tail.c

使用于OS/2下的小工具的C源程序,使用于OS/2下的小工具的C源程序

/*
* TAIL.C - Output the last 10 lines from a text file.
*
* PROGRAMMER:	    Martti Ylikoski
* CREATED:	    5.12.1990
*/
static char *VERSION= "Version  1.1, Copyright(c) Martti Ylikoski, 1990-1992." ;
/*
*/

#include <stdio.h>
#include <time.h>
#include <malloc.h>
#include <stdlib.h>
#include <string.h>
#include <param.h>
#include <paramstd.h>
#define INCL_VIO
#include <os2.h>

static char *progname ;

extern unsigned long pflags ;

ParamEntry pentry[12] = {
     "P", &ParamSetPause, 0,
     "F", &ParamSetFold, 0,
     "V", &ParamSetVerbose, 0,
     "R", &ParamSetReport, 0,
     "S", &ParamSetSubDirs, 0,
     "?", &ParamSetHelp, 1,
     "H", &ParamSetHelp, 1,
     "NOD", &ParamSetNoDefault, 0,
     "TEST", &ParamSetTest, 0,
     "Y", &ParamSetYes, 0,
     "N", &ParamSetTest, 0,
     "\0", NULL, 0
} ;

ParamBlock params = {
    "/-",   IGNORECASE | NOPRIORITY | NOTRIGGERSALLOWED ,
    pentry
} ;


static int count, cols, stdinassumed ;
/* local prototypes */
int tail( char *fname, char **lines ) ;

int main(int argc, char *argv[])
{
int i, j, nargc ;
char **lines, *ptmp;
VIOMODEINFO vioinfo ;
USHORT ret ;

   progname = argv[0] ;
   count = 10 ;
   stdinassumed = FALSE ;

   ParamHandle(&params, &argc, argv) ;

   if (pflags & PA_HELP)
   {
      puts("TAIL - display the last lines from a text file.") ;
      puts(VERSION) ;
      puts("Usage: tail [/H | /?] [-count] [-] file") ;
      return( 0 ) ;
   }

   nargc = argc ;
   for (i = 1 ; i < argc ; i++)
      if (argv[i][0] == '-' || argv[i][0] == '/')
      {
	 if (strlen(argv[i]) == 1)
	 {
	    stdinassumed = TRUE ;
	    argv[i] = NULL ;
	    nargc --;
	    continue ;
	 }
	 count = atoi(&argv[i][1]) ;
	 argv[i] = NULL ;
	 nargc -- ;
      }

   vioinfo.cb = sizeof(vioinfo) ;
   if (( ret = VioGetMode(&vioinfo, 0 )) != 0)
   {
       fprintf(stderr, "%s: error in VioGetMode...\nExiting ...\n", progname) ;
       return( 1 ) ;
   }

   cols = vioinfo.col ;     /* the number of colunms in current video mode */

    lines = (char **) calloc(count, (size_t) sizeof(ptmp) ) ;

    for(i = 0 ; i < count ; i++)
       lines[i] = (char *) calloc( cols, (size_t) 1) ;

   if (nargc == 1)
      tail("-", lines) ;
   else
   {
      for (i = 1 ; i < argc ; i++)
	 if (argv[i] != NULL)
	    tail(argv[i], lines) ;
      if (stdinassumed == TRUE)
	 tail("-", lines) ;
   }

   return( 0 ) ;
}

int tail( char *fname, char **lines )
{
FILE *fptr ;
int i,j ;

  for(i = 0 ; i < count ; i++)
     memset( lines[i], (int) '\0', (size_t) cols ) ;

   fprintf(stderr,"-----FILE : %s\n",fname) ;

   /* open file */
   if (strcmp(fname, "-") == 0)
      fptr = stdin ;
   else
      if ((fptr = fopen(fname, "r")) == NULL)
      {
	 printf("%s: unable to open file %s for reading...\n", progname, fname) ;
	 printf("Exiting...\n") ;
	 return( 1 ) ;
      }

   i = 0 ;
   while (feof(fptr) == 0 && fgets(lines[i%count], cols-1, fptr) != NULL)
   {
      lines[i%count][cols-1] = '\0' ;
      if (lines[i%count][strlen(lines[i%count])-1] != '\n') /* scan to the next line */
      {
	 int c ;
	 while ( (c = fgetc(fptr)) != '\n' && c != EOF)
	    ;
      }
      i++ ;
   }

   for (j = 0 ; j < count ; j++)
      fputs(lines[(i+j)%count], stdout) ;

   /* close file */
   fclose ( fptr ) ;

}