utils.h: added startsWith() and started using it (danmar#5381)

This makes the code much more readable. It also makes it less prone to
errors because we do not need to specify the length of the string to
match and the returnvalue is clear.

The code with the bad returnvalue check was never executed and I added a
test to show that.

Makefile

@@ -618,7 +618,7 @@ $(libcppdir)/symboldatabase.o: lib/symboldatabase.cpp lib/astutils.h lib/color.h
 $(libcppdir)/templatesimplifier.o: lib/templatesimplifier.cpp lib/color.h lib/config.h lib/errorlogger.h lib/errortypes.h lib/importproject.h lib/library.h lib/mathlib.h lib/platform.h lib/settings.h lib/standards.h lib/suppressions.h lib/templatesimplifier.h lib/token.h lib/tokenize.h lib/tokenlist.h lib/utils.h lib/vfvalue.h
 	$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $(libcppdir)/templatesimplifier.cpp
 
-$(libcppdir)/timer.o: lib/timer.cpp lib/config.h lib/timer.h
+$(libcppdir)/timer.o: lib/timer.cpp lib/config.h lib/timer.h lib/utils.h
 	$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $(libcppdir)/timer.cpp
 
 $(libcppdir)/token.o: lib/token.cpp lib/astutils.h lib/config.h lib/errortypes.h lib/importproject.h lib/library.h lib/mathlib.h lib/platform.h lib/settings.h lib/smallvector.h lib/sourcelocation.h lib/standards.h lib/suppressions.h lib/symboldatabase.h lib/templatesimplifier.h lib/token.h lib/tokenlist.h lib/tokenrange.h lib/utils.h lib/valueflow.h lib/vfvalue.h

cli/cmdlineparser.cpp

@@ -1418,5 +1418,5 @@ void CmdLineParser::printHelp()
 bool CmdLineParser::isCppcheckPremium() const {
     if (mSettings.cppcheckCfgProductName.empty())
         mSettings.loadCppcheckCfg();
-    return mSettings.cppcheckCfgProductName.compare(0, 16, "Cppcheck Premium") == 0;
+    return startsWith(mSettings.cppcheckCfgProductName, "Cppcheck Premium");
 }

gui/checkthread.cpp

@@ -27,6 +27,7 @@
 #include "settings.h"
 #include "standards.h"
 #include "threadresult.h"
+#include "utils.h"
 
 #include <algorithm>
 #include <cstddef>
@@ -75,7 +76,7 @@ static bool executeCommand(std::string exe, std::vector<std::string> args, std::
     } else
         output = process.readAllStandardOutput().toStdString();
 
-    if (redirect.compare(0,3,"2> ") == 0) {
+    if (startsWith(redirect, "2> ")) {
         std::ofstream fout(redirect.substr(3));
         fout << process.readAllStandardError().toStdString();
     }
@@ -157,7 +158,7 @@ void CheckThread::runAddonsAndTools(const ImportProject::FileSettings *fileSetti
             if (!fileSettings)
                 continue;
 
-            if (!fileSettings->cfg.empty() && fileSettings->cfg.compare(0,5,"Debug") != 0)
+            if (!fileSettings->cfg.empty() && !startsWith(fileSettings->cfg,"Debug"))
                 continue;
 
             QStringList args;

lib/astutils.cpp

@@ -2407,7 +2407,7 @@ bool isVariableChangedByFunctionCall(const Token *tok, int indirect, const Setti
         return false; // not a function => variable not changed
     if (Token::simpleMatch(tok, "{") && isTrivialConstructor(tok))
         return false;
-    if (tok->isKeyword() && !isCPPCastKeyword(tok) && tok->str().compare(0,8,"operator") != 0)
+    if (tok->isKeyword() && !isCPPCastKeyword(tok) && !startsWith(tok->str(),"operator"))
         return false;
     // A functional cast won't modify the variable
     if (Token::Match(tok, "%type% (|{") && tok->tokType() == Token::eType && astIsPrimitive(tok->next()))

lib/checkleakautovar.cpp

@@ -32,6 +32,7 @@
 #include "symboldatabase.h"
 #include "token.h"
 #include "tokenize.h"
+#include "utils.h"
 #include "vfvalue.h"
 
 #include <algorithm>
@@ -824,7 +825,7 @@ const Token * CheckLeakAutoVar::checkTokenInsideExpression(const Token * const t
                 } else if (rhs->str() == "(" && !mSettings->library.returnValue(rhs->astOperand1()).empty()) {
                     // #9298, assignment through return value of a function
                     const std::string &returnValue = mSettings->library.returnValue(rhs->astOperand1());
-                    if (returnValue.compare(0, 3, "arg") == 0) {
+                    if (startsWith(returnValue, "arg")) {
                         int argn;
                         const Token *func = getTokenArgumentFunction(tok, argn);
                         if (func) {
@@ -850,7 +851,7 @@ const Token * CheckLeakAutoVar::checkTokenInsideExpression(const Token * const t
             alloc.status = VarInfo::NOALLOC;
         functionCall(tok, openingPar, varInfo, alloc, nullptr);
         const std::string &returnValue = mSettings->library.returnValue(tok);
-        if (returnValue.compare(0, 3, "arg") == 0)
+        if (startsWith(returnValue, "arg"))
             // the function returns one of its argument, we need to process a potential assignment
             return openingPar;
         return isCPPCast(tok->astParent()) ? openingPar : openingPar->link();

lib/checkunusedvar.cpp

@@ -1273,7 +1273,7 @@ void CheckUnusedVar::checkFunctionVariableUsage()
                     (!op1Var->valueType() || op1Var->valueType()->type == ValueType::Type::UNKNOWN_TYPE)) {
                     // Check in the library if we should bailout or not..
                     std::string typeName = op1Var->getTypeName();
-                    if (typeName.compare(0, 2, "::") == 0)
+                    if (startsWith(typeName, "::"))
                         typeName.erase(typeName.begin(), typeName.begin() + 2);
                     switch (mSettings->library.getTypeCheck("unusedvar", typeName)) {
                     case Library::TypeCheck::def:

lib/clangimport.cpp

@@ -412,9 +412,9 @@ std::string clangimport::AstNode::getSpelling() const
             return "";
     }
     const std::string &str = mExtTokens[typeIndex - 1];
-    if (str.compare(0,4,"col:") == 0)
+    if (startsWith(str,"col:"))
         return "";
-    if (str.compare(0,8,"<invalid") == 0)
+    if (startsWith(str,"<invalid"))
         return "";
     if (nodeType == RecordDecl && str == "struct")
         return "";
@@ -499,9 +499,9 @@ void clangimport::AstNode::dumpAst(int num, int indent) const
 void clangimport::AstNode::setLocations(TokenList *tokenList, int file, int line, int col)
 {
     for (const std::string &ext: mExtTokens) {
-        if (ext.compare(0, 5, "<col:") == 0)
+        if (startsWith(ext, "<col:"))
             col = strToInt<int>(ext.substr(5, ext.find_first_of(",>", 5) - 5));
-        else if (ext.compare(0, 6, "<line:") == 0) {
+        else if (startsWith(ext, "<line:")) {
             line = strToInt<int>(ext.substr(6, ext.find_first_of(":,>", 6) - 6));
             const auto pos = ext.find(", col:");
             if (pos != std::string::npos)
@@ -542,7 +542,7 @@ const ::Type * clangimport::AstNode::addTypeTokens(TokenList *tokenList, const s
         return addTypeTokens(tokenList, str.substr(0, str.find("\':\'") + 1), scope);
     }
 
-    if (str.compare(0, 16, "'enum (anonymous") == 0)
+    if (startsWith(str, "'enum (anonymous"))
         return nullptr;
 
     std::string type;
@@ -943,7 +943,7 @@ Token *clangimport::AstNode::createTokens(TokenList *tokenList)
     }
     if (nodeType == DeclRefExpr) {
         int addrIndex = mExtTokens.size() - 1;
-        while (addrIndex > 1 && mExtTokens[addrIndex].compare(0,2,"0x") != 0)
+        while (addrIndex > 1 && !startsWith(mExtTokens[addrIndex],"0x"))
             --addrIndex;
         const std::string addr = mExtTokens[addrIndex];
         std::string name = unquote(getSpelling());
@@ -985,7 +985,7 @@ Token *clangimport::AstNode::createTokens(TokenList *tokenList)
     }
     if (nodeType == EnumDecl) {
         int colIndex = mExtTokens.size() - 1;
-        while (colIndex > 0 && mExtTokens[colIndex].compare(0,4,"col:") != 0 && mExtTokens[colIndex].compare(0,5,"line:") != 0)
+        while (colIndex > 0 && !startsWith(mExtTokens[colIndex],"col:") && !startsWith(mExtTokens[colIndex],"line:"))
             --colIndex;
         if (colIndex == 0)
             return nullptr;
@@ -1131,10 +1131,10 @@ Token *clangimport::AstNode::createTokens(TokenList *tokenList)
         Token *s = getChild(0)->createTokens(tokenList);
         Token *dot = addtoken(tokenList, ".");
         std::string memberName = getSpelling();
-        if (memberName.compare(0, 2, "->") == 0) {
+        if (startsWith(memberName, "->")) {
             dot->originalName("->");
             memberName = memberName.substr(2);
-        } else if (memberName.compare(0, 1, ".") == 0) {
+        } else if (startsWith(memberName, ".")) {
             memberName = memberName.substr(1);
         }
         if (memberName.empty())
@@ -1150,7 +1150,7 @@ Token *clangimport::AstNode::createTokens(TokenList *tokenList)
             return nullptr;
         const Token *defToken = addtoken(tokenList, "namespace");
         const std::string &s = mExtTokens[mExtTokens.size() - 2];
-        const Token* nameToken = (s.compare(0, 4, "col:") == 0 || s.compare(0, 5, "line:") == 0) ?
+        const Token* nameToken = (startsWith(s, "col:") || startsWith(s, "line:")) ?
                                  addtoken(tokenList, mExtTokens.back()) : nullptr;
         Scope *scope = createScope(tokenList, Scope::ScopeType::eNamespace, children, defToken);
         if (nameToken)

lib/cppcheck.cpp

@@ -360,7 +360,7 @@ static std::string executeAddon(const AddonInfo &addonInfo,
                 break;
             }
 #endif
-            if (executeCommand(py_exe, split("--version"), redirect, out) && out.compare(0, 7, "Python ") == 0 && std::isdigit(out[7])) {
+            if (executeCommand(py_exe, split("--version"), redirect, out) && startsWith(out, "Python ") && std::isdigit(out[7])) {
                 pythonExe = py_exe;
                 break;
             }
@@ -393,7 +393,7 @@ static std::string executeAddon(const AddonInfo &addonInfo,
     std::istringstream istr(result);
     std::string line;
     while (std::getline(istr, line)) {
-        if (line.compare(0,9,"Checking ", 0, 9) != 0 && !line.empty() && line[0] != '{') {
+        if (!startsWith(line,"Checking ") && !line.empty() && line[0] != '{') {
             result.erase(result.find_last_not_of('\n') + 1, std::string::npos); // Remove trailing newlines
             throw InternalError(nullptr, "Failed to execute '" + pythonExe + " " + args + "'. " + result);
         }
@@ -834,7 +834,7 @@ unsigned int CppCheck::checkFile(const std::string& filename, const std::string
             std::string code;
             const std::list<Directive> &directives = preprocessor.getDirectives();
             for (const Directive &dir : directives) {
-                if (dir.str.compare(0,8,"#define ") == 0 || dir.str.compare(0,9,"#include ") == 0)
+                if (startsWith(dir.str,"#define ") || startsWith(dir.str,"#include "))
                     code += "#line " + std::to_string(dir.linenr) + " \"" + dir.file + "\"\n" + dir.str + '\n';
             }
             Tokenizer tokenizer2(&mSettings, this);
@@ -883,7 +883,7 @@ unsigned int CppCheck::checkFile(const std::string& filename, const std::string
                 std::string codeWithoutCfg = preprocessor.getcode(tokens1, mCurrentConfig, files, true);
                 t.stop();
 
-                if (codeWithoutCfg.compare(0,5,"#file") == 0)
+                if (startsWith(codeWithoutCfg,"#file"))
                     codeWithoutCfg.insert(0U, "//");
                 std::string::size_type pos = 0;
                 while ((pos = codeWithoutCfg.find("\n#file",pos)) != std::string::npos)
@@ -1456,7 +1456,7 @@ void CppCheck::executeAddons(const std::vector<std::string>& files)
         const bool misraC2023 = mSettings.premiumArgs.find("--misra-c-2023") != std::string::npos;
 
         while (std::getline(istr, line)) {
-            if (line.compare(0,1,"{") != 0)
+            if (!startsWith(line,"{"))
                 continue;
 
             picojson::value res;
@@ -1486,7 +1486,7 @@ void CppCheck::executeAddons(const std::vector<std::string>& files)
             }
 
             errmsg.id = obj["addon"].get<std::string>() + "-" + obj["errorId"].get<std::string>();
-            if (misraC2023 && errmsg.id.compare(0, 12, "misra-c2012-") == 0)
+            if (misraC2023 && startsWith(errmsg.id, "misra-c2012-"))
                 errmsg.id = "misra-c2023-" + errmsg.id.substr(12);
             const std::string text = obj["message"].get<std::string>();
             errmsg.setmsg(text);

lib/errorlogger.cpp

@@ -135,7 +135,7 @@ ErrorMessage::ErrorMessage(const ErrorPath &errorPath, const TokenList *tokenLis
 
         std::string info = e.second;
 
-        if (info.compare(0,8,"$symbol:") == 0 && info.find('\n') < info.size()) {
+        if (startsWith(info,"$symbol:") && info.find('\n') < info.size()) {
             const std::string::size_type pos = info.find('\n');
             const std::string &symbolName = info.substr(8, pos - 8);
             info = replaceStr(info.substr(pos+1), "$symbol", symbolName);
@@ -215,7 +215,7 @@ void ErrorMessage::setmsg(const std::string &msg)
     if (pos == std::string::npos) {
         mShortMessage = replaceStr(msg, "$symbol", symbolName);
         mVerboseMessage = replaceStr(msg, "$symbol", symbolName);
-    } else if (msg.compare(0,8,"$symbol:") == 0) {
+    } else if (startsWith(msg,"$symbol:")) {
         mSymbolNames += msg.substr(8, pos-7);
         setmsg(msg.substr(pos + 1));
     } else {

lib/importproject.cpp

@@ -156,7 +156,7 @@ void ImportProject::FileSettings::setIncludePaths(const std::string &basepath, c
     for (const std::string &ipath : copyIn) {
         if (ipath.empty())
             continue;
-        if (ipath.compare(0,2,"%(")==0)
+        if (startsWith(ipath,"%("))
             continue;
         std::string s(Path::fromNativeSeparators(ipath));
         if (!found.insert(s).second)
@@ -298,9 +298,9 @@ void ImportProject::FileSettings::parseCommand(const std::string& command)
         if (F=='D') {
             std::string defval = readUntil(command, &pos, " ");
             defs += fval;
-            if (defval.size() >= 3 && defval.compare(0,2,"=\"")==0 && defval.back()=='\"')
+            if (defval.size() >= 3 && startsWith(defval,"=\"") && defval.back()=='\"')
                 defval = "=" + unescape(defval.substr(2, defval.size() - 3));
-            else if (defval.size() >= 5 && defval.compare(0, 3, "=\\\"") == 0 && endsWith(defval, "\\\""))
+            else if (defval.size() >= 5 && startsWith(defval, "=\\\"") && endsWith(defval, "\\\""))
                 defval = "=\"" + unescape(defval.substr(3, defval.size() - 5)) + "\"";
             if (!defval.empty())
                 defs += defval;
@@ -313,32 +313,9 @@ void ImportProject::FileSettings::parseCommand(const std::string& command)
                 i = unescape(i.substr(1, i.size() - 2));
             if (std::find(includePaths.cbegin(), includePaths.cend(), i) == includePaths.cend())
                 includePaths.push_back(std::move(i));
-        } else if (F=='s' && fval.compare(0,2,"td") == 0) {
+        } else if (F=='s' && startsWith(fval,"td")) {
             ++pos;
-            const std::string stdval = readUntil(command, &pos, " ");
-            standard = stdval;
-            // TODO: use simplecpp::DUI::std instead of specifying it manually
-            if (standard.compare(0, 3, "c++") || standard.compare(0, 5, "gnu++")) {
-                const std::string stddef = simplecpp::getCppStdString(standard);
-                if (stddef.empty()) {
-                    // TODO: log error
-                    continue;
-                }
-
-                defs += "__cplusplus=";
-                defs += stddef;
-                defs += ";";
-            } else if (standard.compare(0, 1, "c") || standard.compare(0, 3, "gnu")) {
-                const std::string stddef = simplecpp::getCStdString(standard);
-                if (stddef.empty()) {
-                    // TODO: log error
-                    continue;
-                }
-
-                defs += "__STDC_VERSION__=";
-                defs += stddef;
-                defs += ";";
-            }
+            standard = readUntil(command, &pos, " ");
         } else if (F == 'i' && fval == "system") {
             ++pos;
             std::string isystem = readUntil(command, &pos, " ");
@@ -459,9 +436,9 @@ bool ImportProject::importSln(std::istream &istr, const std::string &path, const
         return false;
     }
 
-    if (line.find("Microsoft Visual Studio Solution File") != 0) {
+    if (!startsWith(line, "Microsoft Visual Studio Solution File")) {
         // Skip BOM
-        if (!std::getline(istr, line) || line.find("Microsoft Visual Studio Solution File") != 0) {
+        if (!std::getline(istr, line) || !startsWith(line, "Microsoft Visual Studio Solution File")) {
             printError("Visual Studio solution file header not found");
             return false;
         }
@@ -473,7 +450,7 @@ bool ImportProject::importSln(std::istream &istr, const std::string &path, const
     bool found = false;
 
     while (std::getline(istr,line)) {
-        if (line.compare(0,8,"Project(")!=0)
+        if (!startsWith(line,"Project("))
             continue;
         const std::string::size_type pos = line.find(".vcxproj");
         if (pos == std::string::npos)
@@ -1302,7 +1279,7 @@ void ImportProject::selectOneVsConfig(cppcheck::Platform::Type platform)
         }
         const ImportProject::FileSettings &fs = *it;
         bool remove = false;
-        if (fs.cfg.compare(0,5,"Debug") != 0)
+        if (!startsWith(fs.cfg,"Debug"))
             remove = true;
         if (platform == cppcheck::Platform::Type::Win64 && fs.platformType != platform)
             remove = true;

lib/library.cpp

@@ -1174,7 +1174,7 @@ const Library::Container* Library::detectContainerInternal(const Token* const ty
         if (container.startPattern.empty())
             continue;
 
-        const int offset = (withoutStd && container.startPattern2.find("std :: ") == 0) ? 7 : 0;
+        const int offset = (withoutStd && startsWith(container.startPattern2, "std :: ")) ? 7 : 0;
 
         // If endPattern is undefined, it will always match, but itEndPattern has to be defined.
         if (detect != IteratorOnly && container.endPattern.empty()) {
@@ -1754,7 +1754,7 @@ std::shared_ptr<Token> createTokenFromExpression(const std::string& returnValue,
 
     // set varids
     for (Token* tok2 = tokenList->front(); tok2; tok2 = tok2->next()) {
-        if (tok2->str().compare(0, 3, "arg") != 0)
+        if (!startsWith(tok2->str(), "arg"))
             continue;
         nonneg int const id = strToInt<nonneg int>(tok2->str().c_str() + 3);
         tok2->varId(id);

lib/path.cpp

@@ -171,7 +171,7 @@ bool Path::isAbsolute(const std::string& path)
         return false;
 
     // On Windows, 'C:\foo\bar' is an absolute path, while 'C:foo\bar' is not
-    return nativePath.compare(0, 2, "\\\\") == 0 || (std::isalpha(nativePath[0]) != 0 && nativePath.compare(1, 2, ":\\") == 0);
+    return startsWith(nativePath, "\\\\") || (std::isalpha(nativePath[0]) != 0 && nativePath.compare(1, 2, ":\\") == 0);
 #else
     return !nativePath.empty() && nativePath[0] == '/';
 #endif
@@ -227,7 +227,7 @@ bool Path::acceptFile(const std::string &path, const std::set<std::string> &extr
 bool Path::isHeader(const std::string &path)
 {
     const std::string extension = getFilenameExtensionInLowerCase(path);
-    return (extension.compare(0, 2, ".h") == 0);
+    return startsWith(extension, ".h");
 }
 
 std::string Path::getAbsoluteFilePath(const std::string& filePath)

lib/preprocessor.cpp

@@ -27,6 +27,7 @@
 #include "settings.h"
 #include "standards.h"
 #include "suppressions.h"
+#include "utils.h"
 
 #include <algorithm>
 #include <array>
@@ -370,7 +371,7 @@ static const simplecpp::Token *gotoEndIf(const simplecpp::Token *cmdtok)
     int level = 0;
     while (nullptr != (cmdtok = cmdtok->next)) {
         if (cmdtok->op == '#' && !sameline(cmdtok->previous,cmdtok) && sameline(cmdtok, cmdtok->next)) {
-            if (cmdtok->next->str().compare(0,2,"if")==0)
+            if (startsWith(cmdtok->next->str(),"if"))
                 ++level;
             else if (cmdtok->next->str() == "endif") {
                 --level;
@@ -755,7 +756,7 @@ void Preprocessor::reportOutput(const simplecpp::OutputList &outputList, bool sh
     for (const simplecpp::Output &out : outputList) {
         switch (out.type) {
         case simplecpp::Output::ERROR:
-            if (out.msg.compare(0,6,"#error")!=0 || showerror)
+            if (!startsWith(out.msg,"#error") || showerror)
                 error(out.location.file(), out.location.line, out.msg);
             break;
         case simplecpp::Output::WARNING: