Adding upstream version 1.22.1.upstream/1.22.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 78 insertions, 0 deletions

diff --git a/src/cmd/internal/objabi/path.go b/src/cmd/internal/objabi/path.go
new file mode 100644
index 0000000..30301b1
--- /dev/null
+++ b/src/cmd/internal/objabi/path.go
@@ -0,0 +1,78 @@
+// Copyright 2017 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 objabi
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// PathToPrefix converts raw string to the prefix that will be used in the
+// symbol table. All control characters, space, '%' and '"', as well as
+// non-7-bit clean bytes turn into %xx. The period needs escaping only in the
+// last segment of the path, and it makes for happier users if we escape that as
+// little as possible.
+func PathToPrefix(s string) string {
+	slash := strings.LastIndex(s, "/")
+	// check for chars that need escaping
+	n := 0
+	for r := 0; r < len(s); r++ {
+		if c := s[r]; c <= ' ' || (c == '.' && r > slash) || c == '%' || c == '"' || c >= 0x7F {
+			n++
+		}
+	}
+
+	// quick exit
+	if n == 0 {
+		return s
+	}
+
+	// escape
+	const hex = "0123456789abcdef"
+	p := make([]byte, 0, len(s)+2*n)
+	for r := 0; r < len(s); r++ {
+		if c := s[r]; c <= ' ' || (c == '.' && r > slash) || c == '%' || c == '"' || c >= 0x7F {
+			p = append(p, '%', hex[c>>4], hex[c&0xF])
+		} else {
+			p = append(p, c)
+		}
+	}
+
+	return string(p)
+}
+
+// PrefixToPath is the inverse of PathToPrefix, replacing escape sequences with
+// the original character.
+func PrefixToPath(s string) (string, error) {
+	percent := strings.IndexByte(s, '%')
+	if percent == -1 {
+		return s, nil
+	}
+
+	p := make([]byte, 0, len(s))
+	for i := 0; i < len(s); {
+		if s[i] != '%' {
+			p = append(p, s[i])
+			i++
+			continue
+		}
+		if i+2 >= len(s) {
+			// Not enough characters remaining to be a valid escape
+			// sequence.
+			return "", fmt.Errorf("malformed prefix %q: escape sequence must contain two hex digits", s)
+		}
+
+		b, err := strconv.ParseUint(s[i+1:i+3], 16, 8)
+		if err != nil {
+			// Not a valid escape sequence.
+			return "", fmt.Errorf("malformed prefix %q: escape sequence %q must contain two hex digits", s, s[i:i+3])
+		}
+
+		p = append(p, byte(b))
+		i += 3
+	}
+	return string(p), nil
+}