//===- FileCheck.cpp - Check that File's Contents match what is expected --===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // FileCheck does a line-by line check of a file that validates whether it // contains the expected content. This is useful for regression tests etc. // // This program exits with an error status of 2 on error, exit status of 0 if // the file matched the expected contents, and exit status of 1 if it did not // contain the expected contents. // //===----------------------------------------------------------------------===// #include "llvm/ADT/OwningPtr.h" #include "llvm/Support/CommandLine.h" #include "llvm/Support/MemoryBuffer.h" #include "llvm/Support/PrettyStackTrace.h" #include "llvm/Support/Regex.h" #include "llvm/Support/SourceMgr.h" #include "llvm/Support/raw_ostream.h" #include "llvm/Support/Signals.h" #include "llvm/Support/system_error.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/StringMap.h" #include <algorithm> using namespace llvm; static cl::opt<std::string> CheckFilename(cl::Positional, cl::desc("<check-file>"), cl::Required); static cl::opt<std::string> InputFilename("input-file", cl::desc("File to check (defaults to stdin)"), cl::init("-"), cl::value_desc("filename")); static cl::opt<std::string> CheckPrefix("check-prefix", cl::init("CHECK"), cl::desc("Prefix to use from check file (defaults to 'CHECK')")); static cl::opt<bool> NoCanonicalizeWhiteSpace("strict-whitespace", cl::desc("Do not treat all horizontal whitespace as equivalent")); //===----------------------------------------------------------------------===// // Pattern Handling Code. //===----------------------------------------------------------------------===// class Pattern { SMLoc PatternLoc; /// MatchEOF - When set, this pattern only matches the end of file. This is /// used for trailing CHECK-NOTs. bool MatchEOF; /// FixedStr - If non-empty, this pattern is a fixed string match with the /// specified fixed string. StringRef FixedStr; /// RegEx - If non-empty, this is a regex pattern. std::string RegExStr; /// VariableUses - Entries in this vector map to uses of a variable in the /// pattern, e.g. "foo[[bar]]baz". In this case, the RegExStr will contain /// "foobaz" and we'll get an entry in this vector that tells us to insert the /// value of bar at offset 3. std::vector<std::pair<StringRef, unsigned> > VariableUses; /// VariableDefs - Entries in this vector map to definitions of a variable in /// the pattern, e.g. "foo[[bar:.*]]baz". In this case, the RegExStr will /// contain "foo(.*)baz" and VariableDefs will contain the pair "bar",1. The /// index indicates what parenthesized value captures the variable value. std::vector<std::pair<StringRef, unsigned> > VariableDefs; public: Pattern(bool matchEOF = false) : MatchEOF(matchEOF) { } bool ParsePattern(StringRef PatternStr, SourceMgr &SM); /// Match - Match the pattern string against the input buffer Buffer. This /// returns the position that is matched or npos if there is no match. If /// there is a match, the size of the matched string is returned in MatchLen. /// /// The VariableTable StringMap provides the current values of filecheck /// variables and is updated if this match defines new values. size_t Match(StringRef Buffer, size_t &MatchLen, StringMap<StringRef> &VariableTable) const; /// PrintFailureInfo - Print additional information about a failure to match /// involving this pattern. void PrintFailureInfo(const SourceMgr &SM, StringRef Buffer, const StringMap<StringRef> &VariableTable) const; private: static void AddFixedStringToRegEx(StringRef FixedStr, std::string &TheStr); bool AddRegExToRegEx(StringRef RegExStr, unsigned &CurParen, SourceMgr &SM); /// ComputeMatchDistance - Compute an arbitrary estimate for the quality of /// matching this pattern at the start of \arg Buffer; a distance of zero /// should correspond to a perfect match. unsigned ComputeMatchDistance(StringRef Buffer, const StringMap<StringRef> &VariableTable) const; }; bool Pattern::ParsePattern(StringRef PatternStr, SourceMgr &SM) { PatternLoc = SMLoc::getFromPointer(PatternStr.data()); // Ignore trailing whitespace. while (!PatternStr.empty() && (PatternStr.back() == ' ' || PatternStr.back() == '\t')) PatternStr = PatternStr.substr(0, PatternStr.size()-1); // Check that there is something on the line. if (PatternStr.empty()) { SM.PrintMessage(PatternLoc, SourceMgr::DK_Error, "found empty check string with prefix '" + CheckPrefix+":'"); return true; } // Check to see if this is a fixed string, or if it has regex pieces. if (PatternStr.size() < 2 || (PatternStr.find("{{") == StringRef::npos && PatternStr.find("[[") == StringRef::npos)) { FixedStr = PatternStr; return false; } // Paren value #0 is for the fully matched string. Any new parenthesized // values add from there. unsigned CurParen = 1; // Otherwise, there is at least one regex piece. Build up the regex pattern // by escaping scary characters in fixed strings, building up one big regex. while (!PatternStr.empty()) { // RegEx matches. if (PatternStr.startswith("{{")) { // Otherwise, this is the start of a regex match. Scan for the }}. size_t End = PatternStr.find("}}"); if (End == StringRef::npos) { SM.PrintMessage(SMLoc::getFromPointer(PatternStr.data()), SourceMgr::DK_Error, "found start of regex string with no end '}}'"); return true; } // Enclose {{}} patterns in parens just like [[]] even though we're not // capturing the result for any purpose. This is required in case the // expression contains an alternation like: CHECK: abc{{x|z}}def. We // want this to turn into: "abc(x|z)def" not "abcx|zdef". RegExStr += '('; ++CurParen; if (AddRegExToRegEx(PatternStr.substr(2, End-2), CurParen, SM)) return true; RegExStr += ')'; PatternStr = PatternStr.substr(End+2); continue; } // Named RegEx matches. These are of two forms: [[foo:.*]] which matches .* // (or some other regex) and assigns it to the FileCheck variable 'foo'. The // second form is [[foo]] which is a reference to foo. The variable name // itself must be of the form "[a-zA-Z_][0-9a-zA-Z_]*", otherwise we reject // it. This is to catch some common errors. if (PatternStr.startswith("[[")) { // Verify that it is terminated properly. size_t End = PatternStr.find("]]"); if (End == StringRef::npos) { SM.PrintMessage(SMLoc::getFromPointer(PatternStr.data()), SourceMgr::DK_Error, "invalid named regex reference, no ]] found"); return true; } StringRef MatchStr = PatternStr.substr(2, End-2); PatternStr = PatternStr.substr(End+2); // Get the regex name (e.g. "foo"). size_t NameEnd = MatchStr.find(':'); StringRef Name = MatchStr.substr(0, NameEnd); if (Name.empty()) { SM.PrintMessage(SMLoc::getFromPointer(Name.data()), SourceMgr::DK_Error, "invalid name in named regex: empty name"); return true; } // Verify that the name is well formed. for (unsigned i = 0, e = Name.size(); i != e; ++i) if (Name[i] != '_' && !isalnum(Name[i])) { SM.PrintMessage(SMLoc::getFromPointer(Name.data()+i), SourceMgr::DK_Error, "invalid name in named regex"); return true; } // Name can't start with a digit. if (isdigit(Name[0])) { SM.PrintMessage(SMLoc::getFromPointer(Name.data()), SourceMgr::DK_Error, "invalid name in named regex"); return true; } // Handle [[foo]]. if (NameEnd == StringRef::npos) { VariableUses.push_back(std::make_pair(Name, RegExStr.size())); continue; } // Handle [[foo:.*]]. VariableDefs.push_back(std::make_pair(Name, CurParen)); RegExStr += '('; ++CurParen; if (AddRegExToRegEx(MatchStr.substr(NameEnd+1), CurParen, SM)) return true; RegExStr += ')'; } // Handle fixed string matches. // Find the end, which is the start of the next regex. size_t FixedMatchEnd = PatternStr.find("{{"); FixedMatchEnd = std::min(FixedMatchEnd, PatternStr.find("[[")); AddFixedStringToRegEx(PatternStr.substr(0, FixedMatchEnd), RegExStr); PatternStr = PatternStr.substr(FixedMatchEnd); continue; } return false; } void Pattern::AddFixedStringToRegEx(StringRef FixedStr, std::string &TheStr) { // Add the characters from FixedStr to the regex, escaping as needed. This // avoids "leaning toothpicks" in common patterns. for (unsigned i = 0, e = FixedStr.size(); i != e; ++i) { switch (FixedStr[i]) { // These are the special characters matched in "p_ere_exp". case '(': case ')': case '^': case '$': case '|': case '*': case '+': case '?': case '.': case '[': case '\\': case '{': TheStr += '\\'; // FALL THROUGH. default: TheStr += FixedStr[i]; break; } } } bool Pattern::AddRegExToRegEx(StringRef RegexStr, unsigned &CurParen, SourceMgr &SM) { Regex R(RegexStr); std::string Error; if (!R.isValid(Error)) { SM.PrintMessage(SMLoc::getFromPointer(RegexStr.data()), SourceMgr::DK_Error, "invalid regex: " + Error); return true; } RegExStr += RegexStr.str(); CurParen += R.getNumMatches(); return false; } /// Match - Match the pattern string against the input buffer Buffer. This /// returns the position that is matched or npos if there is no match. If /// there is a match, the size of the matched string is returned in MatchLen. size_t Pattern::Match(StringRef Buffer, size_t &MatchLen, StringMap<StringRef> &VariableTable) const { // If this is the EOF pattern, match it immediately. if (MatchEOF) { MatchLen = 0; return Buffer.size(); } // If this is a fixed string pattern, just match it now. if (!FixedStr.empty()) { MatchLen = FixedStr.size(); return Buffer.find(FixedStr); } // Regex match. // If there are variable uses, we need to create a temporary string with the // actual value. StringRef RegExToMatch = RegExStr; std::string TmpStr; if (!VariableUses.empty()) { TmpStr = RegExStr; unsigned InsertOffset = 0; for (unsigned i = 0, e = VariableUses.size(); i != e; ++i) { StringMap<StringRef>::iterator it = VariableTable.find(VariableUses[i].first); // If the variable is undefined, return an error. if (it == VariableTable.end()) return StringRef::npos; // Look up the value and escape it so that we can plop it into the regex. std::string Value; AddFixedStringToRegEx(it->second, Value); // Plop it into the regex at the adjusted offset. TmpStr.insert(TmpStr.begin()+VariableUses[i].second+InsertOffset, Value.begin(), Value.end()); InsertOffset += Value.size(); } // Match the newly constructed regex. RegExToMatch = TmpStr; } SmallVector<StringRef, 4> MatchInfo; if (!Regex(RegExToMatch, Regex::Newline).match(Buffer, &MatchInfo)) return StringRef::npos; // Successful regex match. assert(!MatchInfo.empty() && "Didn't get any match"); StringRef FullMatch = MatchInfo[0]; // If this defines any variables, remember their values. for (unsigned i = 0, e = VariableDefs.size(); i != e; ++i) { assert(VariableDefs[i].second < MatchInfo.size() && "Internal paren error"); VariableTable[VariableDefs[i].first] = MatchInfo[VariableDefs[i].second]; } MatchLen = FullMatch.size(); return FullMatch.data()-Buffer.data(); } unsigned Pattern::ComputeMatchDistance(StringRef Buffer, const StringMap<StringRef> &VariableTable) const { // Just compute the number of matching characters. For regular expressions, we // just compare against the regex itself and hope for the best. // // FIXME: One easy improvement here is have the regex lib generate a single // example regular expression which matches, and use that as the example // string. StringRef ExampleString(FixedStr); if (ExampleString.empty()) ExampleString = RegExStr; // Only compare up to the first line in the buffer, or the string size. StringRef BufferPrefix = Buffer.substr(0, ExampleString.size()); BufferPrefix = BufferPrefix.split('\n').first; return BufferPrefix.edit_distance(ExampleString); } void Pattern::PrintFailureInfo(const SourceMgr &SM, StringRef Buffer, const StringMap<StringRef> &VariableTable) const{ // If this was a regular expression using variables, print the current // variable values. if (!VariableUses.empty()) { for (unsigned i = 0, e = VariableUses.size(); i != e; ++i) { StringRef Var = VariableUses[i].first; StringMap<StringRef>::const_iterator it = VariableTable.find(Var); SmallString<256> Msg; raw_svector_ostream OS(Msg); // Check for undefined variable references. if (it == VariableTable.end()) { OS << "uses undefined variable \""; OS.write_escaped(Var) << "\"";; } else { OS << "with variable \""; OS.write_escaped(Var) << "\" equal to \""; OS.write_escaped(it->second) << "\""; } SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()), SourceMgr::DK_Note, OS.str()); } } // Attempt to find the closest/best fuzzy match. Usually an error happens // because some string in the output didn't exactly match. In these cases, we // would like to show the user a best guess at what "should have" matched, to // save them having to actually check the input manually. size_t NumLinesForward = 0; size_t Best = StringRef::npos; double BestQuality = 0; // Use an arbitrary 4k limit on how far we will search. for (size_t i = 0, e = std::min(size_t(4096), Buffer.size()); i != e; ++i) { if (Buffer[i] == '\n') ++NumLinesForward; // Patterns have leading whitespace stripped, so skip whitespace when // looking for something which looks like a pattern. if (Buffer[i] == ' ' || Buffer[i] == '\t') continue; // Compute the "quality" of this match as an arbitrary combination of the // match distance and the number of lines skipped to get to this match. unsigned Distance = ComputeMatchDistance(Buffer.substr(i), VariableTable); double Quality = Distance + (NumLinesForward / 100.); if (Quality < BestQuality || Best == StringRef::npos) { Best = i; BestQuality = Quality; } } // Print the "possible intended match here" line if we found something // reasonable and not equal to what we showed in the "scanning from here" // line. if (Best && Best != StringRef::npos && BestQuality < 50) { SM.PrintMessage(SMLoc::getFromPointer(Buffer.data() + Best), SourceMgr::DK_Note, "possible intended match here"); // FIXME: If we wanted to be really friendly we would show why the match // failed, as it can be hard to spot simple one character differences. } } //===----------------------------------------------------------------------===// // Check Strings. //===----------------------------------------------------------------------===// /// CheckString - This is a check that we found in the input file. struct CheckString { /// Pat - The pattern to match. Pattern Pat; /// Loc - The location in the match file that the check string was specified. SMLoc Loc; /// IsCheckNext - This is true if this is a CHECK-NEXT: directive (as opposed /// to a CHECK: directive. bool IsCheckNext; /// NotStrings - These are all of the strings that are disallowed from /// occurring between this match string and the previous one (or start of /// file). std::vector<std::pair<SMLoc, Pattern> > NotStrings; CheckString(const Pattern &P, SMLoc L, bool isCheckNext) : Pat(P), Loc(L), IsCheckNext(isCheckNext) {} }; /// CanonicalizeInputFile - Remove duplicate horizontal space from the specified /// memory buffer, free it, and return a new one. static MemoryBuffer *CanonicalizeInputFile(MemoryBuffer *MB) { SmallString<128> NewFile; NewFile.reserve(MB->getBufferSize()); for (const char *Ptr = MB->getBufferStart(), *End = MB->getBufferEnd(); Ptr != End; ++Ptr) { // Eliminate trailing dosish \r. if (Ptr <= End - 2 && Ptr[0] == '\r' && Ptr[1] == '\n') { continue; } // If C is not a horizontal whitespace, skip it. if (*Ptr != ' ' && *Ptr != '\t') { NewFile.push_back(*Ptr); continue; } // Otherwise, add one space and advance over neighboring space. NewFile.push_back(' '); while (Ptr+1 != End && (Ptr[1] == ' ' || Ptr[1] == '\t')) ++Ptr; } // Free the old buffer and return a new one. MemoryBuffer *MB2 = MemoryBuffer::getMemBufferCopy(NewFile.str(), MB->getBufferIdentifier()); delete MB; return MB2; } /// ReadCheckFile - Read the check file, which specifies the sequence of /// expected strings. The strings are added to the CheckStrings vector. static bool ReadCheckFile(SourceMgr &SM, std::vector<CheckString> &CheckStrings) { // Open the check file, and tell SourceMgr about it. OwningPtr<MemoryBuffer> File; if (error_code ec = MemoryBuffer::getFileOrSTDIN(CheckFilename.c_str(), File)) { errs() << "Could not open check file '" << CheckFilename << "': " << ec.message() << '\n'; return true; } MemoryBuffer *F = File.take(); // If we want to canonicalize whitespace, strip excess whitespace from the // buffer containing the CHECK lines. if (!NoCanonicalizeWhiteSpace) F = CanonicalizeInputFile(F); SM.AddNewSourceBuffer(F, SMLoc()); // Find all instances of CheckPrefix followed by : in the file. StringRef Buffer = F->getBuffer(); std::vector<std::pair<SMLoc, Pattern> > NotMatches; while (1) { // See if Prefix occurs in the memory buffer. Buffer = Buffer.substr(Buffer.find(CheckPrefix)); // If we didn't find a match, we're done. if (Buffer.empty()) break; const char *CheckPrefixStart = Buffer.data(); // When we find a check prefix, keep track of whether we find CHECK: or // CHECK-NEXT: bool IsCheckNext = false, IsCheckNot = false; // Verify that the : is present after the prefix. if (Buffer[CheckPrefix.size()] == ':') { Buffer = Buffer.substr(CheckPrefix.size()+1); } else if (Buffer.size() > CheckPrefix.size()+6 && memcmp(Buffer.data()+CheckPrefix.size(), "-NEXT:", 6) == 0) { Buffer = Buffer.substr(CheckPrefix.size()+7); IsCheckNext = true; } else if (Buffer.size() > CheckPrefix.size()+5 && memcmp(Buffer.data()+CheckPrefix.size(), "-NOT:", 5) == 0) { Buffer = Buffer.substr(CheckPrefix.size()+6); IsCheckNot = true; } else { Buffer = Buffer.substr(1); continue; } // Okay, we found the prefix, yay. Remember the rest of the line, but // ignore leading and trailing whitespace. Buffer = Buffer.substr(Buffer.find_first_not_of(" \t")); // Scan ahead to the end of line. size_t EOL = Buffer.find_first_of("\n\r"); // Remember the location of the start of the pattern, for diagnostics. SMLoc PatternLoc = SMLoc::getFromPointer(Buffer.data()); // Parse the pattern. Pattern P; if (P.ParsePattern(Buffer.substr(0, EOL), SM)) return true; Buffer = Buffer.substr(EOL); // Verify that CHECK-NEXT lines have at least one CHECK line before them. if (IsCheckNext && CheckStrings.empty()) { SM.PrintMessage(SMLoc::getFromPointer(CheckPrefixStart), SourceMgr::DK_Error, "found '"+CheckPrefix+"-NEXT:' without previous '"+ CheckPrefix+ ": line"); return true; } // Handle CHECK-NOT. if (IsCheckNot) { NotMatches.push_back(std::make_pair(SMLoc::getFromPointer(Buffer.data()), P)); continue; } // Okay, add the string we captured to the output vector and move on. CheckStrings.push_back(CheckString(P, PatternLoc, IsCheckNext)); std::swap(NotMatches, CheckStrings.back().NotStrings); } // Add an EOF pattern for any trailing CHECK-NOTs. if (!NotMatches.empty()) { CheckStrings.push_back(CheckString(Pattern(true), SMLoc::getFromPointer(Buffer.data()), false)); std::swap(NotMatches, CheckStrings.back().NotStrings); } if (CheckStrings.empty()) { errs() << "error: no check strings found with prefix '" << CheckPrefix << ":'\n"; return true; } return false; } static void PrintCheckFailed(const SourceMgr &SM, const CheckString &CheckStr, StringRef Buffer, StringMap<StringRef> &VariableTable) { // Otherwise, we have an error, emit an error message. SM.PrintMessage(CheckStr.Loc, SourceMgr::DK_Error, "expected string not found in input"); // Print the "scanning from here" line. If the current position is at the // end of a line, advance to the start of the next line. Buffer = Buffer.substr(Buffer.find_first_not_of(" \t\n\r")); SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()), SourceMgr::DK_Note, "scanning from here"); // Allow the pattern to print additional information if desired. CheckStr.Pat.PrintFailureInfo(SM, Buffer, VariableTable); } /// CountNumNewlinesBetween - Count the number of newlines in the specified /// range. static unsigned CountNumNewlinesBetween(StringRef Range) { unsigned NumNewLines = 0; while (1) { // Scan for newline. Range = Range.substr(Range.find_first_of("\n\r")); if (Range.empty()) return NumNewLines; ++NumNewLines; // Handle \n\r and \r\n as a single newline. if (Range.size() > 1 && (Range[1] == '\n' || Range[1] == '\r') && (Range[0] != Range[1])) Range = Range.substr(1); Range = Range.substr(1); } } int main(int argc, char **argv) { sys::PrintStackTraceOnErrorSignal(); PrettyStackTraceProgram X(argc, argv); cl::ParseCommandLineOptions(argc, argv); SourceMgr SM; // Read the expected strings from the check file. std::vector<CheckString> CheckStrings; if (ReadCheckFile(SM, CheckStrings)) return 2; // Open the file to check and add it to SourceMgr. OwningPtr<MemoryBuffer> File; if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputFilename.c_str(), File)) { errs() << "Could not open input file '" << InputFilename << "': " << ec.message() << '\n'; return true; } MemoryBuffer *F = File.take(); if (F->getBufferSize() == 0) { errs() << "FileCheck error: '" << InputFilename << "' is empty.\n"; return 1; } // Remove duplicate spaces in the input file if requested. if (!NoCanonicalizeWhiteSpace) F = CanonicalizeInputFile(F); SM.AddNewSourceBuffer(F, SMLoc()); /// VariableTable - This holds all the current filecheck variables. StringMap<StringRef> VariableTable; // Check that we have all of the expected strings, in order, in the input // file. StringRef Buffer = F->getBuffer(); const char *LastMatch = Buffer.data(); for (unsigned StrNo = 0, e = CheckStrings.size(); StrNo != e; ++StrNo) { const CheckString &CheckStr = CheckStrings[StrNo]; StringRef SearchFrom = Buffer; // Find StrNo in the file. size_t MatchLen = 0; size_t MatchPos = CheckStr.Pat.Match(Buffer, MatchLen, VariableTable); Buffer = Buffer.substr(MatchPos); // If we didn't find a match, reject the input. if (MatchPos == StringRef::npos) { PrintCheckFailed(SM, CheckStr, SearchFrom, VariableTable); return 1; } StringRef SkippedRegion(LastMatch, Buffer.data()-LastMatch); // If this check is a "CHECK-NEXT", verify that the previous match was on // the previous line (i.e. that there is one newline between them). if (CheckStr.IsCheckNext) { // Count the number of newlines between the previous match and this one. assert(LastMatch != F->getBufferStart() && "CHECK-NEXT can't be the first check in a file"); unsigned NumNewLines = CountNumNewlinesBetween(SkippedRegion); if (NumNewLines == 0) { SM.PrintMessage(CheckStr.Loc, SourceMgr::DK_Error, CheckPrefix+"-NEXT: is on the same line as previous match"); SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()), SourceMgr::DK_Note, "'next' match was here"); SM.PrintMessage(SMLoc::getFromPointer(LastMatch), SourceMgr::DK_Note, "previous match was here"); return 1; } if (NumNewLines != 1) { SM.PrintMessage(CheckStr.Loc, SourceMgr::DK_Error, CheckPrefix+ "-NEXT: is not on the line after the previous match"); SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()), SourceMgr::DK_Note, "'next' match was here"); SM.PrintMessage(SMLoc::getFromPointer(LastMatch), SourceMgr::DK_Note, "previous match was here"); return 1; } } // If this match had "not strings", verify that they don't exist in the // skipped region. for (unsigned ChunkNo = 0, e = CheckStr.NotStrings.size(); ChunkNo != e; ++ChunkNo) { size_t MatchLen = 0; size_t Pos = CheckStr.NotStrings[ChunkNo].second.Match(SkippedRegion, MatchLen, VariableTable); if (Pos == StringRef::npos) continue; SM.PrintMessage(SMLoc::getFromPointer(LastMatch+Pos), SourceMgr::DK_Error, CheckPrefix+"-NOT: string occurred!"); SM.PrintMessage(CheckStr.NotStrings[ChunkNo].first, SourceMgr::DK_Note, CheckPrefix+"-NOT: pattern specified here"); return 1; } // Otherwise, everything is good. Step over the matched text and remember // the position after the match as the end of the last match. Buffer = Buffer.substr(MatchLen); LastMatch = Buffer.data(); } return 0; }