Fix off-by-one error and always check buffer length

1 files changed, 28 insertions, 11 deletions

diff --git a/unxml.go b/unxml.go
index 2bdb354..db191c0 100644
--- a/unxml.go
+++ b/unxml.go
@@ -158,16 +158,17 @@ func (r *ElementReader) Read(out []byte) (int, error) {
 			}
 			text := r.xr.tokenizer.Text()
 			lentext := len(text)
-			if lentext <= lenout {
+			if lentext < lenout {
+				//fmt.Printf("HAD SPACE: %q, count: %d\n", text, r.xr.count)
 				n = copy(out[r.xr.count:], text)
 				r.xr.count += n
 				lenout -= n
-				//fmt.Printf("HAD SPACE: %q, count: %d, err: %s\n", text, r.xr.count, err)
 			} else {
-				n = copy(out[r.xr.count:], text[:lenout-1])
+				//fmt.Printf("HAD NO SPACE: count: %d, lenout: %d\n", r.xr.count, lenout)
+				n = copy(out[r.xr.count:], text[:lenout])
 				r.xr.count += n
-				r.xr.lastread = text[lenout-1:]
-				//fmt.Printf("HAD NO SPACE: count: %d, err: %s\n", r.xr.count, err)
+				lenout -= n
+				r.xr.lastread = text[lenout:]
 				return r.xr.count, err
 			}
 
@@ -182,9 +183,17 @@ func (r *ElementReader) Read(out []byte) (int, error) {
 				intagtokeep = true
 				raw := r.xr.tokenizer.Raw()
 				//fmt.Printf("TokenRaw: %s\n", raw)
-				n := copy(out[r.xr.count:], raw)
-				r.xr.count += n
-				lenout -= n
+				if len(raw) < lenout {
+					n := copy(out[r.xr.count:], raw)
+					r.xr.count += n
+					lenout -= n
+				} else {
+					n = copy(out[r.xr.count:], raw[:lenout-1])
+					r.xr.count += n
+					lenout -= n
+					r.xr.lastread = raw[lenout-1:]
+					return r.xr.count, err
+				}
 			}
 
 		case html.EndTagToken:
@@ -199,9 +208,17 @@ func (r *ElementReader) Read(out []byte) (int, error) {
 					r.tagsinstack[string(tn)]--
 				}
 				raw := r.xr.tokenizer.Raw()
-				n := copy(out[r.xr.count:], raw)
-				r.xr.count += n
-				lenout -= n
+				if len(raw) < lenout {
+					n := copy(out[r.xr.count:], raw)
+					r.xr.count += n
+					lenout -= n
+				} else {
+					n = copy(out[r.xr.count:], raw[:lenout-1])
+					r.xr.count += n
+					lenout -= n
+					r.xr.lastread = raw[lenout-1:]
+					return r.xr.count, err
+				}
 			}
 		}
 	}