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#ifndef LM_BINARY_FORMAT__
#define LM_BINARY_FORMAT__
#include "lm/config.hh"
#include "lm/model_type.hh"
#include "lm/read_arpa.hh"
#include "util/file_piece.hh"
#include "util/mmap.hh"
#include "util/scoped.hh"
#include <cstddef>
#include <vector>
#include <stdint.h>
namespace lm {
namespace ngram {
extern const char *kModelNames[6];
/*Inspect a file to determine if it is a binary lm. If not, return false.
* If so, return true and set recognized to the type. This is the only API in
* this header designed for use by decoder authors.
*/
bool RecognizeBinary(const char *file, ModelType &recognized);
struct FixedWidthParameters {
unsigned char order;
float probing_multiplier;
// What type of model is this?
ModelType model_type;
// Does the end of the file have the actual strings in the vocabulary?
bool has_vocabulary;
unsigned int search_version;
};
// This is a macro instead of an inline function so constants can be assigned using it.
#define ALIGN8(a) ((std::ptrdiff_t(((a)-1)/8)+1)*8)
// Parameters stored in the header of a binary file.
struct Parameters {
FixedWidthParameters fixed;
std::vector<uint64_t> counts;
};
class BinaryFormat {
public:
explicit BinaryFormat(const Config &config);
// Reading a binary file:
// Takes ownership of fd
void InitializeBinary(int fd, ModelType model_type, unsigned int search_version, Parameters ¶ms);
// Used to read parts of the file to update the config object before figuring out full size.
void ReadForConfig(void *to, std::size_t amount, uint64_t offset_excluding_header) const;
// Actually load the binary file and return a pointer to the beginning of the search area.
void *LoadBinary(std::size_t size);
uint64_t VocabStringReadingOffset() const {
assert(vocab_string_offset_ != kInvalidOffset);
return vocab_string_offset_;
}
// Writing a binary file or initializing in RAM from ARPA:
// Size for vocabulary.
void *SetupJustVocab(std::size_t memory_size, uint8_t order);
// Warning: can change the vocaulary base pointer.
void *GrowForSearch(std::size_t memory_size, std::size_t vocab_pad, void *&vocab_base);
// Warning: can change vocabulary and search base addresses.
void WriteVocabWords(const std::string &buffer, void *&vocab_base, void *&search_base);
// Write the header at the beginning of the file.
void FinishFile(const Config &config, ModelType model_type, unsigned int search_version, const std::vector<uint64_t> &counts);
private:
void MapFile(void *&vocab_base, void *&search_base);
// Copied from configuration.
const Config::WriteMethod write_method_;
const char *write_mmap_;
util::LoadMethod load_method_;
// File behind memory, if any.
util::scoped_fd file_;
// If there is a file involved, a single mapping.
util::scoped_memory mapping_;
// If the data is only in memory, separately allocate each because the trie
// knows vocab's size before it knows search's size (because SRILM might
// have pruned).
util::scoped_memory memory_vocab_, memory_search_;
// Memory ranges. Note that these may not be contiguous and may not all
// exist.
std::size_t header_size_, vocab_size_, vocab_pad_;
// aka end of search.
uint64_t vocab_string_offset_;
static const uint64_t kInvalidOffset = (uint64_t)-1;
};
bool IsBinaryFormat(int fd);
} // namespace ngram
} // namespace lm
#endif // LM_BINARY_FORMAT__
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