proto.go

// Go support for Protocol Buffers - Google's data interchange format
//
// Copyright 2010 The Go Authors.  All rights reserved.
// https://github.com/golang/protobuf
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

package main

import (
	"bytes"
	"fmt"
)

var (
	newline         = []byte("\n")
	spaces          = []byte("                                        ")
	endBraceNewline = []byte("}\n")
	backslashN      = []byte{'\\', 'n'}
	backslashR      = []byte{'\\', 'r'}
	backslashT      = []byte{'\\', 't'}
	backslashDQ     = []byte{'\\', '"'}
	backslashBS     = []byte{'\\', '\\'}
	posInf          = []byte("inf")
	negInf          = []byte("-inf")
	nan             = []byte("nan")
)

func formatProto(s string) string {
	var buf bytes.Buffer
	// Loop over the bytes, not the runes.
	for i := 0; i < len(s); i++ {
		// Divergence from C++: we don't escape apostrophes.
		// There's no need to escape them, and the C++ parser
		// copes with a naked apostrophe.
		switch c := s[i]; c {
		case '\n':
			buf.Write(backslashN)
		case '\r':
			buf.Write(backslashR)
		case '\t':
			buf.Write(backslashT)
		case '"':
			buf.Write(backslashDQ)
		case '\\':
			buf.Write(backslashBS)
		default:
			if isprint(c) {
				buf.WriteByte(c)
			} else {
				fmt.Fprintf(&buf, "\\%03o", c)
			}
		}
	}
	return buf.String()
}

// equivalent to C's isprint.
func isprint(c byte) bool {
	return c >= 0x20 && c < 0x7f
}