/*
 * testFlt32.c - simple driver to test methods of flt32.h.
 *
 * "Copyright (c) 2012 by Fritz Sieker."
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without written
 * agreement is hereby granted, provided that the above copyright notice
 * and the following two paragraphs appear in all copies of this software.
 *
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
 * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE AUTHOR
 * HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"
 * BASIS, AND THE AUTHOR NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,
 * UPDATES, ENHANCEMENTS, OR MODIFICATIONS."
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "field.h"
#include "flt32.h"

/** @mainpage cs270 Programming Assignment PAx - Floating Point math
 *  \htmlinclude "FLOAT.html"
 */

/** @file: testFlt32.c
 *  @brief Driver to test functions of flt32.c (do not modify)
 *
 * @details This is a driver program to test the functions
 * defined in flt32.h and implemented in flt32.c. The program takes one
 * or more command line parameters and calls one of the methods, then
 * prints the results. To see how to use the program, execute
 * <code>testFlt32</code> in a terminal window. This will print a usage
 * statement defining how to run the program. The first parameter of the
 * program is always a key defining which function to run. The
 * options are:
 * <ul>
 * <li><b>abs</b> absolute value of a floating point number </li>
 * <li><b>all</b> extract sign, exponent, value of a floating point number</li>
 * <li><b>add</b> add two floating point numbers </li>
 * <li><b>bin</b> print binary representation of floating point number </li>
 * <li><b>exp</b> extract exponent of a floating point number </li>
 * <li><b>lm1</b> find the left most 1 bit in number</li>
 * <li><b>neg</b> negate a floating point number </li>
 * <li><b>sign</b> extract sign of floating point number</li>
 * <li><b>sub</b> subract two floating point numbers</li>
 * <li><b>val</b> extract value of floating point number </li>
 * </ul>
 * <p>
 * A sample execution might be: <code>testFlt32 abs -2.5</code>
 * <p>
 * which prints <pre><code>2.5</code></pre>
 * <p>
 * To use the <code>bin</code> option do <code>testFlt32 bin 1.5</code>
 * <p>
 * which prints <pre><code>dec: 1069547520  hex: 0x3FC00000  bin: 0011-1111-1100-0000-0000-0000-0000-0000</code></pre>
 * <p>
 * This is the decimal, hex and binary representation of the floating point
 * number 1.5. You will find the <code>bin</code> option very useful as you
 * can determine what the correct representation of the answer should be. To
 * test you program, choose values where the correct answer is easy to compute
 * in your head. Then use the <code>bin</code> option to determine what the
 * answer looks like. Finally, run your program and if your answer differs
 * from the answer you computed, use the <code>bin</code> option to see the
 * pattern of your answer. Then you need to read your program, perhaps add
 * debugging output, and determine what your program is actually doing.
 * <p>
 * @author Fritz Sieker
 */

/** Print the binary representation of a value starting at the specified
 * bit position. A separator is printed every 4 bits for easy reading.
 * @param value the value to be printed
 * @param msb the bit position to begin printing (31 to 0)
 */
void printBinaryMSB (int value, int msb) {
  while (msb >= 0) {
    putchar(((value & (1 << msb)) ? '1' : '0'));
    if (msb && ((msb & 0x3) == 0))
      putchar('-');
    msb--;
  }
}

/** Print a 32 bit binary representation of a value.
 * @param value the value to be printed
 */
void printBinary (int value) {
  printBinaryMSB(value, 31);
}

/** Print a usage statement, then exit the program returning a non zero
 * value, the Linux convention indicating an error
 */
static void usage() {
  puts("usage: testFlt32 abs FPvalue");
  puts("       testFlt32 all FPvalue");
  puts("       testFlt32 add FPvalue1 FPvalue2");
  puts("       testFlt32 bin FPvalue");
  puts("       testFlt32 exp FPvalue");
  puts("       testFlt32 lm1 Intvalue");
  puts("       testFlt32 neg FPvalue");
  puts("       testFlt32 sign FPvalue");
  puts("       testFlt32 sub FPvalue1 FPvalue2");
  puts("       testFlt32 val FPvalue");
  exit(1);
}

/** print the value in decimal, hex and binary.
 * @param result the value to be printed.
 */
static void print_result (int result) {
  printf("dec: %d  hex: 0x%X  bin: ", result, result);
  printBinary(result);
}

/** Convert string to double, but never return -0.0 */
static double getDouble (const char* str) {
  double val = atof(str);
  return ((val == -0.0) ? 0.0 : val);
}

/** Entry point of the program
 * @param argc count of arguments, will always be at least 1
 * @param argv array of parameters to program argv[0] is the name of
 * the program, so additional parameters will begin at index 1.
 * @return 0 the Linux convention for success.
 */
int main (int argc, char* argv[]) {
  union {
    float f;
    int   i;
  } u;

  int x, y;

  if (argc < 3) {
    usage();
  }

  char* op = argv[1];
  u.f = (float) getDouble(argv[2]);
  x = u.i;

  if (argc > 3) {
    u.f = (float) getDouble(argv[3]);
    y = u.i;
  }

  if ((strcmp(op, "abs") == 0) && (argc == 3)){
    u.i = flt32_abs(x);
    printf("%f\n", u.f);
  }

  else if ((strcmp(op, "all") == 0) && (argc == 3)){
    int sign, exp, val;
    flt32_get_all(x, &sign, &exp, &val);
    printf("sign: %d exp: %d val: %d\n", sign, exp, val);
  }

  else if ((strcmp(op, "add") == 0) && (argc == 4)) {
    u.i = flt32_add(x, y);
    printf("%f\n", u.f);
  }

  else if ((strcmp(op, "bin") == 0) && (argc == 3))  {
    print_result(x);
    puts("\n");
  }

  else if ((strcmp(op, "exp") == 0) && (argc == 3)) {
    printf("%d\n", flt32_get_exp(x));
  }

  else if ((strcmp(op, "lm1") == 0) && (argc == 3)) {
    printf("%d\n", flt32_left_most_1(x));
  }

  else if ((strcmp(op, "neg") == 0) && (argc == 3)) {
    u.i = flt32_negate(x);
    printf("%f\n", u.f);
  }

  else if ((strcmp(op, "sign") == 0) && (argc == 3)) {
    printf("%d\n", flt32_get_sign(x));
  }

  else if ((strcmp(op, "sub") == 0) && (argc == 4)) {
    u.i = flt32_sub(x, y);
    printf("%f\n", u.f);
  }

  else if ((strcmp(op, "val") == 0) && (argc == 3)) {
    print_result(flt32_get_val(x));
    puts("\n");
  }

  else
    usage();
  
  printf("\n");
  return 0;
}