Initial revision

gc/include/private/cord_pos.h

@@ -0,0 +1,118 @@
+/* 
+ * Copyright (c) 1993-1994 by Xerox Corporation.  All rights reserved.
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program
+ * for any purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is granted,
+ * provided the above notices are retained, and a notice that the code was
+ * modified is included with the above copyright notice.
+ */
+/* Boehm, May 19, 1994 2:23 pm PDT */
+# ifndef CORD_POSITION_H
+
+/* The representation of CORD_position.  This is private to the	*/
+/* implementation, but the size is known to clients.  Also	*/
+/* the implementation of some exported macros relies on it.	*/
+/* Don't use anything defined here and not in cord.h.		*/
+
+# define MAX_DEPTH 48
+	/* The maximum depth of a balanced cord + 1.		*/
+	/* We don't let cords get deeper than MAX_DEPTH.	*/
+
+struct CORD_pe {
+    CORD pe_cord;
+    size_t pe_start_pos;
+};
+
+/* A structure describing an entry on the path from the root 	*/
+/* to current position.						*/
+typedef struct CORD_Pos {
+    size_t cur_pos;
+    int path_len;
+#	define CORD_POS_INVALID (0x55555555)
+		/* path_len == INVALID <==> position invalid */
+    const char *cur_leaf;	/* Current leaf, if it is a string.	*/
+    				/* If the current leaf is a function,	*/
+    				/* then this may point to function_buf	*/
+    				/* containing the next few characters.	*/
+    				/* Always points to a valid string	*/
+    				/* containing the current character 	*/
+    				/* unless cur_end is 0.			*/
+    size_t cur_start;	/* Start position of cur_leaf	*/
+    size_t cur_end;	/* Ending position of cur_leaf	*/
+    			/* 0 if cur_leaf is invalid.	*/
+    struct CORD_pe path[MAX_DEPTH + 1];
+    	/* path[path_len] is the leaf corresponding to cur_pos	*/
+    	/* path[0].pe_cord is the cord we point to.		*/
+#   define FUNCTION_BUF_SZ 8
+    char function_buf[FUNCTION_BUF_SZ];	/* Space for next few chars	*/
+    					/* from function node.		*/
+} CORD_pos[1];
+
+/* Extract the cord from a position:	*/
+CORD CORD_pos_to_cord(CORD_pos p);
+	
+/* Extract the current index from a position:	*/
+size_t CORD_pos_to_index(CORD_pos p);
+	
+/* Fetch the character located at the given position:	*/
+char CORD_pos_fetch(CORD_pos p);
+	
+/* Initialize the position to refer to the give cord and index.	*/
+/* Note that this is the most expensive function on positions:	*/
+void CORD_set_pos(CORD_pos p, CORD x, size_t i);
+	
+/* Advance the position to the next character.	*/
+/* P must be initialized and valid.		*/
+/* Invalidates p if past end:			*/
+void CORD_next(CORD_pos p);
+
+/* Move the position to the preceding character.	*/
+/* P must be initialized and valid.			*/
+/* Invalidates p if past beginning:			*/
+void CORD_prev(CORD_pos p);
+	
+/* Is the position valid, i.e. inside the cord?		*/
+int CORD_pos_valid(CORD_pos p);
+
+char CORD__pos_fetch(CORD_pos);
+void CORD__next(CORD_pos);
+void CORD__prev(CORD_pos);
+
+#define CORD_pos_fetch(p)	\
+    (((p)[0].cur_end != 0)? \
+     	(p)[0].cur_leaf[(p)[0].cur_pos - (p)[0].cur_start] \
+     	: CORD__pos_fetch(p))
+
+#define CORD_next(p)	\
+    (((p)[0].cur_pos + 1 < (p)[0].cur_end)? \
+    	(p)[0].cur_pos++ \
+    	: (CORD__next(p), 0))
+
+#define CORD_prev(p)	\
+    (((p)[0].cur_end != 0 && (p)[0].cur_pos > (p)[0].cur_start)? \
+    	(p)[0].cur_pos-- \
+    	: (CORD__prev(p), 0))
+
+#define CORD_pos_to_index(p) ((p)[0].cur_pos)
+
+#define CORD_pos_to_cord(p) ((p)[0].path[0].pe_cord)
+
+#define CORD_pos_valid(p) ((p)[0].path_len != CORD_POS_INVALID)
+
+/* Some grubby stuff for performance-critical friends:	*/
+#define CORD_pos_chars_left(p) ((long)((p)[0].cur_end) - (long)((p)[0].cur_pos))
+	/* Number of characters in cache.  <= 0 ==> none	*/
+
+#define CORD_pos_advance(p,n) ((p)[0].cur_pos += (n) - 1, CORD_next(p))
+	/* Advance position by n characters	*/
+	/* 0 < n < CORD_pos_chars_left(p)	*/
+
+#define CORD_pos_cur_char_addr(p) \
+	(p)[0].cur_leaf + ((p)[0].cur_pos - (p)[0].cur_start)
+	/* address of current character in cache.	*/
+
+#endif