calc.c

#include "jio.c"
#include "graphics.c"
#include <math.h>
#include <assert.h>

// -- keys position mapping from MOUSE click
// Limited. Stores only char of key and
// (x,y) of starting position. Returns index
// into keyc[], keyy[],keyx[].
//
// Assumption: keys are added in x-> and then y-> order.
//
// Matching starts from right bottom, first key (kx,ky)
// that is less than click position (x,y) is returned.

#define NKEYS 64

char keyc[NKEYS]= {0};
int keyy[NKEYS]= {0};
int keyx[NKEYS]= {0};
int nkeys= 0; // ahum, not 0?

// Search key positions to find where clicked
// Returns: 0 if not found, otherwise index
int findnkey(int x, int y) {
  int i;
  for(i=nkeys; i; i--) { 
    //printf("  %d: '%c' x%d y%d for %d %d\n", i, keyc[i], keyx[i], keyy[i], x, y);
    if (keyx[i] > x) continue;
    if (keyy[i] > y) continue;
    //printf("---passed: %d\n", i);
    return i;
  }
  return 0;
}

// assumes *s is start of key string
char* dkey(char* s) {
  char k= *s;

  // remember coordinates
  nkeys++;
  assert(nkeys<NKEYS);
  keyc[nkeys]= k;
  keyx[nkeys]= gx;
  keyy[nkeys]= gy;

  // -- draw
  
  // padding between keys
  if (!*s) return s;
  gx+= 3;

  int x= gx, y= gy;

  // save pos of char for inverse
  while(*s && !isspace(*s)) {
    gputc(*s);
    s++;
  }

  // make it look like "a button"
  ginvert(x-2, y-1, gx-x+2, 8+1);

  // padding between keys
  gx+= 4;

  return s;
}
  
// visually press and depress key
void showkeypress(int i) {
  int x= keyx[i]+1;
  int y= keyy[i]-1;
  int w= keyx[i+1]-keyx[i]-3;
  
  //ginvert(x+5, keyy[i]-1, 8+5, 8+2);
  ginvert(x, y, w, 8+2);
  gupdate();

  // read MOUSE_UP
  ///if (k & MOUSE) key(); 

  usleep(100*1000);
  //ginvert(x, keyy[i]-1, 8+5, 8+2);
  ginvert(x, y, w, 8+2);
  gupdate();
}

void row(char* keys) {
  while(*keys) {
    while(*keys && isspace(*keys)) keys++;
    keys= dkey(keys);
  }
  dkey("");
  gputc('\n'); gy+= 3;
}

void calc() {
  int firsttime= 1;
  gcanvas();

  // clear actual screen
  wclear();
  
  double stack[16]= {0}, *s= stack+1;
  int k;
  do {
    gx= 0; gy= 0;
    int wc= 6*3;
    int w= wc*8;

    // draw result panel
    char r[64]= {0};
    sprintf(r, "%*.*g", wc, wc-5, *s);
    
    // right adjust
    gx= w-8*strlen(r);
    gputs(r);
    gputc('\n'); gy+= 4;

    if (firsttime) {
      // draw keys
      row("7 8 9 * sin e ^");
      row("4 5 6 / cos lne");
      row("1 2 3 - tan dln");
      row(". 0 E + inv < >");
      firsttime= 0;
    }

    gupdate();

    // action by key
    k= key();
    int i;
    if ((k & MOUSE)==MOUSE_DOWN) {
      int r= mouserow(k), c= mousecol(k);
      i= findnkey(c*pixels_per_col, r*pixels_per_row);
      if (i) k=keyc[i];
    } else {
      for(i=nkeys; i; i--)
	if (keyc[i]==k) break;
    }

    // show key pressed down for a while
    if (i) showkeypress(i);

    // take two -- see below
    if (s-stack<2 && strchr("+-*/^", k)) continue;

    // action
    switch(k) {
    case '0' ... '9': *s= 10* *s + k-'0'; break;
    case '.': break; // TODO: enter string?
    case 'E': break; // TODO: 1E5
    case 8: case 127: break; // TODO: backspace

    case ' ': case '\n': case '\r': // or <enter> or space
    case '<': s++; *s= 0; break; // push/enter
    case '>': if (s>stack) s--; break; // pop
      // case ' TODO: dup??? 

      // take two - see above
    case '+': s--; *s= *s+s[1]; break;
    case '-': s--; *s= *s-s[1]; break;
    case '*': s--; *s= *s*s[1]; break;
    case '/': s--; *s= *s/s[1]; break;
    case '^': s--; *s= pow(*s, s[1]); break;

    case 'S': *s= sqrt(*s); break;
    case 'l': *s= log(*s); break;
    case 'e': *s= exp(*s); break;
    case 'd': *s= log10(*s); break;
    case 'b': *s= log2(*s); break;

    case 'i': *s= 1/ *s; break;

    case 's': *s= sin(*s); break;
    case 'c': *s= cos(*s); break;
    case 't': *s= tan(*s); break;
    }

    //printf(" %s %d %x | ", keystring(k), k, k);
  } while(k!=CTRL+'C');
}

int main(void) {
  jio();
  cursoroff();
  
  calc();

  cursoron();
  exit(0);
}