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<
//: Since different 
// Read a single-file C++ program having a very specific structure, and split
// it up into multiple separate compilation units to reduce the work needed to
// rebuild after a small change. Write each compilation unit only if it has
// changed from what was on disk before.
//
// This tool is tightly coupled with the build system for this project. The
// makefile already auto-generates various things; we only do here what
// standard unix tools can't easily do.
//
// Usage:
//  cleave [input C++ file] [existing output directory]
//
// The input C++ file has the following structure:
//   [#includes]
//   [type definitions]
generated by cgit-pink 1.4.1-2-gfad0 (git 2.36.2.497.gbbea4dcf42) at 2024-11-28 03:50:18 +0000
rything before the '// Globals' delimiter // global_definitions_list -- everything between '// Globals' and '// End Globals' delimiters // [.cc files partitioning function definitions] // // Each output function definition file contains: // #include "header" // #include "global_declarations_list" // [function definitions] // // To preserve the original layer-based line numbers in error messages and the // debugger, we'll chunk the files only at boundaries where we encounter a // '#line ' directive (generated by the previous tangle/ stage) between // functions. // // One exception: the first file emitted #includes "global_definitions_list" instead // of "global_declarations_list" // Tune this parameter to balance time for initial vs incremental build. // // decrease value -> faster initial build // increase value -> faster incremental build int Num_compilation_units = 3; #include<assert.h> #include<cstdlib> #include<cstring> #include<vector> using std::vector; #include<list> using std::list; #include<utility> using std::pair; #include<string> using std::string; #include<iostream> using std::istream; using std::ostream; using std::cin; using std::cout; using std::cerr; #include<sstream> using std::istringstream; using std::ostringstream; #include<fstream> using std::ifstream; using std::ofstream; #include <locale> using std::isspace; // unicode-aware string trim(const string& s) { string::const_iterator first = s.begin(); while (first != s.end() && isspace(*first)) ++first; if (first == s.end()) return ""; string::const_iterator last = --s.end(); while (last != s.begin() && isspace(*last)) --last; ++last; return string(first, last); } bool starts_with(const string& s, const string& pat) { string::const_iterator a=s.begin(), b=pat.begin(); for (/*nada*/; a!=s.end() && b!=pat.end(); ++a, ++b) if (*a != *b) return false; return b == pat.end(); } bool has_data(istream& in) { return in && !in.eof(); } void slurp(const string& filename, vector<string>& lines) { lines.clear(); ifstream in(filename.c_str()); while (has_data(in)) { string curr_line; getline(in, curr_line); lines.push_back(curr_line); } } size_t slurp_some_functions(const vector<string>& in, size_t start, vector<string>& out, bool first) { out.clear(); if (start >= in.size()) return start; out.push_back("#include \"header\""); if (first) out.push_back("#include \"global_definitions_list\""); else out.push_back("#include \"global_declarations_list\""); out.push_back(""); size_t curr = start; while (true) { if (curr >= in.size()) break; if (out.size() >= in.size()/Num_compilation_units) break; while (curr < in.size()) { // read functions -- lines until unindented '}' while (curr < in.size()) { const string& line = in.at(curr); //? cerr << curr << ": adding to function: " << line << '\n'; out.push_back(line); ++curr; if (!line.empty() && line.at(0) == '}') break; } // now look for a '#line' directive before the next non-comment non-empty // line while (curr < in.size()) { const string& line = in.at(curr); if (starts_with(line, "#line ")) goto try_return; out.push_back(line); ++curr; if (trim(line).empty()) continue; if (starts_with(trim(line), "//")) continue; break; } } try_return:; } return curr; } // compare contents of a file with a list of lines, ignoring #line directives // on both sides bool no_change(const vector<string>& lines, const string& output_filename) { vector<string> old_lines; slurp(output_filename, old_lines); size_t l=0, o=0; while (true) { while (l < lines.size() && (lines.at(l).empty() || starts_with(lines.at(l), "#line "))) { ++l; } while (o < old_lines.size() && (old_lines.at(o).empty() || starts_with(old_lines.at(o), "#line "))) { ++o; } if (l >= lines.size() && o >= old_lines.size()) return true; // no change if (l >= lines.size() || o >= old_lines.size()) return false; // contents changed //? cerr << "comparing\n"; //? cerr << o << ": " << old_lines.at(o) << '\n'; //? cerr << l << ": " << lines.at(l) << '\n'; if (lines.at(l) != old_lines.at(o)) return false; // contents changed ++l; ++o; } assert(false); } string next_output_filename(const string& output_directory) { static int file_count = 0; ostringstream out; out << output_directory << "/mu_" << file_count << ".cc"; file_count++; return out.str(); } void emit_file(const vector<string>& lines, const string& output_filename) { if (no_change(lines, output_filename)) return; cerr << " updating " << output_filename << '\n'; ofstream out(output_filename.c_str()); for (size_t i = 0; i < lines.size(); ++i) out << lines.at(i) << '\n'; } void emit_compilation_unit(const vector<string>& lines, const string& output_directory) { string output_filename = next_output_filename(output_directory); emit_file(lines, output_filename); } int main(int argc, const char* argv[]) { if (argc != 3) { cerr << "usage: cleave [input .cc file] [output directory]\n"; exit(0); } // read input vector<string> lines; slurp(argv[1], lines); // write header until but excluding '// Global' delimiter string output_directory = argv[2]; size_t line_num = 0; { vector<string> out; while (line_num < lines.size()) { const string& line = lines.at(line_num); if (trim(line) == "// Globals") break; // todo: #line directive for delimiters out.push_back(line); ++line_num; } emit_file(out, output_directory+"/header"); } // write global_definitions_list (including delimiters) { vector<string> out; while (line_num < lines.size()) { const string& line = lines.at(line_num); out.push_back(line); ++line_num; if (trim(line) == "// End Globals") break; } emit_file(out, output_directory+"/global_definitions_list"); } // segment functions // first one is special if (line_num < lines.size()) { vector<string> function; line_num = slurp_some_functions(lines, line_num, function, true); emit_compilation_unit(function, output_directory); } while (line_num < lines.size()) { vector<string> function; line_num = slurp_some_functions(lines, line_num, function, false); emit_compilation_unit(function, output_directory); } }
generated by cgit-pink 1.4.1-2-gfad0 (git 2.36.2.497.gbbea4dcf42) at 2024-11-28 03:50:19 +0000