2.2.5.3 File Contents Request PDU (CLIPRDR_FILECONTENTS_REQUEST)
The File Contents Request PDU is sent by the recipient of the Format List PDU. It is used to request either the size of a remote file copied to the clipboard or a portion of the data in the file.
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clipHeader |
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streamId |
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lindex |
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dwFlags |
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nPositionLow |
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nPositionHigh |
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cbRequested |
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clipDataId (optional) |
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clipHeader (8 bytes): A Clipboard PDU Header. The msgType field of the Clipboard PDU Header MUST be set to CB_FILECONTENTS_REQUEST (0x0008), while the msgFlags field MUST be set to 0x0000.
streamId (4 bytes): An unsigned, 32-bit format ID used to associate the File Contents Request PDU with the corresponding File Contents Response PDU. The File Contents Response PDU is sent as a reply and contains an identical value in the streamId field.
lindex (4 bytes): A signed, 32-bit integer that specifies the numeric ID of the remote file that is the target of the File Contents Request PDU. This field is used as an index that identifies a particular file in a File List. This File List SHOULD have been obtained as clipboard data in a prior Format Data Request PDU and Format Data Response PDU exchange.
dwFlags (4 bytes): An unsigned, 32-bit integer that specifies the type of operation to be performed by the recipient.
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Value
Meaning
FILECONTENTS_SIZE
0x00000001
A request for the size of the file identified by the lindex field. The size MUST be returned as a 64-bit, unsigned integer. The cbRequested field MUST be set to 0x00000008 and both the nPositionLow and nPositionHigh fields MUST be set to 0x00000000.
FILECONTENTS_RANGE
0x00000002
A request for the data present in the file identified by the lindex field. The data to be retrieved is extracted starting from the offset given by the nPositionLow and nPositionHigh fields. The maximum number of bytes to extract is specified by the cbRequested field.
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The FILECONTENTS_SIZE and FILECONTENTS_RANGE flags MUST NOT be set at the same time.
nPositionLow (4 bytes): An unsigned, 32-bit integer that specifies the low bytes of the offset into the remote file, identified by the lindex field, from where the data needs to be extracted to satisfy a FILECONTENTS_RANGE operation. This field SHOULD be set to a value less than 2,147,483,648 unless the recipient of the FILECONTENTS_RANGE operation has specified support for huge files by setting the CB_HUGE_FILE_SUPPORT_ENABLED (0x00000020) flag in the General Capability Set (section 2.2.2.1.1.1) of the Clipboard Capabilities PDU (section 2.2.2.1).<2>
nPositionHigh (4 bytes): An unsigned, 32-bit integer that specifies the high bytes of the offset into the remote file, identified by the lindex field, from where the data needs to be extracted to satisfy a FILECONTENTS_RANGE operation. This field SHOULD be set to zero unless the recipient of the FILECONTENTS_RANGE operation has specified support for huge files by setting the CB_HUGE_FILE_SUPPORT_ENABLED (0x00000020) flag in the General Capability Set (section 2.2.2.1.1.1) of the Clipboard Capabilities PDU (section 2.2.2.1).
cbRequested (4 bytes): An unsigned, 32-bit integer that specifies the size, in bytes, of the data to retrieve. For a FILECONTENTS_SIZE operation, this field MUST be set to 0x00000008. In the case of a FILECONTENTS_RANGE operation, this field contains the maximum number of bytes to read from the remote file.
clipDataId (4 bytes): An optional unsigned, 32-bit integer that identifies File Stream data which was tagged in a prior Lock Clipboard Data PDU (section 2.2.4.1).