ascii.go

Documentation: golang.org/x/text/encoding/ianaindex

     1  // Copyright 2019 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package ianaindex
     6  
     7  import (
     8  	"unicode"
     9  	"unicode/utf8"
    10  
    11  	"golang.org/x/text/encoding"
    12  	"golang.org/x/text/encoding/internal"
    13  	"golang.org/x/text/encoding/internal/identifier"
    14  	"golang.org/x/text/transform"
    15  )
    16  
    17  type asciiDecoder struct {
    18  	transform.NopResetter
    19  }
    20  
    21  func (d asciiDecoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
    22  	for _, c := range src {
    23  		if c > unicode.MaxASCII {
    24  			r := unicode.ReplacementChar
    25  			if nDst+utf8.RuneLen(r) > len(dst) {
    26  				err = transform.ErrShortDst
    27  				break
    28  			}
    29  			nDst += utf8.EncodeRune(dst[nDst:], r)
    30  			nSrc++
    31  			continue
    32  		}
    33  
    34  		if nDst >= len(dst) {
    35  			err = transform.ErrShortDst
    36  			break
    37  		}
    38  		dst[nDst] = c
    39  		nDst++
    40  		nSrc++
    41  	}
    42  	return nDst, nSrc, err
    43  }
    44  
    45  type asciiEncoder struct {
    46  	transform.NopResetter
    47  }
    48  
    49  func (d asciiEncoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
    50  	for _, c := range src {
    51  		if c > unicode.MaxASCII {
    52  			err = internal.RepertoireError(encoding.ASCIISub)
    53  			break
    54  		}
    55  
    56  		if nDst >= len(dst) {
    57  			err = transform.ErrShortDst
    58  			break
    59  		}
    60  		dst[nDst] = c
    61  		nDst++
    62  		nSrc++
    63  	}
    64  	return nDst, nSrc, err
    65  }
    66  
    67  var asciiEnc = &internal.Encoding{
    68  	Encoding: &internal.SimpleEncoding{
    69  		asciiDecoder{},
    70  		asciiEncoder{},
    71  	},
    72  	Name: "US-ASCII",
    73  	MIB:  identifier.ASCII,
    74  }
    75
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