Change ARPA output to use FakeOFStream

lm/filter/arpa_io.cc

@@ -22,14 +22,8 @@ ARPAInputException::ARPAInputException(const StringPiece &message, const StringP
 
 ARPAInputException::~ARPAInputException() throw() {}
 
-ARPAOutputException::ARPAOutputException(const char *message, const std::string &file_name) throw() {
-  *this << message << " in file " << file_name;
-}
-
-ARPAOutputException::~ARPAOutputException() throw() {}
-
 // Seeking is the responsibility of the caller.
-void WriteCounts(std::ostream &out, const std::vector<uint64_t> &number) {
+template <class Stream> void WriteCounts(Stream &out, const std::vector<uint64_t> &number) {
   out << "\n\\data\\\n";
   for (unsigned int i = 0; i < number.size(); ++i) {
     out << "ngram " << i+1 << "=" << number[i] << '\n';
@@ -38,9 +32,10 @@ void WriteCounts(std::ostream &out, const std::vector<uint64_t> &number) {
 }
 
 size_t SizeNeededForCounts(const std::vector<uint64_t> &number) {
-  std::ostringstream buf;
-  WriteCounts(buf, number);
-  return buf.tellp();
+  std::string buf;
+  util::FakeSStream stream(buf);
+  WriteCounts(stream, number);
+  return buf.size();
 }
 
 bool IsEntirelyWhiteSpace(const StringPiece &line) {
@@ -50,59 +45,32 @@ bool IsEntirelyWhiteSpace(const StringPiece &line) {
   return true;
 }
 
-ARPAOutput::ARPAOutput(const char *name, size_t buffer_size) : file_name_(name), buffer_(new char[buffer_size]) {
-  try {
-    file_.exceptions(std::ostream::eofbit | std::ostream::failbit | std::ostream::badbit);
-    if (!file_.rdbuf()->pubsetbuf(buffer_.get(), buffer_size)) {
-      std::cerr << "Warning: could not enlarge buffer for " << name << std::endl;
-      buffer_.reset();
-    }
-    file_.open(name, std::ios::out | std::ios::binary);
-  } catch (const std::ios_base::failure &f) {
-    throw ARPAOutputException("Opening", file_name_);
-  }
-}
+ARPAOutput::ARPAOutput(const char *name, size_t buffer_size) 
+  : file_backing_(util::CreateOrThrow(name)), file_(file_backing_.get(), buffer_size) {}
 
 void ARPAOutput::ReserveForCounts(std::streampos reserve) {
-  try {
-    for (std::streampos i = 0; i < reserve; i += std::streampos(1)) {
-      file_ << '\n';
-    }
-  } catch (const std::ios_base::failure &f) {
-    throw ARPAOutputException("Writing blanks to reserve space for counts to ", file_name_);
+  for (std::streampos i = 0; i < reserve; i += std::streampos(1)) {
+    file_ << '\n';
   }
 }
 
 void ARPAOutput::BeginLength(unsigned int length) {
-  fast_counter_ = 0;
-  try {
-    file_ << '\\' << length << "-grams:" << '\n';
-  } catch (const std::ios_base::failure &f) {
-    throw ARPAOutputException("Writing n-gram header to ", file_name_);
-  }
+  file_ << '\\' << length << "-grams:" << '\n';
 }
 
 void ARPAOutput::EndLength(unsigned int length) {
-  try {
-    file_ << '\n';
-  } catch (const std::ios_base::failure &f) {
-    throw ARPAOutputException("Writing blank at end of count list to ", file_name_);
-  }
+  file_ << '\n';
   if (length > counts_.size()) {
     counts_.resize(length);
   }
   counts_[length - 1] = fast_counter_;
 }
 
 void ARPAOutput::Finish() {
-  try {
-    file_ << "\\end\\\n";
-    file_.seekp(0);
-    WriteCounts(file_, counts_);
-    file_ << std::flush;
-  } catch (const std::ios_base::failure &f) {
-    throw ARPAOutputException("Finishing including writing counts at beginning to ", file_name_);
-  }
+  file_ << "\\end\\\n";
+  file_.seekp(0);
+  WriteCounts(file_, counts_);
+  file_.flush();
 }
 
 } // namespace lm

lm/filter/arpa_io.hh

@@ -4,6 +4,7 @@
  */
 #include "lm/read_arpa.hh"
 #include "util/exception.hh"
+#include "util/fake_ofstream.hh"
 #include "util/string_piece.hh"
 #include "util/tokenize_piece.hh"
 
@@ -28,17 +29,6 @@ class ARPAInputException : public util::Exception {
     virtual ~ARPAInputException() throw();
 };
 
-class ARPAOutputException : public util::ErrnoException {
-  public:
-    ARPAOutputException(const char *prefix, const std::string &file_name) throw();
-    virtual ~ARPAOutputException() throw();
-
-    const std::string &File() const throw() { return file_name_; }
-
-  private:
-    const std::string file_name_;
-};
-
 // Handling for the counts of n-grams at the beginning of ARPA files.
 size_t SizeNeededForCounts(const std::vector<uint64_t> &number);
 
@@ -55,11 +45,7 @@ class ARPAOutput : boost::noncopyable {
     void BeginLength(unsigned int length);
 
     void AddNGram(const StringPiece &line) {
-      try {
-        file_ << line << '\n';
-      } catch (const std::ios_base::failure &f) {
-        throw ARPAOutputException("Writing an n-gram", file_name_);
-      }
+      file_ << line << '\n';
       ++fast_counter_;
     }
 
@@ -76,9 +62,8 @@ class ARPAOutput : boost::noncopyable {
     void Finish();
 
   private:
-    const std::string file_name_;
-    boost::scoped_array<char> buffer_;
-    std::fstream file_;
+    util::scoped_fd file_backing_;
+    util::FakeOFStream file_;
     size_t fast_counter_;
     std::vector<uint64_t> counts_;
 };