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-rw-r--r--mod/hexit.php181
1 files changed, 181 insertions, 0 deletions
diff --git a/mod/hexit.php b/mod/hexit.php
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+<?php
+
+
+
+
+
+
+
+
+
+
+
+
+
+function hexit_content(&$a) {
+
+
+$o .= <<< EOT
+
+<script type="text/javascript">
+/**
+ * A function for converting hex <-> dec w/o loss of precision.
+ *
+ * The problem is that parseInt("0x12345...") isn't precise enough to convert
+ * 64-bit integers correctly.
+ *
+ * Internally, this uses arrays to encode decimal digits starting with the least
+ * significant:
+ * 8 = [8]
+ * 16 = [6, 1]
+ * 1024 = [4, 2, 0, 1]
+ */
+
+// Adds two arrays for the given base (10 or 16), returning the result.
+// This turns out to be the only "primitive" operation we need.
+function add(x, y, base) {
+ var z = [];
+ var n = Math.max(x.length, y.length);
+ var carry = 0;
+ var i = 0;
+ while (i < n || carry) {
+ var xi = i < x.length ? x[i] : 0;
+ var yi = i < y.length ? y[i] : 0;
+ var zi = carry + xi + yi;
+ z.push(zi % base);
+ carry = Math.floor(zi / base);
+ i++;
+ }
+ return z;
+}
+
+// Returns a*x, where x is an array of decimal digits and a is an ordinary
+// JavaScript number. base is the number base of the array x.
+function multiplyByNumber(num, x, base) {
+ if (num < 0) return null;
+ if (num == 0) return [];
+
+ var result = [];
+ var power = x;
+ while (true) {
+ if (num & 1) {
+ result = add(result, power, base);
+ }
+ num = num >> 1;
+ if (num === 0) break;
+ power = add(power, power, base);
+ }
+
+ return result;
+}
+
+function parseToDigitsArray(str, base) {
+ var digits = str.split('');
+ var ary = [];
+ for (var i = digits.length - 1; i >= 0; i--) {
+ var n = parseInt(digits[i], base);
+ if (isNaN(n)) return null;
+ ary.push(n);
+ }
+ return ary;
+}
+
+function convertBase(str, fromBase, toBase) {
+ var digits = parseToDigitsArray(str, fromBase);
+ if (digits === null) return null;
+
+ var outArray = [];
+ var power = [1];
+ for (var i = 0; i < digits.length; i++) {
+ // invariant: at this point, fromBase^i = power
+ if (digits[i]) {
+ outArray = add(outArray, multiplyByNumber(digits[i], power, toBase), toBase);
+ }
+ power = multiplyByNumber(fromBase, power, toBase);
+ }
+
+ var out = '';
+ for (var i = outArray.length - 1; i >= 0; i--) {
+ out += outArray[i].toString(toBase);
+ }
+ return out;
+}
+
+function decToHex(decStr) {
+ var hex = convertBase(decStr, 10, 16);
+ return hex ? '0x' + hex : null;
+}
+
+function hexToDec(hexStr) {
+ if (hexStr.substring(0, 2) === '0x') hexStr = hexStr.substring(2);
+ hexStr = hexStr.toLowerCase();
+ return convertBase(hexStr, 16, 10);
+}
+
+
+
+ function str_or_null(x) {
+ return x === null ? 'null' : x;
+ }
+
+ // "1.234e+5" -> "12340"
+ function expandExponential(x) {
+ var pos = x.indexOf("e");
+ if (pos === -1) pos = x.indexOf("E");
+ if (pos === -1) return x;
+
+ var base = x.substring(0, pos);
+ var pow = parseInt(x.substring(pos + 1), 10);
+ if (pow < 0) return x; // not supported.
+
+ var dotPos = base.indexOf('.');
+ if (dotPos === -1) dotPos = base.length;
+
+ var ret = base.replace('.', '');
+ while (ret.length < dotPos + pow) ret += '0';
+ return ret;
+ }
+
+ function boldDifference(correct, actual) {
+ for (var i = 0, j = 0; i < correct.length && j < actual.length; i++, j++) {
+ if (correct[i] !== actual[j]) {
+ break;
+ }
+ }
+ if (j < actual.length) {
+ return actual.substring(0, j) + '<b>' + actual.substring(j) + '</b>';
+ } else {
+ return actual;
+ }
+ }
+
+ function convert() {
+ var input = document.getElementById("in").value;
+ if (input) {
+ var aHex = str_or_null(decToHex(input));
+ var aDec = str_or_null(hexToDec(input));
+ var bHex = '0x' + (parseInt(input, 10)).toString(16);
+ var bDec = "" + expandExponential("" +parseInt(input, 16));
+
+ var html = '<p></p><p>To Decimal(' + input + ') = ' + aDec + '</p>';
+ html += '<p>To Hex(' + input + ') = ' + aHex + '</p>';
+ document.getElementById('result').innerHTML = html;
+ }
+ }
+ convert();
+
+
+</script>
+
+ <h2>Hexit</h2>
+
+ <p>Type in a hex or decimal string:</p>
+ <input type="text" size=40 id="in" onkeyup="convert()" value="" />
+ <p id="result"></p>
+
+
+
+EOT;
+
+return $o;
+}