minix3/commands/cawf/expr.c

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2020-02-21 00:59:27 +05:30
/*
* expr.c - expression support functions for cawf(1)
*/
/*
* Copyright (c) 1991 Purdue University Research Foundation,
* West Lafayette, Indiana 47907. All rights reserved.
*
* Written by Victor A. Abell <abe@mace.cc.purdue.edu>, Purdue
* University Computing Center. Not derived from licensed software;
* derived from awf(1) by Henry Spencer of the University of Toronto.
*
* Permission is granted to anyone to use this software for any
* purpose on any computer system, and to alter it and redistribute
* it freely, subject to the following restrictions:
*
* 1. The author is not responsible for any consequences of use of
* this software, even if they arise from flaws in it.
*
* 2. The origin of this software must not be misrepresented, either
* by explicit claim or by omission. Credits must appear in the
* documentation.
*
* 3. Altered versions must be plainly marked as such, and must not
* be misrepresented as being the original software. Credits must
* appear in the documentation.
*
* 4. This notice may not be removed or altered.
*/
#include "cawf.h"
/*
* Asmcode(s, c) - assemble number/name code following backslash-character
* definition - e. .g, "\\nPO"
*/
unsigned char *
Asmcode(s, c)
unsigned char **s; /* pointer to character after '\\' */
unsigned char *c; /* code destination (c[3]) */
{
unsigned char *s1;
s1 = *s + 1;
c[0] = c[1] = c[2] = '\0';
if ((c[0] = *s1) == '(') {
s1++;
if ((c[0] = *s1) != '\0') {
s1++;
c[1] = *s1;
}
}
return(s1);
}
/*
* Delnum(nx) - delete number
*/
void
Delnum(nx)
int nx; /* number index */
{
unsigned char buf[MAXLINE]; /* message buffer */
if (nx >= Nnr) {
(void) sprintf((char *)buf, " bad Delnum(%d) index", nx);
Error(FATAL, LINE, (char *)buf, NULL);
}
while (nx < (Nnr - 1)) {
Numb[nx] = Numb[nx + 1];
nx++;
}
Nnr--;
}
/*
* Findnum(n, v, e) - find or optionally enter number value
*/
Findnum(n, v, e)
unsigned char *n; /* register name */
int v; /* value */
int e; /* 0 = find, don't enter
* 1 = enter, don't find */
{
int cmp, low, hi, mid; /* binary search controls */
unsigned char c[3]; /* name buffer */
c[0] = n[0];
c[1] = (n[1] == ' ' || n[1] == '\t') ? '\0' : n[1];
c[2] = '\0';
low = mid = 0;
hi = Nnr - 1;
while (low <= hi) {
mid = (low + hi) / 2;
if ((cmp = strncmp((char *)c, (char *)Numb[mid].nm, 2)) < 0)
hi = mid - 1;
else if (cmp > 0)
low = mid + 1;
else {
if (e)
Numb[mid].val = v;
return(mid);
}
}
if ( ! e)
return(-1);
if (Nnr >= MAXNR)
Error(FATAL, LINE, " out of number registers at ", (char *)c);
if (Nnr) {
if (cmp > 0)
mid++;
for (hi = Nnr - 1; hi >= mid; hi--)
Numb[hi+1] = Numb[hi];
}
Nnr++;
Numb[mid].nm[0] = c[0];
Numb[mid].nm[1] = c[1];
Numb[mid].val = v;
return(mid);
}
/*
* Findparms(n) - find parameter registers
*/
Findparms(n)
unsigned char *n; /* parameter name */
{
unsigned char c[3]; /* character buffer */
int i; /* temporary index */
c[0] = n[0];
c[1] = (n[1] == ' ' || n[1] == '\t') ? '\0' : n[1];
c[2] = '\0';
for (i = 0; Parms[i].nm[0]; i++) {
if (c[0] == Parms[i].nm[0] && c[1] == Parms[i].nm[1])
return(i);
}
return(-1);
}
/*
* Findscale(n, v, e) - find and optionally enter scaling factor value
*/
Findscale(n, v, e)
int n; /* scaling factor name */
double v; /* value */
int e; /* 0 = find, don't enter
* 1 = enter, don't find */
{
int i;
double *pval;
for (i = 0; Scale[i].nm; i++) {
if ((unsigned char )n == Scale[i].nm)
break;
}
if (Scale[i].nm) {
if (e) {
pval = &Scale[i].val;
*pval = v;
}
return(i);
}
return(-1);
}