zlibx: reader -> constants

1 files changed, 52 insertions, 0 deletions

diff --git a/internal/zlibx/constants.go b/internal/zlibx/constants.go
new file mode 100644
index 00000000..161e3458
--- /dev/null
+++ b/internal/zlibx/constants.go
@@ -0,0 +1,52 @@
+// 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 zlibx implements reading of zlib format compressed data,
+as specified in RFC 1950.
+
+This package differs from the standard library's compress/zlib package
+in that it pools readers to reduce allocations. Writing is unsupported.
+
+THis package will likely be refactorered much more for our specific
+use case of only doing full decompressions to byte slices.
+
+Note that closing the reader causes it to be returned to a pool for
+reuse. Therefore, the caller must not retain references to the
+reader after closing it; in the standard library's compress/zlib package,
+it is legal to Reset a closed reader and continue using it; that is
+not allowed here, so there is simply no Resetter interface.
+
+The implementation provides filters that uncompress during reading
+and compress during writing.  For example, to write compressed data
+to a buffer:
+
+	var b bytes.Buffer
+	w := zlib.NewWriter(&b)
+	w.Write([]byte("hello, world\n"))
+	w.Close()
+
+and to read that data back:
+
+	r, err := zlib.NewReader(&b)
+	io.Copy(os.Stdout, r)
+	r.Close()
+*/
+package zlibx
+
+import (
+	"errors"
+)
+
+const (
+	zlibDeflate   = 8
+	zlibMaxWindow = 7
+)
+
+var (
+	// ErrChecksum is returned when reading ZLIB data that has an invalid checksum.
+	ErrChecksum = errors.New("zlib: invalid checksum")
+	// ErrHeader is returned when reading ZLIB data that has an invalid header.
+	ErrHeader = errors.New("zlib: invalid header")
+)