Move the PredictorStream from src/core/stream.js and into its own file
This commit is contained in:
Jonas Jenwald
parent
e938c05edb
commit
66d9d83dcb
@ -33,7 +33,7 @@ import {
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Name,
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Ref,
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} from "./primitives.js";
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import { FlateStream, NullStream, PredictorStream } from "./stream.js";
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import { FlateStream, NullStream } from "./stream.js";
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import { isWhiteSpace, MissingDataException } from "./core_utils.js";
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import { Ascii85Stream } from "./ascii_85_stream.js";
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import { AsciiHexStream } from "./ascii_hex_stream.js";
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@ -42,6 +42,7 @@ import { Jbig2Stream } from "./jbig2_stream.js";
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import { JpegStream } from "./jpeg_stream.js";
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import { JpxStream } from "./jpx_stream.js";
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import { LZWStream } from "./lzw_stream.js";
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import { PredictorStream } from "./predictor_stream.js";
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import { RunLengthStream } from "./run_length_stream.js";
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const MAX_LENGTH_TO_CACHE = 1000;
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243
src/core/predictor_stream.js
Normal file
243
src/core/predictor_stream.js
Normal file
@ -0,0 +1,243 @@
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/* Copyright 2012 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/* eslint-disable no-var */
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import { DecodeStream } from "./stream.js";
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import { FormatError } from "../shared/util.js";
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import { isDict } from "./primitives.js";
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var PredictorStream = (function PredictorStreamClosure() {
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// eslint-disable-next-line no-shadow
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function PredictorStream(str, maybeLength, params) {
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if (!isDict(params)) {
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return str; // no prediction
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}
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var predictor = (this.predictor = params.get("Predictor") || 1);
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if (predictor <= 1) {
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return str; // no prediction
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}
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if (predictor !== 2 && (predictor < 10 || predictor > 15)) {
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throw new FormatError(`Unsupported predictor: ${predictor}`);
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}
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if (predictor === 2) {
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this.readBlock = this.readBlockTiff;
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} else {
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this.readBlock = this.readBlockPng;
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}
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this.str = str;
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this.dict = str.dict;
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var colors = (this.colors = params.get("Colors") || 1);
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var bits = (this.bits = params.get("BitsPerComponent") || 8);
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var columns = (this.columns = params.get("Columns") || 1);
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this.pixBytes = (colors * bits + 7) >> 3;
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this.rowBytes = (columns * colors * bits + 7) >> 3;
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DecodeStream.call(this, maybeLength);
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return this;
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}
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PredictorStream.prototype = Object.create(DecodeStream.prototype);
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PredictorStream.prototype.readBlockTiff = function predictorStreamReadBlockTiff() {
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var rowBytes = this.rowBytes;
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var bufferLength = this.bufferLength;
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var buffer = this.ensureBuffer(bufferLength + rowBytes);
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var bits = this.bits;
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var colors = this.colors;
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var rawBytes = this.str.getBytes(rowBytes);
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this.eof = !rawBytes.length;
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if (this.eof) {
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return;
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}
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var inbuf = 0,
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outbuf = 0;
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var inbits = 0,
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outbits = 0;
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var pos = bufferLength;
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var i;
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if (bits === 1 && colors === 1) {
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// Optimized version of the loop in the "else"-branch
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// for 1 bit-per-component and 1 color TIFF images.
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for (i = 0; i < rowBytes; ++i) {
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var c = rawBytes[i] ^ inbuf;
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c ^= c >> 1;
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c ^= c >> 2;
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c ^= c >> 4;
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inbuf = (c & 1) << 7;
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buffer[pos++] = c;
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}
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} else if (bits === 8) {
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for (i = 0; i < colors; ++i) {
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buffer[pos++] = rawBytes[i];
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}
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for (; i < rowBytes; ++i) {
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buffer[pos] = buffer[pos - colors] + rawBytes[i];
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pos++;
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}
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} else if (bits === 16) {
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var bytesPerPixel = colors * 2;
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for (i = 0; i < bytesPerPixel; ++i) {
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buffer[pos++] = rawBytes[i];
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}
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for (; i < rowBytes; i += 2) {
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var sum =
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((rawBytes[i] & 0xff) << 8) +
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(rawBytes[i + 1] & 0xff) +
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((buffer[pos - bytesPerPixel] & 0xff) << 8) +
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(buffer[pos - bytesPerPixel + 1] & 0xff);
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buffer[pos++] = (sum >> 8) & 0xff;
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buffer[pos++] = sum & 0xff;
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}
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} else {
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var compArray = new Uint8Array(colors + 1);
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var bitMask = (1 << bits) - 1;
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var j = 0,
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k = bufferLength;
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var columns = this.columns;
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for (i = 0; i < columns; ++i) {
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for (var kk = 0; kk < colors; ++kk) {
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if (inbits < bits) {
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inbuf = (inbuf << 8) | (rawBytes[j++] & 0xff);
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inbits += 8;
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}
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compArray[kk] =
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(compArray[kk] + (inbuf >> (inbits - bits))) & bitMask;
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inbits -= bits;
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outbuf = (outbuf << bits) | compArray[kk];
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outbits += bits;
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if (outbits >= 8) {
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buffer[k++] = (outbuf >> (outbits - 8)) & 0xff;
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outbits -= 8;
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}
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}
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}
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if (outbits > 0) {
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buffer[k++] =
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(outbuf << (8 - outbits)) + (inbuf & ((1 << (8 - outbits)) - 1));
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}
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}
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this.bufferLength += rowBytes;
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};
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PredictorStream.prototype.readBlockPng = function predictorStreamReadBlockPng() {
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var rowBytes = this.rowBytes;
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var pixBytes = this.pixBytes;
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var predictor = this.str.getByte();
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var rawBytes = this.str.getBytes(rowBytes);
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this.eof = !rawBytes.length;
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if (this.eof) {
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return;
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}
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var bufferLength = this.bufferLength;
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var buffer = this.ensureBuffer(bufferLength + rowBytes);
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var prevRow = buffer.subarray(bufferLength - rowBytes, bufferLength);
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if (prevRow.length === 0) {
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prevRow = new Uint8Array(rowBytes);
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}
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var i,
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j = bufferLength,
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up,
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c;
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switch (predictor) {
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case 0:
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for (i = 0; i < rowBytes; ++i) {
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buffer[j++] = rawBytes[i];
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}
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break;
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case 1:
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for (i = 0; i < pixBytes; ++i) {
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buffer[j++] = rawBytes[i];
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}
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for (; i < rowBytes; ++i) {
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buffer[j] = (buffer[j - pixBytes] + rawBytes[i]) & 0xff;
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j++;
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}
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break;
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case 2:
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for (i = 0; i < rowBytes; ++i) {
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buffer[j++] = (prevRow[i] + rawBytes[i]) & 0xff;
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}
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break;
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case 3:
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for (i = 0; i < pixBytes; ++i) {
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buffer[j++] = (prevRow[i] >> 1) + rawBytes[i];
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}
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for (; i < rowBytes; ++i) {
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buffer[j] =
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(((prevRow[i] + buffer[j - pixBytes]) >> 1) + rawBytes[i]) & 0xff;
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j++;
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}
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break;
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case 4:
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// we need to save the up left pixels values. the simplest way
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// is to create a new buffer
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for (i = 0; i < pixBytes; ++i) {
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up = prevRow[i];
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c = rawBytes[i];
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buffer[j++] = up + c;
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}
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for (; i < rowBytes; ++i) {
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up = prevRow[i];
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var upLeft = prevRow[i - pixBytes];
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var left = buffer[j - pixBytes];
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var p = left + up - upLeft;
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var pa = p - left;
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if (pa < 0) {
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pa = -pa;
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}
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var pb = p - up;
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if (pb < 0) {
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pb = -pb;
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}
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var pc = p - upLeft;
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if (pc < 0) {
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pc = -pc;
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}
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c = rawBytes[i];
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if (pa <= pb && pa <= pc) {
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buffer[j++] = left + c;
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} else if (pb <= pc) {
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buffer[j++] = up + c;
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} else {
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buffer[j++] = upLeft + c;
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}
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}
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break;
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default:
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throw new FormatError(`Unsupported predictor: ${predictor}`);
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}
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this.bufferLength += rowBytes;
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};
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return PredictorStream;
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})();
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export { PredictorStream };
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@ -21,7 +21,6 @@
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/* eslint-disable no-var */
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import { FormatError, stringToBytes, unreachable } from "../shared/util.js";
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import { isDict } from "./primitives.js";
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var Stream = (function StreamClosure() {
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// eslint-disable-next-line no-shadow
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@ -726,228 +725,6 @@ var FlateStream = (function FlateStreamClosure() {
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return FlateStream;
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})();
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var PredictorStream = (function PredictorStreamClosure() {
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// eslint-disable-next-line no-shadow
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function PredictorStream(str, maybeLength, params) {
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if (!isDict(params)) {
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return str; // no prediction
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}
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var predictor = (this.predictor = params.get("Predictor") || 1);
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if (predictor <= 1) {
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return str; // no prediction
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}
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if (predictor !== 2 && (predictor < 10 || predictor > 15)) {
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throw new FormatError(`Unsupported predictor: ${predictor}`);
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}
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if (predictor === 2) {
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this.readBlock = this.readBlockTiff;
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} else {
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this.readBlock = this.readBlockPng;
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}
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this.str = str;
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this.dict = str.dict;
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var colors = (this.colors = params.get("Colors") || 1);
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var bits = (this.bits = params.get("BitsPerComponent") || 8);
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var columns = (this.columns = params.get("Columns") || 1);
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this.pixBytes = (colors * bits + 7) >> 3;
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this.rowBytes = (columns * colors * bits + 7) >> 3;
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DecodeStream.call(this, maybeLength);
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return this;
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}
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PredictorStream.prototype = Object.create(DecodeStream.prototype);
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PredictorStream.prototype.readBlockTiff = function predictorStreamReadBlockTiff() {
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var rowBytes = this.rowBytes;
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var bufferLength = this.bufferLength;
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var buffer = this.ensureBuffer(bufferLength + rowBytes);
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var bits = this.bits;
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var colors = this.colors;
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var rawBytes = this.str.getBytes(rowBytes);
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this.eof = !rawBytes.length;
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if (this.eof) {
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return;
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}
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var inbuf = 0,
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outbuf = 0;
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var inbits = 0,
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outbits = 0;
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var pos = bufferLength;
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var i;
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if (bits === 1 && colors === 1) {
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// Optimized version of the loop in the "else"-branch
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// for 1 bit-per-component and 1 color TIFF images.
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for (i = 0; i < rowBytes; ++i) {
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var c = rawBytes[i] ^ inbuf;
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c ^= c >> 1;
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c ^= c >> 2;
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c ^= c >> 4;
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inbuf = (c & 1) << 7;
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buffer[pos++] = c;
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}
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} else if (bits === 8) {
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for (i = 0; i < colors; ++i) {
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buffer[pos++] = rawBytes[i];
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}
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for (; i < rowBytes; ++i) {
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buffer[pos] = buffer[pos - colors] + rawBytes[i];
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pos++;
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}
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} else if (bits === 16) {
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var bytesPerPixel = colors * 2;
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for (i = 0; i < bytesPerPixel; ++i) {
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buffer[pos++] = rawBytes[i];
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}
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for (; i < rowBytes; i += 2) {
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var sum =
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((rawBytes[i] & 0xff) << 8) +
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(rawBytes[i + 1] & 0xff) +
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((buffer[pos - bytesPerPixel] & 0xff) << 8) +
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(buffer[pos - bytesPerPixel + 1] & 0xff);
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buffer[pos++] = (sum >> 8) & 0xff;
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buffer[pos++] = sum & 0xff;
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}
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} else {
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var compArray = new Uint8Array(colors + 1);
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var bitMask = (1 << bits) - 1;
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var j = 0,
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k = bufferLength;
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var columns = this.columns;
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for (i = 0; i < columns; ++i) {
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for (var kk = 0; kk < colors; ++kk) {
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if (inbits < bits) {
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inbuf = (inbuf << 8) | (rawBytes[j++] & 0xff);
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inbits += 8;
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}
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compArray[kk] =
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(compArray[kk] + (inbuf >> (inbits - bits))) & bitMask;
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inbits -= bits;
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outbuf = (outbuf << bits) | compArray[kk];
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outbits += bits;
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if (outbits >= 8) {
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buffer[k++] = (outbuf >> (outbits - 8)) & 0xff;
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outbits -= 8;
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}
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}
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}
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if (outbits > 0) {
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buffer[k++] =
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(outbuf << (8 - outbits)) + (inbuf & ((1 << (8 - outbits)) - 1));
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}
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}
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this.bufferLength += rowBytes;
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};
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PredictorStream.prototype.readBlockPng = function predictorStreamReadBlockPng() {
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var rowBytes = this.rowBytes;
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var pixBytes = this.pixBytes;
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var predictor = this.str.getByte();
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var rawBytes = this.str.getBytes(rowBytes);
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this.eof = !rawBytes.length;
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if (this.eof) {
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return;
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}
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var bufferLength = this.bufferLength;
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var buffer = this.ensureBuffer(bufferLength + rowBytes);
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var prevRow = buffer.subarray(bufferLength - rowBytes, bufferLength);
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if (prevRow.length === 0) {
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prevRow = new Uint8Array(rowBytes);
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}
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var i,
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j = bufferLength,
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up,
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c;
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switch (predictor) {
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case 0:
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for (i = 0; i < rowBytes; ++i) {
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buffer[j++] = rawBytes[i];
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}
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break;
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case 1:
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for (i = 0; i < pixBytes; ++i) {
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buffer[j++] = rawBytes[i];
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}
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for (; i < rowBytes; ++i) {
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buffer[j] = (buffer[j - pixBytes] + rawBytes[i]) & 0xff;
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j++;
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}
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break;
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case 2:
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for (i = 0; i < rowBytes; ++i) {
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buffer[j++] = (prevRow[i] + rawBytes[i]) & 0xff;
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}
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break;
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case 3:
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for (i = 0; i < pixBytes; ++i) {
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buffer[j++] = (prevRow[i] >> 1) + rawBytes[i];
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}
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for (; i < rowBytes; ++i) {
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buffer[j] =
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(((prevRow[i] + buffer[j - pixBytes]) >> 1) + rawBytes[i]) & 0xff;
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j++;
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}
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break;
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case 4:
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// we need to save the up left pixels values. the simplest way
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// is to create a new buffer
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for (i = 0; i < pixBytes; ++i) {
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up = prevRow[i];
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c = rawBytes[i];
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buffer[j++] = up + c;
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}
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for (; i < rowBytes; ++i) {
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up = prevRow[i];
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var upLeft = prevRow[i - pixBytes];
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var left = buffer[j - pixBytes];
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var p = left + up - upLeft;
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var pa = p - left;
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if (pa < 0) {
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pa = -pa;
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}
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var pb = p - up;
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if (pb < 0) {
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pb = -pb;
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}
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var pc = p - upLeft;
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if (pc < 0) {
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pc = -pc;
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}
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c = rawBytes[i];
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if (pa <= pb && pa <= pc) {
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buffer[j++] = left + c;
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} else if (pb <= pc) {
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buffer[j++] = up + c;
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} else {
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buffer[j++] = upLeft + c;
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}
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}
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break;
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default:
|
||||
throw new FormatError(`Unsupported predictor: ${predictor}`);
|
||||
}
|
||||
this.bufferLength += rowBytes;
|
||||
};
|
||||
|
||||
return PredictorStream;
|
||||
})();
|
||||
|
||||
var NullStream = (function NullStreamClosure() {
|
||||
// eslint-disable-next-line no-shadow
|
||||
function NullStream() {
|
||||
@ -963,7 +740,6 @@ export {
|
||||
DecodeStream,
|
||||
FlateStream,
|
||||
NullStream,
|
||||
PredictorStream,
|
||||
Stream,
|
||||
StreamsSequenceStream,
|
||||
StringStream,
|
||||
|
||||
@ -13,8 +13,9 @@
|
||||
* limitations under the License.
|
||||
*/
|
||||
|
||||
import { PredictorStream, Stream } from "../../src/core/stream.js";
|
||||
import { Dict } from "../../src/core/primitives.js";
|
||||
import { PredictorStream } from "../../src/core/predictor_stream.js";
|
||||
import { Stream } from "../../src/core/stream.js";
|
||||
|
||||
describe("stream", function () {
|
||||
beforeEach(function () {
|
||||
|
||||
Loading…
Reference in New Issue
Block a user