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Heap performance #56

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60c4f5a
Merge pull request #1 from chafey/master
jkrot Aug 21, 2016
27905c9
Updated some functions for better heap performance
jkrot Sep 16, 2016
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65 changes: 34 additions & 31 deletions dist/dicomParser.js
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
/*! dicom-parser - v1.7.4 - 2016-08-18 | (c) 2014 Chris Hafey | https://github.com/chafey/dicomParser */
/*! dicom-parser - v1.7.4 - 2016-09-13 | (c) 2014 Chris Hafey | https://github.com/chafey/dicomParser */
(function (root, factory) {

// node.js
Expand Down Expand Up @@ -293,11 +293,10 @@ var dicomParser = (function (dicomParser) {
maxElementLength : 128 // maximum element length to try and convert to string format
};

var result = {

};
var result = {};

for(var tag in dataSet.elements) {

var element = dataSet.elements[tag];

// skip this element if it a private element and our options specify that we should
Expand All @@ -314,21 +313,17 @@ var dicomParser = (function (dicomParser) {
}
result[tag] = sequenceItems;
} else {
var asString;
asString = undefined;
if(element.length < options.maxElementLength) {
asString = dicomParser.explicitElementToString(dataSet, element);
}

if(asString !== undefined) {
result[tag] = asString;
} else {
result[tag] = {
dataOffset: element.dataOffset,
length : element.length
};
result[tag] = dicomParser.explicitElementToString(dataSet, element);
if (result[tag] === undefined){
result[tag] = {
dataOffset: element.dataOffset,
length : element.length
};
}
}
}

}

return result;
Expand Down Expand Up @@ -359,8 +354,6 @@ var dicomParser = (function (dicomParser) {
if(element.vr === undefined) {
throw 'dicomParser.explicitElementToString: cannot convert implicit element to string';
}
var vr = element.vr;
var tag = element.tag;

var textResult;

Expand All @@ -370,17 +363,17 @@ var dicomParser = (function (dicomParser) {
if(i !== 0) {
result += '/';
}
result += func.call(dataSet, tag, i).toString();
result += func.call(dataSet, element.tag, i).toString();
}
return result;
}

if(dicomParser.isStringVr(vr) === true)
if(dicomParser.isStringVr(element.vr) === true)
{
textResult = dataSet.string(tag);
textResult = dataSet.string(element.tag);
}
else if (vr == 'AT') {
var num = dataSet.uint32(tag);
else if (element.vr == 'AT') {
var num = dataSet.uint32(element.tag);
if(num === undefined) {
return undefined;
}
Expand All @@ -391,27 +384,27 @@ var dicomParser = (function (dicomParser) {

return 'x' + num.toString(16).toUpperCase();
}
else if (vr == 'US')
else if (element.vr == 'US')
{
textResult = multiElementToString(element.length / 2, dataSet.uint16);
}
else if(vr === 'SS')
else if(element.vr === 'SS')
{
textResult = multiElementToString(element.length / 2, dataSet.int16);
}
else if (vr == 'UL')
else if (element.vr == 'UL')
{
textResult = multiElementToString(element.length / 4, dataSet.uint32);
}
else if(vr === 'SL')
else if(element.vr === 'SL')
{
textResult = multiElementToString(element.length / 4, dataSet.int32);
}
else if(vr == 'FD')
else if(element.vr == 'FD')
{
textResult = multiElementToString(element.length / 8, dataSet.double);
}
else if(vr == 'FL')
else if(element.vr == 'FL')
{
textResult = multiElementToString(element.length / 4, dataSet.float);
}
Expand Down Expand Up @@ -1807,15 +1800,20 @@ var dicomParser = (function (dicomParser)
throw "dicomParser.parseDicomDataSetExplicit: invalid value for parameter 'maxPosition'";
}
var elements = dataSet.elements;
var element;

while(byteStream.position < maxPosition)
{
var element = dicomParser.readDicomElementExplicit(byteStream, dataSet.warnings, options.untilTag);
element = dicomParser.readDicomElementExplicit(byteStream, dataSet.warnings, options.untilTag);
elements[element.tag] = element;
if(element.tag === options.untilTag) {
element = null;
return;
}
}

delete element.tag;

if(byteStream.position > maxPosition) {
throw "dicomParser:parseDicomDataSetExplicit: buffer overrun";
}
Expand All @@ -1841,15 +1839,20 @@ var dicomParser = (function (dicomParser)
}

var elements = dataSet.elements;
var element;

while(byteStream.position < maxPosition)
{
var element = dicomParser.readDicomElementImplicit(byteStream, options.untilTag, options.vrCallback);
element = dicomParser.readDicomElementImplicit(byteStream, options.untilTag, options.vrCallback);
elements[element.tag] = element;
if(element.tag === options.untilTag) {
element = null;
return;
}
}

delete element.tag;

};

return dicomParser;
Expand Down
4 changes: 2 additions & 2 deletions dist/dicomParser.min.js
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14 changes: 12 additions & 2 deletions src/parseDicomDataSet.js
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Original file line number Diff line number Diff line change
Expand Up @@ -30,15 +30,20 @@ var dicomParser = (function (dicomParser)
throw "dicomParser.parseDicomDataSetExplicit: invalid value for parameter 'maxPosition'";
}
var elements = dataSet.elements;
var element;

while(byteStream.position < maxPosition)
{
var element = dicomParser.readDicomElementExplicit(byteStream, dataSet.warnings, options.untilTag);
element = dicomParser.readDicomElementExplicit(byteStream, dataSet.warnings, options.untilTag);
elements[element.tag] = element;
if(element.tag === options.untilTag) {
element = null;
return;
}
}

delete element.tag;

Comment on lines +40 to +46
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@Ragnar-Oock Ragnar-Oock Jul 10, 2025

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same comments as in parseDicomDataSetImplicit

if(byteStream.position > maxPosition) {
throw "dicomParser:parseDicomDataSetExplicit: buffer overrun";
}
Expand All @@ -64,15 +69,20 @@ var dicomParser = (function (dicomParser)
}

var elements = dataSet.elements;
var element;

while(byteStream.position < maxPosition)
{
var element = dicomParser.readDicomElementImplicit(byteStream, options.untilTag, options.vrCallback);
element = dicomParser.readDicomElementImplicit(byteStream, options.untilTag, options.vrCallback);
elements[element.tag] = element;
if(element.tag === options.untilTag) {
element = null;
return;
Comment on lines +79 to 80
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@Ragnar-Oock Ragnar-Oock Jul 10, 2025

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This clean-up is not needed as the whole closure is disposed of with the return statement that follows.

}
}

delete element.tag;
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@Ragnar-Oock Ragnar-Oock Jul 10, 2025

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Why delete the tag property of the last parsed element?


};

return dicomParser;
Expand Down
25 changes: 10 additions & 15 deletions src/util/dataSetToJS.js
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Original file line number Diff line number Diff line change
Expand Up @@ -21,11 +21,10 @@ var dicomParser = (function (dicomParser) {
maxElementLength : 128 // maximum element length to try and convert to string format
};

var result = {

};
var result = {};

for(var tag in dataSet.elements) {

var element = dataSet.elements[tag];

// skip this element if it a private element and our options specify that we should
Expand All @@ -42,21 +41,17 @@ var dicomParser = (function (dicomParser) {
}
result[tag] = sequenceItems;
} else {
var asString;
asString = undefined;
if(element.length < options.maxElementLength) {
asString = dicomParser.explicitElementToString(dataSet, element);
}

if(asString !== undefined) {
result[tag] = asString;
} else {
result[tag] = {
dataOffset: element.dataOffset,
length : element.length
};
result[tag] = dicomParser.explicitElementToString(dataSet, element);
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@Ragnar-Oock Ragnar-Oock Jul 10, 2025

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This will create entries with undefined values in result, which could break client code enumerating on said result, this if rewrite is an API change.

if (result[tag] === undefined){
result[tag] = {
dataOffset: element.dataOffset,
length : element.length
};
}
}
}

}

return result;
Expand Down
24 changes: 11 additions & 13 deletions src/util/elementToString.js
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Original file line number Diff line number Diff line change
Expand Up @@ -20,8 +20,6 @@ var dicomParser = (function (dicomParser) {
if(element.vr === undefined) {
throw 'dicomParser.explicitElementToString: cannot convert implicit element to string';
}
var vr = element.vr;
var tag = element.tag;

var textResult;

Expand All @@ -31,17 +29,17 @@ var dicomParser = (function (dicomParser) {
if(i !== 0) {
result += '/';
}
result += func.call(dataSet, tag, i).toString();
result += func.call(dataSet, element.tag, i).toString();
}
return result;
}

if(dicomParser.isStringVr(vr) === true)
if(dicomParser.isStringVr(element.vr) === true)
{
textResult = dataSet.string(tag);
textResult = dataSet.string(element.tag);
}
else if (vr == 'AT') {
var num = dataSet.uint32(tag);
else if (element.vr == 'AT') {
var num = dataSet.uint32(element.tag);
if(num === undefined) {
return undefined;
}
Expand All @@ -52,27 +50,27 @@ var dicomParser = (function (dicomParser) {

return 'x' + num.toString(16).toUpperCase();
}
else if (vr == 'US')
else if (element.vr == 'US')
{
textResult = multiElementToString(element.length / 2, dataSet.uint16);
}
else if(vr === 'SS')
else if(element.vr === 'SS')
{
textResult = multiElementToString(element.length / 2, dataSet.int16);
}
else if (vr == 'UL')
else if (element.vr == 'UL')
{
textResult = multiElementToString(element.length / 4, dataSet.uint32);
}
else if(vr === 'SL')
else if(element.vr === 'SL')
{
textResult = multiElementToString(element.length / 4, dataSet.int32);
}
else if(vr == 'FD')
else if(element.vr == 'FD')
{
textResult = multiElementToString(element.length / 8, dataSet.double);
}
else if(vr == 'FL')
else if(element.vr == 'FL')
{
textResult = multiElementToString(element.length / 4, dataSet.float);
}
Expand Down