binary search javascript

binarysearch.js

/**
* binarySearch
* efficiently searching a sorted list
* list - array of values sorted in ascending order
* value - the target value to search for
* @author Bijan Vakili
*/
function binarySearch(list, value) {
    var found = -1,
        delta = Math.floor(list.length / 2),
        index = delta,
        curr = list[index],
        iteration = 0,
        maxIteration = 2 + Math.round(Math.log2(list.length));

    while (curr && (found == -1) && iteration < maxIteration) {
        iteration++;
        delta = Math.round(Math.max(1, delta / 2));
        if (curr == value) {
            found = index;
        } else if (value < curr) {
            index = index - delta;
            index = Math.max(0, index);
        } else if (value > curr) {
            index = index + delta;
            index = Math.min(list.length -1, index);
        }
        curr = list[index];
    }
    return found;
}



/********* Begin Test Code **********/
var testList = [];
var errors = 0;

function search(list, value) {
    for (i = 0; i < list.length; i++) {
        if (value == list[i]) {
            return i;
        }
    }
    return -1;
}
function logIt(x) {
    $("#result").append(x + "<br />");
    // console.log(x);
}
for (j = 0; j < 1000; j++ ) {
    if (errors) {
        break;
    }
    logIt("j " + j);
    testList = [];
    c = 0;

    for (i = 0; i < j; i++) {
        c += Math.max(1, Math.floor(Math.random()*10));
        testList.push(c);
    }

    for (b = 0; b < testList.length + 10; b++) {
        if (b > testList.length - 1) {
            searchTarget = Math.floor(Math.random() * 100 + 10);
        } else {
            searchTarget = testList[b];
        }
        
        // logIt("calling binary search");
        result = binarySearch(testList, searchTarget);    
        // logIt("calling search");
        actual = search(testList, searchTarget);

        if (result != actual) {
            logIt("error");
            debug = "testList = [";
            for (k = 0; k < testList.length; k++) {
                debug += testList[k] + ", ";
            }

            debug += "]";
            logIt(debug);
            logIt("target = " + searchTarget + ";")
            errors = 1;
            break;
        }

    }
}

logIt("done");