File sizes
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File sizes
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bwang


Member


Joined: 15 Mar 2009
Posts: 128
Posted: 25 Aug 2010 06:50:48 pm    Post subject:
Is there any way to get the size of a file in C on the Nspire? There's no fseek() and no struct stat to use stat () with.
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bwang


Member


Joined: 15 Mar 2009
Posts: 128
Posted: 25 Aug 2010 08:00:17 pm    Post subject:
w00t!
I figured out.
My code:

Code:

#include <os.h>
#include "utils.h"

asm(".string \"PRG\"\n");

int main(void)
{
  char* s = (char*) malloc(256);
  memset(s, 0x00, 256);
  stat("/documents/Examples/file.tns", s);
  printf("stat struct location: %X\n", s);
  int size = s[20] + 0x100 * s[21] + 0x10000 * s[22] + 0x1000000 * s[23];
  printf("Files Size: %d\n", size);
  printf("%s", "\n");
  return 0;
 }
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ExtendeD


Advanced Newbie


Joined: 30 Aug 2009
Posts: 91
Posted: 26 Aug 2010 02:06:25 pm    Post subject:
Here is the definition of struct stat in the current development branch of Ndless, that you may temporarily add to your common.h before the next release:


Code:
struct stat {
   unsigned short st_dev;
   unsigned int st_ino; // 0
   unsigned int st_mode; // see S_ macros above
   unsigned short st_nlink; // 1
   unsigned short st_uid; // 0
   unsigned short st_gid; // 0
   unsigned short st_rdev; // = st_dev
   unsigned int st_size;
   unsigned int st_atime;
   unsigned int st_mtime;
   unsigned int st_ctime;
};
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bsl


Advanced Newbie


Joined: 09 Jan 2010
Posts: 94
Posted: 27 Aug 2010 05:04:51 pm    Post subject:
Here is one more method that uses fseek and ftell:
put in os.h:

Code:

#define fseek        (_oscall(int,  fseek_, FILE * stream , long offset ,int origin ))
#define ftell        (_oscall(long,  ftell_, FILE * stream  ) )
#define fflush       (_oscall(int,  fflush_, FILE * stream  ) )

put in os_1.1.9253.h:

Code:

#define fseek_            0x10185330
#define ftell_            0x10185480 

put in os_cas_1.1.9174.h:

Code:

#define fseek_            0x10185038
#define ftell_            0x10185188


put in common.h:

Code:

#define SEEK_SET 0   
#define SEEK_CUR 1
#define SEEK_END 2


getsize.c:

Code:

#include <os.h>

asm(".string \"PRG\"\n");
int main ()
{
  FILE *handle;
  long size;

  handle = fopen ("/documents/Examples/fseekftell.tns","rb");
  if (handle==NULL) printf("Error opening file\n");
  else
  {
    fseek (handle, 0, SEEK_END);
    size = ftell (handle);
    fclose (handle);
    printf ("Size of /documents/Examples/fseekftell.tns: %ld bytes.\n",size);
  }
  return 0;
}

[s]
I am making a good guess that the entry is correct because the file routines are grouped in one area on boot2
that use one argument thats a pointer:
[/s] Confirmed !!! attachment below

Code:

boot2_1.4.1571.idc.txt:
0X1185625C   "file_undef1");  takes 1 arg - definitely a pointer - FILE* ? - fflush(handle)??
0X1185634C   "fclose");
0X118563C8   "file_undef2");  takes 1 arg - definitely a pointer to a char: ldrb    r3,[r0]
0X11856460   "file_undef3");  takes 3 args
0X11856590   "fopen");
0x11856688       mov r12, sp    <- unknown entry point   takes 3 args
0X118566CC   "fread");
0X11856808   "fseek");
0X11856958   "file_undef6"); takes 1 arg - definitely a pointer- FILE* ?  - ftell(handle) ?? -> confirmed now !!!
0X11856A80   "fwrite");


Put this file in the examples folder :
[attachment=3261:fseekftell.zip]

Last edited by Guest on 30 Aug 2010 09:50:46 pm; edited 1 time in total
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bsl


Advanced Newbie


Joined: 09 Jan 2010
Posts: 94
Posted: 30 Aug 2010 12:51:12 pm    Post subject:
bwang wrote:


Code:

  int size = s[20] + 0x100 * s[21] + 0x10000 * s[22] + 0x1000000 * s[23];


Another way to do this without defining structures is using read_unaligned_longword
Here you would not need it because 20 is divisible by 4 - so its aligned, but in general without
defining structures read_unaligned_longword will work every time.
I am going to finish off the directory listing code on the other thread using this.
ndless 1.1 was easy to install - I manually editted MSYS for the PATH.
PUT this in os.h:

Code:

#define read_unaligned_longword       (_oscall(unsigned long,  read_unaligned_longword_, void *ptr  ) )

put in os_1.1.9253.h:

Code:

#define read_unaligned_longword_   0x100ec4e4

put in os_cas_1.1.9174.h:

Code:

#define read_unaligned_longword_   0x100ec514

Then:

Code:

  int size = read_unaligned_longword(s[20]);
 UPDATE: int size = read_unaligned_longword(&s[20] or even (void *)&s[20]);


Last edited by Guest on 11 Sep 2010 12:15:48 am; edited 1 time in total
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calc84maniac


Elite


Joined: 22 Jan 2007
Posts: 770
Posted: 31 Aug 2010 09:06:53 am    Post subject:
bsl wrote:

bwang wrote:


Code:

  int size = s[20] + 0x100 * s[21] + 0x10000 * s[22] + 0x1000000 * s[23];


Another way to do this without defining structures is using read_unaligned_longword
Here you would not need it because 20 is divisible by 4 - so its aligned, but in general without
defining structures read_unaligned_longword will work every time.
I am going to finish off the directory listing code on the other thread using this.
ndless 1.1 was easy to install - I manually editted MSYS for the PATH.
PUT this in os.h:

Code:

#define read_unaligned_longword       (_oscall(unsigned long,  read_unaligned_longword_, void *ptr  ) )

put in os_1.1.9253.h:

Code:

#define read_unaligned_longword_   0x100ec4e4

put in os_cas_1.1.9174.h:

Code:

#define read_unaligned_longword_   0x100ec514

Then:

Code:

  int size = read_unaligned_longword(s[20]);



Shouldn't that be


Code:

  int size = read_unaligned_longword(&s[20]);
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bsl


Advanced Newbie


Joined: 09 Jan 2010
Posts: 94
Posted: 31 Aug 2010 10:07:44 am    Post subject:
Yes, thanks...
I am wondering if there is :
write_unaligned_word
write_unaligned_longword
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Goplat


Advanced Newbie


Joined: 26 Jun 2007
Posts: 95
Posted: 03 Sep 2010 10:45:53 am    Post subject:
bwang wrote:

int main(void)
{
char* s = (char*) malloc(256);
...
return 0;
}


Memory allocated by Ndless programs can't be automatically freed on exit like we're used to on both Windows and Unix. You must free every block you allocate, or else that memory becomes unusable until the next reboot.

(Note that for a small temporary object such as this, it would be better to just put it directly on the stack with "char s[256]" anyway.)

Last edited by Guest on 03 Sep 2010 10:46:50 am; edited 1 time in total
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