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 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 |
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 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 |
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
};
}
}
];Copyright (c) 2016-2022, Peculiar Ventures All rights reserved.
Author 2016-2018 Yury Strozhevsky.
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