ngram_read_bin.c File Reference

Read binary foramt N-gram file. More...

#include <sent/stddefs.h>
#include <sent/ngram2.h>

Include dependency graph for ngram_read_bin.c:

Go to the source code of this file.

Functions
static void	rdn (FILE *fp, void *buf, size_t unitbyte, int unitnum)
static void	check_header (FILE *fp)
boolean	ngram_read_bin (FILE *fp, NGRAM_INFO *ndata)
Variables
static int	file_version
	N-gram format version of the file.
static boolean	need_swap
	TRUE if need byte swap.

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Detailed Description

Read binary foramt N-gram file.

Author:

Akinobu LEE

Date:

Wed Feb 16 17:12:08 2005

In binary format, both 2-gram and reverse 3-gram are stored together in one file. This binary format is not compatible with other binary format of language model.

From 3.5, internal format of binary N-gram has changed for using machine-dependent natural byte order (previously fixed to big endian), 24bit index and 2-gram backoff compression. So, binary N-gram generated by mkbingram of 3.5 and later will not work on 3.4.2 and earlier versions.

There is full upward- and cross-machine compatibility in 3.5. Old binary N-gram files still can be read directly, in which case the conversion to 24bit index will performed just after model has been read. Byte order will also considered by header information, so binary N-gram still can be used among different machines.

Revision

1.3

Definition in file ngram_read_bin.c.

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Function Documentation

static void rdn (  FILE *  fp, void *  buf, size_t  unitbyte, int  unitnum )  [static]

Binary read function with byte swap (assume file is BIG ENDIAN) Parameters: fp  [in] file pointer buf  [out] data buffer unitbyte  [in] unit size in bytes unitnum  [in] number of unit to read. Definition at line 75 of file ngram_read_bin.c.

static void check_header (  FILE *  fp  )  [static]

Check header to see whether the version matches. Parameters: fp  [in] file pointer Definition at line 96 of file ngram_read_bin.c. Referenced by ngram_read_bin().

boolean ngram_read_bin (  FILE *  fp, NGRAM_INFO *  ndata )

Read a N-gram binary file and store to data. Parameters: fp  [in] file pointer ndata  [out] N-gram data to store the read data Returns: TRUE on success, FALSE on failure. Definition at line 163 of file ngram_read_bin.c. Referenced by init_ngram_bin().

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