From c7038d65b98ff517726d8cdd7e3393275a20634f Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Fri, 10 Apr 2015 23:22:12 +0200
Subject: output: also collapse goto case branches

---
 src/output.cpp     | 30 ++++++++++++++++++++++++++++++
 src/output.hpp     |  1 +
 src/output_lr0.cpp | 30 +-----------------------------
 src/output_slr.cpp | 30 +-----------------------------
 4 files changed, 33 insertions(+), 58 deletions(-)

diff --git a/src/output.cpp b/src/output.cpp
index cd08a9e..cfefbbb 100644
--- a/src/output.cpp
+++ b/src/output.cpp
@@ -213,6 +213,36 @@ void output_t::emit_reductions() {
 	}
 }
 
+void output_t::emit_gotos(const std::string &lhs) {
+	std::map<unsigned, std::set<unsigned>> gotos;
+
+	for (size_t state = 0; state < get_generator()->get_state_count(); state++) {
+		auto it = get_generator()->get_gotos().find(std::make_pair(state, lhs));
+		if (it == get_generator()->get_gotos().end())
+			continue;
+
+		std::set<unsigned> &states = gotos.insert(std::make_pair(it->second, std::set<unsigned>())).first->second;
+		states.insert(state);
+	}
+
+	if (gotos.size() == 1) {
+		auto it = gotos.begin();
+		std::fprintf(source_file, "\t\t\t\tparser->stack[++parser->top].state = %u;\n", it->first);
+	}
+	else {
+		std::fprintf(source_file, "\t\t\t\tswitch (parser->stack[parser->top].state) {\n");
+
+		for (const auto &entry : gotos) {
+			for (unsigned state : entry.second)
+				std::fprintf(source_file, "\t\t\t\tcase %u:\n", state);
+			std::fprintf(source_file, "\t\t\t\t\tparser->stack[++parser->top].state = %u;\n", entry.first);
+			std::fprintf(source_file, "\t\t\t\t\tbreak;\n\n");
+		}
+
+		std::fprintf(source_file, "\t\t\t\t}\n");
+	}
+}
+
 void output_t::emit_states() {
 	for (size_t state = 0; state < get_generator()->get_state_count(); state++)
 		emit_state(state);
diff --git a/src/output.hpp b/src/output.hpp
index 6704ed4..66baf41 100644
--- a/src/output.hpp
+++ b/src/output.hpp
@@ -65,6 +65,7 @@ protected:
 
 	void emit_reduction(unsigned rule_id);
 	void emit_reductions();
+	void emit_gotos(const std::string &lhs);
 	void emit_states();
 	void emit_header_include();
 	void emit_source();
diff --git a/src/output_lr0.cpp b/src/output_lr0.cpp
index 031ed43..9d4897e 100644
--- a/src/output_lr0.cpp
+++ b/src/output_lr0.cpp
@@ -93,35 +93,7 @@ void output_lr0_t::emit_state_reduce(const item_t &item, int rule_id) {
 		std::fprintf(source_file, ");\n");
 	}
 
-	std::vector<std::pair<unsigned, unsigned>> gotos;
-
-	for (size_t i = 0; i < generator->get_state_count(); i++) {
-		auto it = generator->get_gotos().find(std::make_pair(i, item.get_lhs()));
-		if (it == generator->get_gotos().end())
-			continue;
-
-		gotos.emplace_back(i, it->second);
-	}
-
-	if (gotos.size() == 1) {
-		std::fprintf(source_file, "\t\t\tparser->stack[++parser->top].state = %u;\n", gotos[0].second);
-	}
-	else {
-		std::fprintf(source_file, "\t\t\tswitch (parser->stack[parser->top].state) {\n");
-
-		for (size_t i = 0; i < generator->get_state_count(); i++) {
-			auto it = generator->get_gotos().find(std::make_pair(i, item.get_lhs()));
-			if (it == generator->get_gotos().end())
-				continue;
-
-			std::fprintf(source_file, "\t\t\tcase %u:\n", unsigned(i));
-			std::fprintf(source_file, "\t\t\t\tparser->stack[++parser->top].state = %u;\n", unsigned(it->second));
-			std::fprintf(source_file, "\t\t\t\tbreak;\n");
-		}
-
-
-		std::fprintf(source_file, "\t\t\t}\n");
-	}
+	emit_gotos(item.get_lhs());
 }
 
 void output_lr0_t::emit_state(unsigned state) {
diff --git a/src/output_slr.cpp b/src/output_slr.cpp
index 563fd60..4a7b463 100644
--- a/src/output_slr.cpp
+++ b/src/output_slr.cpp
@@ -94,35 +94,7 @@ void output_slr_t::emit_state_reduce_code(const item_t &item, int rule_id) {
 		std::fprintf(source_file, ");\n");
 	}
 
-	std::vector<std::pair<unsigned, unsigned>> gotos;
-
-	for (size_t i = 0; i < generator->get_state_count(); i++) {
-		auto it = generator->get_gotos().find(std::make_pair(i, item.get_lhs()));
-		if (it == generator->get_gotos().end())
-			continue;
-
-		gotos.emplace_back(i, it->second);
-	}
-
-	if (gotos.size() == 1) {
-		std::fprintf(source_file, "\t\t\t\tparser->stack[++parser->top].state = %u;\n", gotos[0].second);
-	}
-	else {
-		std::fprintf(source_file, "\t\t\t\tswitch (parser->stack[parser->top].state) {\n");
-
-		for (size_t i = 0; i < generator->get_state_count(); i++) {
-			auto it = generator->get_gotos().find(std::make_pair(i, item.get_lhs()));
-			if (it == generator->get_gotos().end())
-				continue;
-
-			std::fprintf(source_file, "\t\t\t\tcase %u:\n", unsigned(i));
-			std::fprintf(source_file, "\t\t\t\t\tparser->stack[++parser->top].state = %u;\n", unsigned(it->second));
-			std::fprintf(source_file, "\t\t\t\t\tbreak;\n\n");
-		}
-
-
-		std::fprintf(source_file, "\t\t\t\t}\n");
-	}
+	emit_gotos(item.get_lhs());
 }
 
 bool output_slr_t::emit_state_reduce(unsigned state) {
-- 
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