Optimized function.js / 2x Faster PDFFunction_constructPostScriptFromIR

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p01 2014-05-14 16:06:28 +02:00
parent 0d8e3cc8ca
commit 95fda4fcdc

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@ -385,66 +385,57 @@ var PDFFunction = (function PDFFunctionClosure() {
var domain = IR[1]; var domain = IR[1];
var range = IR[2]; var range = IR[2];
var code = IR[3]; var code = IR[3];
var numOutputs = range.length / 2; var numOutputs = range.length >> 1;
var numInputs = domain.length >> 1;
var evaluator = new PostScriptEvaluator(code); var evaluator = new PostScriptEvaluator(code);
// Cache the values for a big speed up, the cache size is limited though // Cache the values for a big speed up, the cache size is limited though
// since the number of possible values can be huge from a PS function. // since the number of possible values can be huge from a PS function.
var cache = new FunctionCache(); var cache = {};
// The MAX_CACHE_SIZE is set to ~4x the maximum number of distinct values
// seen in our tests.
var MAX_CACHE_SIZE = 2048 * 4;
var cache_available = MAX_CACHE_SIZE;
return function constructPostScriptFromIRResult(args) { return function constructPostScriptFromIRResult(args) {
var initialStack = []; var i, value;
for (var i = 0, ii = (domain.length / 2); i < ii; ++i) { var key = '';
initialStack.push(args[i]); var input = new Array(numInputs);
for (i = 0; i < numInputs; i++) {
value = args[i];
input[i] = value;
key += value + '_';
} }
var key = initialStack.join('_'); var cachedValue = cache[key];
if (cache.has(key)) { if (cachedValue !== undefined) {
return cache.get(key); return cachedValue;
} }
var stack = evaluator.execute(initialStack); var output = new Array(numOutputs);
var transformed = []; var stack = evaluator.execute(input);
for (i = numOutputs - 1; i >= 0; --i) { var stackIndex = stack.length - numOutputs;
var out = stack.pop(); for (i = 0; i < numOutputs; i++) {
var rangeIndex = 2 * i; value = stack[stackIndex + i];
if (out < range[rangeIndex]) { var bound = range[i * 2];
out = range[rangeIndex]; if (value < bound) {
} else if (out > range[rangeIndex + 1]) { value = bound;
out = range[rangeIndex + 1]; } else {
bound = range[i * 2 +1];
if (value > bound) {
value = bound;
}
} }
transformed[i] = out; output[i] = value;
} }
cache.set(key, transformed); if (cache_available > 0) {
return transformed; cache_available--;
cache[key] = output;
}
return output;
}; };
} }
}; };
})(); })();
var FunctionCache = (function FunctionCacheClosure() {
// Of 10 PDF's with type4 functions the maxium number of distinct values seen
// was 256. This still may need some tweaking in the future though.
var MAX_CACHE_SIZE = 1024;
function FunctionCache() {
this.cache = {};
this.total = 0;
}
FunctionCache.prototype = {
has: function FunctionCache_has(key) {
return key in this.cache;
},
get: function FunctionCache_get(key) {
return this.cache[key];
},
set: function FunctionCache_set(key, value) {
if (this.total < MAX_CACHE_SIZE) {
this.cache[key] = value;
this.total++;
}
}
};
return FunctionCache;
})();
var PostScriptStack = (function PostScriptStackClosure() { var PostScriptStack = (function PostScriptStackClosure() {
var MAX_STACK_SIZE = 100; var MAX_STACK_SIZE = 100;
function PostScriptStack(initialStack) { function PostScriptStack(initialStack) {