date and time created 83/04/18 13:46:11 by slatteng

SCCS-vsn: local/ditroff/ditroff.old.okeeffe/gremlin.aed/gremlin/undodb.c 1.1

diff --git a/usr/src/local/ditroff/ditroff.old.okeeffe/gremlin.aed/gremlin/undodb.c b/usr/src/local/ditroff/ditroff.old.okeeffe/gremlin.aed/gremlin/undodb.c
new file mode 100644 (file)
index 0000000..27a0116
--- /dev/null
+++ b/usr/src/local/ditroff/ditroff.old.okeeffe/gremlin.aed/gremlin/undodb.c
@@ -0,0 +1,136 @@
+\f
+/* undodb.c -
+ *
+ * Copyright -C- 1982 Barry S. Roitblat
+ *
+ *
+ *      This file contains routines for recording (remembering) database
+ * activity to provide an undo capability for the gremlin picture editor.
+ */
+
+#include "gremlin.h"
+#include "grem2.h"
+
+/* The following are used to point to the undo database lists */
+
+UNELT *unlist, *unback;
+
+/* imports from point.c */
+
+POINT *PTInit(), *PTMakePoint();
+
+/* imports from c */
+
+extern char *malloc();
+extern char *strcpy();
+
+/* imports from db1.c */
+
+extern DBClearElt();
+
+\f
+UNRembAdd(element, db)
+ELT *element, *(*db);
+/*
+ *      This routine records an addition to the database by saving
+ * a pointer to the new element
+ */
+
+{
+    UNELT *temp;
+
+    temp = (UNELT *) malloc(sizeof(UNELT));
+    temp->action = ADD;
+    temp->dbase  = db;
+    temp->oldelt = NULL;
+    temp->newelt = element;
+    temp->nextun = unlist;
+    unlist = temp;
+}  /* end RembAdd */
+
+UNRembDelete(element, db)
+ELT *element, *(*db);
+/*
+ *      This routine records a deletion from the database by saving
+ * a pointer to the deleted element
+ */
+
+{
+    UNELT *temp;
+
+    temp = (UNELT *) malloc(sizeof(UNELT));
+    temp->action = DELETE;
+    temp->dbase  = db;
+    temp->oldelt = element;
+    temp->newelt = NULL;
+    temp->nextun = unlist;
+    unlist = temp;
+}  /* end RembDelete */
+
+\f
+UNRembMod(element, db)
+ELT *element, *(*db);
+/*
+ *      This routine records a modification to the database.  The
+ * element passed to it is the element which will be modified and it
+ * is therefore copied (copying the text and pointlist also)
+ * and save as oldelt.  A pointer of the element (which will be
+ * modified) is saved in newelt.
+ */
+
+{
+    POINT *pt;
+    UNELT *temp;
+    ELT *hold;
+
+    temp = (UNELT *) malloc(sizeof(UNELT));
+    temp->action = MOD;
+    temp->dbase = db;
+    temp->newelt = element;
+    temp->oldelt = hold = (ELT *) malloc(sizeof(ELT));
+    hold->type = element->type;
+    hold->brushf = element->brushf;
+    hold->size = element->size;
+    hold->textpt = malloc((unsigned) strlen(element->textpt) + 1);
+    (void) strcpy(hold->textpt, element->textpt);
+    pt = element->ptlist;
+    hold->ptlist = PTInit();
+    while ( !Nullpoint(pt) )
+    {
+        (void) PTMakePoint(pt->x, pt->y, &(hold->ptlist));
+        pt = PTNextPoint(pt);
+    }  /* end while */
+    temp->nextun = unlist;
+    unlist = temp;
+}  /* end RembMod */
+
+UNForget()
+/*
+ *      This routine clears the undo database.  The database is copied
+ * into the backup database and elements from the backup database
+ * are deleted and returned to free storage.  If nothing is in the undo
+ * database, the backup database is preserved.
+ */
+
+{
+    UNELT *temp;
+
+    if (unlist == nullun) return;
+    while (unback != nullun)
+    {
+        temp = unback->nextun;
+        switch (unback->action)
+        {
+               case ADD: free((char *) unback);
+                         break;
+
+               case MOD:
+            case DELETE: DBClearElt(unback->oldelt);
+                         free((char *) unback);
+                         break;
+        }  /* end switch */;
+        unback = temp;
+    }  /* end while */;
+    unback = unlist;
+    unlist = nullun;
+}  /* end Forget */