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#include "lm/vocab.hh"
#include "lm/binary_format.hh"
#include "lm/enumerate_vocab.hh"
#include "lm/lm_exception.hh"
#include "lm/config.hh"
#include "lm/weights.hh"
#include "util/exception.hh"
#include "util/joint_sort.hh"
#include "util/murmur_hash.hh"
#include "util/probing_hash_table.hh"
#include <string>
namespace lm {
namespace ngram {
namespace detail {
uint64_t HashForVocab(const char *str, std::size_t len) {
// This proved faster than Boost's hash in speed trials: total load time Murmur 67090000, Boost 72210000
// Chose to use 64A instead of native so binary format will be portable across 64 and 32 bit.
return util::MurmurHash64A(str, len, 0);
}
} // namespace detail
namespace {
// Normally static initialization is a bad idea but MurmurHash is pure arithmetic, so this is ok.
const uint64_t kUnknownHash = detail::HashForVocab("<unk>", 5);
// Sadly some LMs have <UNK>.
const uint64_t kUnknownCapHash = detail::HashForVocab("<UNK>", 5);
WordIndex ReadWords(int fd, EnumerateVocab *enumerate) {
if (!enumerate) return std::numeric_limits<WordIndex>::max();
const std::size_t kInitialRead = 16384;
std::string buf;
buf.reserve(kInitialRead + 100);
buf.resize(kInitialRead);
WordIndex index = 0;
while (true) {
ssize_t got = read(fd, &buf[0], kInitialRead);
UTIL_THROW_IF(got == -1, util::ErrnoException, "Reading vocabulary words");
if (got == 0) return index;
buf.resize(got);
while (buf[buf.size() - 1]) {
char next_char;
ssize_t ret = read(fd, &next_char, 1);
UTIL_THROW_IF(ret == -1, util::ErrnoException, "Reading vocabulary words");
UTIL_THROW_IF(ret == 0, FormatLoadException, "Missing null terminator on a vocab word.");
buf.push_back(next_char);
}
// Ok now we have null terminated strings.
for (const char *i = buf.data(); i != buf.data() + buf.size();) {
std::size_t length = strlen(i);
enumerate->Add(index++, StringPiece(i, length));
i += length + 1 /* null byte */;
}
}
}
} // namespace
WriteWordsWrapper::WriteWordsWrapper(EnumerateVocab *inner) : inner_(inner) {}
WriteWordsWrapper::~WriteWordsWrapper() {}
void WriteWordsWrapper::Add(WordIndex index, const StringPiece &str) {
if (inner_) inner_->Add(index, str);
buffer_.append(str.data(), str.size());
buffer_.push_back(0);
}
void WriteWordsWrapper::Write(int fd) {
if ((off_t)-1 == lseek(fd, 0, SEEK_END))
UTIL_THROW(util::ErrnoException, "Failed to seek in binary to vocab words");
util::WriteOrThrow(fd, buffer_.data(), buffer_.size());
}
SortedVocabulary::SortedVocabulary() : begin_(NULL), end_(NULL), enumerate_(NULL) {}
std::size_t SortedVocabulary::Size(std::size_t entries, const Config &/*config*/) {
// Lead with the number of entries.
return sizeof(uint64_t) + sizeof(uint64_t) * entries;
}
void SortedVocabulary::SetupMemory(void *start, std::size_t allocated, std::size_t entries, const Config &config) {
assert(allocated >= Size(entries, config));
// Leave space for number of entries.
begin_ = reinterpret_cast<uint64_t*>(start) + 1;
end_ = begin_;
saw_unk_ = false;
}
void SortedVocabulary::ConfigureEnumerate(EnumerateVocab *to, std::size_t max_entries) {
enumerate_ = to;
if (enumerate_) {
enumerate_->Add(0, "<unk>");
strings_to_enumerate_.resize(max_entries);
}
}
WordIndex SortedVocabulary::Insert(const StringPiece &str) {
uint64_t hashed = detail::HashForVocab(str);
if (hashed == kUnknownHash || hashed == kUnknownCapHash) {
saw_unk_ = true;
return 0;
}
*end_ = hashed;
if (enumerate_) {
strings_to_enumerate_[end_ - begin_].assign(str.data(), str.size());
}
++end_;
// This is 1 + the offset where it was inserted to make room for unk.
return end_ - begin_;
}
void SortedVocabulary::FinishedLoading(ProbBackoff *reorder_vocab) {
if (enumerate_) {
util::PairedIterator<ProbBackoff*, std::string*> values(reorder_vocab + 1, &*strings_to_enumerate_.begin());
util::JointSort(begin_, end_, values);
for (WordIndex i = 0; i < static_cast<WordIndex>(end_ - begin_); ++i) {
// <unk> strikes again: +1 here.
enumerate_->Add(i + 1, strings_to_enumerate_[i]);
}
strings_to_enumerate_.clear();
} else {
util::JointSort(begin_, end_, reorder_vocab + 1);
}
SetSpecial(Index("<s>"), Index("</s>"), 0);
// Save size. Excludes UNK.
*(reinterpret_cast<uint64_t*>(begin_) - 1) = end_ - begin_;
// Includes UNK.
bound_ = end_ - begin_ + 1;
}
void SortedVocabulary::LoadedBinary(int fd, EnumerateVocab *to) {
end_ = begin_ + *(reinterpret_cast<const uint64_t*>(begin_) - 1);
ReadWords(fd, to);
SetSpecial(Index("<s>"), Index("</s>"), 0);
bound_ = end_ - begin_ + 1;
}
namespace {
const unsigned int kProbingVocabularyVersion = 0;
} // namespace
namespace detail {
struct ProbingVocabularyHeader {
// Lowest unused vocab id. This is also the number of words, including <unk>.
unsigned int version;
WordIndex bound;
};
} // namespace detail
ProbingVocabulary::ProbingVocabulary() : enumerate_(NULL) {}
std::size_t ProbingVocabulary::Size(std::size_t entries, const Config &config) {
return Align8(sizeof(detail::ProbingVocabularyHeader)) + Lookup::Size(entries, config.probing_multiplier);
}
void ProbingVocabulary::SetupMemory(void *start, std::size_t allocated, std::size_t /*entries*/, const Config &/*config*/) {
header_ = static_cast<detail::ProbingVocabularyHeader*>(start);
lookup_ = Lookup(static_cast<uint8_t*>(start) + Align8(sizeof(detail::ProbingVocabularyHeader)), allocated);
bound_ = 1;
saw_unk_ = false;
}
void ProbingVocabulary::ConfigureEnumerate(EnumerateVocab *to, std::size_t /*max_entries*/) {
enumerate_ = to;
if (enumerate_) {
enumerate_->Add(0, "<unk>");
}
}
WordIndex ProbingVocabulary::Insert(const StringPiece &str) {
uint64_t hashed = detail::HashForVocab(str);
// Prevent unknown from going into the table.
if (hashed == kUnknownHash || hashed == kUnknownCapHash) {
saw_unk_ = true;
return 0;
} else {
if (enumerate_) enumerate_->Add(bound_, str);
lookup_.Insert(Lookup::Packing::Make(hashed, bound_));
return bound_++;
}
}
void ProbingVocabulary::FinishedLoading(ProbBackoff * /*reorder_vocab*/) {
lookup_.FinishedInserting();
header_->bound = bound_;
header_->version = kProbingVocabularyVersion;
SetSpecial(Index("<s>"), Index("</s>"), 0);
}
void ProbingVocabulary::LoadedBinary(int fd, EnumerateVocab *to) {
UTIL_THROW_IF(header_->version != kProbingVocabularyVersion, FormatLoadException, "The binary file has probing version " << header_->version << " but the code expects version " << kProbingVocabularyVersion << ". Please rerun build_binary using the same version of the code.");
lookup_.LoadedBinary();
ReadWords(fd, to);
bound_ = header_->bound;
SetSpecial(Index("<s>"), Index("</s>"), 0);
}
void MissingUnknown(const Config &config) throw(SpecialWordMissingException) {
switch(config.unknown_missing) {
case SILENT:
return;
case COMPLAIN:
if (config.messages) *config.messages << "The ARPA file is missing <unk>. Substituting log10 probability " << config.unknown_missing_logprob << "." << std::endl;
break;
case THROW_UP:
UTIL_THROW(SpecialWordMissingException, "The ARPA file is missing <unk> and the model is configured to throw an exception.");
}
}
void MissingSentenceMarker(const Config &config, const char *str) throw(SpecialWordMissingException) {
switch (config.sentence_marker_missing) {
case SILENT:
return;
case COMPLAIN:
if (config.messages) *config.messages << "Missing special word " << str << "; will treat it as <unk>.";
break;
case THROW_UP:
UTIL_THROW(SpecialWordMissingException, "The ARPA file is missing " << str << " and the model is configured to reject these models. Run build_binary -s to disable this check.");
}
}
} // namespace ngram
} // namespace lm
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