Merge remote-tracking branch 'gnu/gcc-4_7-branch' into rework

[pf3gnuchains/gcc-fork.git] / libgo / go / go / doc / synopsis.go

diff --git a/libgo/go/go/doc/synopsis.go b/libgo/go/go/doc/synopsis.go
new file mode 100644 (file)
index 0000000..2192d78
--- /dev/null
+++ b/libgo/go/go/doc/synopsis.go
@@ -0,0 +1,52 @@
+// Copyright 2012 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 doc
+
+import "unicode"
+
+// firstSentenceLen returns the length of the first sentence in s.
+// The sentence ends after the first period followed by space and
+// not preceded by exactly one uppercase letter.
+//
+func firstSentenceLen(s string) int {
+       var ppp, pp, p rune
+       for i, q := range s {
+               if q == '\n' || q == '\r' || q == '\t' {
+                       q = ' '
+               }
+               if q == ' ' && p == '.' && (!unicode.IsUpper(pp) || unicode.IsUpper(ppp)) {
+                       return i
+               }
+               ppp, pp, p = pp, p, q
+       }
+       return len(s)
+}
+
+// Synopsis returns a cleaned version of the first sentence in s.
+// That sentence ends after the first period followed by space and
+// not preceded by exactly one uppercase letter. The result string
+// has no \n, \r, or \t characters and uses only single spaces between
+// words.
+//
+func Synopsis(s string) string {
+       n := firstSentenceLen(s)
+       var b []byte
+       p := byte(' ')
+       for i := 0; i < n; i++ {
+               q := s[i]
+               if q == '\n' || q == '\r' || q == '\t' {
+                       q = ' '
+               }
+               if q != ' ' || p != ' ' {
+                       b = append(b, q)
+                       p = q
+               }
+       }
+       // remove trailing blank, if any
+       if n := len(b); n > 0 && p == ' ' {
+               b = b[0 : n-1]
+       }
+       return string(b)
+}