*table string comment

1 files changed, 10 insertions, 6 deletions

diff --git a/src/lua51/ltable.c b/src/lua51/ltable.c
index 73464a0..38f4218 100644
--- a/src/lua51/ltable.c
+++ b/src/lua51/ltable.c
@@ -92,7 +92,7 @@ static Node *hashnum (const Table *t, lua_Number n) {
 }
 
 
-
+//c 计算hash不同key类型的hash值
 /*
 ** returns the `main' position of an element in a table (that is, the index
 ** of its hash value)
@@ -404,7 +404,7 @@ static Node *getfreepos (Table *t) {
 }
 
 
-//c 表新建key
+//c 表新建key，规则如下↓
 /*
 ** inserts a new key into a hash table; first, check whether key's main 
 ** position is free. If not, check whether colliding node is in its main 
@@ -416,6 +416,7 @@ static TValue *newkey (lua_State *L, Table *t, const TValue *key) {
   Node *mp = mainposition(t, key);
   if (!ttisnil(gval(mp)) || mp == dummynode) {//c mainposition上已经有数据
     Node *othern;
+		//c 取一个空桶，后面可能会用到
     Node *n = getfreepos(t);  /* get a free place */
 		//c 如果没有空位，扩展hash table大小为2倍
     if (n == NULL) {  /* cannot find a free place? */
@@ -425,8 +426,9 @@ static TValue *newkey (lua_State *L, Table *t, const TValue *key) {
     }
     lua_assert(n != dummynode);
 		//c 先看一下现在mainposition上的这个node，它的mainposition是不是这个值
-	  //c 不是的话给新的key让路
-    othern = mainposition(t, key2tval(mp));
+	  //c 不是的话说明这个node是临时放在这里的，给新的key让路，把这个node移到一个空位上
+		//c othern是原先mp位置的这个key应该对应的位置
+    othern = mainposition(t, key2tval(mp)); //c key2tval(mp)那大mp的key地址，用来计算hash
     if (othern != mp) {  /* is colliding node out of its main position? */
 			// 把mp空出来,mp里的值移到n(freeposition)
       /* yes; move colliding node into free position */
@@ -434,8 +436,9 @@ static TValue *newkey (lua_State *L, Table *t, const TValue *key) {
       while (gnext(othern) != mp) othern = gnext(othern);  /* find previous */
       gnext(othern) = n;  /* redo the chain with `n' in place of `mp' */
       *n = *mp;  /* copy colliding node into free pos. (mp->next also goes) */
+
       gnext(mp) = NULL;  /* now `mp' is free */
-      setnilvalue(gval(mp));
+      setnilvalue(gval(mp)); // 清空这个位置，留个要加的这个key用
 			//mp是要赋值的位置，即新key的元素的位置
     }
     else {  /* colliding node is in its own main position */
@@ -443,7 +446,8 @@ static TValue *newkey (lua_State *L, Table *t, const TValue *key) {
 			//c 将free position插入到mp后第一个
       gnext(n) = gnext(mp);  /* chain new position */
       gnext(mp) = n;
-			//c 修改一下mp指针，指向freeposition，留个后续使用
+
+			//c 修改一下mp指针，指向freeposition，留给后续使用。一个hack，这样就可以和mainposition位置上是空的兼容
       mp = n;
     }
   }