RepairQDFFile

Debugging, Document repair

Description

Repairs a QDF PDF after human edits have changed stream lengths or object byte positions

The repair pass scans object boundaries without trusting stale cross-reference offsets, recalculates stream lengths, updates indirect length objects, and rebuilds the free list, cross-reference table, trailer, startxref, and /Size

Stream data containing endstream and endobj lines is preserved when the object has an unambiguous QDF stream marker. Invalid QDF input and repeated markers for the same object are rejected before the destination is opened, preserving an existing output file even during in-place repair

Syntax

Delphi

Function TPDFlib.RepairQDFFile(Const InputFileName, OutputFileName: WideString): Integer;

DLL

int DLRepairQDFFile(int InstanceID, const wchar_t* InputFileName, const wchar_t* OutputFileName);

ActiveX

Function PDFlib::RepairQDFFile(InputFileName As String, OutputFileName As String) As Long

Parameters

InputFileName	The edited QDF PDF
OutputFileName	The repaired PDF path, which may be identical to the input path

Return values

1	The edited QDF was repaired
0	The input was not a repairable QDF or the destination could not be written

Errors

LastErrorCode 401 reports an input read failure, 107 reports invalid or ambiguous QDF structure or another repair failure, and 305 reports an output write failure

Remarks

The complete source is repaired in memory, then written to an exclusively created temporary file in the destination directory. The file is flushed and closed before a same-volume replacement publishes the result. A write, flush, or replacement failure preserves the existing destination bytes and returns error 305; input read failures return 401

The destination directory must allow temporary file creation and replacement. Windows targets that are read-only or opened without delete sharing cannot be replaced. Existing target DACL permissions are copied to the temporary file before any repaired data is written; inaccessible permissions, a target without an explicit DACL, or an EFS-encrypted target cause error 305. Successful replacement creates a new file identity and does not preserve alternate data streams or ordinary file attributes. Temporary files are removed after ordinary success or failure; abrupt process termination may leave a temporary file. This API does not guarantee survival of power loss or concurrent changes by another writer