From 5bbe4dbe1099ff9e0c4adb36ebfd99e2b79ec72c Mon Sep 17 00:00:00 2001
From: jim teeuwen <jimteeuwen@gmail.com>
Date: Tue, 24 Nov 2009 17:49:27 +0100
Subject: [PATCH] added HtmlToUTF8() and UTF8ToHTML() functions for converting
 non-standard html entities.

---
 src/document.go  |  2 +-
 src/entitymap.go | 52 +++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/src/document.go b/src/document.go
index 1cb6842..9fd7665 100644
--- a/src/document.go
+++ b/src/document.go
@@ -60,7 +60,7 @@ func New() *Document {
 // if need be, this method can be called to fill the map with the entire set
 // defined on http://www.w3.org/TR/html4/sgml/entities.html
 func (this *Document) LoadExtendedEntityMap() {
-	entitymap_load(&this.Entity);
+	loadNonStandardEntities(&this.Entity);
 }
 
 func (this *Document) String() string {
diff --git a/src/entitymap.go b/src/entitymap.go
index d51f46d..b6a016c 100644
--- a/src/entitymap.go
+++ b/src/entitymap.go
@@ -1,12 +1,54 @@
 package xmlx
 
+import "fmt"
+import "utf8"
+import "regexp"
+import "strconv"
+
+var reg_entity = regexp.MustCompile("^&#[0-9]+;$");
+
+// Converts a single numerical html entity to a regular Go utf-token.
+//    ex: "&#9827;" -> "♣"
+func HtmlToUTF8(entity string) string {
+	// Make sure we have a valid entity: &#123;
+	ok := reg_entity.MatchString(entity);
+	if !ok { return "" }
+
+	// Convert entity to number
+	num, err := strconv.Atoi(entity[2:len(entity)-1]);
+	if err != nil { return "" }
+
+	var arr [3]byte;
+	size := utf8.EncodeRune(num, &arr);
+	if size == 0 { return "" }
+
+	return string(&arr);
+}
+
+// Converts a single Go utf-token to it's an Html entity.
+//   ex: "♣" -> "&#9827;"
+func UTF8ToHtml(token string) string {
+	rune, size := utf8.DecodeRuneInString(token);
+	if size == 0 { return "" }
+	return fmt.Sprintf("&#%d;", rune);
+}
+
+
 /*
-     Portions © International Organization for Standardization 1986
-     Permission to copy in any form is granted for use with
-     conforming SGML systems and applications as defined in
-     ISO 8879, provided this notice is included in all copies.
+	http://www.w3.org/TR/html4/sgml/entities.html
+
+	Portions © International Organization for Standardization 1986
+	Permission to copy in any form is granted for use with
+	conforming SGML systems and applications as defined in
+	ISO 8879, provided this notice is included in all copies.
+
+	Fills the supplied map with html entities mapped to their Go utf8
+	equivalents. This map can be assigned to xml.Parser.Entity
+	It will be used to map non-standard xml entities to a proper value.
+	If the parser encounters any unknown entities, it will throw a syntax
+	error and abort the parsing. Hence the ability to supply this map.
  */
-func entitymap_load(em *map[string]string) {
+func loadNonStandardEntities(em *map[string]string) {
 	// Generic entities string([]uint8{160});
 	(*em)["nbsp"] = " ";
 	(*em)["iexcl"] = "¡";