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encodeAndAttachIfd: Corrected IFD chain allocation arithmetic.

pull/3/head
Dustin Oprea 2018-04-30 03:30:34 -04:00
parent fe20d2c334
commit 3a20f12306
1 changed files with 10 additions and 5 deletions
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15
ifd_builder_encode.go
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@ -348,24 +348,29 @@ func (ibe *IfdByteEncoder) encodeAndAttachIfd(ib *IfdBuilder, ifdAddressableOffs
for thisIb := ib; thisIb != nil; thisIb = thisIb.nextIb {
// Do a dry-run in order to pre-determine its size requirement.
rawBytes, _, _, _, err := ibe.encodeIfdToBytes(ib, ifdAddressableOffset, 0, false)
_, tableSize, allocatedDataSize, _, err := ibe.encodeIfdToBytes(ib, ifdAddressableOffset, 0, false)
log.PanicIf(err)
nextIfdOffsetToWrite = ifdAddressableOffset + uint32(len(rawBytes))
addressableOffset := ifdAddressableOffset + tableSize
nextIfdOffsetToWrite = addressableOffset + allocatedDataSize
// Write our IFD as well as any child-IFDs (now that we know the offset
// where new IFDs and their data will be allocated).
setNextIb := thisIb.nextIb != nil
// TODO(dustin): !! Test the output sizes.
rawBytes, _, _, _, err = ibe.encodeIfdToBytes(ib, ifdAddressableOffset, nextIfdOffsetToWrite, setNextIb)
tableAndAllocated, tableSize, allocatedDataSize, _, err := ibe.encodeIfdToBytes(ib, addressableOffset, nextIfdOffsetToWrite, setNextIb)
log.PanicIf(err)
_, err = b.Write(rawBytes)
if len(tableAndAllocated) != int(tableSize + allocatedDataSize) {
log.Panicf("IFD table and data is not a consistent size: (%d) != (%d)", len(tableAndAllocated), tableSize + allocatedDataSize)
}
_, err = b.Write(tableAndAllocated)
log.PanicIf(err)
// This will include the child-IFDs, as well. This will actually advance the offset for our next loop.
ifdAddressableOffset = ifdAddressableOffset + uint32(len(rawBytes))
ifdAddressableOffset = ifdAddressableOffset + uint32(tableSize + allocatedDataSize)
}
return b.Bytes(), nil