From be46d3177260d2a4042c3dc86528816713b37ffb Mon Sep 17 00:00:00 2001
From: yuin <yuin@inforno.net>
Date: Sun, 18 Sep 2016 17:16:45 +0900
Subject: [PATCH] Issue #81 : Fix an infinite loop when tables contain numeric
 Zero as an index

---
 _glua-tests/issues.lua | 22 +++++++++++++++++++
 table.go               | 49 ++++++++++++++++++------------------------
 utils.go               |  2 +-
 3 files changed, 44 insertions(+), 29 deletions(-)

diff --git a/_glua-tests/issues.lua b/_glua-tests/issues.lua
index 22eb8ba2..e2f59a60 100644
--- a/_glua-tests/issues.lua
+++ b/_glua-tests/issues.lua
@@ -114,3 +114,25 @@ stack traceback:
 @TAB@issues.lua:103: in main chunk
 @TAB@[G]: ?]], "@TAB@", "\t"))
 
+-- issue 81
+local tbl = {
+        [-1] = "a",
+        [0] = "b",
+        [1] = "c",
+}
+local a, b = next(tbl, nil)
+assert( a == -1 and b == "a" or a == 0 and b == "b" or a == 1 and b == "c")
+local a, b = next(tbl, a)
+assert( a == -1 and b == "a" or a == 0 and b == "b" or a == 1 and b == "c")
+local a, b = next(tbl, a)
+assert( a == -1 and b == "a" or a == 0 and b == "b" or a == 1 and b == "c")
+local a, b = next(tbl, a)
+assert( a == nil and b == nil)
+
+local tbl = {'a', 'b'}
+local a, b = next(tbl, nil)
+assert(a == 1 and b == "a")
+local a, b = next(tbl, a)
+assert(a == 2 and b == "b")
+local a, b = next(tbl, a)
+assert(a == nil and b == nil)
diff --git a/table.go b/table.go
index 5a103d8d..71c8b086 100644
--- a/table.go
+++ b/table.go
@@ -316,10 +316,12 @@ func (tb *LTable) ForEach(cb func(LValue, LValue)) {
 // This function is equivalent to lua_next ( http://www.lua.org/manual/5.1/manual.html#lua_next ).
 func (tb *LTable) Next(key LValue) (LValue, LValue) {
 	// TODO: inefficient way
+	init := false
 	if key == LNil {
 		tb.keys = nil
 		tb.k2i = nil
 		key = LNumber(0)
+		init = true
 	}
 
 	length := 0
@@ -350,43 +352,34 @@ func (tb *LTable) Next(key LValue) (LValue, LValue) {
 		}
 	}
 
-	if kv, ok := key.(LNumber); ok && isInteger(kv) && int(kv) >= 0 {
-		index := int(kv)
-		if tb.array != nil {
-			for ; index < len(tb.array); index++ {
-				if v := tb.array[index]; v != LNil {
-					return LNumber(index + 1), v
+	if init || key != LNumber(0) {
+		if kv, ok := key.(LNumber); ok && isInteger(kv) && int(kv) >= 0 {
+			index := int(kv)
+			if tb.array != nil {
+				for ; index < len(tb.array); index++ {
+					if v := tb.array[index]; v != LNil {
+						return LNumber(index + 1), v
+					}
 				}
 			}
-		}
-		if tb.array == nil || index == len(tb.array) {
-			if (tb.dict == nil || len(tb.dict) == 0) && (tb.strdict == nil || len(tb.strdict) == 0) {
-				tb.keys = nil
-				tb.k2i = nil
-				return LNil, LNil
-			}
-			key = tb.keys[0]
-			if skey, sok := key.(LString); sok && tb.strdict != nil {
-				if sv, svok := tb.strdict[string(skey)]; svok && sv != LNil {
-					return key, sv
+			if tb.array == nil || index == len(tb.array) {
+				if (tb.dict == nil || len(tb.dict) == 0) && (tb.strdict == nil || len(tb.strdict) == 0) {
+					tb.keys = nil
+					tb.k2i = nil
+					return LNil, LNil
 				}
-			} else if tb.dict != nil {
-				if v, vok := tb.dict[key]; vok && v != LNil {
+				key = tb.keys[0]
+				if v := tb.RawGetH(key); v != LNil {
 					return key, v
 				}
 			}
 		}
 	}
+
 	for i := tb.k2i[key] + 1; i < length; i++ {
-		key = tb.keys[i]
-		if skey, sok := key.(LString); sok && tb.strdict != nil {
-			if sv, svok := tb.strdict[string(skey)]; svok && sv != LNil {
-				return key, sv
-			}
-		} else if tb.dict != nil {
-			if v, vok := tb.dict[key]; vok && v != LNil {
-				return key, v
-			}
+		key = tb.keys[tb.k2i[key]+1]
+		if v := tb.RawGetH(key); v != LNil {
+			return key, v
 		}
 	}
 	tb.keys = nil
diff --git a/utils.go b/utils.go
index 2e5fb097..05e4b2f4 100644
--- a/utils.go
+++ b/utils.go
@@ -100,7 +100,7 @@ func (fs *flagScanner) Next() (byte, bool) {
 var cDateFlagToGo = map[byte]string{
 	'a': "mon", 'A': "Monday", 'b': "Jan", 'B': "January", 'c': "02 Jan 06 15:04 MST", 'd': "02",
 	'F': "2006-01-02", 'H': "15", 'I': "03", 'm': "01", 'M': "04", 'p': "PM", 'P': "pm", 'S': "05",
-	'x': "15/04/05", 'X': "15:04:05",'y': "06", 'Y': "2006", 'z': "-0700", 'Z': "MST"}
+	'x': "15/04/05", 'X': "15:04:05", 'y': "06", 'Y': "2006", 'z': "-0700", 'Z': "MST"}
 
 func strftime(t time.Time, cfmt string) string {
 	sc := newFlagScanner('%', "", "", cfmt)