Meeting Pearls 1/Meeting Pearls Vol 1 (1994).iso/installed_progs/util/shell+startup-tools/extracmds/source_etc.lha/src/Head.c

C/C++ Source or Header | 1993-10-22 | 5.2 KB | 210 lines

/*   ---------------------------------      -------
 *   |\  | | | | |  |.| |   \|  |/ /|\      |||||||
 *   | | | |/  | |\ |/  |/|  |\ |/  |    ?  ---+---  =<
 *   | | | |   | |  |     |  |  |   |     \qqqqqqqqq/
 *   ---------------------------------  ~~~~~~~~~~~~~~~~
 *  Head - Display first few lines of specified files.
 *  Copyright (C) 1992, 1993 Torsten Poulin
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *  The author can be contacted by s-mail at
 *    Torsten Poulin
 *    Banebrinken 99, 2, 77
 *    DK-2400 Copenhagen NV
 *    DENMARK
 *
 * Created 11-Feb-92 Version 37.1 =TP=
 * $Id: Head.c,v 37.7 93/03/01 12:36:57 Torsten Rel $
 * $Log:    Head.c,v $
 * Revision 37.7  93/03/01  12:36:57  Torsten
 * Changed all occurrences of "struct DosBase *" to "struct DosLibrary *"
 *
 * Revision 37.6  93/02/24  00:13:13  Torsten
 * Bug fix: called FreeArgs() too soon.
 * The TO argument is now functional.
 * Eliminated goto statement in entrypoint().
 * Removed unnecessary auto variable err in head().
 *
 * Revision 37.5  93/02/22  17:37:22  Torsten
 * Moved some functions to the support library.
 *
 * Revision 37.4  93/02/20  11:51:12  Torsten
 * head() now returns the correct value, if a Ctrl-C is recieved.
 *
 * Revision 37.3  93/02/20  11:45:08  Torsten
 * Rewritten almost from scratch.
 *
 * Revision 37.2  93/02/13  15:56:39  Torsten
 * Reformatted source.
 * Replaced exec.library/SetSignal() with dos.library/CheckSignal().
 *
 */

#include <exec/types.h>
#include <exec/memory.h>
#include <dos/dos.h>
#include <dos/dosasl.h>
#include <clib/dos_protos.h>
#include <clib/exec_protos.h>
#ifdef __SASC
#include <pragmas/dos_pragmas.h>
#include <pragmas/exec_pragmas.h>
#endif
#include "tastlib.h"
#include "head_rev.h"

#define PROGNAME "Head"
#define TEMPLATE "FROM/M,TO/K,NUM=NUMBER/N/K"
#define OPT_FROM 0
#define OPT_TO   1
#define OPT_NUM  2

char const versionID[] = VERSTAG;
char const copyright[] = "$COPYRIGHT:Copyright © 1992,1993 Torsten Poulin$";

typedef struct {
  struct DosLibrary *DOSBase;
  ULONG number;
  BOOL  header;
  BPTR  output;
} Global;

LONG head(UBYTE *filename, Global *global);


LONG entrypoint(VOID)
{
  struct DosLibrary *DOSBase;
  struct RDArgs *args;
  Global *global;
  LONG arg[3];
  LONG rc = RETURN_OK;

  if (!(DOSBase = (struct DosLibrary *) OpenLibrary("dos.library", 37L)))
    return RETURN_FAIL;

  if (!(global = AllocVec(sizeof(Global), MEMF_PUBLIC | MEMF_CLEAR)))
  {
    PrintFault(ERROR_NO_FREE_STORE, PROGNAME);
    rc = RETURN_FAIL;
  }
  else
  {
    global->DOSBase = DOSBase;

    arg[OPT_FROM] = arg[OPT_TO] = arg[OPT_NUM] = 0L;

    if (!(args = ReadArgs(TEMPLATE, arg, NULL)))
    {
      printerror(PROGNAME, global);
      rc = RETURN_ERROR;
    }
    else
    {
      if (!arg[OPT_NUM])
    global->number = 10L;
      else
      {
    global->number = *(ULONG *) arg[OPT_NUM];
    if (global->number < 1L)
      global->number = 1L;
      }

      if (!arg[OPT_TO])
    global->output = Output();
      else if (!(global->output = Open((UBYTE *)arg[OPT_TO], MODE_NEWFILE)))
      {
    PutStr("Cannot open ");
    PutStr((UBYTE *) arg[OPT_TO]);
    PutStr("\n");
    rc = RETURN_ERROR;
      }

      if (global->output)
    if (!arg[OPT_FROM])
      rc = head(NULL, global);
    else if ((rc = severalnames((UBYTE **) arg[OPT_FROM], global))
         != ERROR_NO_FREE_STORE)
    {
      global->header = (BOOL) rc;
      rc = foreach((UBYTE **) arg[OPT_FROM], head, global);
    }
      if (arg[OPT_TO])
    Close(global->output);

      FreeArgs(args);

      if (rc == ERROR_BREAK)
      {
    PrintFault(ERROR_BREAK, NULL);
    rc = RETURN_WARN;
      }
      else if (rc == ERROR_NO_FREE_STORE)
      {
    PrintFault(ERROR_NO_FREE_STORE, PROGNAME);
    rc = RETURN_FAIL;
      }
      else if (rc != RETURN_OK)
    printerror(PROGNAME, global);
    }
    FreeVec(global);
  }
  CloseLibrary((struct Library *) DOSBase);
  return rc;
}


LONG head(UBYTE *filename, Global *global)
{
  struct DosLibrary *DOSBase = global->DOSBase;
  register UBYTE breakcheck = 0;
  LONG  c;
  ULONG count = 0;
  LONG  rc = RETURN_OK;
  BPTR  input = Input();

  if (filename)
  {
    if (global->header)
    {
      FPuts(global->output, "==>");
      FPuts(global->output, filename);
      FPuts(global->output, "<==\n");
    }
    if (!(input = Open(filename, MODE_OLDFILE)))
    {
      PrintFault(IoErr(), filename);
      return RETURN_ERROR;
    }
  }

  while ((c = FGetC(input)) != EOF && count < global->number)
  {
    if (c == '\n')
      ++count;
    FPutC(global->output, c);

    if (!(breakcheck -= 4) && CheckSignal(SIGBREAKF_CTRL_C))
    {
      rc = ERROR_BREAK;
      break;
    }
  }
  if (filename)
    Close(input);
  return rc;
}