/*
 * testField.c - simple driver to test methods of field.h.
 *
 * "Copyright (c) 2013-15 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"

/** @mainpage cs270 Programming Assignment PAx - Bit Fields in C
 *  \htmlinclude "FIELD.html"
 */

/** @file: testField.c
 *  @brief Driver to test functions of field.c (do not modify)
 *
 * @details This is a driver program to test the functions
 * defined in field.h and implemented in field.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>testField</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>bin</b> print the next parameter in decimal, hex and binary</li>
 * <li><b>fits</b> check if value will fit in a field</li>
 * <li><b>get</b> get a field from a value</li>
 * <li><b>getB</b> get a bit from a value</li>
 * <li><b>set</b> set a field in a value</li>
 * <li><b>setB</b> set a bit in a value</li>
 * </ul>
 * <p>
 * A sample execution might be: <code>testField get 0xABCD 9 4 0</code>
 * <p>
 * which prints <pre><code>dec: 60  hex: 0x3C  bin: 0000-0000-0000-0000-0000-0000-0011-1100</code></pre>
 * <p>
 * All values may be entered as signed decimal numbers or as hex values
 * by beginning it with <code>0x</code>, or as binary numbers by beginning with
 * <code>0b</code>.
 * <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: testField bin  value");
  puts("       testField fits value width isSigned");
  puts("       testField get  value hi lo isSigned");
  puts("       testField getB value index");
  puts("       testField set  value hi lo newValue");
  puts("       testField setB value index newValue");
  exit(1);
}

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

/** Get int value from argument, allowing binary input like 0b0111001
 * @param arg string containing value (decimal, octal, hex, binary)
 * @return value
 */
static int getArg (char* arg) {
  char* junk;
  int   value = (int) strtol(arg, &junk, 0);

  if ((*junk == 'B') || (*junk == 'b')) { /* user entered binary value */
    value = (int) strtol(junk + 1, &junk, 2); /* skip over 'B/b' */
    if (arg[0] == '-') {
      value = -value;
    }
  }

  if (*junk) {
    printf("ERROR - bad format: %s\n", arg);
  }

  return value;
}

/** 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[]) {
  int value, hi, lo, isSigned, width;

  if (argc < 3)
    usage();
  
  char* op = argv[1];

  if ((strcmp(op, "bin") == 0) && (argc == 3)) {
    printResult(getArg(argv[2]));
  }

  else if ((strcmp(op, "fits") == 0) && (argc == 5)) {
    value    = getArg(argv[2]);
    width    = getArg(argv[3]);
    isSigned = getArg(argv[4]);
    printf("%s", (fieldFits(value, width, isSigned) ? "true" : "false"));
  }

  else if ((strcmp(op, "get") == 0) && (argc == 6)) {
    value    = getArg(argv[2]);
    hi       = getArg(argv[3]);
    lo       = getArg(argv[4]);
    isSigned = getArg(argv[5]);
    printResult(getField(value, hi, lo, isSigned));
  }

  else if ((strcmp(op, "getB") == 0) && (argc == 4)) {
    value    = getArg(argv[2]);
    hi       = getArg(argv[3]);
    printf("%d\n", getBit(value, hi));
  }

  else if ((strcmp(op, "set") == 0) && (argc == 6)) {
    value = getArg(argv[2]);
    hi    = getArg(argv[3]);
    lo    = getArg(argv[4]);
    printResult(setField(value, hi, lo, getArg(argv[5])));
  }

  else if ((strcmp(op, "setB") == 0) && (argc == 5)) {
    value = getArg(argv[2]);
    hi    = getArg(argv[3]);
    printResult(setBit(value, hi, getArg(argv[4])));
  }

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