1 files changed, 291 insertions, 0 deletions
diff --git a/vendor/github.com/vincent-petithory/dataurl/dataurl.go b/vendor/github.com/vincent-petithory/dataurl/dataurl.go
new file mode 100644
index 00000000..7a9fe67e
--- /dev/null
+++ b/vendor/github.com/vincent-petithory/dataurl/dataurl.go
@@ -0,0 +1,291 @@
+package dataurl
+
+import (
+	"bytes"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+const (
+	// EncodingBase64 is base64 encoding for the data url
+	EncodingBase64 = "base64"
+	// EncodingASCII is ascii encoding for the data url
+	EncodingASCII = "ascii"
+)
+
+func defaultMediaType() MediaType {
+	return MediaType{
+		"text",
+		"plain",
+		map[string]string{"charset": "US-ASCII"},
+	}
+}
+
+// MediaType is the combination of a media type, a media subtype
+// and optional parameters.
+type MediaType struct {
+	Type    string
+	Subtype string
+	Params  map[string]string
+}
+
+// ContentType returns the content type of the dataurl's data, in the form type/subtype.
+func (mt *MediaType) ContentType() string {
+	return fmt.Sprintf("%s/%s", mt.Type, mt.Subtype)
+}
+
+// String implements the Stringer interface.
+//
+// Params values are escaped with the Escape function, rather than in a quoted string.
+func (mt *MediaType) String() string {
+	var (
+		buf  bytes.Buffer
+		keys = make([]string, len(mt.Params))
+		i    int
+	)
+	for k := range mt.Params {
+		keys[i] = k
+		i++
+	}
+	sort.Strings(keys)
+	for _, k := range keys {
+		v := mt.Params[k]
+		fmt.Fprintf(&buf, ";%s=%s", k, EscapeString(v))
+	}
+	return mt.ContentType() + (&buf).String()
+}
+
+// DataURL is the combination of a MediaType describing the type of its Data.
+type DataURL struct {
+	MediaType
+	Encoding string
+	Data     []byte
+}
+
+// New returns a new DataURL initialized with data and
+// a MediaType parsed from mediatype and paramPairs.
+// mediatype must be of the form "type/subtype" or it will panic.
+// paramPairs must have an even number of elements or it will panic.
+// For more complex DataURL, initialize a DataURL struct.
+// The DataURL is initialized with base64 encoding.
+func New(data []byte, mediatype string, paramPairs ...string) *DataURL {
+	parts := strings.Split(mediatype, "/")
+	if len(parts) != 2 {
+		panic("dataurl: invalid mediatype")
+	}
+
+	nParams := len(paramPairs)
+	if nParams%2 != 0 {
+		panic("dataurl: requires an even number of param pairs")
+	}
+	params := make(map[string]string)
+	for i := 0; i < nParams; i += 2 {
+		params[paramPairs[i]] = paramPairs[i+1]
+	}
+
+	mt := MediaType{
+		parts[0],
+		parts[1],
+		params,
+	}
+	return &DataURL{
+		MediaType: mt,
+		Encoding:  EncodingBase64,
+		Data:      data,
+	}
+}
+
+// String implements the Stringer interface.
+//
+// Note: it doesn't guarantee the returned string is equal to
+// the initial source string that was used to create this DataURL.
+// The reasons for that are:
+//  * Insertion of default values for MediaType that were maybe not in the initial string,
+//  * Various ways to encode the MediaType parameters (quoted string or url encoded string, the latter is used),
+func (du *DataURL) String() string {
+	var buf bytes.Buffer
+	du.WriteTo(&buf)
+	return (&buf).String()
+}
+
+// WriteTo implements the WriterTo interface.
+// See the note about String().
+func (du *DataURL) WriteTo(w io.Writer) (n int64, err error) {
+	var ni int
+	ni, _ = fmt.Fprint(w, "data:")
+	n += int64(ni)
+
+	ni, _ = fmt.Fprint(w, du.MediaType.String())
+	n += int64(ni)
+
+	if du.Encoding == EncodingBase64 {
+		ni, _ = fmt.Fprint(w, ";base64")
+		n += int64(ni)
+	}
+
+	ni, _ = fmt.Fprint(w, ",")
+	n += int64(ni)
+
+	if du.Encoding == EncodingBase64 {
+		encoder := base64.NewEncoder(base64.StdEncoding, w)
+		ni, err = encoder.Write(du.Data)
+		if err != nil {
+			return
+		}
+		encoder.Close()
+	} else if du.Encoding == EncodingASCII {
+		ni, _ = fmt.Fprint(w, Escape(du.Data))
+		n += int64(ni)
+	} else {
+		err = fmt.Errorf("dataurl: invalid encoding %s", du.Encoding)
+		return
+	}
+
+	return
+}
+
+// UnmarshalText decodes a Data URL string and sets it to *du
+func (du *DataURL) UnmarshalText(text []byte) error {
+	decoded, err := DecodeString(string(text))
+	if err != nil {
+		return err
+	}
+	*du = *decoded
+	return nil
+}
+
+// MarshalText writes du as a Data URL
+func (du *DataURL) MarshalText() ([]byte, error) {
+	buf := bytes.NewBuffer(nil)
+	if _, err := du.WriteTo(buf); err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+type encodedDataReader func(string) ([]byte, error)
+
+var asciiDataReader encodedDataReader = func(s string) ([]byte, error) {
+	us, err := Unescape(s)
+	if err != nil {
+		return nil, err
+	}
+	return []byte(us), nil
+}
+
+var base64DataReader encodedDataReader = func(s string) ([]byte, error) {
+	data, err := base64.StdEncoding.DecodeString(s)
+	if err != nil {
+		return nil, err
+	}
+	return []byte(data), nil
+}
+
+type parser struct {
+	du                  *DataURL
+	l                   *lexer
+	currentAttr         string
+	unquoteParamVal     bool
+	encodedDataReaderFn encodedDataReader
+}
+
+func (p *parser) parse() error {
+	for item := range p.l.items {
+		switch item.t {
+		case itemError:
+			return errors.New(item.String())
+		case itemMediaType:
+			p.du.MediaType.Type = item.val
+			// Should we clear the default
+			// "charset" parameter at this point?
+			delete(p.du.MediaType.Params, "charset")
+		case itemMediaSubType:
+			p.du.MediaType.Subtype = item.val
+		case itemParamAttr:
+			p.currentAttr = item.val
+		case itemLeftStringQuote:
+			p.unquoteParamVal = true
+		case itemParamVal:
+			val := item.val
+			if p.unquoteParamVal {
+				p.unquoteParamVal = false
+				us, err := strconv.Unquote("\"" + val + "\"")
+				if err != nil {
+					return err
+				}
+				val = us
+			} else {
+				us, err := UnescapeToString(val)
+				if err != nil {
+					return err
+				}
+				val = us
+			}
+			p.du.MediaType.Params[p.currentAttr] = val
+		case itemBase64Enc:
+			p.du.Encoding = EncodingBase64
+			p.encodedDataReaderFn = base64DataReader
+		case itemDataComma:
+			if p.encodedDataReaderFn == nil {
+				p.encodedDataReaderFn = asciiDataReader
+			}
+		case itemData:
+			reader, err := p.encodedDataReaderFn(item.val)
+			if err != nil {
+				return err
+			}
+			p.du.Data = reader
+		case itemEOF:
+			if p.du.Data == nil {
+				p.du.Data = []byte("")
+			}
+			return nil
+		}
+	}
+	panic("EOF not found")
+}
+
+// DecodeString decodes a Data URL scheme string.
+func DecodeString(s string) (*DataURL, error) {
+	du := &DataURL{
+		MediaType: defaultMediaType(),
+		Encoding:  EncodingASCII,
+	}
+
+	parser := &parser{
+		du: du,
+		l:  lex(s),
+	}
+	if err := parser.parse(); err != nil {
+		return nil, err
+	}
+	return du, nil
+}
+
+// Decode decodes a Data URL scheme from a io.Reader.
+func Decode(r io.Reader) (*DataURL, error) {
+	data, err := ioutil.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+	return DecodeString(string(data))
+}
+
+// EncodeBytes encodes the data bytes into a Data URL string, using base 64 encoding.
+//
+// The media type of data is detected using http.DetectContentType.
+func EncodeBytes(data []byte) string {
+	mt := http.DetectContentType(data)
+	// http.DetectContentType may add spurious spaces between ; and a parameter.
+	// The canonical way is to not have them.
+	cleanedMt := strings.Replace(mt, "; ", ";", -1)
+
+	return New(data, cleanedMt).String()
+}