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read_arpa.cc
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read_arpa.cc
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#include "lm/read_arpa.hh"
#include "lm/blank.hh"
#include "util/file.hh"
#include <cmath>
#include <cstdlib>
#include <iostream>
#include <sstream>
#include <vector>
#include <cctype>
#include <cstring>
#include <stdint.h>
#ifdef WIN32
#include <float.h>
#endif
namespace lm {
// 1 for '\t', '\n', and ' '. This is stricter than isspace.
const bool kARPASpaces[256] = {0,0,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
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;
}
const char kBinaryMagic[] = "mmap lm http://kheafield.com/code";
// strtoull isn't portable enough :-(
uint64_t ReadCount(const std::string &from) {
std::stringstream stream(from);
uint64_t ret;
stream >> ret;
UTIL_THROW_IF(!stream, FormatLoadException, "Bad count " << from);
return ret;
}
} // namespace
void ReadARPACounts(util::FilePiece &in, std::vector<uint64_t> &number) {
number.clear();
StringPiece line = in.ReadLine();
// In general, ARPA files can have arbitrary text before "\data\"
// But in KenLM, we require such lines to start with "#", so that
// we can do stricter error checking
while (IsEntirelyWhiteSpace(line) || starts_with(line, "#")) {
line = in.ReadLine();
}
if (line != "\\data\\") {
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, pipe " << in.FileName() << " through zcat. If this already in binary format, you need to decompress it because mmap doesn't work on top of gzip.");
}
if (static_cast<size_t>(line.size()) >= strlen(kBinaryMagic) && StringPiece(line.data(), strlen(kBinaryMagic)) == kBinaryMagic)
UTIL_THROW(FormatLoadException, "This looks like a binary file but got sent to the ARPA parser. Did you compress the binary file or pass a binary file where only ARPA files are accepted?");
UTIL_THROW_IF(line.size() >= 4 && StringPiece(line.data(), 4) == "blmt", FormatLoadException, "This looks like an IRSTLM binary file. Did you forget to pass --text yes to compile-lm?");
UTIL_THROW_IF(line == "iARPA", FormatLoadException, "This looks like an IRSTLM iARPA file. You need an ARPA file. Run\n compile-lm --text yes " << in.FileName() << " " << in.FileName() << ".arpa\nfirst.");
UTIL_THROW(FormatLoadException, "first non-empty 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 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;
number.push_back(ReadCount(end_ptr));
}
}
void ReadNGramHeader(util::FilePiece &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");
}
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 for backoff");
}
}
void ReadBackoff(util::FilePiece &in, float &backoff) {
// Always make zero negative.
// Negative zero means that no (n+1)-gram has this n-gram as context.
// Therefore the hypothesis state can be shorter. Of course, many n-grams
// are context for (n+1)-grams. An algorithm in the data structure will go
// back and set the backoff to positive zero in these cases.
switch (in.get()) {
case '\t':
backoff = in.ReadFloat();
if (backoff == ngram::kExtensionBackoff) backoff = ngram::kNoExtensionBackoff;
{
#if defined(WIN32) && !defined(__MINGW32__)
int float_class = _fpclass(backoff);
UTIL_THROW_IF(float_class == _FPCLASS_SNAN || float_class == _FPCLASS_QNAN || float_class == _FPCLASS_NINF || float_class == _FPCLASS_PINF, FormatLoadException, "Bad backoff " << backoff);
#else
int float_class = std::fpclassify(backoff);
UTIL_THROW_IF(float_class == FP_NAN || float_class == FP_INFINITE, FormatLoadException, "Bad backoff " << backoff);
#endif
}
UTIL_THROW_IF(in.get() != '\n', FormatLoadException, "Expected newline after backoff");
break;
case '\n':
backoff = ngram::kNoExtensionBackoff;
break;
default:
UTIL_THROW(FormatLoadException, "Expected tab or newline for backoff");
}
}
void ReadEnd(util::FilePiece &in) {
StringPiece line;
do {
line = in.ReadLine();
} while (IsEntirelyWhiteSpace(line));
if (line != "\\end\\") UTIL_THROW(FormatLoadException, "Expected \\end\\ but the ARPA file has " << line);
try {
while (true) {
line = in.ReadLine();
if (!IsEntirelyWhiteSpace(line)) UTIL_THROW(FormatLoadException, "Trailing line " << line);
}
} catch (const util::EndOfFileException &e) {}
}
void PositiveProbWarn::Warn(float prob) {
switch (action_) {
case THROW_UP:
UTIL_THROW(FormatLoadException, "Positive log probability " << prob << " in the model. This is a bug in IRSTLM; you can set config.positive_log_probability = SILENT or pass -i to build_binary to substitute 0.0 for the log probability. Error");
case COMPLAIN:
std::cerr << "There's a positive log probability " << prob << " in the APRA file, probably because of a bug in IRSTLM. This and subsequent entires will be mapped to 0 log probability." << std::endl;
action_ = SILENT;
break;
case SILENT:
break;
}
}
} // namespace lm