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authorDaniel J Walsh <dwalsh@redhat.com>2019-08-01 03:46:14 -0400
committerDaniel J Walsh <dwalsh@redhat.com>2019-08-01 03:46:14 -0400
commit9d6dce119949d340ebb42becae018a3c11148690 (patch)
treec0bb999f9bddbc9379f9f7b159194d35c077fb36 /vendor/github.com/klauspost/compress/zstd/zstd.go
parent39de184b8bfb14954f77190f0e6127c1ddc363c0 (diff)
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github.com/containers/storage v1.12.13
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>
Diffstat (limited to 'vendor/github.com/klauspost/compress/zstd/zstd.go')
-rw-r--r--vendor/github.com/klauspost/compress/zstd/zstd.go135
1 files changed, 135 insertions, 0 deletions
diff --git a/vendor/github.com/klauspost/compress/zstd/zstd.go b/vendor/github.com/klauspost/compress/zstd/zstd.go
new file mode 100644
index 000000000..b975954c1
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/zstd/zstd.go
@@ -0,0 +1,135 @@
+// Package zstd provides decompression of zstandard files.
+//
+// For advanced usage and examples, go to the README: https://github.com/klauspost/compress/tree/master/zstd#zstd
+package zstd
+
+import (
+ "errors"
+ "log"
+ "math/bits"
+)
+
+const debug = false
+const debugSequences = false
+
+// force encoder to use predefined tables.
+const forcePreDef = false
+
+// zstdMinMatch is the minimum zstd match length.
+const zstdMinMatch = 3
+
+var (
+ // ErrReservedBlockType is returned when a reserved block type is found.
+ // Typically this indicates wrong or corrupted input.
+ ErrReservedBlockType = errors.New("invalid input: reserved block type encountered")
+
+ // ErrCompressedSizeTooBig is returned when a block is bigger than allowed.
+ // Typically this indicates wrong or corrupted input.
+ ErrCompressedSizeTooBig = errors.New("invalid input: compressed size too big")
+
+ // ErrBlockTooSmall is returned when a block is too small to be decoded.
+ // Typically returned on invalid input.
+ ErrBlockTooSmall = errors.New("block too small")
+
+ // ErrMagicMismatch is returned when a "magic" number isn't what is expected.
+ // Typically this indicates wrong or corrupted input.
+ ErrMagicMismatch = errors.New("invalid input: magic number mismatch")
+
+ // ErrWindowSizeExceeded is returned when a reference exceeds the valid window size.
+ // Typically this indicates wrong or corrupted input.
+ ErrWindowSizeExceeded = errors.New("window size exceeded")
+
+ // ErrWindowSizeTooSmall is returned when no window size is specified.
+ // Typically this indicates wrong or corrupted input.
+ ErrWindowSizeTooSmall = errors.New("invalid input: window size was too small")
+
+ // ErrDecoderSizeExceeded is returned if decompressed size exceeds the configured limit.
+ ErrDecoderSizeExceeded = errors.New("decompressed size exceeds configured limit")
+
+ // ErrUnknownDictionary is returned if the dictionary ID is unknown.
+ // For the time being dictionaries are not supported.
+ ErrUnknownDictionary = errors.New("unknown dictionary")
+
+ // ErrFrameSizeExceeded is returned if the stated frame size is exceeded.
+ // This is only returned if SingleSegment is specified on the frame.
+ ErrFrameSizeExceeded = errors.New("frame size exceeded")
+
+ // ErrCRCMismatch is returned if CRC mismatches.
+ ErrCRCMismatch = errors.New("CRC check failed")
+
+ // ErrDecoderClosed will be returned if the Decoder was used after
+ // Close has been called.
+ ErrDecoderClosed = errors.New("decoder used after Close")
+)
+
+func println(a ...interface{}) {
+ if debug {
+ log.Println(a...)
+ }
+}
+
+func printf(format string, a ...interface{}) {
+ if debug {
+ log.Printf(format, a...)
+ }
+}
+
+// matchLen returns the maximum length.
+// a must be the shortest of the two.
+// The function also returns whether all bytes matched.
+func matchLen(a, b []byte) int {
+ b = b[:len(a)]
+ for i := 0; i < len(a)-7; i += 8 {
+ if diff := load64(a, i) ^ load64(b, i); diff != 0 {
+ return i + (bits.TrailingZeros64(diff) >> 3)
+ }
+ }
+ checked := (len(a) >> 3) << 3
+ a = a[checked:]
+ b = b[checked:]
+ // TODO: We could do a 4 check.
+ for i := range a {
+ if a[i] != b[i] {
+ return int(i) + checked
+ }
+ }
+ return len(a) + checked
+}
+
+// matchLen returns a match length in src between index s and t
+func matchLenIn(src []byte, s, t int32) int32 {
+ s1 := len(src)
+ b := src[t:]
+ a := src[s:s1]
+ b = b[:len(a)]
+ // Extend the match to be as long as possible.
+ for i := range a {
+ if a[i] != b[i] {
+ return int32(i)
+ }
+ }
+ return int32(len(a))
+}
+
+func load3232(b []byte, i int32) uint32 {
+ // Help the compiler eliminate bounds checks on the read so it can be done in a single read.
+ b = b[i:]
+ b = b[:4]
+ return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
+}
+
+func load6432(b []byte, i int32) uint64 {
+ // Help the compiler eliminate bounds checks on the read so it can be done in a single read.
+ b = b[i:]
+ b = b[:8]
+ 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
+}
+
+func load64(b []byte, i int) uint64 {
+ // Help the compiler eliminate bounds checks on the read so it can be done in a single read.
+ b = b[i:]
+ b = b[:8]
+ 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
+}