Initial revision

gc/include/ec.h

@@ -0,0 +1,70 @@
+# ifndef EC_H
+# define EC_H
+
+# ifndef CORD_H
+#  include "cord.h"
+# endif
+
+/* Extensible cords are strings that may be destructively appended to.	*/
+/* They allow fast construction of cords from characters that are	*/
+/* being read from a stream.						*/
+/*
+ * A client might look like:
+ *
+ *	{
+ *	    CORD_ec x;
+ *	    CORD result;
+ *	    char c;
+ *	    FILE *f;
+ *
+ *	    ...
+ *	    CORD_ec_init(x);
+ *	    while(...) {
+ *		c = getc(f);
+ *		...
+ *		CORD_ec_append(x, c);
+ *	    }
+ *	    result = CORD_balance(CORD_ec_to_cord(x));
+ *
+ * If a C string is desired as the final result, the call to CORD_balance
+ * may be replaced by a call to CORD_to_char_star.
+ */
+
+# ifndef CORD_BUFSZ
+#   define CORD_BUFSZ 128
+# endif
+
+typedef struct CORD_ec_struct {
+    CORD ec_cord;
+    char * ec_bufptr;
+    char ec_buf[CORD_BUFSZ+1];
+} CORD_ec[1];
+
+/* This structure represents the concatenation of ec_cord with		*/
+/* ec_buf[0 ... (ec_bufptr-ec_buf-1)]					*/
+
+/* Flush the buffer part of the extended chord into ec_cord.	*/
+/* Note that this is almost the only real function, and it is	*/
+/* implemented in 6 lines in cordxtra.c				*/
+void CORD_ec_flush_buf(CORD_ec x);
+      
+/* Convert an extensible cord to a cord. */
+# define CORD_ec_to_cord(x) (CORD_ec_flush_buf(x), (x)[0].ec_cord)
+
+/* Initialize an extensible cord. */
+# define CORD_ec_init(x) ((x)[0].ec_cord = 0, (x)[0].ec_bufptr = (x)[0].ec_buf)
+
+/* Append a character to an extensible cord.	*/
+# define CORD_ec_append(x, c) \
+    {  \
+	if ((x)[0].ec_bufptr == (x)[0].ec_buf + CORD_BUFSZ) { \
+	  	CORD_ec_flush_buf(x); \
+	} \
+	*((x)[0].ec_bufptr)++ = (c); \
+    }
+
+/* Append a cord to an extensible cord.  Structure remains shared with 	*/
+/* original.								*/
+void CORD_ec_append_cord(CORD_ec x, CORD s);
+
+# endif /* EC_H */