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bytestreamjs

1.0.29 • Public • Published

ByteStream.js

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ByteStream class

ByteStream class is the major class for all others. It provides many useful function for making search for patterns and data transformation. Optimized for fast as possible data processing.

Method Description
clear Clear existing stream
fromArrayBuffer Initialize "Stream" object from existing "ArrayBuffer"
fromUint8Array Initialize "Stream" object from existing "Uint8Array"
fromString Initialize "Stream" object from existing string
toString Represent "Stream" object content as a string
fromHexString Initialize "Stream" object from existing hexdecimal string
toHexString Represent "Stream" object content as a hexdecimal string
copy Return copy of existing "Stream"
slice Return slice of existing "Stream"
realloc Change size of existing "Stream"
append Append a new "Stream" content to the current "Stream"
insert Insert "Stream" content to the current "Stream" at specific position
isEqual Check that two "Stream" objects has equal content
isEqualView Check that current "Stream" objects has equal content with input "Uint8Array"
findPattern Find any byte pattern in "Stream"
findFirstIn Find first position of any pattern from input array
findAllIn Find all positions of any pattern from input array
findAllPatternIn Find all positions of a pattern
findFirstNotIn Find first position of data, not included in patterns from input array
findAllNotIn Find all positions of data, not included in patterns from input array
findFirstSequence Find position of a sequence of any patterns from input array
findAllSequences Find all positions of a sequence of any patterns from input array
findPairedPatterns Find all paired patterns in the stream
findPairedArrays Find all paired patterns in the stream
replacePattern Replace one patter with other
skipPatterns Skip any pattern from input array
skipNotPatterns Skip any pattern not from input array

SeqStream class

SeqStream class is the aux class for sequential reading/writing data from/to ByteStream underline class.

Method Description
resetPosition Reset current position of the "SeqStream"
findPattern Find any byte pattern in "ByteStream"
findFirstIn Find first position of any pattern from input array
findAllIn Find all positions of any pattern from input array
findFirstNotIn Find first position of data, not included in patterns from input array
findAllNotIn Find all positions of data, not included in patterns from input array
findFirstSequence Find position of a sequence of any patterns from input array
findAllSequences Find position of a sequence of any patterns from input array
findPairedPatterns Find all paired patterns in the stream
findPairedArrays Find all paired patterns in the stream
replacePattern Replace one patter with other
skipPatterns Skip of any pattern from input array
skipNotPatterns Skip of any pattern from input array
append Append a new "Stream" content to the current "Stream"
appendView Append a "view" content to the current "Stream"
appendChar Append a new char to the current "Stream"
getBlock Get a block of data
getUint32 Get 4-byte unsigned integer value

BitStream class

Main purpose of the BitStream is manipulating of each bit inside any ByteStream data.

Method Description
clear Clear existing stream
fromByteStream Initialize "BitStream" by data from existing "ByteStream"
fromArrayBuffer Initialize "BitStream" object from existing "ArrayBuffer"
fromUint8Array Initialize "BitStream" object from existing "Uint8Array"
fromString Initialize "BitStream" object from existing bit string
toString Represent "BitStream" object content as a string
shiftRight Shift entire "BitStream" value right to number of bits
shiftLeft Shift entire "BitStream" value left to number of bits
slice Return slice of existing "BitStream"
copy Return copy of existing "BitStream"
shrink Shrink unnecessary bytes in current stream accordingly to "bitsCount" value
reverseBytes Reverse bits order in each byte in the stream
reverseValue Reverse all bits in entire "BitStream"
getNumberValue Trying to represent entire "BitStream" as an unsigned integer
findPattern Find any bit pattern in "BitStream"
findFirstIn Find first position of any pattern from input array
findAllIn Find all positions of any pattern from input array
findAllPatternIn Find all positions of a pattern
findFirstNotIn Find first position of data, not included in patterns from input array
findAllNotIn Find all positions of data, not included in patterns from input array
findFirstSequence Find position of a sequence of any patterns from input array
findAllSequences Find position of a sequence of any patterns from input array
findPairedPatterns Find all paired patterns in the stream
findPairedArrays Find all paired patterns in the stream
replacePattern Replace one pattern with other
skipPatterns Skip any pattern from input array
skipNotPatterns Skip any pattern not from input array
append Append a new "BitStream" content to the current "BitStream"

SeqBitStream class

SeqBitStream class is the aux class for sequential reading/writing data from/to BitStream underline class.

Method Description
getBits Get next "length" bits from the stream
getBitsString Get string representation for the next "length" bits from the stream
getBitsReversedValue Get number value representation of the next "length" bits from the stream, preliminary reversed
toString Represent remaining bits in "BitStream" as a string

parseByteMap functionality

The parseByteMap function is intended to parse and check byte streams with determinated structure.

Example of map used as a kind of template. Exactly this map is using for parsing PDF xref table:

let map = [
    {
        type: "string",
        name: "type",
        minlength: 1,
        maxlength: 1,
        func: function(array){
            let result = {
                status: (-1),
                length: 1
            };
            
            switch(array[0])
            {
                case 0x6E: // "n"
                    result.value = "n";
                    break;
                case 0x66: // "f"
                    result.value = "f";
                    break;
                default:
                    return result;
            }
            
            result.status = 1;
            
            return result;
        }
    },
    {
        type: "check",
        minlength: 1,
        maxlength: 2,
        func: function(array){
            let position = (-1);
            
            if(array[0] == 0x0A)
                position = 1;
            if(array[1] == 0x0A)
                position = 2;
            
            return {
                status: (position > 0) ? 1 : (-1),
                length: position
            };
        }
    }
];

License

Copyright (c) 2016-2018, Peculiar Ventures All rights reserved.

Author 2016-2018 Yury Strozhevsky.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

  2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

  3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Install

npm i bytestreamjs

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5,531

Version

1.0.29

License

BSD-3-Clause

Unpacked Size

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Total Files

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