github.com/google/grumpy@v0.0.0-20171122020858-3ec87959189c/runtime/basestring.go (about)

     1  // Copyright 2016 Google Inc. All Rights Reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package grumpy
    16  
    17  import (
    18  	"regexp"
    19  	"strings"
    20  )
    21  
    22  // EncodeDefault is the system default encoding.
    23  const EncodeDefault = "utf8"
    24  
    25  // Error handling modes that dictate the behavior of *Str.Decode and
    26  // *Unicode.Encode when they encounter bad chars.
    27  const (
    28  	// EncodeStrict causes UnicodeError to be raised on bad chars.
    29  	EncodeStrict = "strict"
    30  	// EncodeReplace replaces bad chars with "\ufffd".
    31  	EncodeReplace = "replace"
    32  	// EncodeIgnore discards bad chars.
    33  	EncodeIgnore = "ignore"
    34  )
    35  
    36  var (
    37  	// BaseStringType is the object representing the Python 'basestring'
    38  	// type.
    39  	BaseStringType        = newSimpleType("basestring", ObjectType)
    40  	encodingGarbageRegexp = regexp.MustCompile(`[^A-Za-z0-9]+`)
    41  	escapeMap             = map[rune]string{
    42  		'\\': `\\`,
    43  		'\'': `\'`,
    44  		'\n': `\n`,
    45  		'\r': `\r`,
    46  		'\t': `\t`,
    47  	}
    48  )
    49  
    50  func initBaseStringType(map[string]*Object) {
    51  	BaseStringType.flags &^= typeFlagInstantiable
    52  }
    53  
    54  func normalizeEncoding(encoding string) string {
    55  	return strings.ToLower(encodingGarbageRegexp.ReplaceAllString(encoding, ""))
    56  }
    57  
    58  func escapeRune(r rune) []byte {
    59  	const hexTable = "0123456789abcdef"
    60  
    61  	if r < 0x100 {
    62  		return []byte{'\\', 'x', hexTable[r>>4], hexTable[r&0x0F]}
    63  	}
    64  
    65  	if r < 0x10000 {
    66  		return []byte{'\\', 'u',
    67  			hexTable[r>>12], hexTable[r>>8&0x0F],
    68  			hexTable[r>>4&0x0F], hexTable[r&0x0F]}
    69  	}
    70  
    71  	return []byte{'\\', 'U',
    72  		hexTable[r>>28], hexTable[r>>24&0x0F],
    73  		hexTable[r>>20&0x0F], hexTable[r>>16&0x0F],
    74  		hexTable[r>>12&0x0F], hexTable[r>>8&0x0F],
    75  		hexTable[r>>4&0x0F], hexTable[r&0x0F]}
    76  }