The Atari Compendium/The Atari Compendium (Toad Computers) (1994).iso/files/prgtools/langs/xlisp2.1/xldist02.zoo/sources/xlio.c

C/C++ Source or Header | 1990-11-09 | 4.4 KB | 235 lines

/* xlio - xlisp i/o routines */
/*        Copyright (c) 1985, by David Michael Betz
        All Rights Reserved
        Permission is granted for unrestricted non-commercial use        */

#include "xlisp.h"

/* external variables */
extern LVAL s_stdout,s_stderr,s_debugio,s_traceout;
extern int xlfsize;

/* xlgetc - get a character from a file or stream */
int xlgetc(fptr)
  LVAL fptr;
{
    LVAL lptr,cptr;
    FILE *fp;
    int ch;

    /* check for input from nil */
    if (fptr == NIL)
        ch = EOF;

    /* otherwise, check for input from a stream */
    else if (ustreamp(fptr)) {
        if ((lptr = gethead(fptr)) == NIL)
            ch = EOF;
        else {
            if (!consp(lptr) || (cptr = car(lptr)) == NIL || !charp(cptr))
                xlfail("bad stream");
            sethead(fptr,lptr = cdr(lptr));
            if (lptr == NIL)
                settail(fptr,NIL);
            ch = getchcode(cptr);
        }
    }

    /* otherwise, check for a buffered character */
    else if ((ch = getsavech(fptr)) != 0)
        setsavech(fptr,'\0');

    /* otherwise, check for terminal input or file input */
    else {
        fp = getfile(fptr);
        if (fp == stdin || fp == stderr)
            ch = ostgetc();
        else {
#ifdef BETTERIO
            if ((fptr->n_sflags & S_READING) == 0) {
                /* possible direction change*/
                if (fptr->n_sflags & S_WRITING) {
                    fseek(fp,0L,SEEK_CUR);
                }
                fptr->n_sflags = S_READING;
            }
#endif
            ch = fgetc(fp);
        }
    }

    /* return the character */
    return (ch);
}

/* xlungetc - unget a character */
VOID xlungetc(fptr,ch)
  LVAL fptr; int ch;
{
    LVAL lptr;

    /* check for ungetc from nil */
    if (fptr == NIL)
        ;

    /* otherwise, check for ungetc to a stream */
    else if (ustreamp(fptr)) {
        if (ch != EOF) {
            lptr = cons(cvchar(ch),gethead(fptr));
            if (gethead(fptr) == NIL)
                settail(fptr,lptr);
            sethead(fptr,lptr);
        }
    }

    /* otherwise, it must be a file */
    else
        setsavech(fptr,ch);
}

/* xlpeek - peek at a character from a file or stream */
int xlpeek(fptr)
  LVAL fptr;
{
    LVAL lptr,cptr;
    int ch;

    /* check for input from nil */
    if (fptr == NIL)
        ch = EOF;

    /* otherwise, check for input from a stream */
    else if (ustreamp(fptr)) {
        if ((lptr = gethead(fptr)) == NIL)
            ch = EOF;
        else {
            if (!consp(lptr) || (cptr = car(lptr)) == NIL || !charp(cptr))
                xlfail("bad stream");
            ch = getchcode(cptr);
        }
    }

    /* otherwise, get the next file character and save it */
    else {
        ch = xlgetc(fptr);
        setsavech(fptr,ch);
    }

    /* return the character */
    return (ch);
}

/* xlputc - put a character to a file or stream */
VOID xlputc(fptr,ch)
  LVAL fptr; int ch;
{
    LVAL lptr;
    FILE *fp;

    /* count the character */
    ++xlfsize;

    /* check for output to nil */
    if (fptr == NIL)
        ;

    /* otherwise, check for output to an unnamed stream */
    else if (ustreamp(fptr)) {
        lptr = consa(cvchar(ch));
        if (gettail(fptr))
            rplacd(gettail(fptr),lptr);
        else
            sethead(fptr,lptr);
        settail(fptr,lptr);
    }

    /* otherwise, check for terminal output or file output */
    else {
        fp = getfile(fptr);
        if (fp == stdout || fp == stderr)
            ostputc(ch);
        else {
#ifdef BETTERIO
            if ((fptr->n_sflags & S_WRITING) == 0) {
                /* possible direction change*/
                if (fptr->n_sflags & S_READING) {
                    fseek(fp,
                        (getsavech(fptr)?(setsavech(fptr,'\0'),-1L):0L),
                        SEEK_CUR);
                }
                fptr->n_sflags = S_WRITING;
            }
#endif
            if (fputc(ch,fp)==EOF)    /* TAA MOD to check for write to RO file*/
                xlfail("write failed");
        }
    }
}

/* xlflush - flush the input buffer */
VOID xlflush()
{
    osflush();
}

/* stdprint - print to *standard-output* */
VOID stdprint(expr)
  LVAL expr;
{
    xlprint(getvalue(s_stdout),expr,TRUE);
    xlterpri(getvalue(s_stdout));
}

/* stdputstr - print a string to *standard-output* */
VOID stdputstr(str)
  char *str;
{
    xlputstr(getvalue(s_stdout),str);
}

/* errprint - print to *error-output* */
VOID errprint(expr)
  LVAL expr;
{
    xlprint(getvalue(s_stderr),expr,TRUE);
    xlterpri(getvalue(s_stderr));
}

/* errputstr - print a string to *error-output* */
VOID errputstr(str)
  char *str;
{
    xlputstr(getvalue(s_stderr),str);
}

/* dbgprint - print to *debug-io* */
VOID dbgprint(expr)
  LVAL expr;
{
    xlprint(getvalue(s_debugio),expr,TRUE);
    xlterpri(getvalue(s_debugio));
}

/* dbgputstr - print a string to *debug-io* */
VOID dbgputstr(str)
  char *str;
{
    xlputstr(getvalue(s_debugio),str);
}

/* trcprin1 - print to *trace-output* */
VOID trcprin1(expr)
  LVAL expr;
{
    xlprint(getvalue(s_traceout),expr,TRUE);
}

/* trcputstr - print a string to *trace-output* */
VOID trcputstr(str)
  char *str;
{
    xlputstr(getvalue(s_traceout),str);
}