64(diff) >> 3)
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}
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checked += 8
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a = a[8:]
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b = b[8:]
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}
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}
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b = b[:len(a)]
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for i := range a {
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if a[i] != b[i] {
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return int(i) + checked
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}
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}
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return len(a) + checked
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}
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// input must be > inputMargin
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func calcBlockSize(src []byte, _ *[32768]byte) (d int) {
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// Initialize the hash table.
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const (
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tableBits = 13
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maxTableSize = 1 << tableBits
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)
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var table [maxTableSize]uint32
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// sLimit is when to stop looking for offset/length copies. The inputMargin
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// lets us use a fast path for emitLiteral in the main loop, while we are
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// looking for copies.
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sLimit := len(src) - inputMargin
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// Bail if we can't compress to at least this.
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dstLimit := len(src) - len(src)>>5 - 5
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|
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// nextEmit is where in src the next emitLiteral should start from.
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nextEmit := 0
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// The encoded form must start with a literal, as there are no previous
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// bytes to copy, so we start looking for hash matches at s == 1.
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s := 1
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cv := load64(src, s)
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// We search for a repeat at -1, but don't output repeats when nextEmit == 0
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repeat := 1
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for {
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candidate := 0
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for {
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// Next src position to check
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nextS := s + (s-nextEmit)>>6 + 4
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if nextS > sLimit {
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goto emitRemainder
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}
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hash0 := hash6(cv, tableBits)
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hash1 := hash6(cv>>8, tableBits)
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candidate = int(table[hash0])
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candidate2 := int(table[hash1])
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table[hash0] = uint32(s)
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table[hash1] = uint32(s + 1)
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hash2 := hash6(cv>>16, tableBits)
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// Check repeat at offset checkRep.
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const checkRep = 1
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if uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
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base := s + checkRep
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// Extend back
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for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
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i--
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base--
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}
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d += emitLiteralSize(src[nextEmit:base])
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|
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// Extend forward
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candidate := s - repeat + 4 + checkRep
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s += 4 + checkRep
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for s <= sLimit {
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if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
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s += bits.TrailingZeros64(diff) >> 3
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break
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}
|
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s += 8
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candidate += 8
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}
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|
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d += emitCopyNoRepeatSize(repeat, s-base)
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nextEmit = s
|
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if s >= sLimit {
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goto emitRemainder
|
|
}
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cv = load64(src, s)
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|
continue
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|
}
|
|
|
|
if uint32(cv) == load32(src, candidate) {
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|
break
|
|
}
|
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candidate = int(table[hash2])
|
|
if uint32(cv>>8) == load32(src, candidate2) {
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table[hash2] = uint32(s + 2)
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candidate = candidate2
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s++
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break
|
|
}
|
|
table[hash2] = uint32(s + 2)
|
|
if uint32(cv>>16) == load32(src, candidate) {
|
|
s += 2
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break
|
|
}
|
|
|
|
cv = load64(src, nextS)
|
|
s = nextS
|
|
}
|
|
|
|
// Extend backwards
|
|
for candidate > 0 && s > nextEmit && src[candidate-1] == src[s-1] {
|
|
candidate--
|
|
s--
|
|
}
|
|
|
|
// Bail if we exceed the maximum size.
|
|
if d+(s-nextEmit) > dstLimit {
|
|
return 0
|
|
}
|
|
|
|
// 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 += emitLiteralSize(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
|
|
repeat = base - candidate
|
|
|
|
// Extend the 4-byte match as long as possible.
|
|
s += 4
|
|
candidate += 4
|
|
for s <= len(src)-8 {
|
|
if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
|
|
s += bits.TrailingZeros64(diff) >> 3
|
|
break
|
|
}
|
|
s += 8
|
|
candidate += 8
|
|
}
|
|
|
|
d += emitCopyNoRepeatSize(repeat, s-base)
|
|
if false {
|
|
// Validate match.
|
|
a := src[base:s]
|
|
b := src[base-repeat : base-repeat+(s-base)]
|
|
if !bytes.Equal(a, b) {
|
|
panic("mismatch")
|
|
}
|
|
}
|
|
|
|
nextEmit = s
|
|
if s >= sLimit {
|
|
goto emitRemainder
|
|
}
|
|
|
|
if d > dstLimit {
|
|
// Do we have space for more, if not bail.
|
|
return 0
|
|
}
|
|
// Check for an immediate match, otherwise start search at s+1
|
|
x := load64(src, s-2)
|
|
m2Hash := hash6(x, tableBits)
|
|
currHash := hash6(x>>16, tableBits)
|
|
candidate = int(table[currHash])
|
|
table[m2Hash] = uint32(s - 2)
|
|
table[currHash] = uint32(s)
|
|
if uint32(x>>16) != load32(src, candidate) {
|
|
cv = load64(src, s+1)
|
|
s++
|
|
break
|
|
}
|
|
}
|
|
}
|
|
|
|
emitRemainder:
|
|
if nextEmit < len(src) {
|
|
// Bail if we exceed the maximum size.
|
|
if d+len(src)-nextEmit > dstLimit {
|
|
return 0
|
|
}
|
|
d += emitLiteralSize(src[nextEmit:])
|
|
}
|
|
return d
|
|
}
|
|
|
|
// length must be > inputMargin.
|
|
func calcBlockSizeSmall(src []byte, _ *[2048]byte) (d int) {
|
|
// Initialize the hash table.
|
|
const (
|
|
tableBits = 9
|
|
maxTableSize = 1 << tableBits
|
|
)
|
|
|
|
var table [maxTableSize]uint32
|
|
|
|
// 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
|
|
|
|
// Bail if we can't compress to at least this.
|
|
dstLimit := len(src) - len(src)>>5 - 5
|
|
|
|
// 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
|
|
cv := load64(src, s)
|
|
|
|
// We search for a repeat at -1, but don't output repeats when nextEmit == 0
|
|
repeat := 1
|
|
|
|
for {
|
|
candidate := 0
|
|
for {
|
|
// Next src position to check
|
|
nextS := s + (s-nextEmit)>>6 + 4
|
|
if nextS > sLimit {
|
|
goto emitRemainder
|
|
}
|
|
hash0 := hash6(cv, tableBits)
|
|
hash1 := hash6(cv>>8, tableBits)
|
|
candidate = int(table[hash0])
|
|
candidate2 := int(table[hash1])
|
|
table[hash0] = uint32(s)
|
|
table[hash1] = uint32(s + 1)
|
|
hash2 := hash6(cv>>16, tableBits)
|
|
|
|
// Check repeat at offset checkRep.
|
|
const checkRep = 1
|
|
if uint32(cv>>(checkRep*8)) == load32(src, s-repeat+checkRep) {
|
|
base := s + checkRep
|
|
// Extend back
|
|
for i := base - repeat; base > nextEmit && i > 0 && src[i-1] == src[base-1]; {
|
|
i--
|
|
base--
|
|
}
|
|
d += emitLiteralSize(src[nextEmit:base])
|
|
|
|
// Extend forward
|
|
candidate := s - repeat + 4 + checkRep
|
|
s += 4 + checkRep
|
|
for s <= sLimit {
|
|
if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
|
|
s += bits.TrailingZeros64(diff) >> 3
|
|
break
|
|
}
|
|
s += 8
|
|
candidate += 8
|
|
}
|
|
|
|
d += emitCopyNoRepeatSize(repeat, s-base)
|
|
nextEmit = s
|
|
if s >= sLimit {
|
|
goto emitRemainder
|
|
}
|
|
|
|
cv = load64(src, s)
|
|
continue
|
|
}
|
|
|
|
if uint32(cv) == load32(src, candidate) {
|
|
break
|
|
}
|
|
candidate = int(table[hash2])
|
|
if uint32(cv>>8) == load32(src, candidate2) {
|
|
table[hash2] = uint32(s + 2)
|
|
candidate = candidate2
|
|
s++
|
|
break
|
|
}
|
|
table[hash2] = uint32(s + 2)
|
|
if uint32(cv>>16) == load32(src, candidate) {
|
|
s += 2
|
|
break
|
|
}
|
|
|
|
cv = load64(src, nextS)
|
|
s = nextS
|
|
}
|
|
|
|
// Extend backwards
|
|
for candidate > 0 && s > nextEmit && src[candidate-1] == src[s-1] {
|
|
candidate--
|
|
s--
|
|
}
|
|
|
|
// Bail if we exceed the maximum size.
|
|
if d+(s-nextEmit) > dstLimit {
|
|
return 0
|
|
}
|
|
|
|
// 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 += emitLiteralSize(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
|
|
repeat = base - candidate
|
|
|
|
// Extend the 4-byte match as long as possible.
|
|
s += 4
|
|
candidate += 4
|
|
for s <= len(src)-8 {
|
|
if diff := load64(src, s) ^ load64(src, candidate); diff != 0 {
|
|
s += bits.TrailingZeros64(diff) >> 3
|
|
break
|
|
}
|
|
s += 8
|
|
candidate += 8
|
|
}
|
|
|
|
d += emitCopyNoRepeatSize(repeat, s-base)
|
|
if false {
|
|
// Validate match.
|
|
a := src[base:s]
|
|
b := src[base-repeat : base-repeat+(s-base)]
|
|
if !bytes.Equal(a, b) {
|
|
panic("mismatch")
|
|
}
|
|
}
|
|
|
|
nextEmit = s
|
|
if s >= sLimit {
|
|
goto emitRemainder
|
|
}
|
|
|
|
if d > dstLimit {
|
|
// Do we have space for more, if not bail.
|
|
return 0
|
|
}
|
|
// Check for an immediate match, otherwise start search at s+1
|
|
x := load64(src, s-2)
|
|
m2Hash := hash6(x, tableBits)
|
|
currHash := hash6(x>>16, tableBits)
|
|
candidate = int(table[currHash])
|
|
table[m2Hash] = uint32(s - 2)
|
|
table[currHash] = uint32(s)
|
|
if uint32(x>>16) != load32(src, candidate) {
|
|
cv = load64(src, s+1)
|
|
s++
|
|
break
|
|
}
|
|
}
|
|
}
|
|
|
|
emitRemainder:
|
|
if nextEmit < len(src) {
|
|
// Bail if we exceed the maximum size.
|
|
if d+len(src)-nextEmit > dstLimit {
|
|
return 0
|
|
}
|
|
d += emitLiteralSize(src[nextEmit:])
|
|
}
|
|
return d
|
|
}
|
|
|
|
// emitLiteral writes a literal chunk and returns the number of bytes written.
|
|
//
|
|
// It assumes that:
|
|
//
|
|
// dst is long enough to hold the encoded bytes
|
|
// 0 <= len(lit) && len(lit) <= math.MaxUint32
|
|
func emitLiteralSize(lit []byte) int {
|
|
if len(lit) == 0 {
|
|
return 0
|
|
}
|
|
switch {
|
|
case len(lit) <= 60:
|
|
return len(lit) + 1
|
|
case len(lit) <= 1<<8:
|
|
return len(lit) + 2
|
|
case len(lit) <= 1<<16:
|
|
return len(lit) + 3
|
|
case len(lit) <= 1<<24:
|
|
return len(lit) + 4
|
|
default:
|
|
return len(lit) + 5
|
|
}
|
|
}
|
|
|
|
func cvtLZ4BlockAsm(dst []byte, src []byte) (uncompressed int, dstUsed int) {
|
|
panic("cvtLZ4BlockAsm should be unreachable")
|
|
}
|
|
|
|
func cvtLZ4BlockSnappyAsm(dst []byte, src []byte) (uncompressed int, dstUsed int) {
|
|
panic("cvtLZ4BlockSnappyAsm should be unreachable")
|
|
}
|
|
|
|
func cvtLZ4sBlockAsm(dst []byte, src []byte) (uncompressed int, dstUsed int) {
|
|
panic("cvtLZ4sBlockAsm should be unreachable")
|
|
}
|
|
|
|
func cvtLZ4sBlockSnappyAsm(dst []byte, src []byte) (uncompressed int, dstUsed int) {
|
|
panic("cvtLZ4sBlockSnappyAsm should be unreachable")
|
|
}
|