1 files changed, 154 insertions, 0 deletions
diff --git a/klm/lm/read_arpa.cc b/klm/lm/read_arpa.cc
new file mode 100644
index 00000000..8e9a770d
--- /dev/null
+++ b/klm/lm/read_arpa.cc
@@ -0,0 +1,154 @@
+#include "lm/read_arpa.hh"
+
+#include <cstdlib>
+#include <vector>
+
+#include <ctype.h>
+#include <inttypes.h>
+
+namespace lm {
+
+namespace {
+
+bool IsEntirelyWhiteSpace(const StringPiece &line) {
+  for (size_t i = 0; i < static_cast<size_t>(line.size()); ++i) {
+    if (!isspace(line.data()[i])) return false;
+  }
+  return true;
+}
+
+template <class F> void GenericReadARPACounts(F &in, std::vector<uint64_t> &number) {
+  number.clear();
+  StringPiece line;
+  if (!IsEntirelyWhiteSpace(line = in.ReadLine())) {
+    if ((line.size() >= 2) && (line.data()[0] == 0x1f) && (static_cast<unsigned char>(line.data()[1]) == 0x8b)) {
+      UTIL_THROW(FormatLoadException, "Looks like a gzip file.  If this is an ARPA file, run\nzcat " << in.FileName() << " |kenlm/build_binary /dev/stdin " << in.FileName() << ".binary\nIf this already in binary format, you need to decompress it because mmap doesn't work on top of gzip.");
+    }
+    UTIL_THROW(FormatLoadException, "First line was \"" << static_cast<int>(line.data()[1]) << "\" not blank");
+  }
+  if ((line = in.ReadLine()) != "\\data\\") UTIL_THROW(FormatLoadException, "second line was \"" << line << "\" not \\data\\.");
+  while (!IsEntirelyWhiteSpace(line = in.ReadLine())) {
+    if (line.size() < 6 || strncmp(line.data(), "ngram ", 6)) UTIL_THROW(FormatLoadException, "count line \"" << line << "\"doesn't begin with \"ngram \"");
+    // So strtol doesn't go off the end of line.  
+    std::string remaining(line.data() + 6, line.size() - 6);
+    char *end_ptr;
+    unsigned long int length = std::strtol(remaining.c_str(), &end_ptr, 10);
+    if ((end_ptr == remaining.c_str()) || (length - 1 != number.size())) UTIL_THROW(FormatLoadException, "ngram count lengths should be consecutive starting with 1: " << line);
+    if (*end_ptr != '=') UTIL_THROW(FormatLoadException, "Expected = immediately following the first number in the count line " << line);
+    ++end_ptr;
+    const char *start = end_ptr;
+    long int count = std::strtol(start, &end_ptr, 10);
+    if (count < 0) UTIL_THROW(FormatLoadException, "Negative n-gram count " << count);
+    if (start == end_ptr) UTIL_THROW(FormatLoadException, "Couldn't parse n-gram count from " << line);
+    number.push_back(count);
+  }
+}
+
+template <class F> void GenericReadNGramHeader(F &in, unsigned int length) {
+  StringPiece line;
+  while (IsEntirelyWhiteSpace(line = in.ReadLine())) {}
+  std::stringstream expected;
+  expected << '\\' << length << "-grams:";
+  if (line != expected.str()) UTIL_THROW(FormatLoadException, "Was expecting n-gram header " << expected.str() << " but got " << line << " instead.  ");
+}
+
+template <class F> void GenericReadEnd(F &in) {
+  StringPiece line;
+  do {
+    line = in.ReadLine();
+  } while (IsEntirelyWhiteSpace(line));
+  if (line != "\\end\\") UTIL_THROW(FormatLoadException, "Expected \\end\\ but the ARPA file has " << line);
+}
+
+class FakeFilePiece {
+  public:
+    explicit FakeFilePiece(std::istream &in) : in_(in) {
+      in_.exceptions(std::ios::failbit | std::ios::badbit | std::ios::eofbit);
+    }
+
+    StringPiece ReadLine() throw(util::EndOfFileException) {
+      getline(in_, buffer_);
+      return StringPiece(buffer_);
+    }
+
+    float ReadFloat() {
+      float ret;
+      in_ >> ret;
+      return ret;
+    }
+
+    const char *FileName() const {
+      // This only used for error messages and we don't know the file name. . . 
+      return "$file";
+    }
+
+  private:
+    std::istream &in_;
+    std::string buffer_;
+};
+
+} // namespace
+
+void ReadARPACounts(util::FilePiece &in, std::vector<uint64_t> &number) {
+  GenericReadARPACounts(in, number);
+}
+void ReadARPACounts(std::istream &in, std::vector<uint64_t> &number) {
+  FakeFilePiece fake(in);
+  GenericReadARPACounts(fake, number);
+}
+void ReadNGramHeader(util::FilePiece &in, unsigned int length) {
+  GenericReadNGramHeader(in, length);
+}
+void ReadNGramHeader(std::istream &in, unsigned int length) {
+  FakeFilePiece fake(in);
+  GenericReadNGramHeader(fake, length);
+}
+
+void ReadBackoff(util::FilePiece &in, Prob &/*weights*/) {
+  switch (in.get()) {
+    case '\t':
+      {
+        float got = in.ReadFloat();
+        if (got != 0.0)
+          UTIL_THROW(FormatLoadException, "Non-zero backoff " << got << " provided for an n-gram that should have no backoff.");
+      }
+      break;
+    case '\n':
+      break;
+    default:
+      UTIL_THROW(FormatLoadException, "Expected tab or newline after unigram");
+  }
+}
+
+void ReadBackoff(util::FilePiece &in, ProbBackoff &weights) {
+  switch (in.get()) {
+    case '\t':
+      weights.backoff = in.ReadFloat();
+      if ((in.get() != '\n')) UTIL_THROW(FormatLoadException, "Expected newline after backoff");
+      break;
+    case '\n':
+      weights.backoff = 0.0;
+      break;
+    default:
+      UTIL_THROW(FormatLoadException, "Expected tab or newline after unigram");
+  }
+}
+
+void ReadEnd(util::FilePiece &in) {
+  GenericReadEnd(in);
+  StringPiece line;
+  try {
+    while (true) {
+      line = in.ReadLine();
+      if (!IsEntirelyWhiteSpace(line)) UTIL_THROW(FormatLoadException, "Trailing line " << line);
+    }
+  } catch (const util::EndOfFileException &e) {
+    return;
+  }
+}
+void ReadEnd(std::istream &in) {
+  FakeFilePiece fake(in);
+  GenericReadEnd(fake);
+}
+
+} // namespace lm