gen_next_match() becomes m4 code.

To verify this patch, notice that the non-whitespace changes in the
generated C from the tests are of only three kinds:

1. Addition of comments.  I elected to copy the comments from the
generator functions into their corresponding m4 macros in hopes of
making the generated code less nasty to read.

2. Lines like "if ( yy_current_state >= 12 )" changing so the numeric
literal is replaced by YY_JAMSTATE + 1. This was a consequence of the
change in #15 to simplify the C code generators so they could be
translated into static nacros.

3. "YY_CHAR yy_c = yy_ec[YY_SC_TO_UI(*yy_cp)]" being replaced by
"YY_CHAR yy_c = *(yy_ec+YY_SC_TO_UI(*yy_cp));".  The strange way of indexing yy_ec
avoids a syntactic collision with the use of [] as m4 quotes.

#20 in the retargeting patch series

3 files changed, 89 insertions, 107 deletions

diff --git a/src/cpp-flex.skl b/src/cpp-flex.skl
index 90f7c78..25ee2df 100644
--- a/src/cpp-flex.skl
+++ b/src/cpp-flex.skl
@@ -1209,6 +1209,35 @@ m4_ifdef([[M4_MODE_NO_FULLSPD]], [[
 ]])
 ]])
 
+m4_define([[M4_GEN_NEXT_COMPRESSED_STATE]], [[
+	YY_CHAR yy_c = $1;
+	/* Save the backing-up info \before/ computing the next state
+	 * because we always compute one more state than needed - we
+	 * always proceed until we reach a jam state
+	 */
+	M4_GEN_BACKING_UP
+
+	while ( yy_chk[yy_base[yy_current_state] + yy_c] != yy_current_state )
+		{
+		yy_current_state = (int) yy_def[yy_current_state];
+
+m4_ifdef([[M4_MODE_USEMECS]], [[
+		/* We've arranged it so that templates are never chained
+		 * to one another.  This means we can afford to make a
+		 * very simple test to see if we need to convert to
+		 * yy_c's meta-equivalence class without worrying
+		 * about erroneously looking up the meta-equivalence
+		 * class twice
+		 */
+
+		/* lastdfa + 2 == YY_JAMSTATE + 1 is the beginning of the templates */
+		if (yy_current_state >= YY_JAMSTATE + 1)
+			yy_c = yy_meta[yy_c];
+]])
+		}
+	yy_current_state = yy_nxt[yy_base[yy_current_state] + yy_c];
+]])
+
 m4_define([[M4_GEN_START_STATE]], [[
 	/* Generate the code to find the start state. */
 m4_ifdef([[M4_MODE_FULLSPD]], [[
@@ -1226,6 +1255,26 @@ m4_ifdef([[M4_MODE_BOL_NEEDED]], [[yy_current_state += YY_AT_BOL();]])
 ]])
 ]])
 
+m4_define([[M4_GEN_NEXT_MATCH_FULLSPD]], [[
+		{
+			const struct yy_trans_info *yy_trans_info;
+			YY_CHAR yy_c;
+
+			for ( yy_c = $1;
+			      (yy_trans_info = &yy_current_state[yy_c])->yy_verify == yy_c;
+			      yy_c = $2 )
+			{
+				yy_current_state += yy_trans_info->yy_nxt;
+
+				M4_GEN_BACKING_UP
+			}
+		}
+]])
+
+%# Conditional indirection through an equivalence map
+m4_ifdef([[M4_MODE_USEECS]], m4_define([[M4_EC]], [[*(yy_ec+$1)]]))
+m4_ifdef([[M4_NOT_MODE_USEECS]], [[m4_define([[M4_EC]], [[$1]])]])
+
 %not-for-header
 /** The main scanner function which does all the work.
  */
@@ -1321,6 +1370,46 @@ m4_ifdef( [[M4_MODE_USES_REJECT]],
 
 %% [9.0] code to set up and find next match goes here
 
+		/* Generate the code to find the next match. */
+m4_ifdef([[M4_MODE_FULLTBL]], [[
+m4_ifdef([[M4_MODE_GENTABLES]], [[
+		while ((yy_current_state = yy_nxt[yy_current_state][ M4_EC(YY_SC_TO_UI(*yy_cp)) ]) > 0) {
+]])
+m4_ifdef([[M4_MODE_NO_GENTABLES]], [[
+		while ((yy_current_state = yy_nxt[yy_current_state*YY_NXT_LOLEN + M4_EC(YY_SC_TO_UI(*yy_cp)) ]) > 0)
+			{
+]])
+M4_GEN_BACKING_UP
+			yy_cp++;
+			}
+		yy_current_state = -yy_current_state;
+]])
+m4_ifdef([[M4_MODE_FULLSPD]], [[
+		M4_GEN_NEXT_MATCH_FULLSPD(M4_EC(YY_SC_TO_UI(*yy_cp)), M4_EC(YY_SC_TO_UI(*++yy_cp)))
+]])
+m4_ifdef([[M4_MODE_NO_FULLSPD_OR_FULLTBL]], [[
+		do
+			{
+			M4_GEN_NEXT_COMPRESSED_STATE(M4_EC(YY_SC_TO_UI(*yy_cp)))
+
+			m4_ifdef([[M4_MODE_USES_REJECT]], [[*YY_G(yy_state_ptr)++ = yy_current_state;]])
+			++yy_cp;
+
+			}
+		m4_ifdef([[M4_MODE_INTERACTIVE]], [[while ( yy_base[yy_current_state] != YY_JAMBASE );]])
+		m4_ifdef([[M4_MODE_NO_INTERACTIVE]], [[while ( yy_current_state != YY_JAMSTATE );]])
+
+m4_ifdef([[M4_MODE_NO_USES_REJECT]], [[
+m4_ifdef([[M4_MODE_NO_INTERACTIVE]], [[
+	/* Do the guaranteed-needed backing up to figure out
+	 * the match.
+	 */
+	yy_cp = YY_G(yy_last_accepting_cpos);
+	yy_current_state = YY_G(yy_last_accepting_state);
+]])
+]])
+]])
+
 yy_find_action:
 %% [10.0] code to find the action number goes here
 	m4_ifdef([[M4_MODE_FULLSPD]], [[yy_act = yy_current_state[-1].yy_nxt;]])
diff --git a/src/flexdef.h b/src/flexdef.h
index e84de08..b1de1b6 100644
--- a/src/flexdef.h
+++ b/src/flexdef.h
@@ -789,9 +789,6 @@ extern void genftbl(void);	/* generate full transition table */
 /* Generate the code to find the next compressed-table state. */
 extern void gen_next_compressed_state(char *);
 
-/* Generate the code to find the next match. */
-extern void gen_next_match(void);
-
 /* Generate the code to find the next state. */
 extern void gen_next_state(int);
 
diff --git a/src/gen.c b/src/gen.c
index 07341ba..2b726a4 100644
--- a/src/gen.c
+++ b/src/gen.c
@@ -541,109 +541,6 @@ void gen_next_compressed_state (char *char_map)
 }
 
 
-/* Generate the code to find the next match. */
-
-void gen_next_match (void)
-{
-	/* NOTE - changes in here should be reflected in gen_next_state() and
-	 * gen_NUL_trans().
-	 */
-	char   *char_map = useecs ?
-		"yy_ec[YY_SC_TO_UI(*yy_cp)] " : "YY_SC_TO_UI(*yy_cp)";
-
-	char   *char_map_2 = useecs ?
-		"yy_ec[YY_SC_TO_UI(*++yy_cp)] " : "YY_SC_TO_UI(*++yy_cp)";
-
-	if (fulltbl) {
-		if (gentables)
-			indent_put2s
-				("while ( (yy_current_state = yy_nxt[yy_current_state][ %s ]) > 0 )",
-				 char_map);
-		else
-			indent_put2s
-				("while ( (yy_current_state = yy_nxt[yy_current_state*YY_NXT_LOLEN +  %s ]) > 0 )",
-				 char_map);
-
-		++indent_level;
-
-		if (num_backing_up > 0) {
-			indent_puts ("{");
-			outn ("M4_GEN_BACKING_UP");
-			outc ('\n');
-		}
-
-		indent_puts ("++yy_cp;");
-
-		if (num_backing_up > 0)
-			outn ("M4_GEN_BACKING_UP");
-			indent_puts ("}");
-
-		--indent_level;
-
-		outc ('\n');
-		indent_puts ("yy_current_state = -yy_current_state;");
-	}
-
-	else if (fullspd) {
-		indent_puts ("{");
-		indent_puts
-			("const struct yy_trans_info *yy_trans_info;\n");
-		indent_puts ("YY_CHAR yy_c;\n");
-		indent_put2s ("for ( yy_c = %s;", char_map);
-		indent_puts
-			("      (yy_trans_info = &yy_current_state[yy_c])->");
-		indent_puts ("yy_verify == yy_c;");
-		indent_put2s ("      yy_c = %s )", char_map_2);
-
-		++indent_level;
-
-		if (num_backing_up > 0)
-			indent_puts ("{");
-
-		indent_puts ("yy_current_state += yy_trans_info->yy_nxt;");
-
-		if (num_backing_up > 0) {
-			outc ('\n');
-			outn ("M4_GEN_BACKING_UP");
-			indent_puts ("}");
-		}
-
-		--indent_level;
-		indent_puts ("}");
-	}
-
-	else {			/* compressed */
-		indent_puts ("do");
-
-		++indent_level;
-		indent_puts ("{");
-
-		gen_next_state (false);
-
-		indent_puts ("++yy_cp;");
-
-
-		indent_puts ("}");
-		--indent_level;
-
-		if (interactive)
-			indent_puts ("while ( yy_base[yy_current_state] != YY_JAMBASE );");
-		else
-			indent_puts ("while ( yy_current_state != YY_JAMSTATE );");
-
-		if (!reject && !interactive) {
-			/* Do the guaranteed-needed backing up to figure out
-			 * the match.
-			 */
-			indent_puts
-				("yy_cp = YY_G(yy_last_accepting_cpos);");
-			indent_puts
-				("yy_current_state = YY_G(yy_last_accepting_state);");
-		}
-	}
-}
-
-
 /* Generate the code to find the next state. */
 
 void gen_next_state (int worry_about_NULs)
@@ -1677,7 +1574,6 @@ void make_tables (void)
 
 	/* Note, don't use any indentation. */
 	outn ("yy_match:");
-	gen_next_match ();
 
 	skelout ();		/* %% [10.0] - break point in skel */
 	set_indent (2);