Changes in / [7f54356:b9376fe]

File:

• libcfa/src/containers/list2.hfa (modified) (7 diffs)

libcfa/src/containers/list2.hfa

@@ -39 +39 @@
 
 
-// The origin is the position encountered at the start of iteration,
-// signifying, "need to advance to the first element," and at the end
-// of iteration, signifying, "no more elements."  Normal comsumption of
-// an iterator runs ?`moveNext as the first step, and uses the return
-// of ?`moveNext as a guard, before dereferencing the iterator.  So
-// normal consumption of an iterator does not dereference an iterator
-// in origin position.  The value of a pointer (underlying a refence)
-// that is exposed publicly as an iteraor, and also a pointer stored
-// internally in a link field, is tagged, to indicate "is the origin"
-// (internally, is the list-head sentinel node), or untagged, to indicate
-// "is a regular node."  Intent is to help a user who dereferences an
-// iterator in origin position (which would be an API-use error on their
-// part), by failing fast.
-
-#if defined( __x86_64 )
-    // Preferred case: tag in the most-significant bit.  Dereference
-    // has been shown to segfault consistently.  Maintenance should
-    // list more architectures as "ok" here, to let them use the
-    // preferred case, when valid.
-    #define ORIGIN_TAG_BITNO ( 8 * sizeof( size_t ) - 1 )
-#else
-    // Fallback case: tag in the least-significant bit.  Dereference
-    // will often give an alignment error, but may not, e.g. if
-    // accessing a char-typed member.  32-bit x86 uses the most-
-    // significant bit for real room on the heap.
-    #define ORIGIN_TAG_BITNO 0
-#endif
+
+
+#define ORIGIN_TAG_BITNO 63
 #define ORIGIN_TAG_MASK (((size_t)1) << ORIGIN_TAG_BITNO)
 
@@ -71 +47 @@
 #define ORIGIN_TAG_CLEAR(p) ((p) & ~ORIGIN_TAG_MASK)
 #define ORIGIN_TAG_QUERY(p) ((p) &  ORIGIN_TAG_MASK)
+
+// #define ORIGIN_TAG_SET(p)   (p)
+// #define ORIGIN_TAG_CLEAR(p) (p)
+// #define ORIGIN_TAG_QUERY(p) (0)
 
 
@@ -130 +110 @@
         tE & list_pos_raw = list_pos;
         tE & list_pos_elem = * (tE *) ORIGIN_TAG_CLEAR( (size_t) & list_pos_raw );
-        asm( "" : : : "memory" );
         tE & after_raw = * (list_pos_elem`inner`inner).next;
         tE & after_elem = * (tE *) ORIGIN_TAG_CLEAR( (size_t) & after_raw );
@@ -137 +116 @@
         (after_elem`inner`inner).prev = &to_insert;
                 (list_pos_elem`inner`inner).next = &to_insert;
-        asm( "" : : : "memory" );
         }
 
@@ -148 +126 @@
         tE & list_pos_raw = list_pos;
         tE & list_pos_elem = * (tE *) ORIGIN_TAG_CLEAR( (size_t) & list_pos_raw );
-        asm( "" : : : "memory" );
         tE & before_raw = * (list_pos_elem`inner`inner).prev;
         tE & before_elem = * (tE *) ORIGIN_TAG_CLEAR( (size_t) & before_raw );
@@ -155 +132 @@
         (before_elem`inner`inner).next = &to_insert;
                 (list_pos_elem`inner`inner).prev = &to_insert;
+        }
+
+    static inline void doRemove(
+        dlink(tE) & this_links, dlink(tE) & before_links, dlink(tE) & after_links,
+        tE & before_target, tE & after_target ) {
+
+        before_links.next = &after_target;
+        after_links.prev = &before_target;
+
         asm( "" : : : "memory" );
-        }
-
+
+                this_links.prev = 0p;
+                this_links.next = 0p;
+    }
+
+        static inline tE & remove(diref(tE, tLinks) list_pos) {
+                verify (&list_pos != 0p);
+        tE & list_pos_elem = list_pos;
+        verify( ! ORIGIN_TAG_QUERY((size_t) & list_pos_elem) );
+        dlink(tE) & list_pos_links = list_pos_elem`inner`inner;
+        tE & before_raw = * list_pos_links.prev;
+        tE & before_elem = * (tE *) ORIGIN_TAG_CLEAR( (size_t) & before_raw );
+        dlink(tE) & before_links = before_elem`inner`inner;
+        tE & after_raw = * list_pos_links.next;
+        tE & after_elem = * (tE *) ORIGIN_TAG_CLEAR( (size_t) & after_raw );
+        dlink(tE) & after_links = after_elem`inner`inner;
+
+        doRemove(list_pos_links, before_links, after_links, before_raw, after_raw);
+
+        return list_pos_elem;
+        }
+/*    
         static inline tE & remove(diref(tE, tLinks) list_pos) {
                 verify (&list_pos != 0p);
@@ -171 +177 @@
         before_links.next = &after_raw;
         after_links.prev = &before_raw;
-        asm( "" : : : "memory" );
+asm( "" : : : "memory" );
                 list_pos_links.prev = 0p;
                 list_pos_links.next = 0p;
-        asm( "" : : : "memory" );
         return list_pos_elem;
         }
-
+*/
     static inline diref(tE, tLinks) ?`first( dlist(tE, tLinks) &lst ) {
         tE * firstPtr = lst.next;