avoid constructing strings when char* is passed as an argument

Author: soheilshahrouz

libs/libvtrutil/src/vtr_util.cpp

@@ -72,18 +72,18 @@ std::vector<std::string> split(std::string_view text, std::string_view delims) {
 }
 
 ///@brief Returns 'input' with the first instance of 'search' replaced with 'replace'
-std::string replace_first(const std::string& input, const std::string& search, const std::string& replace) {
+std::string replace_first(std::string_view input, std::string_view search, std::string_view replace) {
     auto pos = input.find(search);
 
     std::string output(input, 0, pos);
     output += replace;
-    output += std::string(input, pos + search.size());
+    output += input.substr(pos + search.size());
 
     return output;
 }
 
 ///@brief Returns 'input' with all instances of 'search' replaced with 'replace'
-std::string replace_all(const std::string& input, const std::string& search, const std::string& replace) {
+std::string replace_all(std::string_view input, std::string_view search, std::string_view replace) {
     std::string output;
 
     size_t last = 0;
@@ -101,8 +101,8 @@ std::string replace_all(const std::string& input, const std::string& search, con
     return output;
 }
 
-///@brief Retruns true if str starts with prefix
-bool starts_with(const std::string& str, const std::string& prefix) {
+///@brief Returns true if str starts with prefix
+bool starts_with(const std::string& str, std::string_view prefix) {
     return str.find(prefix) == 0;
 }
 
@@ -195,7 +195,7 @@ char* strdup(const char* str) {
  * and/or correct 'unexpected' behaviour of the standard c-functions
  */
 template<class T>
-T atoT(const std::string& value, const std::string& type_name) {
+T atoT(const std::string& value, std::string_view type_name) {
     //The c version of atof doesn't catch errors.
     //
     //This version uses stringstream to detect conversion errors
@@ -461,8 +461,8 @@ bool file_exists(const char* filename) {
  *
  * Returns true if the extension is correct, and false otherwise.
  */
-bool check_file_name_extension(const std::string& file_name,
-                               const std::string& file_extension) {
+bool check_file_name_extension(std::string_view file_name,
+                               std::string_view file_extension) {
     auto ext = std::filesystem::path(file_name).extension();
     return ext == file_extension;
 }

libs/libvtrutil/src/vtr_util.h

@@ -19,13 +19,13 @@ std::vector<std::string> split(const char* text, std::string_view string_view =
 std::vector<std::string> split(std::string_view text, std::string_view delims = " \t\n");
 
 ///@brief Returns 'input' with the first instance of 'search' replaced with 'replace'
-std::string replace_first(const std::string& input, const std::string& search, const std::string& replace);
+std::string replace_first(std::string_view input, std::string_view search, std::string_view replace);
 
 ///@brief Returns 'input' with all instances of 'search' replaced with 'replace'
-std::string replace_all(const std::string& input, const std::string& search, const std::string& replace);
+std::string replace_all(std::string_view input, std::string_view search, std::string_view replace);
 
 ///@brief Retruns true if str starts with prefix
-bool starts_with(const std::string& str, const std::string& prefix);
+bool starts_with(const std::string& str, std::string_view prefix);
 
 ///@brief Returns a std::string formatted using a printf-style format string
 std::string string_fmt(const char* fmt, ...);
@@ -40,13 +40,13 @@ std::string vstring_fmt(const char* fmt, va_list args);
  *  would return "home/user/my_files/test.blif"
  */
 template<typename Iter>
-std::string join(Iter begin, Iter end, std::string delim);
+std::string join(Iter begin, Iter end, std::string_view delim);
 
 template<typename Container>
-std::string join(Container container, std::string delim);
+std::string join(Container container, std::string_view delim);
 
 template<typename T>
-std::string join(std::initializer_list<T> list, std::string delim);
+std::string join(std::initializer_list<T> list, std::string_view delim);
 
 template<typename Container>
 void uniquify(Container container);
@@ -70,7 +70,7 @@ double atod(const std::string& value);
  */
 int get_file_line_number_of_last_opened_file();
 bool file_exists(const char* filename);
-bool check_file_name_extension(const std::string& file_name, const std::string& file_extension);
+bool check_file_name_extension(std::string_view file_name, std::string_view file_extension);
 
 extern std::string out_file_prefix;
 
@@ -83,7 +83,7 @@ std::vector<std::string> ReadLineTokens(FILE* InFile, int* LineNum);
  * @brief Template join function implementation
  */
 template<typename Iter>
-std::string join(Iter begin, Iter end, std::string delim) {
+std::string join(Iter begin, Iter end, std::string_view delim) {
     std::string joined_str;
     for (auto iter = begin; iter != end; ++iter) {
         joined_str += *iter;
@@ -95,12 +95,12 @@ std::string join(Iter begin, Iter end, std::string delim) {
 }
 
 template<typename Container>
-std::string join(Container container, std::string delim) {
+std::string join(Container container, std::string_view delim) {
     return join(std::begin(container), std::end(container), delim);
 }
 
 template<typename T>
-std::string join(std::initializer_list<T> list, std::string delim) {
+std::string join(std::initializer_list<T> list, std::string_view delim) {
     return join(list.begin(), list.end(), delim);
 }
 

vpr/src/base/read_blif.cpp

@@ -443,7 +443,7 @@ struct BlifAllocCallback : public blifparse::Callback {
     }
 
   private:
-    const t_model* find_model(std::string name) {
+    const t_model* find_model(std::string_view name) {
         const t_model* arch_model = nullptr;
         for (const t_model* arch_models : {user_arch_models_, library_arch_models_}) {
             arch_model = arch_models;
@@ -461,12 +461,12 @@ struct BlifAllocCallback : public blifparse::Callback {
         }
         if (!arch_model) {
             vpr_throw(VPR_ERROR_BLIF_F, filename_.c_str(), lineno_, "Failed to find matching architecture model for '%s'\n",
-                      name.c_str());
+                      name.data());
         }
         return arch_model;
     }
 
-    const t_model_ports* find_model_port(const t_model* blk_model, std::string port_name) {
+    const t_model_ports* find_model_port(const t_model* blk_model, const std::string& port_name) {
         //We need to handle both single, and multi-bit port names
         //
         //By convention multi-bit port names have the bit index stored in square brackets
@@ -582,7 +582,7 @@ struct BlifAllocCallback : public blifparse::Callback {
             } else {
                 VTR_ASSERT(blif_model.block_type(blk_id) == AtomBlockType::OUTPAD);
 
-                auto raw_output_name = blif_model.block_name(blk_id);
+                const auto& raw_output_name = blif_model.block_name(blk_id);
 
                 std::string output_name = vtr::replace_first(raw_output_name, OUTPAD_NAME_PREFIX, "");
 
@@ -618,7 +618,7 @@ struct BlifAllocCallback : public blifparse::Callback {
      * @brief Merges all the recorded net pairs which need to be merged
      *
      * This should only be called at the end of a .model to ensure that
-     * all the associated driver/sink pins have been delcared and connected
+     * all the associated driver/sink pins have been declared and connected
      * to their nets
      */
     void merge_conn_nets() {
@@ -668,7 +668,7 @@ vtr::LogicValue to_vtr_logic_value(blifparse::LogicValue val) {
             new_val = vtr::LogicValue::UNKOWN;
             break;
         default:
-            VTR_ASSERT_OPT_MSG(false, "Unkown logic value");
+            VTR_ASSERT_OPT_MSG(false, "Unknown logic value");
     }
     return new_val;
 }