5 files changed, 30 insertions, 22 deletions
diff --git a/frontends/verilog/lexer.l b/frontends/verilog/lexer.l
index f79f81a9..c9302aba 100644
--- a/frontends/verilog/lexer.l
+++ b/frontends/verilog/lexer.l
@@ -63,6 +63,9 @@ YOSYS_NAMESPACE_END
 	frontend_verilog_yylval.string = new std::string(std::string("\\") + yytext); \
 	return TOK_ID;
 
+#define YY_INPUT(buf,result,max_size) \
+	result = lexin->readsome(buf, max_size);
+
 %}
 
 %option yylineno
diff --git a/frontends/verilog/parser.y b/frontends/verilog/parser.y
index 3512538c..a9f69a49 100644
--- a/frontends/verilog/parser.y
+++ b/frontends/verilog/parser.y
@@ -58,6 +58,7 @@ namespace VERILOG_FRONTEND {
 	bool do_not_require_port_stubs;
 	bool default_nettype_wire;
 	bool sv_mode;
+	std::istream *lexin;
 }
 YOSYS_NAMESPACE_END
 
diff --git a/frontends/verilog/preproc.cc b/frontends/verilog/preproc.cc
index ae139741..f8343321 100644
--- a/frontends/verilog/preproc.cc
+++ b/frontends/verilog/preproc.cc
@@ -193,7 +193,7 @@ static std::string next_token(bool pass_newline = false)
 	return token;
 }
 
-static void input_file(FILE *f, std::string filename)
+static void input_file(std::istream &f, std::string filename)
 {
 	char buffer[513];
 	int rc;
@@ -202,14 +202,14 @@ static void input_file(FILE *f, std::string filename)
 	auto it = input_buffer.begin();
 
 	input_buffer.insert(it, "`file_push " + filename + "\n");
-	while ((rc = fread(buffer, 1, sizeof(buffer)-1, f)) > 0) {
+	while ((rc = f.readsome(buffer, sizeof(buffer)-1)) > 0) {
 		buffer[rc] = 0;
 		input_buffer.insert(it, buffer);
 	}
 	input_buffer.insert(it, "\n`file_pop\n");
 }
 
-std::string frontend_verilog_preproc(FILE *f, std::string filename, const std::map<std::string, std::string> pre_defines_map, const std::list<std::string> include_dirs)
+std::string frontend_verilog_preproc(std::istream &f, std::string filename, const std::map<std::string, std::string> pre_defines_map, const std::list<std::string> include_dirs)
 {
 	std::set<std::string> defines_with_args;
 	std::map<std::string, std::string> defines_map(pre_defines_map);
@@ -288,27 +288,28 @@ std::string frontend_verilog_preproc(FILE *f, std::string filename, const std::m
 				else
 					fn = fn.substr(0, pos) + fn.substr(pos+1);
 			}
-			FILE *fp = fopen(fn.c_str(), "r");
-			if (fp == NULL && fn.size() > 0 && fn[0] != '/' && filename.find('/') != std::string::npos) {
+			std::ifstream ff;
+			ff.clear();
+			ff.open(fn.c_str());
+			if (ff.fail() && fn.size() > 0 && fn[0] != '/' && filename.find('/') != std::string::npos) {
 				// if the include file was not found, it is not given with an absolute path, and the
 				// currently read file is given with a path, then try again relative to its directory
-				std::string fn2 = filename.substr(0, filename.rfind('/')+1) + fn;
-				fp = fopen(fn2.c_str(), "r");
+				ff.clear();
+				ff.open(filename.substr(0, filename.rfind('/')+1) + fn);
 			}
-			if (fp == NULL && fn.size() > 0 && fn[0] != '/') {
+			if (ff.fail() && fn.size() > 0 && fn[0] != '/') {
 				// if the include file was not found and it is not given with an absolute path, then
 				// search it in the include path
 				for (auto incdir : include_dirs) {
-					std::string fn2 = incdir + '/' + fn;
-					fp = fopen(fn2.c_str(), "r");
-					if (fp != NULL) break;
+					ff.clear();
+					ff.open(incdir + '/' + fn);
+					if (!ff.fail()) break;
 				}
 			}
-			if (fp != NULL) {
-				input_file(fp, fn);
-				fclose(fp);
-			} else
+			if (ff.fail())
 				output_code.push_back("`file_notfound " + fn);
+			else
+				input_file(ff, fn);
 			continue;
 		}
 
diff --git a/frontends/verilog/verilog_frontend.cc b/frontends/verilog/verilog_frontend.cc
index 19578908..c63fbb08 100644
--- a/frontends/verilog/verilog_frontend.cc
+++ b/frontends/verilog/verilog_frontend.cc
@@ -136,7 +136,7 @@ struct VerilogFrontend : public Frontend {
 		log("the syntax of the code, rather than to rely on read_verilog for that.\n");
 		log("\n");
 	}
-	virtual void execute(FILE *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
+	virtual void execute(std::istream *&f, std::string filename, std::vector<std::string> args, RTLIL::Design *design)
 	{
 		bool flag_dump_ast1 = false;
 		bool flag_dump_ast2 = false;
@@ -269,18 +269,18 @@ struct VerilogFrontend : public Frontend {
 		current_ast = new AST::AstNode(AST::AST_DESIGN);
 		default_nettype_wire = true;
 
-		FILE *fp = f;
+		lexin = f;
 		std::string code_after_preproc;
 
 		if (!flag_nopp) {
-			code_after_preproc = frontend_verilog_preproc(f, filename, defines_map, include_dirs);
+			code_after_preproc = frontend_verilog_preproc(*f, filename, defines_map, include_dirs);
 			if (flag_ppdump)
 				log("-- Verilog code after preprocessor --\n%s-- END OF DUMP --\n", code_after_preproc.c_str());
-			fp = fmemopen((void*)code_after_preproc.c_str(), code_after_preproc.size(), "r");
+			lexin = new std::istringstream(code_after_preproc);
 		}
 
 		frontend_verilog_yyset_lineno(1);
-		frontend_verilog_yyrestart(fp);
+		frontend_verilog_yyrestart(NULL);
 		frontend_verilog_yyparse();
 		frontend_verilog_yylex_destroy();
 
@@ -294,7 +294,7 @@ struct VerilogFrontend : public Frontend {
 		AST::process(design, current_ast, flag_dump_ast1, flag_dump_ast2, flag_dump_vlog, flag_nolatches, flag_nomem2reg, flag_mem2reg, flag_lib, flag_noopt, flag_icells, flag_ignore_redef, flag_defer, default_nettype_wire);
 
 		if (!flag_nopp)
-			fclose(fp);
+			delete lexin;
 
 		delete current_ast;
 		current_ast = NULL;
diff --git a/frontends/verilog/verilog_frontend.h b/frontends/verilog/verilog_frontend.h
index dac5b3d0..af6495f8 100644
--- a/frontends/verilog/verilog_frontend.h
+++ b/frontends/verilog/verilog_frontend.h
@@ -50,10 +50,13 @@ namespace VERILOG_FRONTEND
 
 	// running in SystemVerilog mode
 	extern bool sv_mode;
+
+	// lexer input stream
+	extern std::istream *lexin;
 }
 
 // the pre-processor
-std::string frontend_verilog_preproc(FILE *f, std::string filename, const std::map<std::string, std::string> pre_defines_map, const std::list<std::string> include_dirs);
+std::string frontend_verilog_preproc(std::istream &f, std::string filename, const std::map<std::string, std::string> pre_defines_map, const std::list<std::string> include_dirs);
 
 YOSYS_NAMESPACE_END