Skip to content

Commit

Permalink
units.js
Browse files Browse the repository at this point in the history 
+ More code cleanup / refactoring
  • Loading branch information
bwrobinett committed Aug 2, 2011
1 parent 8c92194 commit 598b417
Showing 1 changed file with 87 additions and 112 deletions.
199 changes: 87 additions & 112 deletions UnitConvertion/units.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -35,23 +35,23 @@ var GLOBAL = this;
var ONE = {dim:{}, factor:1}, NEGATIVE_ONE = {dim:{}, factor:-1}, ZERO = {dim:{}, factor:0};

function toUnitObj(x) {
var resultUnit, xNum = +x;
var result, xNum = +x;
if (x.factor != null) {
resultUnit = x;
result = x;
} else if (isNaN(xNum)) {
resultUnit = UNIT[x];
result = UNIT[x];
} else {
resultUnit = {dim:{}, factor:xNum};
result = {dim:{}, factor:xNum};
}
return resultUnit;
return result;
}

function unitPlus(u1, u2) {
var resultUnit = {dim:{}}, dimAreCompatible = true;
var result = {dim:{}}, dimAreCompatible = true;
if (u1 == null) {
resultUnit = toUnitObj(0);
result = toUnitObj(0);
} else if (u2 == null) {
resultUnit = toUnitObj(u1);
result = toUnitObj(u1);
} else {
u1 = toUnitObj(u1);
u2 = toUnitObj(u2);
Expand All @@ -61,131 +61,121 @@ var GLOBAL = this;
}

if (dimAreCompatible) {
// copy dim to resultUnit
// copy dim to result
for (var key in u1.dim) {
resultUnit.dim[key] = u1.dim[key];
result.dim[key] = u1.dim[key];
}
// add factors
resultUnit.factor = u1.factor + u2.factor;
result.factor = u1.factor + u2.factor;
} else {
resultUnit.incompatibleDim = true;
result.incompatibleDim = true;
}
}
//console.debug("resultUnit", resultUnit);
return resultUnit;
//console.debug("result", result);
return result;
}

function unitMinus(u1, u2) {
var resultUnit;
var result;
if (u1 == null) {
resultUnit = toUnitObj(0);
result = toUnitObj(0);
} else if (u2 == null) {
resultUnit = toUnitObj(u1);
result = toUnitObj(u1);
} else {
resultUnit = unitPlus(u1, unitTimes(u2, -1));
result = unitPlus(u1, unitTimes(u2, -1));
}
return resultUnit;
return result;
}

function unitTimes(u1, u2) {
//console.debug("unitTImes u1, u2", u1, u2);
var resultUnit = {dim:{}};
function unitTimes(u1, u2) {
var result = {dim:{}};
if (u1 == null) {
resultUnit = toUnitObj(1);
result = toUnitObj(1);
} else if (u2 == null) {
resultUnit = toUnitObj(u1);
result = toUnitObj(u1);
} else {
u1 = toUnitObj(u1);
u2 = toUnitObj(u2);
for (var key in DIM) {
// add matching dimension powers
//console.debug("dfs", u1, u2);
resultUnit.dim[key] = (u1.dim[key] || 0) + (u2.dim[key] || 0);
//console.debug("resultUnit.dim[key]", resultUnit.dim[key]);
// add matching dimension powers
result.dim[key] = (u1.dim[key] || 0) + (u2.dim[key] || 0);

// remove any 0 dimension
if (!resultUnit.dim[key]) {
delete resultUnit.dim[key];
if (!result.dim[key]) {
delete result.dim[key];
}

// multiply matching dimension factors
resultUnit.factor = u1.factor*u2.factor;
result.factor = u1.factor*u2.factor;
}
}
//console.debug("resultUnit", resultUnit);
return resultUnit;
}
return result;
}

function unitDiv(u1, u2) {
//console.debug("u1, u2", u1, u2);
var resultUnit;
function unitDiv(u1, u2) {
var result;
if (u1 == null) {
resultUnit = toUnitObj(1);
result = toUnitObj(1);
} else if (u2 == null) {
resultUnit = toUnitObj(u1);
result = toUnitObj(u1);
} else {
resultUnit = unitTimes(u1, unitPow(u2, -1));
result = unitTimes(u1, unitPow(u2, -1));
}
return resultUnit;
return result;
}

function unitPow(u, p) {
var resultUnit;
var result;

if (u == null) {
resultUnit = toUnitObj(1);
result = toUnitObj(1);
} else if (p == null) {
resultUnit = toUnitObj(u);
result = toUnitObj(u);
} else {
// p should be dimensionless
p = toNum(p);
if (p != null) {
resultUnit = {dim:{}};
result = {dim:{}};
u = toUnitObj(u);
for (var key in u.dim) {
resultUnit.dim[key] = u.dim[key]*p
result.dim[key] = u.dim[key]*p
}
resultUnit.factor = Math.pow(u.factor, p);
result.factor = Math.pow(u.factor, p);
}
}
//console.debug("resultUnit unitDiv ", u, p, resultUnit);
return resultUnit;
}
return result;
}

function toNum(x) {
// x can't be converted to number unless it's dimensionless
var resultNum, xNum = +x;
var result, xNum = +x;
if (!isNaN(xNum)) {
resultNum = xNum;
} else if (x.dim != null) {
for (var key in x.dim) {
break;
}
if (!key) {
resultNum = x.factor;
}
result = xNum;
} else if (x.dim) {
for (var key in x.dim) {break;}
if (!key) {result = x.factor;}
}
return resultNum;
return result;
}

function applyOpToArr(op, arr) {
if (op.inReverse) {
arr.reverse();
}
var resultUnit, dimAreCompatible = true;
resultUnit = unitTimes(1, arr[0]);
for (var i = 1, len = arr.length; i < len && !resultUnit.incompatibleDim; i++) {
resultUnit = op(resultUnit, arr[i]);
}
//console.debug("resultUnit", resultUnit);
return resultUnit;
var result, dimAreCompatible = true;
result = unitTimes(1, arr[0]);
for (var i = 1, len = arr.length; i < len && !result.incompatibleDim; i++) {
result = op.inReverse ? op(arr[i], result) : op(result, arr[i]);
}
return result;
}

function groupString(str) {
str = str.replace(/[(]/g, "group('");
str = str.replace(/[)]/g, "')");
return str;
}

function parseString(str) {
//console.debug("// str\n", str);
// normalize space
Expand Down Expand Up @@ -224,62 +214,48 @@ var GLOBAL = this;
str = str.replace(/^\s+|\s+$/g, "");
console.debug("// trim\n", str);
// create an array from the string
var arrPlus = str.split("+"), arrMinus, arrTimes, arrDiv, arrUnitTimes, arrUnitDiv, arrPow;
var iPlus = arrPlus.length, iMinus, iTimes, iDiv, iUnitTimes, iUnitDiv, iPow;
while (iPlus--) {
arrPlus[iPlus] = arrMinus = arrPlus[iPlus].split(/~/);
iMinus = arrMinus.length;
while (iMinus--) {
arrMinus[iMinus] = arrTimes = arrMinus[iMinus].split("*");
iTimes = arrTimes.length;
while (iTimes--) {
arrTimes[iTimes] = arrDiv = arrTimes[iTimes].split("/");
iDiv = arrDiv.length;
while (iDiv--) {
arrDiv[iDiv] = arrUnitTimes = arrDiv[iDiv].split("|");
iUnitTimes = arrUnitTimes.length;
while (iUnitTimes--) {
arrUnitTimes[iUnitTimes] = arrUnitDiv = arrUnitTimes[iUnitTimes].split("`");
iUnitDiv = arrUnitDiv.length;
while (iUnitDiv--) {
arrUnitDiv[iUnitDiv] = arrPow = arrUnitDiv[iUnitDiv].split("^");
}
}
}
}
}
}

//console.debug(arrPlus);
return arrPlus;
}
return splitToNestedArr([str], generateOrderedOpStrArray())[0];
}

unitPow.inReverse = true;
function generateOrderedOpArray() {
return [unitPlus, unitMinus, unitTimes, unitDiv, unitTimes, unitDiv, unitPow];
// We create an array with a bunch of levels so we can easily keep track of the order of operations.
// Plus is at the lowest level; Power is at the highest.
// ~ is used for minus so we can treat it differently than the negative sign
// We have couple extra operators so we can bind all units following a number together.
// ...This lets interpret something like "10 m/s / 10 ft/s" as "(10 m/s) / (10 ft/s) " instead of "(10 / 10) m*ft/s^2"
function generateOrderedOpStrArray() {return ["+", "~", "*", "/", "|", "`", "^"];}
function splitToNestedArr(arr, orderedOpStrArr) {
orderedOpStrArr || (orderedOpStrArr = generateOrderedOpStrArray());
var opStr = orderedOpStrArr.shift();
if (opStr) {
var i = arr.length;
while (i--) {
arr[i] = arr[i].split(opStr);
splitToNestedArr(arr[i], copyArr(orderedOpStrArr));
}
}
return arr;
}

unitPow.inReverse = true;
function generateorderedOpArr() {return [unitPlus, unitMinus, unitTimes, unitDiv, unitTimes, unitDiv, unitPow];}
function copyArr(arr) {
var i = arr.length, copy = [];
while (i--) {
copy[i] = arr[i];
}
while (i--) {copy[i] = arr[i];}
return copy;
}

function calcUnitResult(str) {
return calcOpsFromFullArr(parseString(str), generateOrderedOpArray());
}

function calcOpsFromFullArr(arr, orderedOpArray) {
var nextFunc = orderedOpArray.length > 1 ? calcOpsFromFullArr : toUnitObj,
op = orderedOpArray.shift();
function calcUnitResult(str) {return calcOpsFromFullArr(parseString(str), generateorderedOpArr());}
function calcOpsFromFullArr(arr, orderedOpArr) {
var nextFunc = orderedOpArr.length > 1 ? calcOpsFromFullArr : toUnitObj,
op = orderedOpArr.shift();

for (var i = 0, len = arr.length; i < len; i++) {
arr[i] = nextFunc(arr[i], copyArr(orderedOpArray));
arr[i] = nextFunc(arr[i], copyArr(orderedOpArr));
}

return applyOpToArr(op , arr);
}
}

// export to GLOBAL
GLOBAL["unitPlus"] = unitPlus;
Expand All @@ -292,8 +268,7 @@ var GLOBAL = this;
GLOBAL["calcUnitResult"] = calcUnitResult;
GLOBAL["toNum"] = toNum;
GLOBAL["toUnitObj"] = toUnitObj;


GLOBAL["splitToNestedArr"] = splitToNestedArr;
}());
//unitTimes({dim:{L:1, T:-3}, factor:3}, {dim:{L:2, T:3}, factor:5});
//unitPlus({dim:{L:1, T:-3}, factor:13}, {dim:{L:1, T:-3}, factor:5});
Expand Down

0 comments on commit 598b417

Please sign in to comment.