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diff --git a/src/include/regex/regexport.h b/src/include/regex/regexport.h
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+/*-------------------------------------------------------------------------
+ *
+ * regexport.h
+ *	  Declarations for exporting info about a regex's NFA (nondeterministic
+ *	  finite automaton)
+ *
+ * The functions declared here provide accessors to extract the NFA state
+ * graph and color character sets of a successfully-compiled regex.
+ *
+ * An NFA contains one or more states, numbered 0..N-1.  There is an initial
+ * state, as well as a final state --- reaching the final state denotes
+ * successful matching of an input string.  Each state except the final one
+ * has some out-arcs that lead to successor states, each arc being labeled
+ * with a color that represents one or more concrete character codes.
+ * (The colors of a state's out-arcs need not be distinct, since this is an
+ * NFA not a DFA.)	There are also "pseudocolors" representing start/end of
+ * line and start/end of string.  Colors are numbered 0..C-1, but note that
+ * color 0 is "white" (all unused characters) and can generally be ignored.
+ *
+ * Portions Copyright (c) 2013-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1998, 1999 Henry Spencer
+ *
+ * IDENTIFICATION
+ *	  src/include/regex/regexport.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef _REGEXPORT_H_
+#define _REGEXPORT_H_
+
+#include "regex/regex.h"
+
+/* These macros must match corresponding ones in regguts.h: */
+#define COLOR_WHITE		0		/* color for chars not appearing in regex */
+#define COLOR_RAINBOW	(-2)	/* represents all colors except pseudocolors */
+
+/* information about one arc of a regex's NFA */
+typedef struct
+{
+	int			co;				/* label (character-set color) of arc */
+	int			to;				/* next state number */
+} regex_arc_t;
+
+
+/* Functions for gathering information about NFA states and arcs */
+extern int	pg_reg_getnumstates(const regex_t *regex);
+extern int	pg_reg_getinitialstate(const regex_t *regex);
+extern int	pg_reg_getfinalstate(const regex_t *regex);
+extern int	pg_reg_getnumoutarcs(const regex_t *regex, int st);
+extern void pg_reg_getoutarcs(const regex_t *regex, int st,
+							  regex_arc_t *arcs, int arcs_len);
+
+/* Functions for gathering information about colors */
+extern int	pg_reg_getnumcolors(const regex_t *regex);
+extern int	pg_reg_colorisbegin(const regex_t *regex, int co);
+extern int	pg_reg_colorisend(const regex_t *regex, int co);
+extern int	pg_reg_getnumcharacters(const regex_t *regex, int co);
+extern void pg_reg_getcharacters(const regex_t *regex, int co,
+								 pg_wchar *chars, int chars_len);
+
+#endif							/* _REGEXPORT_H_ */