1 files changed, 292 insertions, 0 deletions

diff --git a/vendor/github.com/klauspost/compress/s2/decode_other.go b/vendor/github.com/klauspost/compress/s2/decode_other.go
new file mode 100644
index 0000000..2cb55c2
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/s2/decode_other.go
@@ -0,0 +1,292 @@
+// Copyright 2016 The Snappy-Go Authors. All rights reserved.
+// Copyright (c) 2019 Klaus Post. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build (!amd64 && !arm64) || appengine || !gc || noasm
+// +build !amd64,!arm64 appengine !gc noasm
+
+package s2
+
+import (
+        "fmt"
+        "strconv"
+)
+
+// decode writes the decoding of src to dst. It assumes that the varint-encoded
+// length of the decompressed bytes has already been read, and that len(dst)
+// equals that length.
+//
+// It returns 0 on success or a decodeErrCodeXxx error code on failure.
+func s2Decode(dst, src []byte) int {
+        const debug = false
+        if debug {
+                fmt.Println("Starting decode, dst len:", len(dst))
+        }
+        var d, s, length int
+        offset := 0
+
+        // As long as we can read at least 5 bytes...
+        for s < len(src)-5 {
+                // Removing bounds checks is SLOWER, when if doing
+                // in := src[s:s+5]
+                // Checked on Go 1.18
+                switch src[s] & 0x03 {
+                case tagLiteral:
+                        x := uint32(src[s] >> 2)
+                        switch {
+                        case x < 60:
+                                s++
+                        case x == 60:
+                                s += 2
+                                x = uint32(src[s-1])
+                        case x == 61:
+                                in := src[s : s+3]
+                                x = uint32(in[1]) | uint32(in[2])<<8
+                                s += 3
+                        case x == 62:
+                                in := src[s : s+4]
+                                // Load as 32 bit and shift down.
+                                x = uint32(in[0]) | uint32(in[1])<<8 | uint32(in[2])<<16 | uint32(in[3])<<24
+                                x >>= 8
+                                s += 4
+                        case x == 63:
+                                in := src[s : s+5]
+                                x = uint32(in[1]) | uint32(in[2])<<8 | uint32(in[3])<<16 | uint32(in[4])<<24
+                                s += 5
+                        }
+                        length = int(x) + 1
+                        if length > len(dst)-d || length > len(src)-s || (strconv.IntSize == 32 && length <= 0) {
+                                if debug {
+                                        fmt.Println("corrupt: lit size", length)
+                                }
+                                return decodeErrCodeCorrupt
+                        }
+                        if debug {
+                                fmt.Println("literals, length:", length, "d-after:", d+length)
+                        }
+
+                        copy(dst[d:], src[s:s+length])
+                        d += length
+                        s += length
+                        continue
+
+                case tagCopy1:
+                        s += 2
+                        toffset := int(uint32(src[s-2])&0xe0<<3 | uint32(src[s-1]))
+                        length = int(src[s-2]) >> 2 & 0x7
+                        if toffset == 0 {
+                                if debug {
+                                        fmt.Print("(repeat) ")
+                                }
+                                // keep last offset
+                                switch length {
+                                case 5:
+                                        length = int(src[s]) + 4
+                                        s += 1
+                                case 6:
+                                        in := src[s : s+2]
+                                        length = int(uint32(in[0])|(uint32(in[1])<<8)) + (1 << 8)
+                                        s += 2
+                                case 7:
+                                        in := src[s : s+3]
+                                        length = int((uint32(in[2])<<16)|(uint32(in[1])<<8)|uint32(in[0])) + (1 << 16)
+                                        s += 3
+                                default: // 0-> 4
+                                }
+                        } else {
+                                offset = toffset
+                        }
+                        length += 4
+                case tagCopy2:
+                        in := src[s : s+3]
+                        offset = int(uint32(in[1]) | uint32(in[2])<<8)
+                        length = 1 + int(in[0])>>2
+                        s += 3
+
+                case tagCopy4:
+                        in := src[s : s+5]
+                        offset = int(uint32(in[1]) | uint32(in[2])<<8 | uint32(in[3])<<16 | uint32(in[4])<<24)
+                        length = 1 + int(in[0])>>2
+                        s += 5
+                }
+
+                if offset <= 0 || d < offset || length > len(dst)-d {
+                        if debug {
+                                fmt.Println("corrupt: match, length", length, "offset:", offset, "dst avail:", len(dst)-d, "dst pos:", d)
+                        }
+
+                        return decodeErrCodeCorrupt
+                }
+
+                if debug {
+                        fmt.Println("copy, length:", length, "offset:", offset, "d-after:", d+length)
+                }
+
+                // Copy from an earlier sub-slice of dst to a later sub-slice.
+                // If no overlap, use the built-in copy:
+                if offset > length {
+                        copy(dst[d:d+length], dst[d-offset:])
+                        d += length
+                        continue
+                }
+
+                // Unlike the built-in copy function, this byte-by-byte copy always runs
+                // forwards, even if the slices overlap. Conceptually, this is:
+                //
+                // d += forwardCopy(dst[d:d+length], dst[d-offset:])
+                //
+                // We align the slices into a and b and show the compiler they are the same size.
+                // This allows the loop to run without bounds checks.
+                a := dst[d : d+length]
+                b := dst[d-offset:]
+                b = b[:len(a)]
+                for i := range a {
+                        a[i] = b[i]
+                }
+                d += length
+        }
+
+        // Remaining with extra checks...
+        for s < len(src) {
+                switch src[s] & 0x03 {
+                case tagLiteral:
+                        x := uint32(src[s] >> 2)
+                        switch {
+                        case x < 60:
+                                s++
+                        case x == 60:
+                                s += 2
+                                if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
+                                        return decodeErrCodeCorrupt
+                                }
+                                x = uint32(src[s-1])
+                        case x == 61:
+                                s += 3
+                                if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
+                                        return decodeErrCodeCorrupt
+                                }
+                                x = uint32(src[s-2]) | uint32(src[s-1])<<8
+                        case x == 62:
+                                s += 4
+                                if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
+                                        return decodeErrCodeCorrupt
+                                }
+                                x = uint32(src[s-3]) | uint32(src[s-2])<<8 | uint32(src[s-1])<<16
+                        case x == 63:
+                                s += 5
+                                if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
+                                        return decodeErrCodeCorrupt
+                                }
+                                x = uint32(src[s-4]) | uint32(src[s-3])<<8 | uint32(src[s-2])<<16 | uint32(src[s-1])<<24
+                        }
+                        length = int(x) + 1
+                        if length > len(dst)-d || length > len(src)-s || (strconv.IntSize == 32 && length <= 0) {
+                                if debug {
+                                        fmt.Println("corrupt: lit size", length)
+                                }
+                                return decodeErrCodeCorrupt
+                        }
+                        if debug {
+                                fmt.Println("literals, length:", length, "d-after:", d+length)
+                        }
+
+                        copy(dst[d:], src[s:s+length])
+                        d += length
+                        s += length
+                        continue
+
+                case tagCopy1:
+                        s += 2
+                        if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
+                                return decodeErrCodeCorrupt
+                        }
+                        length = int(src[s-2]) >> 2 & 0x7
+                        toffset := int(uint32(src[s-2])&0xe0<<3 | uint32(src[s-1]))
+                        if toffset == 0 {
+                                if debug {
+                                        fmt.Print("(repeat) ")
+                                }
+                                // keep last offset
+                                switch length {
+                                case 5:
+                                        s += 1
+                                        if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
+                                                return decodeErrCodeCorrupt
+                                        }
+                                        length = int(uint32(src[s-1])) + 4
+                                case 6:
+                                        s += 2
+                                        if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
+                                                return decodeErrCodeCorrupt
+                                        }
+                                        length = int(uint32(src[s-2])|(uint32(src[s-1])<<8)) + (1 << 8)
+                                case 7:
+                                        s += 3
+                                        if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
+                                                return decodeErrCodeCorrupt
+                                        }
+                                        length = int(uint32(src[s-3])|(uint32(src[s-2])<<8)|(uint32(src[s-1])<<16)) + (1 << 16)
+                                default: // 0-> 4
+                                }
+                        } else {
+                                offset = toffset
+                        }
+                        length += 4
+                case tagCopy2:
+                        s += 3
+                        if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
+                                return decodeErrCodeCorrupt
+                        }
+                        length = 1 + int(src[s-3])>>2
+                        offset = int(uint32(src[s-2]) | uint32(src[s-1])<<8)
+
+                case tagCopy4:
+                        s += 5
+                        if uint(s) > uint(len(src)) { // The uint conversions catch overflow from the previous line.
+                                return decodeErrCodeCorrupt
+                        }
+                        length = 1 + int(src[s-5])>>2
+                        offset = int(uint32(src[s-4]) | uint32(src[s-3])<<8 | uint32(src[s-2])<<16 | uint32(src[s-1])<<24)
+                }
+
+                if offset <= 0 || d < offset || length > len(dst)-d {
+                        if debug {
+                                fmt.Println("corrupt: match, length", length, "offset:", offset, "dst avail:", len(dst)-d, "dst pos:", d)
+                        }
+                        return decodeErrCodeCorrupt
+                }
+
+                if debug {
+                        fmt.Println("copy, length:", length, "offset:", offset, "d-after:", d+length)
+                }
+
+                // Copy from an earlier sub-slice of dst to a later sub-slice.
+                // If no overlap, use the built-in copy:
+                if offset > length {
+                        copy(dst[d:d+length], dst[d-offset:])
+                        d += length
+                        continue
+                }
+
+                // Unlike the built-in copy function, this byte-by-byte copy always runs
+                // forwards, even if the slices overlap. Conceptually, this is:
+                //
+                // d += forwardCopy(dst[d:d+length], dst[d-offset:])
+                //
+                // We align the slices into a and b and show the compiler they are the same size.
+                // This allows the loop to run without bounds checks.
+                a := dst[d : d+length]
+                b := dst[d-offset:]
+                b = b[:len(a)]
+                for i := range a {
+                        a[i] = b[i]
+                }
+                d += length
+        }
+
+        if d != len(dst) {
+                return decodeErrCodeCorrupt
+        }
+        return 0
+}