PpContext.h

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#ifndef PPCONTEXT_H
#define PPCONTEXT_H

#include <stack>
#include <unordered_map>
#include <sstream>

#include "../ParseHelper.h"

/* windows only pragma */
#ifdef _MSC_VER
 #pragma warning(disable : 4127)
#endif

namespace glslang {

class TPpToken {
public:
 TPpToken() { clear(); }
 void clear()
 {
 space = false;
 i64val = 0;
 loc.init();
 name[0] = 0;
 }

 // Used for comparing macro definitions, so checks what is relevant for that.
 bool operator==(const TPpToken& right)
 {
 return space == right.space &&
 ival == right.ival && dval == right.dval && i64val == right.i64val &&
 strncmp(name, right.name, MaxTokenLength) == 0;
 }
 bool operator!=(const TPpToken& right) { return ! operator==(right); }

 TSourceLoc loc;
 // True if a space (for white space or a removed comment) should also be
 // recognized, in front of the token returned:
 bool space;
 // Numeric value of the token:
 union {
 int ival;
 double dval;
 long long i64val;
 };
 // Text string of the token:
 char name[MaxTokenLength + 1];
};

class TStringAtomMap {
//
// Implementation is in PpAtom.cpp
//
// Maintain a bi-directional mapping between relevant preprocessor strings and
// "atoms" which a unique integers (small, contiguous, not hash-like) per string.
//
public:
 TStringAtomMap();

 // Map string -> atom.
 // Return 0 if no existing string.
 int getAtom(const char* s) const
 {
 auto it = atomMap.find(s);
 return it == atomMap.end() ? 0 : it->second;
 }

 // Map a new or existing string -> atom, inventing a new atom if necessary.
 int getAddAtom(const char* s)
 {
 int atom = getAtom(s);
 if (atom == 0) {
 atom = nextAtom++;
 addAtomFixed(s, atom);
 }
 return atom;
 }

 // Map atom -> string.
 const char* getString(int atom) const { return stringMap[atom]->c_str(); }

protected:
 TStringAtomMap(TStringAtomMap&);
 TStringAtomMap& operator=(TStringAtomMap&);

 TUnorderedMap<TString, int> atomMap;
 TVector<const TString*> stringMap; // these point into the TString in atomMap
 int nextAtom;

 // Bad source characters can lead to bad atoms, so gracefully handle those by
 // pre-filling the table with them (to avoid if tests later).
 TString badToken;

 // Add bi-directional mappings:
 // - string -> atom
 // - atom -> string
 void addAtomFixed(const char* s, int atom)
 {
 auto it = atomMap.insert(std::pair<TString, int>(s, atom)).first;
 if (stringMap.size() < (size_t)atom + 1)
 stringMap.resize(atom + 100, &badToken);
 stringMap[atom] = &it->first;
 }
};

class TInputScanner;

// This class is the result of turning a huge pile of C code communicating through globals
// into a class. This was done to allowing instancing to attain thread safety.
// Don't expect too much in terms of OO design.
class TPpContext {
public:
 TPpContext(TParseContextBase&, const std::string& rootFileName, TShader::Includer&);
 virtual ~TPpContext();

 void setPreamble(const char* preamble, size_t length);

 int tokenize(TPpToken& ppToken);
 int tokenPaste(int token, TPpToken&);

 class tInput {
 public:
 tInput(TPpContext* p) : done(false), pp(p) { }
 virtual ~tInput() { }

 virtual int scan(TPpToken*) = 0;
 virtual int getch() = 0;
 virtual void ungetch() = 0;
 virtual bool peekPasting() { return false; } // true when about to see ##
 virtual bool endOfReplacementList() { return false; } // true when at the end of a macro replacement list (RHS of #define)
 virtual bool isMacroInput() { return false; }

 // Will be called when we start reading tokens from this instance
 virtual void notifyActivated() {}
 // Will be called when we do not read tokens from this instance anymore
 virtual void notifyDeleted() {}
 protected:
 bool done;
 TPpContext* pp;
 };

 void setInput(TInputScanner& input, bool versionWillBeError);

 void pushInput(tInput* in)
 {
 inputStack.push_back(in);
 in->notifyActivated();
 }
 void popInput()
 {
 inputStack.back()->notifyDeleted();
 delete inputStack.back();
 inputStack.pop_back();
 }

 //
 // From PpTokens.cpp
 //

 class TokenStream {
 public:
 TokenStream() : current(0) { }

 void putToken(int token, TPpToken* ppToken);
 int getToken(TParseContextBase&, TPpToken*);
 bool atEnd() { return current >= data.size(); }
 bool peekTokenizedPasting(bool lastTokenPastes);
 bool peekUntokenizedPasting();
 void reset() { current = 0; }

 protected:
 void putSubtoken(char);
 int getSubtoken();
 void ungetSubtoken();

 TVector<unsigned char> data;
 size_t current;
 };

 //
 // From Pp.cpp
 //

 struct MacroSymbol {
 MacroSymbol() : emptyArgs(0), busy(0), undef(0) { }
 TVector<int> args;
 TokenStream body;
 unsigned emptyArgs : 1;
 unsigned busy : 1;
 unsigned undef : 1;
 };

 typedef TMap<int, MacroSymbol> TSymbolMap;
 TSymbolMap macroDefs; // map atoms to macro definitions
 MacroSymbol* lookupMacroDef(int atom)
 {
 auto existingMacroIt = macroDefs.find(atom);
 return (existingMacroIt == macroDefs.end()) ? nullptr : &(existingMacroIt->second);
 }
 void addMacroDef(int atom, MacroSymbol& macroDef) { macroDefs[atom] = macroDef; }

protected:
 TPpContext(TPpContext&);
 TPpContext& operator=(TPpContext&);

 TStringAtomMap atomStrings;
 char* preamble; // string to parse, all before line 1 of string 0, it is 0 if no preamble
 int preambleLength;
 char** strings; // official strings of shader, starting a string 0 line 1
 size_t* lengths;
 int numStrings; // how many official strings there are
 int currentString; // which string we're currently parsing (-1 for preamble)

 // Scanner data:
 int previous_token;
 TParseContextBase& _parseContext;

 // Get the next token from *stack* of input sources, popping input sources
 // that are out of tokens, down until an input source is found that has a token.
 // Return EndOfInput when there are no more tokens to be found by doing this.
 int scanToken(TPpToken* ppToken)
 {
 int token = EndOfInput;

 while (! inputStack.empty()) {
 token = inputStack.back()->scan(ppToken);
 if (token != EndOfInput || inputStack.empty())
 break;
 popInput();
 }

 return token;
 }
 int getChar() { return inputStack.back()->getch(); }
 void ungetChar() { inputStack.back()->ungetch(); }
 bool peekPasting() { return !inputStack.empty() && inputStack.back()->peekPasting(); }
 bool endOfReplacementList() { return inputStack.empty() || inputStack.back()->endOfReplacementList(); }
 bool isMacroInput() { return inputStack.size() > 0 && inputStack.back()->isMacroInput(); }

 static const int maxIfNesting = 65;

 int ifdepth; // current #if-#else-#endif nesting in the cpp.c file (pre-processor)
 bool elseSeen[maxIfNesting]; // Keep a track of whether an else has been seen at a particular depth
 int elsetracker; // #if-#else and #endif constructs...Counter.

 class tMacroInput : public tInput {
 public:
 tMacroInput(TPpContext* pp) : tInput(pp), prepaste(false), postpaste(false) { }
 virtual ~tMacroInput()
 {
 for (size_t i = 0; i < args.size(); ++i)
 delete args[i];
 for (size_t i = 0; i < expandedArgs.size(); ++i)
 delete expandedArgs[i];
 }

 virtual int scan(TPpToken*) override;
 virtual int getch() override { assert(0); return EndOfInput; }
 virtual void ungetch() override { assert(0); }
 bool peekPasting() override { return prepaste; }
 bool endOfReplacementList() override { return mac->body.atEnd(); }
 bool isMacroInput() override { return true; }

 MacroSymbol *mac;
 TVector<TokenStream*> args;
 TVector<TokenStream*> expandedArgs;

 protected:
 bool prepaste; // true if we are just before ##
 bool postpaste; // true if we are right after ##
 };

 class tMarkerInput : public tInput {
 public:
 tMarkerInput(TPpContext* pp) : tInput(pp) { }
 virtual int scan(TPpToken*) override
 {
 if (done)
 return EndOfInput;
 done = true;

 return marker;
 }
 virtual int getch() override { assert(0); return EndOfInput; }
 virtual void ungetch() override { assert(0); }
 static const int marker = -3;
 };

 class tZeroInput : public tInput {
 public:
 tZeroInput(TPpContext* pp) : tInput(pp) { }
 virtual int scan(TPpToken*) override;
 virtual int getch() override { assert(0); return EndOfInput; }
 virtual void ungetch() override { assert(0); }
 };

 std::vector<tInput*> inputStack;
 bool errorOnVersion;
 bool versionSeen;

 //
 // from Pp.cpp
 //

 // Used to obtain #include content.
 TShader::Includer& includer;

 int CPPdefine(TPpToken * ppToken);
 int CPPundef(TPpToken * ppToken);
 int CPPelse(int matchelse, TPpToken * ppToken);
 int extraTokenCheck(int atom, TPpToken* ppToken, int token);
 int eval(int token, int precedence, bool shortCircuit, int& res, bool& err, TPpToken * ppToken);
 int evalToToken(int token, bool shortCircuit, int& res, bool& err, TPpToken * ppToken);
 int CPPif (TPpToken * ppToken);
 int CPPifdef(int defined, TPpToken * ppToken);
 int CPPinclude(TPpToken * ppToken);
 int CPPline(TPpToken * ppToken);
 int CPPerror(TPpToken * ppToken);
 int CPPpragma(TPpToken * ppToken);
 int CPPversion(TPpToken * ppToken);
 int CPPextension(TPpToken * ppToken);
 int readCPPline(TPpToken * ppToken);
 int scanHeaderName(TPpToken* ppToken, char delimit);
 TokenStream* PrescanMacroArg(TokenStream&, TPpToken*, bool newLineOkay);
 int MacroExpand(TPpToken* ppToken, bool expandUndef, bool newLineOkay);

 //
 // From PpTokens.cpp
 //
 void pushTokenStreamInput(TokenStream&, bool pasting = false);
 void UngetToken(int token, TPpToken*);

 class tTokenInput : public tInput {
 public:
 tTokenInput(TPpContext* pp, TokenStream* t, bool prepasting) : tInput(pp), tokens(t), lastTokenPastes(prepasting) { }
 virtual int scan(TPpToken *ppToken) override { return tokens->getToken(pp->_parseContext, ppToken); }
 virtual int getch() override { assert(0); return EndOfInput; }
 virtual void ungetch() override { assert(0); }
 virtual bool peekPasting() override { return tokens->peekTokenizedPasting(lastTokenPastes); }
 protected:
 TokenStream* tokens;
 bool lastTokenPastes; // true if the last token in the input is to be pasted, rather than consumed as a token
 };

 class tUngotTokenInput : public tInput {
 public:
 tUngotTokenInput(TPpContext* pp, int t, TPpToken* p) : tInput(pp), token(t), lval(*p) { }
 virtual int scan(TPpToken *) override;
 virtual int getch() override { assert(0); return EndOfInput; }
 virtual void ungetch() override { assert(0); }
 protected:
 int token;
 TPpToken lval;
 };

 //
 // From PpScanner.cpp
 //
 class tStringInput : public tInput {
 public:
 tStringInput(TPpContext* pp, TInputScanner& i) : tInput(pp), input(&i) { }
 virtual int scan(TPpToken*) override;

 // Scanner used to get source stream characters.
 // - Escaped newlines are handled here, invisibly to the caller.
 // - All forms of newline are handled, and turned into just a '\n'.
 int getch() override
 {
 int ch = input->get();

 if (ch == '\\') {
 // Move past escaped newlines, as many as sequentially exist
 do {
 if (input->peek() == '\r' || input->peek() == '\n') {
 bool allowed = pp->_parseContext.lineContinuationCheck(input->getSourceLoc(), pp->inComment);
 if (! allowed && pp->inComment)
 return '\\';

 // escape one newline now
 ch = input->get();
 int nextch = input->get();
 if (ch == '\r' && nextch == '\n')
 ch = input->get();
 else
 ch = nextch;
 } else
 return '\\';
 } while (ch == '\\');
 }

 // handle any non-escaped newline
 if (ch == '\r' || ch == '\n') {
 if (ch == '\r' && input->peek() == '\n')
 input->get();
 return '\n';
 }

 return ch;
 }

 // Scanner used to backup the source stream characters. Newlines are
 // handled here, invisibly to the caller, meaning have to undo exactly
 // what getch() above does (e.g., don't leave things in the middle of a
 // sequence of escaped newlines).
 void ungetch() override
 {
 input->unget();

 do {
 int ch = input->peek();
 if (ch == '\r' || ch == '\n') {
 if (ch == '\n') {
 // correct for two-character newline
 input->unget();
 if (input->peek() != '\r')
 input->get();
 }
 // now in front of a complete newline, move past an escape character
 input->unget();
 if (input->peek() == '\\')
 input->unget();
 else {
 input->get();
 break;
 }
 } else
 break;
 } while (true);
 }

 protected:
 TInputScanner* input;
 };

 // Holds a reference to included file data, as well as a
 // prologue and an epilogue string. This can be scanned using the tInput
 // interface and acts as a single source string.
 class TokenizableIncludeFile : public tInput {
 public:
 // Copies prologue and epilogue. The includedFile must remain valid
 // until this TokenizableIncludeFile is no longer used.
 TokenizableIncludeFile(const TSourceLoc& startLoc,
 const std::string& prologue,
 TShader::Includer::IncludeResult* includedFile,
 const std::string& epilogue,
 TPpContext* pp)
 : tInput(pp),
 prologue_(prologue),
 epilogue_(epilogue),
 includedFile_(includedFile),
 scanner(3, strings, lengths, names, 0, 0, true),
 prevScanner(nullptr),
 stringInput(pp, scanner)
 {
 strings[0] = prologue_.data();
 strings[1] = includedFile_->headerData;
 strings[2] = epilogue_.data();

 lengths[0] = prologue_.size();
 lengths[1] = includedFile_->headerLength;
 lengths[2] = epilogue_.size();

 scanner.setLine(startLoc.line);
 scanner.setString(startLoc.string);

 scanner.setFile(startLoc.name, 0);
 scanner.setFile(startLoc.name, 1);
 scanner.setFile(startLoc.name, 2);
 }

 // tInput methods:
 int scan(TPpToken* t) override { return stringInput.scan(t); }
 int getch() override { return stringInput.getch(); }
 void ungetch() override { stringInput.ungetch(); }

 void notifyActivated() override
 {
 prevScanner = pp->_parseContext.getScanner();
 pp->_parseContext.setScanner(&scanner);
 pp->push_include(includedFile_);
 }

 void notifyDeleted() override
 {
 pp->_parseContext.setScanner(prevScanner);
 pp->pop_include();
 }

 private:
 TokenizableIncludeFile& operator=(const TokenizableIncludeFile&);

 // Stores the prologue for this string.
 const std::string prologue_;

 // Stores the epilogue for this string.
 const std::string epilogue_;

 // Points to the IncludeResult that this TokenizableIncludeFile represents.
 TShader::Includer::IncludeResult* includedFile_;

 // Will point to prologue_, includedFile_->headerData and epilogue_
 // This is passed to scanner constructor.
 // These do not own the storage and it must remain valid until this
 // object has been destroyed.
 const char* strings[3];
 // Length of str_, passed to scanner constructor.
 size_t lengths[3];
 // String names
 const char* names[3];
 // Scans over str_.
 TInputScanner scanner;
 // The previous effective scanner before the scanner in this instance
 // has been activated.
 TInputScanner* prevScanner;
 // Delegate object implementing the tInput interface.
 tStringInput stringInput;
 };

 int ScanFromString(char* s);
 void missingEndifCheck();
 int lFloatConst(int len, int ch, TPpToken* ppToken);
 int characterLiteral(TPpToken* ppToken);

 void push_include(TShader::Includer::IncludeResult* result)
 {
 currentSourceFile = result->headerName;
 includeStack.push(result);
 }

 void pop_include()
 {
 TShader::Includer::IncludeResult* include = includeStack.top();
 includeStack.pop();
 includer.releaseInclude(include);
 if (includeStack.empty()) {
 currentSourceFile = rootFileName;
 } else {
 currentSourceFile = includeStack.top()->headerName;
 }
 }

 bool inComment;
 std::string rootFileName;
 std::stack<TShader::Includer::IncludeResult*> includeStack;
 std::string currentSourceFile;

 std::istringstream strtodStream;
};

} // end namespace glslang

#endif // PPCONTEXT_H