var hpack = require('../hpack');
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var utils = hpack.utils;
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var assert = utils.assert;
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function Table(options) {
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this['static'] = hpack['static-table'];
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this.dynamic = [];
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this.size = 0;
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this.maxSize = 0;
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this.length = this['static'].table.length;
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this.protocolMaxSize = options.maxSize;
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this.maxSize = this.protocolMaxSize;
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this.lookupDepth = options.lookupDepth || 32;
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}
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module.exports = Table;
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Table.create = function create(options) {
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return new Table(options);
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};
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Table.prototype.lookup = function lookup(index) {
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assert(index !== 0, 'Zero indexed field');
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assert(index <= this.length, 'Indexed field OOB')
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if (index <= this['static'].table.length)
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return this['static'].table[index - 1];
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else
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return this.dynamic[this.length - index];
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};
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Table.prototype.reverseLookup = function reverseLookup(name, value) {
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var staticEntry = this['static'].map[name];
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if (staticEntry && staticEntry.values[value])
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return staticEntry.values[value];
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// Reverse search dynamic table (new items are at the end of it)
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var limit = Math.max(0, this.dynamic.length - this.lookupDepth);
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for (var i = this.dynamic.length - 1; i >= limit; i--) {
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var entry = this.dynamic[i];
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if (entry.name === name && entry.value === value)
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return this.length - i;
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if (entry.name === name) {
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// Prefer smaller index
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if (staticEntry)
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break;
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return -(this.length - i);
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}
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}
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if (staticEntry)
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return -staticEntry.index;
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return 0;
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};
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Table.prototype.add = function add(name, value, nameSize, valueSize) {
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var totalSize = nameSize + valueSize + 32;
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this.dynamic.push({
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name: name,
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value: value,
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nameSize: nameSize,
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totalSize: totalSize
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});
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this.size += totalSize;
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this.length++;
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this.evict();
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};
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Table.prototype.evict = function evict() {
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while (this.size > this.maxSize) {
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var entry = this.dynamic.shift();
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this.size -= entry.totalSize;
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this.length--;
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}
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assert(this.size >= 0, 'Table size sanity check failed');
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};
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Table.prototype.updateSize = function updateSize(size) {
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assert(size <= this.protocolMaxSize, 'Table size bigger than maximum');
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this.maxSize = size;
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this.evict();
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};
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