new TlvDecoder(input)
Create a new TlvDecoder for decoding the input in the NDN-TLV wire format.
Parameters:
| Name | Type | Description |
|---|---|---|
input |
Buffer | The buffer with the bytes to decode. |
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Methods
finishNestedTlvs(endOffset, skipCritical)
Call this after reading all nested TLVs to skip any remaining unrecognized
TLVs and to check if the offset after the final nested TLV matches the
endOffset returned by readNestedTlvsStart. Update the offset as needed if
skipping TLVs.
Parameters:
| Name | Type | Description |
|---|---|---|
endOffset |
number | The offset of the end of the parent TLV, returned by readNestedTlvsStart. |
skipCritical |
boolean | (optional) If omitted or false and the unrecognized type code to skip is critical, throw an exception. If true, then skip the unrecognized type code without error. |
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Throws:
DecodingException if the TLV length does not equal the total length
of the nested TLVs.
getOffset() → {number}
Get the offset into the input, used for the next read.
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Returns:
The offset.
- Type
- number
getSlice(beginOffset, endOffset) → {Buffer}
Return an array of a slice of the input for the given offset range.
Parameters:
| Name | Type | Description |
|---|---|---|
beginOffset |
number | The offset in the input of the beginning of the slice. |
endOffset |
number | The offset in the input of the end of the slice. |
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Returns:
The bytes in the value as a slice on the buffer. This is
not a copy of the bytes in the input buffer. If you need a copy, then you
must make a copy of the return value.
- Type
- Buffer
peekType(expectedType, endOffset) → {boolean}
Decode the type from this's input starting at offset, and if it is the
expectedType, then return true, else false. However, if this's offset is
greater than or equal to endOffset, then return false and don't try to read
the type. Do not update offset.
Parameters:
| Name | Type | Description |
|---|---|---|
expectedType |
number | The expected type. |
endOffset |
number | The offset of the end of the parent TLV, returned by readNestedTlvsStart. |
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Returns:
true if the type of the next TLV is the expectedType,
otherwise false.
- Type
- boolean
readBlobTlv(expectedType) → {Buffer}
Decode the type and length from this's input starting at offset, expecting
the type to be expectedType. Then return an array of the bytes in the value.
Update offset.
Parameters:
| Name | Type | Description |
|---|---|---|
expectedType |
number | The expected type. |
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Throws:
DecodingException if did not get the expected TLV type.
Returns:
The bytes in the value as a slice on the buffer. This is
not a copy of the bytes in the input buffer. If you need a copy, then you
must make a copy of the return value.
- Type
- Buffer
readBooleanTlv(expectedType, endOffset) → {boolean}
Peek at the next TLV, and if it has the expectedType then read a type and
value, ignoring the value, and return true. Otherwise, return false.
However, if this's offset is greater than or equal to endOffset, then return
false and don't try to read the type.
Parameters:
| Name | Type | Description |
|---|---|---|
expectedType |
number | The expected type. |
endOffset |
number | The offset of the end of the parent TLV, returned by readNestedTlvsStart. |
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Returns:
true, or else false if the next TLV doesn't have the
expected type.
- Type
- boolean
readExtendedVarNumber(firstOctet) → {number}
A private function to do the work of readVarNumber, given the firstOctet
which is >= 253.
Parameters:
| Name | Type | Description |
|---|---|---|
firstOctet |
number | The first octet which is >= 253, used to decode the remaining bytes. |
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Returns:
The decoded VAR-NUMBER.
- Type
- number
readNestedTlvsStart(expectedType) → {number}
Decode the type and length from the input starting at offset, expecting the
type to be expectedType. Update offset. Also make sure the decoded length
does not exceed the number of bytes remaining in the input. Return the offset
of the end of this parent TLV, which is used in decoding optional nested
TLVs. After reading all nested TLVs, call finishNestedTlvs.
Parameters:
| Name | Type | Description |
|---|---|---|
expectedType |
number | The expected type. |
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Throws:
DecodingException if did not get the expected TLV type or the TLV
length exceeds the buffer length.
Returns:
The offset of the end of the parent TLV.
- Type
- number
readNonNegativeInteger(length) → {number}
Decode a non-negative integer in NDN-TLV and return it. Update offset by
length.
Parameters:
| Name | Type | Description |
|---|---|---|
length |
number | The number of bytes in the encoded integer. |
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Throws:
DecodingException if length is an invalid length for a TLV
non-negative integer.
Returns:
The integer.
- Type
- number
readNonNegativeIntegerTlv(expectedType) → {number}
Decode the type and length from this's input starting at offset, expecting
the type to be expectedType. Then decode a non-negative integer in NDN-TLV
and return it. Update offset.
Parameters:
| Name | Type | Description |
|---|---|---|
expectedType |
number | The expected type. |
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Throws:
DecodingException if did not get the expected TLV type or can't
decode the value.
Returns:
The integer.
- Type
- number
readOptionalBlobTlv(expectedType, endOffset) → {Buffer}
Peek at the next TLV, and if it has the expectedType then call readBlobTlv
and return the value. Otherwise, return null. However, if this's offset is
greater than or equal to endOffset, then return null and don't try to read
the type.
Parameters:
| Name | Type | Description |
|---|---|---|
expectedType |
number | The expected type. |
endOffset |
number | The offset of the end of the parent TLV, returned by readNestedTlvsStart. |
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Returns:
The bytes in the value as a slice on the buffer or null if
the next TLV doesn't have the expected type. This is not a copy of the bytes
in the input buffer. If you need a copy, then you must make a copy of the
return value.
- Type
- Buffer
readOptionalNonNegativeIntegerTlv(expectedType, endOffset) → {number}
Peek at the next TLV, and if it has the expectedType then call
readNonNegativeIntegerTlv and return the integer. Otherwise, return null.
However, if this's offset is greater than or equal to endOffset, then return
null and don't try to read the type.
Parameters:
| Name | Type | Description |
|---|---|---|
expectedType |
number | The expected type. |
endOffset |
number | The offset of the end of the parent TLV, returned by readNestedTlvsStart. |
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Returns:
The integer or null if the next TLV doesn't have the
expected type.
- Type
- number
readTypeAndLength(expectedType) → {number}
Decode the type and length from this's input starting at offset, expecting
the type to be expectedType and return the length. Update offset. Also make
sure the decoded length does not exceed the number of bytes remaining in the
input.
Parameters:
| Name | Type | Description |
|---|---|---|
expectedType |
number | The expected type. |
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Throws:
DecodingException if (did not get the expected TLV type or the TLV length
exceeds the buffer length.
Returns:
The length of the TLV.
- Type
- number
readVarNumber() → {number}
Decode VAR-NUMBER in NDN-TLV and return it. Update offset.
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Returns:
The decoded VAR-NUMBER.
- Type
- number
seek(offset)
Set the offset into the input, used for the next read.
Parameters:
| Name | Type | Description |
|---|---|---|
offset |
number | The new offset. |
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