minix/commands/cawf/expr.c

   1 /*
   2  *      expr.c - expression support functions for cawf(1)
   3  */
   4
   5 /*
   6  *      Copyright (c) 1991 Purdue University Research Foundation,
   7  *      West Lafayette, Indiana 47907.  All rights reserved.
   8  *
   9  *      Written by Victor A. Abell <abe@mace.cc.purdue.edu>,  Purdue
  10  *      University Computing Center.  Not derived from licensed software;
  11  *      derived from awf(1) by Henry Spencer of the University of Toronto.
  12  *
  13  *      Permission is granted to anyone to use this software for any
  14  *      purpose on any computer system, and to alter it and redistribute
  15  *      it freely, subject to the following restrictions:
  16  *
  17  *      1. The author is not responsible for any consequences of use of
  18  *         this software, even if they arise from flaws in it.
  19  *
  20  *      2. The origin of this software must not be misrepresented, either
  21  *         by explicit claim or by omission.  Credits must appear in the
  22  *         documentation.
  23  *
  24  *      3. Altered versions must be plainly marked as such, and must not
  25  *         be misrepresented as being the original software.  Credits must
  26  *         appear in the documentation.
  27  *
  28  *      4. This notice may not be removed or altered.
  29  */
  30
  31 #include "cawf.h"
  32
  33
  34 /*
  35  * Asmcode(s, c) - assemble number/name code following backslash-character
  36  *                 definition  - e. .g, "\\nPO"
  37  */
  38
  39 unsigned char *Asmcode(unsigned char **s, unsigned char *c) {
  40 /* pointer to character after '\\' s
  41  * code destination (c[3]) c
  42  */
  43         unsigned char *s1;
  44
  45         s1 = *s + 1;
  46         c[0] = c[1] = c[2] = '\0';
  47         if ((c[0] = *s1) == '(') {
  48                 s1++;
  49                 if ((c[0] = *s1) != '\0') {
  50                         s1++;
  51                         c[1] = *s1;
  52                 }
  53         }
  54         return(s1);
  55 }
  56
  57
  58 /*
  59  * Delnum(nx) - delete number
  60  */
  61
  62 void Delnum(int nx) {
  63 /* number index nx */
  64
  65         unsigned char buf[MAXLINE];     /* message buffer */
  66
  67         if (nx >= Nnr) {
  68                 (void) sprintf((char *)buf, " bad Delnum(%d) index", nx);
  69                 Error(FATAL, LINE, (char *)buf, NULL);
  70         }
  71         while (nx < (Nnr - 1)) {
  72                 Numb[nx] = Numb[nx + 1];
  73                 nx++;
  74         }
  75         Nnr--;
  76 }
  77
  78
  79 /*
  80  * Findnum(n, v, e) - find or optionally enter number value
  81  */
  82
  83 int Findnum(unsigned char *n, int v, int e) {
  84 /* register name n
  85  * value v
  86  * e = 0 = find, don't enter
  87  * e = 1 = enter, don't find
  88  */
  89         int cmp, low, hi, mid;          /* binary search controls */
  90         unsigned char c[3];             /* name buffer */
  91
  92         c[0] = n[0];
  93         c[1] = (n[1] == ' ' || n[1] == '\t') ? '\0' : n[1];
  94         c[2] = '\0';
  95         low = mid = 0;
  96         hi = Nnr - 1;
  97         while (low <= hi) {
  98                 mid = (low + hi) / 2;
  99                 if ((cmp = strncmp((char *)c, (char *)Numb[mid].nm, 2)) < 0)
 100                         hi = mid - 1;
 101                 else if (cmp > 0)
 102                         low = mid + 1;
 103                 else {
 104                         if (e)
 105                                 Numb[mid].val = v;
 106                         return(mid);
 107                 }
 108         }
 109         if ( ! e)
 110                 return(-1);
 111         if (Nnr >= MAXNR)
 112                 Error(FATAL, LINE, " out of number registers at ", (char *)c);
 113         if (Nnr) {
 114                 if (cmp > 0)
 115                         mid++;
 116                 for (hi = Nnr - 1; hi >= mid; hi--)
 117                         Numb[hi+1] = Numb[hi];
 118         }
 119         Nnr++;
 120         Numb[mid].nm[0] = c[0];
 121         Numb[mid].nm[1] = c[1];
 122         Numb[mid].val = v;
 123         return(mid);
 124 }
 125
 126
 127 /*
 128  * Findparms(n) - find parameter registers
 129  */
 130
 131 int Findparms(unsigned char *n) {
 132 /* parameter name n */
 133         unsigned char c[3];             /* character buffer */
 134         int i;                          /* temporary index */
 135
 136         c[0] = n[0];
 137         c[1] = (n[1] == ' ' || n[1] == '\t') ? '\0' : n[1];
 138         c[2] = '\0';
 139         for (i = 0; Parms[i].nm[0]; i++) {
 140                 if (c[0] == Parms[i].nm[0] && c[1] == Parms[i].nm[1])
 141                         return(i);
 142         }
 143         return(-1);
 144 }
 145
 146
 147 /*
 148  * Findscale(n, v, e) - find and optionally enter scaling factor value
 149  */
 150
 151 int Findscale(int n, double v, int e) {
 152 /* scaling factor name n
 153  * value v
 154  * e = 0 = find, don't enter
 155  * e = 1 = enter, don't find
 156  */
 157         int i;
 158         double *pval;
 159
 160         for (i = 0; Scale[i].nm; i++) {
 161                 if ((unsigned char )n == Scale[i].nm)
 162                         break;
 163         }
 164         if (Scale[i].nm) {
 165                 if (e) {
 166                         pval = &Scale[i].val;
 167                         *pval = v;
 168                 }
 169                 return(i);
 170         }
 171         return(-1);
 172 }