Usenet 1994 January/usenetsourcesnewsgroupsinfomagicjanuary1994.iso/sources/unix/volume4/68kdisassem/part1/file.c

C/C++ Source or Header | 1986-11-30 | 4.1 KB | 209 lines

/*
 *    SCCS:    @(#)file.c    1.2    11/2/84    14:17:35
 *    Various operations on files.
 *
 ***********************************************************************
 *    This software is copyright of
 *
 *        John M Collins
 *        47 Cedarwood Drive
 *        St Albans
 *        Herts, AL4 0DN
 *        England            [phone]
 *
 *    and is released into the public domain on the following conditions:
 *
 *        1.  No free maintenance will be guaranteed.
 *        2.  Nothing may be based on this software without
 *            acknowledgement, including incorporation of this
 *            notice.
 *
 *    Notwithstanding the above, the author welcomes correspondence and bug
 *    fixes.
 ***********************************************************************
 */

#include <stdio.h>
#include <a.out.h>
#include "unc.h"

long    lseek();
void    unimpl();

/*
 *    Validate addr and get text entry corresponding to it from the given
 *    file.
 */

void    gette(fid, addr, te)
register  ef_fid  fid;
register  long    addr;
t_entry    *te;
{
    addr -= fid->ef_tbase;
    if  (addr < 0  ||  addr > fid->ef_tsize  || (addr & 1) != 0)  {
        (void) fprintf(stderr, "Invalid text address %lx\n", addr);
        exit(200);
    }
    (void) lseek(fid->ef_t, (long)(addr * sizeof(t_entry)/2), 0);
    if  (read(fid->ef_t, (char *) te, sizeof(t_entry)) != sizeof(t_entry))  {
        (void) fprintf(stderr, "Trouble reading text at %lx\n", addr);
        exit(201);
    }
}

/*
 *    Store a text entry.
 */

void    putte(fid, addr, te)
register  ef_fid  fid;
register  long    addr;
t_entry    *te;
{
    addr -= fid->ef_tbase;
    if  (addr < 0  ||  addr > fid->ef_tsize  ||  (addr & 1) != 0)  {
        (void) fprintf(stderr, "Invalid text address %lx\n", addr);
        exit(200);
    }
    (void) lseek(fid->ef_t, (long)(addr * sizeof(t_entry)/2), 0);
    (void) write(fid->ef_t, (char *) te, sizeof(t_entry));
}

/*
 *    Validate addr and get data entry corresponding to it from the given
 *    file.
 */

void    getde(fid, addr, de)
register  ef_fid  fid;
register  long    addr;
d_entry    *de;
{
    if  (addr < fid->ef_dbase  ||  addr > fid->ef_end)  {
        (void) fprintf(stderr, "Invalid data address %lx\n", addr);
        exit(200);
    }
    addr -= fid->ef_dbase;
    (void) lseek(fid->ef_d, (long)(addr * sizeof(d_entry)), 0);
    if  (read(fid->ef_d, (char *) de, sizeof(d_entry)) != sizeof(d_entry))  {
        (void) fprintf(stderr, "Trouble reading data at %lx\n", addr);
        exit(201);
    }
}

/*
 *    Store a data entry.
 */

void    putde(fid, addr, de)
register  ef_fid  fid;
register  long    addr;
d_entry    *de;
{
    if  (addr < fid->ef_dbase  ||  addr > fid->ef_end)  {
        (void) fprintf(stderr, "Invalid data address %lx\n", addr);
        exit(200);
    }
    addr -= fid->ef_dbase;
    (void) lseek(fid->ef_d, (long)(addr * sizeof(d_entry)), 0);
    (void) write(fid->ef_d, (char *) de, sizeof(d_entry));
}

/*
 *    Set type and length of given data entry.
 */

void    setde(fid, addr, type, lng)
ef_fid    fid;
long    addr;
unsigned  type;
int    lng;
{
    d_entry    dat;

    if  (addr > fid->ef_end)
        return;
    getde(fid, addr, &dat);
    if  (type == D_CONT  &&  dat.d_reloc != R_NONE)  {
        char    obuf[30];
        (void) sprintf(obuf, "overlapped reloc 0x%x", addr);
        unimpl(obuf);
    }
    dat.d_type = type;
    dat.d_lng = lng;
    putde(fid, addr, &dat);
}

/*
 *    Get a word of data file, size as requested.
 */

long    getdw(fid, pos, size)
register  ef_fid  fid;
long    pos;
int    size;
{
    d_entry    dat;
    register  long    res;
    register  int    i, lt;

    getde(fid, pos, &dat);

    switch  (size)  {
    case  R_BYTE:
        return    dat.d_contents;

    case  R_LONG:
        lt = 4;
        goto  rest;

    case  R_WORD:
        lt = 2;
    rest:
        res = dat.d_contents;
        for  (i = 1;  i < lt; i++)  {
            getde(fid, pos+i, &dat);
            res = (res << 8) + dat.d_contents;
        }
        return    res;

    default:
        (void) fprintf(stderr, "Data word size error\n");
        exit(20);
    }
    /*NOTREACHED*/
}

/*
 *    Get a word of text file.
 */

long    gettw(fid, pos, size)
register  ef_fid  fid;
long    pos;
int    size;
{
    t_entry    tex;
    long    res;

    gette(fid, pos, &tex);

    switch  (size)  {
    case  R_BYTE:
        return    tex.t_contents >> 8;

    case  R_WORD:
        return    tex.t_contents;

    case  R_LONG:
        res = tex.t_contents;
        gette(fid, pos+2, &tex);
        return    (res << 16) + tex.t_contents;
    default:
        (void) fprintf(stderr, "Text word size error\n");
        exit(20);
    }
    /*NOTREACHED*/
}