C/C++ Interactive Reference Guide/C-C++ Interactive Reference Guide.iso/c_ref/csource3/114_01/ed8.bds

Text File | 1987-07-15 | 4.5 KB | 286 lines

/* Screen editor:  operating system module
 *           BDS C version
 *
 * Source:  ed8.cc
 * Version: June 19, 1981.
 */

/* define globals */

#include ed.h
#include bdscio.h
#include ed1.ccc
#include edext.cc

/* globals used by this module -----

#define NSECTS 8
#define SECSIZ 128
#define BUFSIZ (NSECTS * SECSIZ + 6)

int  iormode;        'r' 'w' or 'c'
char iobuf1[BUFSIZ];    file buffer

----- */

/* all calls to the operating system are made here.
 * only this module will have to be
 * rewritten for a new operating system.
 */

/* the routines syscstat(), syscin() and syscout() come in
 * two flavors:  CP/M version 2.2 and CP/M version 1.4.
 * Comment out which ever you don't use.
 */

/* CP/M 2.2 versions of syscstat(), syscin(), syscout() */

/* return -1 if no character is ready from the console.
 * otherwise, return the character.
 */

syscstat()
{
    return(bdos(6,-1));
}

/* wait for next character from the console.
 * do not echo it.
 */

syscin()
{
int c;
    while ((c=bdos(6,-1))==0) {
        ;
    }
    return(c);
}

/* print character on the console */

syscout(c) char c;
{
    bdos(6,c);
    return(c);
}

/* CP/M 1.4 versions of syscstat(), syscin(), syscout() */

/* start comment out ----------
syscstat()
{
    if (bios(2,0)==255) {
        return(-1);
    }
    else {
        return(0);
    }
}

syscin()
{
    return(bios(3,0));
}

syscout(c) char c;
{
    bios(4,c);
    return(c);
}
---------- end comment out */


/* print character on the printer */

syslout(c) char c;
{
    bdos(5,c);
    return(c);
}

/*
 * return address of last usable memory location.
 */

sysend()
{
    return(topofmem());
}

/* open a file */

sysopen(name,mode) char *name, *mode;
{
int file;
int m;
    m=tolower(mode[0]);
    if (m=='r') {
        if ((file=fopen(name,iobuf1))==-1) {
            iormode='c';
            fclose(iobuf1);
            return(ERR);
        }
        else {
            iormode=m;
            return(iobuf1);
        }
    }
    else if (m=='w') {
        if ((file=fcreat(name,iobuf1))==-1) {
            iormode='c';
            fclose(iobuf1);
            return(ERR);
        }
        else {
            iormode=m;
            return(iobuf1);
        }
    }
    else {
        iormode='c';
        syserr("fopen: bad mode");
        return(ERR);
    }
}

/* close a file */

sysclose(file) int file;
{
    if (iormode=='w') {
        /* write end of file byte */
        putc(0x1a,iobuf1);
        fflush(iobuf1);
    }
    iormode='c';
    fclose(iobuf1);
    return(OK);
}

/* read next char from file */

sysrdch(file) int file;
{
int c;
    while ((c=sysrdc1())==LF) {
        ;
    }
    return(c);
}

sysrdc1()
{
int c;
    if (iormode!='r') {
        error ("sysrdch:  read in w mode");
        return(ERR);
    }
    if ((c=getc(iobuf1))==-1) {
        return(EOF);
    }
    else if (c==0x1a) {
        return(EOF);
    }
    else {
        return(c);
    }
}

/* write next char to file */

syspshch(c,file) char c; int file;
{
    if (c!=CR) {
        return(syspshc1(c,file));
    }
    else if (syspshc1(c,file)==ERR) {
        return(ERR);
    }
    else {
        return(syspshc1(LF,file));
    }
}

syspshc1(c,file) char c; int file;
{
    if (iormode!='w') {
        error("syspshch:  write in r mode");
        return(ERR);
    }
    if (putc(c,iobuf1)==-1) {
        error("disk write failed");
        return(ERR);
    }
    else {
        return(c);
    }
}

/* read one char from END of file */

syspopch(file) int file;
{
    error("syspopch() not implemented");
    return(ERR);
}

/* check file name for syntax */

syschkfn(args) char *args;
{
    return(OK);
}

/* copy file name from args to buffer */

syscopfn(args,buffer) char *args, *buffer;
{
int n;
    n=0;
    while (n<(SYSFNMAX-1)) {
        if (args[n]==EOS) {
            break;
        }
        else {
            buffer[n]=args[n];
            n++;
        }
    }
    buffer[n]=EOS;
}

/* move a block of n bytes down (towards HIGH addresses).
 * block starts at source and the first byte goes to dest.
 * this routine is only called from bufmovdn() as follows:
 *    sysmovdn( n=to-from+1, dest=to+length, source=to);
 */

sysmovdn(n,dest,source) int n; char *dest, *source;
{
    if (n>0) {
        movmem(source-n+1,dest-n+1,n);
    }
}

/* move a block of n bytes up (towards LOW addresses).
 * the block starts at source and the first byte goes to dest.
 * this routine is called only from bufmovup() as follows:
 *     sysmovup( n=to-from+1, dest=from-length, source=from);
 */

sysmovup(n,dest,source) int n; char *dest, *source;
{
    if (n>0) {
        movmem(source,dest,n);
    }
}

e name for syntax */

syschkfn(args) char *args;
{
    return(OK);
}

/* copy file name fr