1 files changed, 115 insertions, 0 deletions
diff --git a/modules/mahonia/charset.go b/modules/mahonia/charset.go
new file mode 100644
index 00000000..14fa3b88
--- /dev/null
+++ b/modules/mahonia/charset.go
@@ -0,0 +1,115 @@
+// This package is a character-set conversion library for Go.
+//
+// (DEPRECATED: use code.google.com/p/go.text/encoding, perhaps along with
+// code.google.com/p/go.net/html/charset)
+package mahonia
+
+import (
+	"bytes"
+	"unicode"
+)
+
+// Status is the type for the status return value from a Decoder or Encoder.
+type Status int
+
+const (
+	// SUCCESS means that the character was converted with no problems.
+	SUCCESS = Status(iota)
+
+	// INVALID_CHAR means that the source contained invalid bytes, or that the character
+	// could not be represented in the destination encoding.
+	// The Encoder or Decoder should have output a substitute character.
+	INVALID_CHAR
+
+	// NO_ROOM means there were not enough input bytes to form a complete character,
+	// or there was not enough room in the output buffer to write a complete character.
+	// No bytes were written, and no internal state was changed in the Encoder or Decoder.
+	NO_ROOM
+
+	// STATE_ONLY means that bytes were read or written indicating a state transition,
+	// but no actual character was processed. (Examples: byte order marks, ISO-2022 escape sequences)
+	STATE_ONLY
+)
+
+// A Decoder is a function that decodes a character set, one character at a time.
+// It works much like utf8.DecodeRune, but has an aditional status return value.
+type Decoder func(p []byte) (c rune, size int, status Status)
+
+// An Encoder is a function that encodes a character set, one character at a time.
+// It works much like utf8.EncodeRune, but has an additional status return value.
+type Encoder func(p []byte, c rune) (size int, status Status)
+
+// A Charset represents a character set that can be converted, and contains functions
+// to create Converters to encode and decode strings in that character set.
+type Charset struct {
+	// Name is the character set's canonical name.
+	Name string
+
+	// Aliases returns a list of alternate names.
+	Aliases []string
+
+	// NewDecoder returns a Decoder to convert from the charset to Unicode.
+	NewDecoder func() Decoder
+
+	// NewEncoder returns an Encoder to convert from Unicode to the charset.
+	NewEncoder func() Encoder
+}
+
+// The charsets are stored in charsets under their canonical names.
+var charsets = make(map[string]*Charset)
+
+// aliases maps their aliases to their canonical names.
+var aliases = make(map[string]string)
+
+// simplifyName converts a name to lower case and removes non-alphanumeric characters.
+// This is how the names are used as keys to the maps.
+func simplifyName(name string) string {
+	var buf bytes.Buffer
+	for _, c := range name {
+		switch {
+		case unicode.IsDigit(c):
+			buf.WriteRune(c)
+		case unicode.IsLetter(c):
+			buf.WriteRune(unicode.ToLower(c))
+		default:
+
+		}
+	}
+
+	return buf.String()
+}
+
+// RegisterCharset adds a charset to the charsetMap.
+func RegisterCharset(cs *Charset) {
+	name := cs.Name
+	charsets[name] = cs
+	aliases[simplifyName(name)] = name
+	for _, alias := range cs.Aliases {
+		aliases[simplifyName(alias)] = name
+	}
+}
+
+// GetCharset fetches a charset by name.
+// If the name is not found, it returns nil.
+func GetCharset(name string) *Charset {
+	return charsets[aliases[simplifyName(name)]]
+}
+
+// NewDecoder returns a Decoder to decode the named charset.
+// If the name is not found, it returns nil.
+func NewDecoder(name string) Decoder {
+	cs := GetCharset(name)
+	if cs == nil {
+		return nil
+	}
+	return cs.NewDecoder()
+}
+
+// NewEncoder returns an Encoder to encode the named charset.
+func NewEncoder(name string) Encoder {
+	cs := GetCharset(name)
+	if cs == nil {
+		return nil
+	}
+	return cs.NewEncoder()
+}