1 files changed, 144 insertions, 0 deletions
diff --git a/libgo/go/http/lex.go b/libgo/go/http/lex.go
new file mode 100644
index 000000000..93b67e701
--- /dev/null
+++ b/libgo/go/http/lex.go
@@ -0,0 +1,144 @@
+// 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 http
+
+// This file deals with lexical matters of HTTP
+
+func isSeparator(c byte) bool {
+	switch c {
+	case '(', ')', '<', '>', '@', ',', ';', ':', '\\', '"', '/', '[', ']', '?', '=', '{', '}', ' ', '\t':
+		return true
+	}
+	return false
+}
+
+func isSpace(c byte) bool {
+	switch c {
+	case ' ', '\t', '\r', '\n':
+		return true
+	}
+	return false
+}
+
+func isCtl(c byte) bool { return (0 <= c && c <= 31) || c == 127 }
+
+func isChar(c byte) bool { return 0 <= c && c <= 127 }
+
+func isAnyText(c byte) bool { return !isCtl(c) }
+
+func isQdText(c byte) bool { return isAnyText(c) && c != '"' }
+
+func isToken(c byte) bool { return isChar(c) && !isCtl(c) && !isSeparator(c) }
+
+// Valid escaped sequences are not specified in RFC 2616, so for now, we assume
+// that they coincide with the common sense ones used by GO. Malformed
+// characters should probably not be treated as errors by a robust (forgiving)
+// parser, so we replace them with the '?' character.
+func httpUnquotePair(b byte) byte {
+	// skip the first byte, which should always be '\'
+	switch b {
+	case 'a':
+		return '\a'
+	case 'b':
+		return '\b'
+	case 'f':
+		return '\f'
+	case 'n':
+		return '\n'
+	case 'r':
+		return '\r'
+	case 't':
+		return '\t'
+	case 'v':
+		return '\v'
+	case '\\':
+		return '\\'
+	case '\'':
+		return '\''
+	case '"':
+		return '"'
+	}
+	return '?'
+}
+
+// raw must begin with a valid quoted string. Only the first quoted string is
+// parsed and is unquoted in result. eaten is the number of bytes parsed, or -1
+// upon failure.
+func httpUnquote(raw []byte) (eaten int, result string) {
+	buf := make([]byte, len(raw))
+	if raw[0] != '"' {
+		return -1, ""
+	}
+	eaten = 1
+	j := 0 // # of bytes written in buf
+	for i := 1; i < len(raw); i++ {
+		switch b := raw[i]; b {
+		case '"':
+			eaten++
+			buf = buf[0:j]
+			return i + 1, string(buf)
+		case '\\':
+			if len(raw) < i+2 {
+				return -1, ""
+			}
+			buf[j] = httpUnquotePair(raw[i+1])
+			eaten += 2
+			j++
+			i++
+		default:
+			if isQdText(b) {
+				buf[j] = b
+			} else {
+				buf[j] = '?'
+			}
+			eaten++
+			j++
+		}
+	}
+	return -1, ""
+}
+
+// This is a best effort parse, so errors are not returned, instead not all of
+// the input string might be parsed. result is always non-nil.
+func httpSplitFieldValue(fv string) (eaten int, result []string) {
+	result = make([]string, 0, len(fv))
+	raw := []byte(fv)
+	i := 0
+	chunk := ""
+	for i < len(raw) {
+		b := raw[i]
+		switch {
+		case b == '"':
+			eaten, unq := httpUnquote(raw[i:len(raw)])
+			if eaten < 0 {
+				return i, result
+			} else {
+				i += eaten
+				chunk += unq
+			}
+		case isSeparator(b):
+			if chunk != "" {
+				result = result[0 : len(result)+1]
+				result[len(result)-1] = chunk
+				chunk = ""
+			}
+			i++
+		case isToken(b):
+			chunk += string(b)
+			i++
+		case b == '\n' || b == '\r':
+			i++
+		default:
+			chunk += "?"
+			i++
+		}
+	}
+	if chunk != "" {
+		result = result[0 : len(result)+1]
+		result[len(result)-1] = chunk
+		chunk = ""
+	}
+	return i, result
+}