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bwb_inp.c
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1992-11-12
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/***************************************************************
bwb_inp.c Input Routines
for Bywater BASIC Interpreter
Commands: DATA
READ
RESTORE
INPUT
LINE INPUT
Copyright (c) 1992, Ted A. Campbell
Bywater Software
P. O. Box 4023
Duke Station
Durham, NC 27706
email: tcamp@acpub.duke.edu
Copyright and Permissions Information:
All U.S. and international copyrights are claimed by the
author. The author grants permission to use this code
and software based on it under the following conditions:
(a) in general, the code and software based upon it may be
used by individuals and by non-profit organizations; (b) it
may also be utilized by governmental agencies in any country,
with the exception of military agencies; (c) the code and/or
software based upon it may not be sold for a profit without
an explicit and specific permission from the author, except
that a minimal fee may be charged for media on which it is
copied, and for copying and handling; (d) the code must be
distributed in the form in which it has been released by the
author; and (e) the code and software based upon it may not
be used for illegal activities.
***************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <math.h>
#include "bwbasic.h"
#include "bwb_mes.h"
struct bwb_line *data_line;
int data_pos;
/* Declarations of functions visible to this file only */
static struct bwb_line *bwb_xinp( struct bwb_line *l, FILE *f );
static struct bwb_line *inp_str( struct bwb_line *l, char *buffer,
char *var_list, int *position );
static int inp_const( char *m_buffer, char *s_buffer, int *position );
static int inp_assign( char *b, struct bwb_variable *v );
static int inp_advws( FILE *f );
static int inp_xgetc( FILE *f, int is_string );
static int inp_eatcomma( FILE *f );
static char_saved = FALSE;
static cs;
/***************************************************************
FUNCTION: bwb_read()
DESCRIPTION: This function implements the BASIC READ
statement.
SYNTAX: READ variable[, variable...]
***************************************************************/
struct bwb_line *
bwb_read( struct bwb_line *l )
{
int pos;
register int n;
int main_loop, adv_loop;
struct bwb_variable *v;
int n_params; /* number of parameters */
int *pp; /* pointer to parameter values */
char tbuf[ MAXSTRINGSIZE + 1 ];
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_read(): buffer <%s>",
&( l->buffer[ l->position ]));
bwb_debug( bwb_ebuf );
#endif
/* Process each variable read from the READ statement */
main_loop = TRUE;
while ( main_loop == TRUE )
{
/* first check position in l->buffer and advance beyond whitespace */
adv_loop = TRUE;
while( adv_loop == TRUE )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_read() adv_loop char <%d> = <%c>",
l->buffer[ l->position ], l->buffer[ l->position ] );
bwb_debug( bwb_ebuf );
#endif
switch ( l->buffer[ l->position ] )
{
case ',': /* comma delimiter */
case ' ': /* whitespace */
case '\t':
++l->position;
break;
case ':': /* end of line segment */
case '\n': /* end of line */
case '\r':
case '\0':
adv_loop = FALSE; /* break out of advance loop */
main_loop = FALSE; /* break out of main loop */
break;
default: /* anything else */
adv_loop = FALSE; /* break out of advance loop */
break;
}
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_read(): end of adv_loop <%d> main_loop <%d>",
adv_loop, main_loop );
bwb_debug( bwb_ebuf );
#endif
/* be sure main_loop id still valid after checking the line */
if ( main_loop == TRUE )
{
/* Read a variable name */
bwb_getvarname( l->buffer, tbuf, &( l->position ) );
inp_adv( l->buffer, &( l->position ) );
v = var_find( tbuf );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_read(): line <%d> variable <%s>",
l->number, v->name );
bwb_debug( bwb_ebuf );
sprintf( bwb_ebuf, "in bwb_read(): remaining line <%s>",
&( l->buffer[ l->position ] ) );
bwb_debug( bwb_ebuf );
#endif
/* advance beyond whitespace or comma in data buffer */
inp_adv( data_line->buffer, &data_pos );
/* Advance to next line if end of buffer */
switch( data_line->buffer[ data_pos ] )
{
case '\0': /* end of buffer */
case '\n':
case '\r':
data_line = data_line->next;
/* advance farther to line with DATA statement if necessary */
pos = 0;
line_start( data_line->buffer, &pos,
&( data_line->lnpos ),
&( data_line->lnum ),
&( data_line->cmdpos ),
&( data_line->cmdnum ),
&( data_line->startpos ) );
data_pos = data_line->startpos;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_read(): current data line: <%s>",
data_line->buffer );
bwb_debug( bwb_ebuf );
#endif
break;
}
while ( bwb_cmdtable[ data_line->cmdnum ].vector != bwb_data )
{
if ( data_line == &bwb_end )
{
data_line = bwb_start.next;
}
else
{
data_line = data_line->next;
}
pos = 0;
line_start( data_line->buffer, &pos,
&( data_line->lnpos ),
&( data_line->lnum ),
&( data_line->cmdpos ),
&( data_line->cmdnum ),
&( data_line->startpos ) );
data_pos = data_line->startpos;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_read(): advance to data line: <%s>",
data_line->buffer );
bwb_debug( bwb_ebuf );
#endif
}
/* advance beyond whitespace in data buffer */
adv_loop = TRUE;
while ( adv_loop == TRUE )
{
switch( data_line->buffer[ data_pos ] )
{
case '\0': /* end of buffer */
case '\n':
case '\r':
bwb_error( err_od );
l->next->position = 0;
return l->next;
case ' ': /* whitespace */
case '\t':
++data_pos;
break;
default:
adv_loop = FALSE; /* carry on */
break;
}
}
/* now at last we have a variable in v that needs to be
assigned data from the data_buffer at position data_pos.
What remains to be done is to get one single bit of data,
a string constant or numerical constant, into the small
buffer */
inp_const( data_line->buffer, tbuf, &data_pos );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_read(): data constant is <%s>", tbuf );
bwb_debug( bwb_ebuf );
#endif
/* get parameters if the variable is dimensioned */
adv_ws( l->buffer, &( l->position ) );
if ( l->buffer[ l->position ] == '(' )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_read(): variable <%s> is dimensioned",
v->name );
bwb_debug( bwb_ebuf );
#endif
dim_getparams( l->buffer, &( l->position ), &n_params, &pp );
for ( n = 0; n < v->dimensions; ++n )
{
v->array_pos[ n ] = pp[ n ];
}
}
#if INTENSIVE_DEBUG
else
{
sprintf( bwb_ebuf, "in bwb_read(): variable <%s> is NOT dimensioned",
v->name );
bwb_debug( bwb_ebuf );
sprintf( bwb_ebuf, "in bwb_read(): remaining line <%s>",
&( l->buffer[ l->position ] ) );
bwb_debug( bwb_ebuf );
}
#endif
/* finally assign the data to the variable */
inp_assign( tbuf, v );
} /* end of remainder of main loop */
} /* end of main_loop */
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_read(): exiting function, line <%s> ",
&( l->buffer[ l->position ] ) );
bwb_debug( bwb_ebuf );
#endif
l->next->position = 0;
return l->next;
}
/***************************************************************
FUNCTION: bwb_data()
DESCRIPTION: This function implements the BASIC DATA
statement, although at the point at which
DATA statements are encountered, no
processing is done. All actual processing
of DATA statements is accomplished by READ
(bwb_read()).
SYNTAX: DATA constant[, constant]...
***************************************************************/
struct bwb_line *
bwb_data( struct bwb_line *l )
{
l->next->position = 0;
return l->next;
}
/***************************************************************
FUNCTION: bwb_restore()
DESCRIPTION: This function implements the BASIC RESTORE
statement.
SYNTAX: RESTORE [line number]
***************************************************************/
struct bwb_line *
bwb_restore( struct bwb_line *l )
{
struct bwb_line *r;
struct bwb_line *r_line;
int n;
int pos;
char tbuf[ MAXSTRINGSIZE + 1 ];
/* get the first element beyond the starting position */
adv_element( l->buffer, &( l->position ), tbuf );
/* if the line is not a numerical constant, then there is no
argument; set the current line to the first in the program */
if ( is_numconst( tbuf ) != TRUE )
{
data_line = &bwb_start;
data_pos = 0;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_restore(): RESTORE w/ no argument " );
bwb_debug( bwb_ebuf );
#endif
l->next->position = 0;
return l->next;
}
/* find the line */
n = atoi( tbuf );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_restore(): line for restore is <%d>", n );
bwb_debug( bwb_ebuf );
#endif
r_line = NULL;
for ( r = bwb_start.next; r != &bwb_end; r = r->next )
{
if ( r->number == n )
{
r_line = r;
}
}
if ( r_line == NULL )
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "at line %d: Can't find line number for RESTORE.",
l->number );
bwb_error( bwb_ebuf );
#else
sprintf( bwb_ebuf, err_lnnotfound, n );
bwb_error( bwb_ebuf );
#endif
l->next->position = 0;
return l->next;
}
/* initialize variables for the line */
pos = 0;
line_start( r_line->buffer, &pos,
&( r_line->lnpos ),
&( r_line->lnum ),
&( r_line->cmdpos ),
&( r_line->cmdnum ),
&( r_line->startpos ) );
/* verify that line is a data statement */
if ( bwb_cmdtable[ r_line->cmdnum ].vector != bwb_data )
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "at line %d: Line %d is not a DATA statement.",
l->number, r_line->number );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
l->next->position = 0;
return l->next;
}
/* reassign data_line */
data_line = r_line;
data_pos = data_line->startpos;
l->next->position = 0;
return l->next;
}
/***************************************************************
FUNCTION: bwb_input()
DESCRIPTION: This function implements the BASIC INPUT
statement.
SYNTAX: INPUT [;][prompt$;]variable[$,variable]...
INPUT #n variable[$,variable]...
***************************************************************/
struct bwb_line *
bwb_input( struct bwb_line *l )
{
FILE *fp;
int pos;
int req_devnumber;
struct exp_ese *v;
int is_prompt;
int suppress_qm;
static char tbuf[ MAXSTRINGSIZE + 1 ];
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_input(): enter function" );
bwb_debug( bwb_ebuf );
#endif
/* advance beyond whitespace and check for the '#' sign */
adv_ws( l->buffer, &( l->position ) );
if ( l->buffer[ l->position ] == '#' )
{
++( l->position );
adv_element( l->buffer, &( l->position ), tbuf );
pos = 0;
v = bwb_exp( tbuf, FALSE, &pos );
adv_ws( l->buffer, &( l->position ) );
if ( l->buffer[ l->position ] == ',' )
{
++( l->position );
}
else
{
#if PROG_ERRORS
bwb_error( "in bwb_input(): no comma after #n" );
#else
bwb_error( err_syntax );
#endif
l->next->position = 0;
return l->next;
}
req_devnumber = exp_getival( v );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_input(): requested device number <%d>",
req_devnumber );
bwb_debug( bwb_ebuf );
#endif
/* check the requested device number */
if ( ( req_devnumber < 0 ) || ( req_devnumber >= DEF_DEVICES ))
{
#if PROG_ERRORS
bwb_error( "in bwb_input(): Requested device number is out if range." );
#else
bwb_error( err_devnum );
#endif
l->next->position = 0;
return l->next;
}
if ( ( dev_table[ req_devnumber ].mode == DEVMODE_CLOSED ) ||
( dev_table[ req_devnumber ].mode == DEVMODE_AVAILABLE ) )
{
#if PROG_ERRORS
bwb_error( "in bwb_input(): Requested device number is not open." );
#else
bwb_error( err_devnum );
#endif
l->next->position = 0;
return l->next;
}
if ( dev_table[ req_devnumber ].mode != DEVMODE_INPUT )
{
#if PROG_ERRORS
bwb_error( "in bwb_input(): Requested device is not open for INPUT." );
#else
bwb_error( err_devnum );
#endif
l->next->position = 0;
return l->next;
}
/* look up the requested device in the device table */
fp = dev_table[ req_devnumber ].cfp;
}
else
{
fp = stdin;
}
/* if input is not from stdin, then branch to bwb_xinp() */
if ( fp != stdin )
{
return bwb_xinp( l, fp );
}
/* from this point we presume that input is from stdin */
/* check for a semicolon or a quotation mark, not in
first position: this should indicate a prompt string */
suppress_qm = is_prompt = FALSE;
adv_ws( l->buffer, &( l->position ) );
switch( l->buffer[ l->position ] )
{
case '\"':
is_prompt = TRUE;
break;
case ';':
/* AGENDA: add code to suppress newline if a
semicolon is used here; this may not be possible
using ANSI C alone, since it has not functions for
unechoed console input. */
is_prompt = TRUE;
++l->position;
break;
case ',':
/* QUERY: why is this code here? the question mark should
be suppressed if a comma <follows> the prompt string. */
#if INTENSIVE_DEBUG
bwb_debug( "in bwb_input(): found initial comma" );
#endif
suppress_qm = TRUE;
++l->position;
break;
}
/* get prompt string and print it */
if ( is_prompt == TRUE )
{
/* get string element */
inp_const( l->buffer, tbuf, &( l->position ) );
/* advance past semicolon to beginning of variable */
suppress_qm = inp_adv( l->buffer, &( l->position ) );
/* print the prompt string */
xprintf( stdout, tbuf );
} /* end condition: prompt string */
/* print out the question mark delimiter unless it has been
suppressed */
if ( suppress_qm != TRUE )
{
xprintf( stdout, "? " );
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_input(): ready to get input line" );
bwb_debug( bwb_ebuf );
#endif
/* read a line into the input buffer */
fflush( stdin );
fgets( tbuf, MAXSTRINGSIZE, stdin );
bwb_stripcr( tbuf );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_input(): received line <%s>", tbuf );
bwb_debug( bwb_ebuf );
bwb_debug( "Press RETURN: " );
getchar();
#endif
/* reset print column to account for LF at end of fgets() */
* prn_getcol( stdout ) = 1;
return inp_str( l, tbuf, l->buffer, &( l->position ) );
}
/***************************************************************
FUNCTION: bwb_xinp()
DESCRIPTION: This function does the bulk of processing
for INPUT #, and so is file independent.
***************************************************************/
struct bwb_line *
bwb_xinp( struct bwb_line *l, FILE *f )
{
int loop;
struct bwb_variable *v;
char c;
register int n;
int pos;
int *pp;
int n_params;
char tbuf[ MAXSTRINGSIZE + 1 ];
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_xinp(): buffer <%s>",
&( l->buffer[ l->position ] ) );
bwb_debug( bwb_ebuf );
#endif
/* loop through elements required */
loop = TRUE;
while ( loop == TRUE )
{
/* read a variable from the list */
bwb_getvarname( l->buffer, tbuf, &( l->position ) );
v = var_find( tbuf );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_xinp(): found variable name <%s>",
v->name );
bwb_debug( bwb_ebuf );
#endif
/* read subscripts */
adv_ws( l->buffer, &( l->position ) );
if ( l->buffer[ l->position ] == ')' )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_xinp(): variable <%s> has dimensions",
v->name );
bwb_debug( bwb_ebuf );
#endif
dim_getparams( l->buffer, &( l->position ), &n_params, &pp );
for ( n = 0; n < v->dimensions; ++n )
{
v->array_pos[ n ] = pp[ n ];
}
}
inp_advws( f );
/* perform type-specific input */
switch( v->type )
{
case STRING:
if ( inp_xgetc( f, TRUE ) != '\"' )
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "in bwb_xinp(): expected quotation mark" );
bwb_error( bwb_ebuf );
#else
bwb_error( err_mismatch );
#endif
}
n = 0;
while ( ( c = (char) inp_xgetc( f, TRUE )) != '\"' )
{
tbuf[ n ] = c;
++n;
tbuf[ n ] = '\0';
}
str_ctob( var_findsval( v, v->array_pos ), tbuf );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_xinp(): read STRING <%s>",
tbuf );
bwb_debug( bwb_ebuf );
#endif
inp_eatcomma( f );
break;
case INTEGER:
n = 0;
while ( ( c = (char) inp_xgetc( f, FALSE )) != ',' )
{
tbuf[ n ] = c;
++n;
tbuf[ n ] = '\0';
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_xinp(): read INTEGER <%s>",
tbuf );
bwb_debug( bwb_ebuf );
#endif
* var_findival( v, v->array_pos ) = atoi( tbuf );
break;
case DOUBLE:
n = 0;
while ( ( c = (char) inp_xgetc( f, FALSE )) != ',' )
{
tbuf[ n ] = c;
++n;
tbuf[ n ] = '\0';
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_xinp(): read DOUBLE <%s>",
tbuf );
bwb_debug( bwb_ebuf );
#endif
* var_finddval( v, v->array_pos ) = (double) atof( tbuf );
break;
default: /* take SINGLE as default */
n = 0;
while ( ( c = (char) inp_xgetc( f, FALSE )) != ',' )
{
tbuf[ n ] = c;
++n;
tbuf[ n ] = '\0';
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_xinp(): read SINGLE <%s>",
tbuf );
bwb_debug( bwb_ebuf );
#endif
* var_findfval( v, v->array_pos ) = (float) atof( tbuf );
break;
} /* end of switch for type-specific input */
/* check for comma */
adv_ws( l->buffer, &( l->position ) );
if ( l->buffer[ l->position ] == ',' )
{
++( l->position );
}
else
{
loop = FALSE;
}
}
/* return */
return l;
}
/***************************************************************
FUNCTION: inp_advws()
DESCRIPTION:
***************************************************************/
int
inp_advws( FILE *f )
{
register int c;
int loop;
loop = TRUE;
while ( loop == TRUE )
{
c = (char) inp_xgetc( f, TRUE );
switch( c )
{
case '\n':
case '\r':
case ' ':
case '\t':
break;
default:
char_saved = TRUE;
cs = c;
loop = FALSE;
break;
}
}
return TRUE;
}
/***************************************************************
FUNCTION: inp_xgetc()
DESCRIPTION:
***************************************************************/
int
inp_xgetc( FILE *f, int is_string )
{
register int c;
static int prev_eof = FALSE;
if ( char_saved == TRUE )
{
char_saved = FALSE;
return cs;
}
if ( feof( f ) != 0 )
{
if ( prev_eof == TRUE )
{
bwb_error( err_od );
}
else
{
prev_eof = TRUE;
return (int) ',';
}
}
prev_eof = FALSE;
c = fgetc( f );
if ( is_string == TRUE )
{
return c;
}
switch( c )
{
case ' ':
case '\n':
case ',':
case '\r':
return ',';
}
return c;
}
/***************************************************************
FUNCTION: inp_eatcomma()
DESCRIPTION:
***************************************************************/
int
inp_eatcomma( FILE *f )
{
char c;
while ( ( c = (char) inp_xgetc( f, TRUE ) ) == ',' )
{
}
char_saved = TRUE;
cs = c;
return TRUE;
}
/***************************************************************
FUNCTION: inp_str()
DESCRIPTION: This function does INPUT processing
from a determined string of input
data and a determined variable list
(both in memory). This presupposes
that input has been taken from stdin,
not from a disk file or device.
***************************************************************/
struct bwb_line *
inp_str( struct bwb_line *l, char *input_buffer, char *var_list, int *vl_position )
{
int i;
register int n;
struct bwb_variable *v;
int loop;
int *pp;
int n_params;
char ttbuf[ MAXSTRINGSIZE + 1 ]; /* build element */
char varname[ MAXSTRINGSIZE + 1 ]; /* build element */
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in inp_str(): received line <%s>",
l->buffer );
bwb_debug( bwb_ebuf );
sprintf( bwb_ebuf, "in inp_str(): received variable list <%s>.",
&( var_list[ *vl_position ] ) );
bwb_debug( bwb_ebuf );
sprintf( bwb_ebuf, "in inp_str(): received input buffer <%s>.",
input_buffer );
bwb_debug( bwb_ebuf );
#endif
/* Read elements, and assign them to variables */
i = 0;
loop = TRUE;
while ( loop == TRUE )
{
/* get a variable name from the list */
bwb_getvarname( var_list, varname, vl_position ); /* get name */
v = var_find( varname );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in inp_str(): found variable buffer <%s> name <%s>",
varname, v->name );
bwb_debug( bwb_ebuf );
#endif
/* read subscripts if appropriate */
adv_ws( var_list, vl_position );
if ( var_list[ *vl_position ] == ')' )
{
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in inp_str(): variable <%s> has dimensions",
v->name );
bwb_debug( bwb_ebuf );
#endif
dim_getparams( var_list, vl_position, &n_params, &pp );
for ( n = 0; n < v->dimensions; ++n )
{
v->array_pos[ n ] = pp[ n ];
}
}
/* build string from input buffer in ttbuf */
n = 0;
ttbuf[ 0 ] = '\0';
while ( ( input_buffer[ i ] != ',' )
&& ( input_buffer[ i ] != '\0' ))
{
ttbuf[ n ] = input_buffer[ i ];
++n;
++i;
ttbuf[ n ] = '\0';
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in inp_str(): string for input <%s>",
ttbuf );
bwb_debug( bwb_ebuf );
#endif
/* perform type-specific input */
inp_assign( ttbuf, v );
/* check for commas in variable list and input list and advance */
adv_ws( var_list, vl_position );
switch( var_list[ *vl_position ] )
{
case '\n':
case '\r':
case '\0':
case ':':
loop = FALSE;
break;
case ',':
++( *vl_position );
break;
}
adv_ws( var_list, vl_position );
adv_ws( input_buffer, &i );
switch ( input_buffer[ i ] )
{
case '\n':
case '\r':
case '\0':
case ':':
loop = FALSE;
break;
case ',':
++i;
break;
}
adv_ws( input_buffer, &i );
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in inp_str(): exit, line buffer <%s>",
&( l->buffer[ l->position ] ) );
bwb_debug( bwb_ebuf );
#endif
/* return */
l->next->position = 0;
return l->next;
}
/***************************************************************
FUNCTION: inp_assign()
DESCRIPTION: This function assigns the value of a
numerical or string constant to a
variable.
***************************************************************/
int
inp_assign( char *b, struct bwb_variable *v )
{
switch( v->type )
{
case STRING:
str_ctob( var_findsval( v, v->array_pos ), b );
break;
case DOUBLE:
if ( strlen( b ) == 0 )
{
*( var_finddval( v, v->array_pos )) = (double) 0.0;
}
else
{
*( var_finddval( v, v->array_pos )) = (double) atof( b );
}
break;
case SINGLE:
if ( strlen( b ) == 0 )
{
*( var_findfval( v, v->array_pos )) = (float) 0.0;
}
else
{
*( var_findfval( v, v->array_pos )) = (float) atof( b );
}
break;
case INTEGER:
if ( strlen( b ) == 0 )
{
*( var_findival( v, v->array_pos )) = 0;
}
else
{
*( var_findival( v, v->array_pos )) = atoi( b );
}
break;
default:
#if PROG_ERRORS
sprintf( bwb_ebuf, "in inp_assign(): variable <%s> of unknown type",
v->name );
bwb_error( bwb_ebuf );
#else
bwb_error( err_mismatch );
#endif
return FALSE;
}
return FALSE;
}
/***************************************************************
FUNCTION: inp_adv()
DESCRIPTION: This function advances the string pointer
past whitespace and the item delimiter
(comma).
***************************************************************/
int
inp_adv( char *b, int *c )
{
int rval;
rval = FALSE;
while( TRUE )
{
switch( b[ *c ] )
{
case ' ': /* whitespace */
case '\t':
case ';': /* semicolon, end of prompt string */
++*c;
break;
case ',': /* comma, variable delimiter */
rval = TRUE;
++*c;
break;
case '\0': /* end of line */
case ':': /* end of line segment */
rval = TRUE;
return rval;
default:
return rval;
}
}
}
/***************************************************************
FUNCTION: inp_const()
DESCRIPTION: This function reads a numerical or string
constant from <m_buffer> into <s_buffer>,
incrementing <position> appropriately.
***************************************************************/
int
inp_const( char *m_buffer, char *s_buffer, int *position )
{
int string;
int s_pos;
int loop;
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in inp_const(): received argument <%s>.",
&( m_buffer[ *position ] ) );
bwb_debug( bwb_ebuf );
#endif
string = FALSE;
/* first detect string constant */
if ( m_buffer[ *position ] == '\"' )
{
string = TRUE;
++( *position );
}
else
{
string = FALSE;
}
/* build the constant string */
s_buffer[ 0 ] = '\0';
s_pos = 0;
loop = TRUE;
while ( loop == TRUE )
{
switch ( m_buffer[ *position ] )
{
case '\0': /* end of string */
case '\n':
case '\r':
return TRUE;
case ' ': /* whitespace */
case '\t':
case ',': /* or end of argument */
if ( string == FALSE )
{
return TRUE;
}
else
{
s_buffer[ s_pos ] = m_buffer[ *position ];
++( *position );
++s_buffer;
s_buffer[ s_pos ] = '\0';
}
break;
case '\"':
if ( string == TRUE )
{
++( *position ); /* advance beyond quotation mark */
inp_adv( m_buffer, position );
return TRUE;
}
else
{
#if PROG_ERRORS
sprintf( bwb_ebuf, "Unexpected character in numerical constant." );
bwb_error( bwb_ebuf );
#else
bwb_error( err_syntax );
#endif
return FALSE;
}
default:
s_buffer[ s_pos ] = m_buffer[ *position ];
++( *position );
++s_buffer;
s_buffer[ s_pos ] = '\0';
break;
}
}
return NULL;
}
/***************************************************************
FUNCTION: bwb_line()
DESCRIPTION: This function implements the BASIC LINE
INPUT statement.
SYNTAX: LINE INPUT
***************************************************************/
struct bwb_line *
bwb_line( struct bwb_line *l )
{
int dev_no;
struct bwb_variable *v;
FILE *inp_device;
char tbuf[ MAXSTRINGSIZE + 1 ];
/* assign default values */
inp_device = stdin;
l->next->position = 0;
/* advance to first element (INPUT statement) */
adv_element( l->buffer, &( l->position ), tbuf );
bwb_strtoupper( tbuf );
if ( strcmp( tbuf, "INPUT" ) != 0 )
{
bwb_error( err_syntax );
return l->next;
}
adv_ws( l->buffer, &( l->position ) );
/* check for semicolon in first position */
if ( l->buffer[ l->position ] == ';' )
{
++l->position;
adv_ws( l->buffer, &( l->position ) );
}
/* else check for # for file number in first position */
else if ( l->buffer[ l->position ] == '#' )
{
++l->position;
adv_element( l->buffer, &( l->position ), tbuf );
adv_ws( l->buffer, &( l->position ));
dev_no = atoi( tbuf );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_line(): file number requested <%d>", dev_no );
bwb_debug( bwb_ebuf );
#endif
if ( dev_table[ dev_no ].cfp == NULL )
{
bwb_error( err_dev );
return l->next;
}
else
{
inp_device = dev_table[ dev_no ].cfp;
}
}
/* check for comma */
if ( l->buffer[ l->position ] == ',' )
{
++( l->position );
adv_ws( l->buffer, &( l->position ));
}
/* check for quotation mark indicating prompt */
if ( l->buffer[ l->position ] == '\"' )
{
inp_const( l->buffer, tbuf, &( l->position ) );
xprintf( stdout, tbuf );
}
/* read the variable for assignment */
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_line(): tbuf <%s>",
tbuf );
bwb_debug( bwb_ebuf );
sprintf( bwb_ebuf, "in bwb_line(): line buffer <%s>",
&( l->buffer[ l->position ] ) );
bwb_debug( bwb_ebuf );
#endif
adv_element( l->buffer, &( l->position ), tbuf );
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_line(): variable buffer <%s>", tbuf );
bwb_debug( bwb_ebuf );
#endif
v = var_find( tbuf );
if ( v->type != STRING )
{
#if PROG_ERRORS
bwb_error( "in bwb_line(): String variable required" );
#else
bwb_error( err_syntax );
#endif
return l->next;
}
#if INTENSIVE_DEBUG
sprintf( bwb_ebuf, "in bwb_line(): variable for assignment <%s>", v->name );
bwb_debug( bwb_ebuf );
#endif
/* read a line of text into the bufffer */
fgets( tbuf, MAXSTRINGSIZE, inp_device );
bwb_stripcr( tbuf );
str_ctob( var_findsval( v, v->array_pos ), tbuf );
/* end: return next line */
return l->next;
}