I'm guessing the problem is somewhere around lines 603-608 of StructIO.java:

        aggregatedField.alignment = Math.max(
            aggregatedField.alignment, 
            field.desc.alignment >= 0 ?
            field.desc.alignment :
            field.desc.byteLength
        );

Possibly this needs to check Platform.isLinux(), and whether the field is a double or not, and whether the platform is 32-bits, and align to 4-bytes if: isLInux() && isDouble() && is32Bits() ?

Note that this issue does not exist in 64-bit (understandable since linux double aligns on 8-byte in 64-bit). It is specific to 32-bit linux.

Hi Olivier,

Did you have any thoughts on this? I have the same problem and wrote a Customizer to correct it:

public class ScoreAlignmentCustomizer extends DefaultCustomizer {
    @Override
    public void beforeLayout(StructIO io, List<AggregatedFieldDesc> aggregatedFields) {
        for (AggregatedFieldDesc field : aggregatedFields) {
            if (field.fields.get(0).toString().contains("score")) {
                if (Platform.isLinux() && !Platform.is64Bits()) {
                    field.alignment = 4;
                } else {
                    field.alignment = 8;
                }
            }
        }
    }
}

However it results in an "Unaligned pointer access" exception from BridJ. I enabled SUPPORTS_UNALIGNED_ACCESS for all platforms in bridj.hpp and it now all works correctly but obviously I'm concerned about the impact of enabling SUPPORTS_UNALIGNED_ACCESS under Linux and also the inelegance of the customizer.

I would be happy to try and update the code in StructIO and generate a pull request to avoid the Customizer but that will still result in the Unaligned error.

Any help would be greatly appreciated.

Hi @hughperkins , @ESTW ,

This should be fixed in the next release (0.6.2), which I'm unfortunately taking an unusually long time to perform (I'm still waiting for the renewal of my code signing certificates to publish to Maven Central :-S).

Will let you know here when it's available, in the meanwhile please build from sources.

Cheers

Hi @ochafik

Thanks, that's great. I have tested it and it has resolved the need for the Customizer however with the latest source it still results in the "Unaligned pointer access !" error i.e.

java.lang.RuntimeException: Unaligned pointer access !
    at org.bridj.JNI.get_double(Native Method) ~[bridj-0.6.3-SNAPSHOT.jar:na]
    at org.bridj.Pointer$OrderedPointer.getDoubleAtOffset(Pointer.java:484) ~[bridj-0.6.3-SNAPSHOT.jar:na]
    at org.bridj.StructIO.getDoubleField(StructIO.java:1003) ~[bridj-0.6.3-SNAPSHOT.jar:na]

This appears to work by defining SUPPORTS_UNALIGNED_ACCESS in BridJ/src/main/cpp/bridj/bridj.hpp for Linux however I'm not sure if that's the right solution?

Thanks again.

Ouch, sorry about that one! Pointer-related code must indeed let this half-alignment pass through properly.
Reopening this issue.

Sorry about the huge delay!
The latest 0.7-SNAPSHOT should contain a fix, please let me know of any issue!

Great, thanks Olivier. I'll give it a run through this week and let you
know.

On Sun, Jun 9, 2013 at 8:18 PM, Olivier Chafik notifications@github.comwrote:

Sorry about the huge delay!
The latest 0.7-SNAPSHOT should contain a fix, please let me know of any
issue!

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/320#issuecomment-19171667
.