generic-driver.h

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/*
Copyright (C) 2007-12 Andrea Vedaldi and Brian Fulkerson.
Copyright (C) 2013 Andrea Vedaldi.
All rights reserved.

This file is part of the VLFeat library and is made available under
the terms of the BSD license (see the COPYING file).
*/

#ifndef VL_GENERIC_DRIVER
#define VL_GENERIC_DRIVER

#include <vl/generic.h>
#include <vl/stringop.h>

#include <stdio.h>
#include <assert.h>

struct _VlFileMeta
{
  vl_bool active ;          
  char    pattern [1024] ;  
  int     protocol ;        
  char    name [1024] ;     
  FILE *  file ;            
} ;

typedef struct _VlFileMeta VlFileMeta ;

/* ----------------------------------------------------------------- */
static int
vl_file_meta_parse (VlFileMeta * self, char const * optarg)
{
  vl_size q ;
  self->active = 1 ;

  if (optarg) {
    int protocol ;
    char const * arg = vl_string_parse_protocol (optarg, &protocol) ;

    /* parse the (optional) protocol part */
    switch (protocol) {
    case VL_PROT_UNKNOWN :
      return VL_ERR_BAD_ARG  ;

    case VL_PROT_ASCII  :
    case VL_PROT_BINARY :
      self->protocol = protocol ;
      break ;

    case VL_PROT_NONE :
      break ;
    }

    if (vl_string_length (arg) > 0) {
      q = vl_string_copy
        (self->pattern, sizeof (self->pattern), arg) ;

      if (q >= sizeof(self->pattern)) {
        return VL_ERR_OVERFLOW ;
      }
    }

  }
  return VL_ERR_OK ;
}

/* ----------------------------------------------------------------- */
static int
vl_file_meta_open (VlFileMeta * self, char const * basename, char const * mode)
{
  vl_size q ;

  if (! self->active) {
    return VL_ERR_OK ;
  }

  q = vl_string_replace_wildcard (self->name,
                                  sizeof(self->name),
                                  self -> pattern,
                                  '%', '\0',
                                  basename) ;

  if (q >= sizeof(self->name)) {
    return vl_set_last_error (VL_ERR_OVERFLOW, NULL) ;
  }

  if (self->active) {
    self->file = fopen (self->name, mode) ;
    if (! self->file) {
      return vl_set_last_error(VL_ERR_IO, NULL) ;
    }
  }
  return 0 ;
}

/* ----------------------------------------------------------------- */
static void
vl_file_meta_close (VlFileMeta * self)
{
  if (self -> file) {
    fclose (self -> file) ;
    self -> file = 0 ;
  }
}

/* ----------------------------------------------------------------- */
VL_INLINE int
vl_file_meta_put_double (VlFileMeta * self, double x)
{
  int err ;
  size_t n ;
  double y ;

  switch (self -> protocol) {

  case VL_PROT_ASCII :
    err = fprintf (self -> file, "%g ", x) ;
    break ;

  case VL_PROT_BINARY :
    vl_swap_host_big_endianness_8 (&y, &x) ;
    n = fwrite (&y, sizeof(double), 1, self -> file) ;
    err = n < 1 ;
    break ;

  default :
    abort() ;
  }

  return err ? VL_ERR_ALLOC : VL_ERR_OK ;
}

/* ----------------------------------------------------------------- */
VL_INLINE int
vl_file_meta_put_uint8 (VlFileMeta *self, vl_uint8 x)
{
  size_t n ;
  int err ;

  switch (self -> protocol) {

  case VL_PROT_ASCII :
    err = fprintf (self -> file, "%d ", x) ;
    if (err) return VL_ERR_ALLOC ;
    break ;

  case VL_PROT_BINARY :
    n = fwrite (&x, sizeof(vl_uint8), 1, self -> file) ;
    if (n < 1) return VL_ERR_ALLOC ;
    break ;

  default :
    abort() ;
  }

  return VL_ERR_OK ;
}

/* ----------------------------------------------------------------- */
VL_INLINE int
vl_file_meta_get_double (VlFileMeta *self, double *x)
{
  int err ;
  size_t n ;
  double y ;

  switch (self -> protocol) {

  case VL_PROT_ASCII :
    err = fscanf (self -> file, " ") ;
    if (err == EOF) return VL_ERR_EOF ;
    err = fscanf (self -> file, "%lg", x) ;
    if (err == EOF) return VL_ERR_EOF ;
    if (err <  1  ) return VL_ERR_BAD_ARG ;
    break ;

  case VL_PROT_BINARY :
    n = fread (&y, sizeof(double), 1, self -> file) ;
    if (n < 1) return VL_ERR_BAD_ARG ;
    vl_swap_host_big_endianness_8 (x, &y) ;
    break ;

  default :
    abort() ;
  }

  return VL_ERR_OK ;
}



/* VL_GENERIC_DRIVER */
#endif