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The C Users' Group Library 1994 August
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wc-cdrom-cusersgrouplibrary-1994-08.iso
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vol_300
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334_03
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util2.c
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1991-02-05
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/*
*
* G N U P L O T -- util.c
*
* Copyright (C) 1986 Thomas Williams, Colin Kelley
*
* You may use this code as you wish if credit is given and this message
* is retained.
*
* Please e-mail any useful additions to vu-vlsi!plot so they may be
* included in later releases.
*
* This file should be edited with 4-column tabs! (:set ts=4 sw=4 in vi)
*/
#include <ctype.h>
#include <setjmp.h>
#include <stdio.h>
#include <errno.h>
#include "plot.h"
#ifndef vms
extern int errno, sys_nerr;
extern char *sys_errlist[];
#endif /* vms */
extern int inline; /* line number of input */
extern char input_line[MAX_LINE_LEN];
extern struct lexical_unit token[MAX_TOKENS];
extern jmp_buf env; /* from plot.c */
/*
* equals() compares string value of token number t_num with str[], and
* returns TRUE if they are identical.
*/
equals(t_num, str)
int t_num;
char *str;
{
register int i;
if (!token[t_num].is_token)
return(FALSE); /* must be a value--can't be equal */
for (i = 0; i < token[t_num].length; i++) {
if (input_line[token[t_num].start_index+i] != str[i])
return(FALSE);
}
/* now return TRUE if at end of str[], FALSE if not */
return(str[i] == '\0');
}
/*
* almost_equals() compares string value of token number t_num with str[], and
* returns TRUE if they are identical up to the first $ in str[].
*/
almost_equals(t_num, str)
int t_num;
char *str;
{
register int i;
register int after = 0;
register start = token[t_num].start_index;
register length = token[t_num].length;
if (!token[t_num].is_token)
return(FALSE); /* must be a value--can't be equal */
for (i = 0; i < length + after; i++) {
if (str[i] != input_line[start + i]) {
if (str[i] != '$')
return(FALSE);
else {
after = 1;
start--; /* back up token ptr */
}
}
}
/* i now beyond end of token string */
return(after || str[i] == '$' || str[i] == '\0');
}
isstring(t_num)
int t_num;
{
return(token[t_num].is_token &&
(input_line[token[t_num].start_index] == '\'' ||
input_line[token[t_num].start_index] == '\"'));
}
isnumber(t_num)
int t_num;
{
return(!token[t_num].is_token);
}
isletter(t_num)
int t_num;
{
return(token[t_num].is_token &&
(isalpha(input_line[token[t_num].start_index])));
}
/*
* is_definition() returns TRUE if the next tokens are of the form
* identifier =
* -or-
* identifier ( identifer ) =
*/
is_definition(t_num)
int t_num;
{
return (isletter(t_num) &&
(equals(t_num+1,"=") || /* variable */
(equals(t_num+1,"(") && /* function */
isletter(t_num+2) &&
equals(t_num+3,")") &&
equals(t_num+4,"=") )
));
}
/*
* copy_str() copies the string in token number t_num into str, appending
* a null. No more than MAX_ID_LEN chars are copied.
*/
copy_str(str, t_num)
char str[];
int t_num;
{
register int i = 0;
register int start = token[t_num].start_index;
register int count;
if ((count = token[t_num].length) > MAX_ID_LEN)
count = MAX_ID_LEN;
do {
str[i++] = input_line[start++];
} while (i != count);
str[i] = '\0';
}
/*
* quote_str() does the same thing as copy_str, except it ignores the
* quotes at both ends. This seems redundant, but is done for
* efficency.
*/
quote_str(str, t_num)
char str[];
int t_num;
{
register int i = 0;
register int start = token[t_num].start_index + 1;
register int count;
if ((count = token[t_num].length - 2) > MAX_ID_LEN)
count = MAX_ID_LEN;
while (i != count) {
str[i++] = input_line[start++];
}
str[i] = '\0';
}
/*
* capture() returns in str[] the the part of input_line[] which lies
* between the begining of token[start] and end of token[end]
*/
capture(str,start,end)
char str[];
int start,end;
{
register int i,j;
char *s = str;
j = token[end].start_index + token[end].length;
for (i = token[start].start_index; i < j && input_line[i] != '\0'; i++)
*s++ = input_line[i];
*s = '\0';
}
convert(val_ptr, t_num)
struct value *val_ptr;
int t_num;
{
*val_ptr = token[t_num].l_val;
}
show_value(fp,val)
FILE *fp;
struct value *val;
{
switch(val->type) {
case INT:
fprintf(fp,"%d",val->v.int_val);
break;
case CMPLX:
if (val->v.cmplx_val.imag != 0.0 )
fprintf(fp,"{%g, %g}",
val->v.cmplx_val.real,val->v.cmplx_val.imag);
else
fprintf(fp,"%g", val->v.cmplx_val.real);
break;
default:
int_error("unknown type in show_value()",NO_CARET);
}
}
double
real(val) /* returns the real part of val */
struct value *val;
{
switch(val->type) {
case INT:
return((double) val->v.int_val);
break;
case CMPLX:
return(val->v.cmplx_val.real);
}
int_error("unknown type in real()",NO_CARET);
/* NOTREACHED */
}
double
imag(val) /* returns the imag part of val */
struct value *val;
{
switch(val->type) {
case INT:
return(0.0);
break;
case CMPLX:
return(val->v.cmplx_val.imag);
}
int_error("unknown type in real()",NO_CARET);
/* NOTREACHED */
}
double
magnitude(val) /* returns the magnitude of val */
struct value *val;
{
double sqrt();
switch(val->type) {
case INT:
return((double) abs(val->v.int_val));
break;
case CMPLX:
return(sqrt(val->v.cmplx_val.real*
val->v.cmplx_val.real +
val->v.cmplx_val.imag*
val->v.cmplx_val.imag));
}
int_error("unknown type in magnitude()",NO_CARET);
/* NOTREACHED */
}
double
angle(val) /* returns the angle of val */
struct value *val;
{
double atan2();
switch(val->type) {
case INT:
return((val->v.int_val > 0) ? 0.0 : Pi);
break;
case CMPLX:
if (val->v.cmplx_val.imag == 0.0) {
if (val->v.cmplx_val.real >= 0.0)
return(0.0);
else
return(Pi);
}
return(atan2(val->v.cmplx_val.imag,
val->v.cmplx_val.real));
}
int_error("unknown type in angle()",NO_CARET);
/* NOTREACHED */
}
struct value *
complex(a,realpart,imagpart)
struct value *a;
double realpart, imagpart;
{
a->type = CMPLX;
a->v.cmplx_val.real = realpart;
a->v.cmplx_val.imag = imagpart;
return(a);
}
struct value *
integer(a,i)
struct value *a;
int i;
{
a->type = INT;
a->v.int_val = i;
return(a);
}
/* Lower-case the given string (DFK) */
/* Done in place. */
void
lower_case(s)
char *s;
{
register char *p = s;
while (*p != '\0') {
if (*p >= 'A' && *p <= 'Z')
*p = *p - 'A' + 'a';
p++;
}
}
int space_count(line, t_num)
int line;
int t_num;
{
char string[20];
sprintf(string, "---%d: ", line);
return(strlen(string) + token[t_num].start_index);
}
show_line(always)
BOOLEAN always;
{
static int last_line_printed = 0; /* number of line printed out last. */
if (always || inline != last_line_printed) {
/* print line if not printed yet */
fprintf(stderr,"\n---%d: %s\n", inline, input_line);
last_line_printed = inline;
}
}
os_error(str,t_num)
char str[];
int t_num;
{
#ifdef vms
static status[2] = {1, 0}; /* 1 is count of error msgs */
#endif
register int i;
int count;
show_line(TRUE);
if (t_num != NO_CARET) { /* put caret under error */
count = space_count(inline, t_num);
for (i = 0; i < count; i++) {
(void) putc((input_line[i] == '\t') ? '\t' : ' ',stderr);
}
(void) putc('^',stderr);
(void) putc('\n',stderr);
}
fprintf(stderr,"###%d: %s\n",str);
#ifdef vms
status[1] = vaxc$errno;
sys$putmsg(status);
(void) putc('\n',stderr);
#else
if (errno >= sys_nerr)
fprintf(stderr, "unknown errno %d\n\n", errno);
else
fprintf(stderr,"(%s)\n",sys_errlist[errno]);
#endif
longjmp(env, TRUE); /* bail out to command line */
}
/* fatal error for this line; no return */
int_error(str,t_num)
char str[];
int t_num;
{
register int i;
int count;
show_line(TRUE);
if (t_num != NO_CARET) { /* put caret under error */
count = space_count(inline, t_num);
for (i = 0; i < count; i++) {
(void) putc((input_line[i] == '\t') ? '\t' : ' ',stderr);
}
(void) putc('^',stderr);
(void) putc('\n',stderr);
}
fprintf(stderr,"###%d: %s\n", inline, str);
longjmp(env, TRUE); /* bail out to command line */
}
/* print an error for this line and return */
err_msg(str)
char str[];
{
show_line(FALSE);
fprintf(stderr,"***%d: %s\n", inline, str);
}
/* find char c in string str; return p such that str[p]==c;
* if c not in str then p=strlen(str)
*/
int
instring(str, c)
char *str;
char c;
{
int pos = 0;
while (str != NULL && *str != '\0' && c != *str) {
str++;
pos++;
}
return (pos);
}