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Diffstat (limited to 'libgo/go/json/indent.go')
-rw-r--r--libgo/go/json/indent.go116
1 files changed, 116 insertions, 0 deletions
diff --git a/libgo/go/json/indent.go b/libgo/go/json/indent.go
new file mode 100644
index 000000000..000da42f6
--- /dev/null
+++ b/libgo/go/json/indent.go
@@ -0,0 +1,116 @@
+// Copyright 2010 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 json
+
+import (
+ "bytes"
+ "os"
+)
+
+// Compact appends to dst the JSON-encoded src with
+// insignificant space characters elided.
+func Compact(dst *bytes.Buffer, src []byte) os.Error {
+ origLen := dst.Len()
+ var scan scanner
+ scan.reset()
+ start := 0
+ for i, c := range src {
+ v := scan.step(&scan, int(c))
+ if v >= scanSkipSpace {
+ if v == scanError {
+ break
+ }
+ if start < i {
+ dst.Write(src[start:i])
+ }
+ start = i + 1
+ }
+ }
+ if scan.eof() == scanError {
+ dst.Truncate(origLen)
+ return scan.err
+ }
+ if start < len(src) {
+ dst.Write(src[start:])
+ }
+ return nil
+}
+
+func newline(dst *bytes.Buffer, prefix, indent string, depth int) {
+ dst.WriteByte('\n')
+ dst.WriteString(prefix)
+ for i := 0; i < depth; i++ {
+ dst.WriteString(indent)
+ }
+}
+
+// Indent appends to dst an indented form of the JSON-encoded src.
+// Each element in a JSON object or array begins on a new,
+// indented line beginning with prefix followed by one or more
+// copies of indent according to the indentation nesting.
+// The data appended to dst has no trailing newline, to make it easier
+// to embed inside other formatted JSON data.
+func Indent(dst *bytes.Buffer, src []byte, prefix, indent string) os.Error {
+ origLen := dst.Len()
+ var scan scanner
+ scan.reset()
+ needIndent := false
+ depth := 0
+ for _, c := range src {
+ v := scan.step(&scan, int(c))
+ if v == scanSkipSpace {
+ continue
+ }
+ if v == scanError {
+ break
+ }
+ if needIndent && v != scanEndObject && v != scanEndArray {
+ needIndent = false
+ depth++
+ newline(dst, prefix, indent, depth)
+ }
+
+ // Emit semantically uninteresting bytes
+ // (in particular, punctuation in strings) unmodified.
+ if v == scanContinue {
+ dst.WriteByte(c)
+ continue
+ }
+
+ // Add spacing around real punctuation.
+ switch c {
+ case '{', '[':
+ // delay indent so that empty object and array are formatted as {} and [].
+ needIndent = true
+ dst.WriteByte(c)
+
+ case ',':
+ dst.WriteByte(c)
+ newline(dst, prefix, indent, depth)
+
+ case ':':
+ dst.WriteByte(c)
+ dst.WriteByte(' ')
+
+ case '}', ']':
+ if needIndent {
+ // suppress indent in empty object/array
+ needIndent = false
+ } else {
+ depth--
+ newline(dst, prefix, indent, depth)
+ }
+ dst.WriteByte(c)
+
+ default:
+ dst.WriteByte(c)
+ }
+ }
+ if scan.eof() == scanError {
+ dst.Truncate(origLen)
+ return scan.err
+ }
+ return nil
+}