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optimized handling of file and line preprocessor directives #502

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c6536fa
optimized handling of file and line preprocessor directives
firewave Aug 15, 2025
f9a15b6
avoid some redundant checks in preprocessor directive handling
firewave Aug 23, 2025
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104 changes: 50 additions & 54 deletions simplecpp.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -678,33 +678,55 @@ void simplecpp::TokenList::readfile(Stream &stream, const std::string &filename,

if (oldLastToken != cback()) {
oldLastToken = cback();
if (!isLastLinePreprocessor())
const Token * const llTok = isLastLinePreprocessor();
if (!llTok)
continue;
const std::string lastline(lastLine());
if (lastline == "# file %str%") {
const Token *strtok = cback();
while (strtok->comment)
strtok = strtok->previous;
loc.push(location);
location.fileIndex = fileIndex(strtok->str().substr(1U, strtok->str().size() - 2U));
location.line = 1U;
} else if (lastline == "# line %num%") {
const Token *numtok = cback();
while (numtok->comment)
numtok = numtok->previous;
lineDirective(location.fileIndex, std::atol(numtok->str().c_str()), &location);
} else if (lastline == "# %num% %str%" || lastline == "# line %num% %str%") {
const Token *strtok = cback();
while (strtok->comment)
strtok = strtok->previous;
const Token *numtok = strtok->previous;
while (numtok->comment)
numtok = numtok->previous;
lineDirective(fileIndex(replaceAll(strtok->str().substr(1U, strtok->str().size() - 2U),"\\\\","\\")),
std::atol(numtok->str().c_str()), &location);
const Token * const llNextToken = llTok->next;
if (!llTok->next)
continue;
if (llNextToken->next) {
// #file "file.c"
if (llNextToken->str() == "file" &&
llNextToken->next->str()[0] == '\"')
{
const Token *strtok = cback();
while (strtok->comment)
strtok = strtok->previous;
loc.push(location);
location.fileIndex = fileIndex(strtok->str().substr(1U, strtok->str().size() - 2U));
location.line = 1U;
}
// #3 "file.c"
// #line 3 "file.c"
else if ((llNextToken->number &&
llNextToken->next->str()[0] == '\"') ||
(llNextToken->str() == "line" &&
llNextToken->next->number &&
llNextToken->next->next &&
llNextToken->next->next->str()[0] == '\"'))
{
const Token *strtok = cback();
while (strtok->comment)
strtok = strtok->previous;
const Token *numtok = strtok->previous;
while (numtok->comment)
numtok = numtok->previous;
lineDirective(fileIndex(replaceAll(strtok->str().substr(1U, strtok->str().size() - 2U),"\\\\","\\")),
std::atol(numtok->str().c_str()), &location);
}
// #line 3
else if (llNextToken->str() == "line" &&
llNextToken->next->number)
{
const Token *numtok = cback();
while (numtok->comment)
numtok = numtok->previous;
lineDirective(location.fileIndex, std::atol(numtok->str().c_str()), &location);
}
}
// #endfile
else if (lastline == "# endfile" && !loc.empty()) {
else if (llNextToken->str() == "endfile" && !loc.empty())
{
location = loc.top();
loc.pop();
}
Expand Down Expand Up @@ -1398,34 +1420,6 @@ std::string simplecpp::TokenList::readUntil(Stream &stream, const Location &loca
return ret;
}

std::string simplecpp::TokenList::lastLine(int maxsize) const
{
std::string ret;
int count = 0;
for (const Token *tok = cback(); ; tok = tok->previous) {
if (!sameline(tok, cback())) {
break;
}
if (tok->comment)
continue;
if (++count > maxsize)
return "";
if (!ret.empty())
ret += ' ';
// add tokens in reverse for performance reasons
if (tok->str()[0] == '\"')
ret += "%rts%"; // %str%
else if (tok->number)
ret += "%mun%"; // %num%
else {
ret += tok->str();
std::reverse(ret.end() - tok->str().length(), ret.end());
}
}
std::reverse(ret.begin(), ret.end());
return ret;
}

const simplecpp::Token* simplecpp::TokenList::lastLineTok(int maxsize) const
{
const Token* prevTok = nullptr;
Expand All @@ -1442,10 +1436,12 @@ const simplecpp::Token* simplecpp::TokenList::lastLineTok(int maxsize) const
return prevTok;
}

bool simplecpp::TokenList::isLastLinePreprocessor(int maxsize) const
const simplecpp::Token* simplecpp::TokenList::isLastLinePreprocessor(int maxsize) const
{
const Token * const prevTok = lastLineTok(maxsize);
return prevTok && prevTok->op == '#';
if (prevTok && prevTok->op == '#')
return prevTok;
return nullptr;
}

unsigned int simplecpp::TokenList::fileIndex(const std::string &filename)
Expand Down
3 changes: 1 addition & 2 deletions simplecpp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -365,9 +365,8 @@ namespace simplecpp {
std::string readUntil(Stream &stream, const Location &location, char start, char end, OutputList *outputList);
void lineDirective(unsigned int fileIndex, unsigned int line, Location *location);

std::string lastLine(int maxsize=1000) const;
const Token* lastLineTok(int maxsize=1000) const;
bool isLastLinePreprocessor(int maxsize=1000) const;
const Token* isLastLinePreprocessor(int maxsize=1000) const;

unsigned int fileIndex(const std::string &filename);

Expand Down