1 files changed, 301 insertions, 0 deletions
diff --git a/vendor/github.com/paulrosania/go-charset/charset/charset.go b/vendor/github.com/paulrosania/go-charset/charset/charset.go
new file mode 100644
index 00000000..6ab6cf89
--- /dev/null
+++ b/vendor/github.com/paulrosania/go-charset/charset/charset.go
@@ -0,0 +1,301 @@
+// The charset package implements translation between character sets.
+// It uses Unicode as the intermediate representation.
+// Because it can be large, the character set data is separated
+// from the charset package. It can be embedded in the Go
+// executable by importing the data package:
+//
+//	import _ "github.com/paulrosania/go-charset/data"
+//
+// It can also made available in a data directory (by settting CharsetDir).
+package charset
+
+import (
+	"io"
+	"strings"
+	"unicode/utf8"
+)
+
+// Charset holds information about a given character set.
+type Charset struct {
+	Name    string   // Canonical name of character set.
+	Aliases []string // Known aliases.
+	Desc    string   // Description.
+	NoFrom  bool     // Not possible to translate from this charset.
+	NoTo    bool     // Not possible to translate to this charset.
+}
+
+// Translator represents a character set converter.
+// The Translate method translates the given data,
+// and returns the number of bytes of data consumed,
+// a slice containing the converted data (which may be
+// overwritten on the next call to Translate), and any
+// conversion error. If eof is true, the data represents
+// the final bytes of the input.
+type Translator interface {
+	Translate(data []byte, eof bool) (n int, cdata []byte, err error)
+}
+
+// A Factory can be used to make character set translators.
+type Factory interface {
+	// TranslatorFrom creates a translator that will translate from the named character
+	// set to UTF-8.
+	TranslatorFrom(name string) (Translator, error) // Create a Translator from this character set to.
+
+	// TranslatorTo creates a translator that will translate from UTF-8 to the named character set.
+	TranslatorTo(name string) (Translator, error) // Create a Translator To this character set.
+
+	// Names returns all the character set names accessibile through the factory.
+	Names() []string
+
+	// Info returns information on the named character set. It returns nil if the
+	// factory doesn't recognise the given name.
+	Info(name string) *Charset
+}
+
+var factories = []Factory{localFactory{}}
+
+// Register registers a new Factory which will be consulted when NewReader
+// or NewWriter needs a character set translator for a given name.
+func Register(factory Factory) {
+	factories = append(factories, factory)
+}
+
+// NewReader returns a new Reader that translates from the named
+// character set to UTF-8 as it reads r.
+func NewReader(charset string, r io.Reader) (io.Reader, error) {
+	tr, err := TranslatorFrom(charset)
+	if err != nil {
+		return nil, err
+	}
+	return NewTranslatingReader(r, tr), nil
+}
+
+// NewWriter returns a new WriteCloser writing to w.  It converts writes
+// of UTF-8 text into writes on w of text in the named character set.
+// The Close is necessary to flush any remaining partially translated
+// characters to the output.
+func NewWriter(charset string, w io.Writer) (io.WriteCloser, error) {
+	tr, err := TranslatorTo(charset)
+	if err != nil {
+		return nil, err
+	}
+	return NewTranslatingWriter(w, tr), nil
+}
+
+// Info returns information about a character set, or nil
+// if the character set is not found.
+func Info(name string) *Charset {
+	for _, f := range factories {
+		if info := f.Info(name); info != nil {
+			return info
+		}
+	}
+	return nil
+}
+
+// Names returns the canonical names of all supported character sets, in alphabetical order.
+func Names() []string {
+	// TODO eliminate duplicates
+	var names []string
+	for _, f := range factories {
+		names = append(names, f.Names()...)
+	}
+	return names
+}
+
+// TranslatorFrom returns a translator that will translate from
+// the named character set to UTF-8.
+func TranslatorFrom(charset string) (Translator, error) {
+	var err error
+	var tr Translator
+	for _, f := range factories {
+		tr, err = f.TranslatorFrom(charset)
+		if err == nil {
+			break
+		}
+	}
+	if tr == nil {
+		return nil, err
+	}
+	return tr, nil
+}
+
+// TranslatorTo returns a translator that will translate from UTF-8
+// to the named character set.
+func TranslatorTo(charset string) (Translator, error) {
+	var err error
+	var tr Translator
+	for _, f := range factories {
+		tr, err = f.TranslatorTo(charset)
+		if err == nil {
+			break
+		}
+	}
+	if tr == nil {
+		return nil, err
+	}
+	return tr, nil
+}
+
+func normalizedChar(c rune) rune {
+	switch {
+	case c >= 'A' && c <= 'Z':
+		c = c - 'A' + 'a'
+	case c == '_':
+		c = '-'
+	}
+	return c
+}
+
+// NormalisedName returns s with all Roman capitals
+// mapped to lower case, and '_' mapped to '-'
+func NormalizedName(s string) string {
+	return strings.Map(normalizedChar, s)
+}
+
+type translatingWriter struct {
+	w   io.Writer
+	tr  Translator
+	buf []byte // unconsumed data from writer.
+}
+
+// NewTranslatingWriter returns a new WriteCloser writing to w.
+// It passes the written bytes through the given Translator.
+func NewTranslatingWriter(w io.Writer, tr Translator) io.WriteCloser {
+	return &translatingWriter{w: w, tr: tr}
+}
+
+func (w *translatingWriter) Write(data []byte) (rn int, rerr error) {
+	wdata := data
+	if len(w.buf) > 0 {
+		w.buf = append(w.buf, data...)
+		wdata = w.buf
+	}
+	n, cdata, err := w.tr.Translate(wdata, false)
+	if err != nil {
+		// TODO
+	}
+	if n > 0 {
+		_, err = w.w.Write(cdata)
+		if err != nil {
+			return 0, err
+		}
+	}
+	w.buf = w.buf[:0]
+	if n < len(wdata) {
+		w.buf = append(w.buf, wdata[n:]...)
+	}
+	return len(data), nil
+}
+
+func (p *translatingWriter) Close() error {
+	for {
+		n, data, err := p.tr.Translate(p.buf, true)
+		p.buf = p.buf[n:]
+		if err != nil {
+			// TODO
+		}
+		// If the Translator produces no data
+		// at EOF, then assume that it never will.
+		if len(data) == 0 {
+			break
+		}
+		n, err = p.w.Write(data)
+		if err != nil {
+			return err
+		}
+		if n < len(data) {
+			return io.ErrShortWrite
+		}
+		if len(p.buf) == 0 {
+			break
+		}
+	}
+	return nil
+}
+
+type translatingReader struct {
+	r     io.Reader
+	tr    Translator
+	cdata []byte // unconsumed data from converter.
+	rdata []byte // unconverted data from reader.
+	err   error  // final error from reader.
+}
+
+// NewTranslatingReader returns a new Reader that
+// translates data using the given Translator as it reads r.
+func NewTranslatingReader(r io.Reader, tr Translator) io.Reader {
+	return &translatingReader{r: r, tr: tr}
+}
+
+func (r *translatingReader) Read(buf []byte) (int, error) {
+	for {
+		if len(r.cdata) > 0 {
+			n := copy(buf, r.cdata)
+			r.cdata = r.cdata[n:]
+			return n, nil
+		}
+		if r.err == nil {
+			r.rdata = ensureCap(r.rdata, len(r.rdata)+len(buf))
+			n, err := r.r.Read(r.rdata[len(r.rdata):cap(r.rdata)])
+			// Guard against non-compliant Readers.
+			if n == 0 && err == nil {
+				err = io.EOF
+			}
+			r.rdata = r.rdata[0 : len(r.rdata)+n]
+			r.err = err
+		} else if len(r.rdata) == 0 {
+			break
+		}
+		nc, cdata, cvterr := r.tr.Translate(r.rdata, r.err != nil)
+		if cvterr != nil {
+			// TODO
+		}
+		r.cdata = cdata
+
+		// Ensure that we consume all bytes at eof
+		// if the converter refuses them.
+		if nc == 0 && r.err != nil {
+			nc = len(r.rdata)
+		}
+
+		// Copy unconsumed data to the start of the rdata buffer.
+		r.rdata = r.rdata[0:copy(r.rdata, r.rdata[nc:])]
+	}
+	return 0, r.err
+}
+
+// ensureCap returns s with a capacity of at least n bytes.
+// If cap(s) < n, then it returns a new copy of s with the
+// required capacity.
+func ensureCap(s []byte, n int) []byte {
+	if n <= cap(s) {
+		return s
+	}
+	// logic adapted from appendslice1 in runtime
+	m := cap(s)
+	if m == 0 {
+		m = n
+	} else {
+		for {
+			if m < 1024 {
+				m += m
+			} else {
+				m += m / 4
+			}
+			if m >= n {
+				break
+			}
+		}
+	}
+	t := make([]byte, len(s), m)
+	copy(t, s)
+	return t
+}
+
+func appendRune(buf []byte, r rune) []byte {
+	n := len(buf)
+	buf = ensureCap(buf, n+utf8.UTFMax)
+	nu := utf8.EncodeRune(buf[n:n+utf8.UTFMax], r)
+	return buf[0 : n+nu]
+}