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Jython is an implementation of the high-level, dynamic, object-oriented language Python written in 100% Pure Java, and seamlessly integrated with the Java platform. It thus allows you to run Python on any Java platform.

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package org.python.modules.jffi;


import com.kenai.jffi.CallingConvention;
import com.kenai.jffi.Platform;

/**
 *
 */
final class FastIntMethodGenerator extends AbstractNumericMethodGenerator {
    private static final int MAX_PARAMETERS = getMaximumFastIntParameters();

    private static final String[] signatures = buildSignatures(int.class, MAX_PARAMETERS);

    private static final String[] methodNames = {
        "invokeVrI", "invokeIrI", "invokeIIrI", "invokeIIIrI", "invokeIIIIrI", "invokeIIIIIrI", "invokeIIIIIIrI"
    };

    private static final String[] noErrnoMethodNames = {
        "invokeNoErrnoVrI", "invokeNoErrnoIrI", "invokeNoErrnoIIrI", "invokeNoErrnoIIIrI"
    };
    
    String getInvokerMethodName(JITSignature signature) {

        final int parameterCount = signature.getParameterCount();

        if (signature.isIgnoreError() && parameterCount <= MAX_PARAMETERS && parameterCount <= noErrnoMethodNames.length) {
            return noErrnoMethodNames[signature.getParameterCount()];

        } else if (parameterCount <= MAX_PARAMETERS && parameterCount <= methodNames.length) {
            return methodNames[parameterCount];

        } else {
            throw new IllegalArgumentException("invalid fast-int parameter count: " + parameterCount);
        }
    }

    String getInvokerSignature(int parameterCount) {
        if (parameterCount <= MAX_PARAMETERS && parameterCount <= signatures.length) {
            return signatures[parameterCount];
        }
        throw new IllegalArgumentException("invalid fast-int parameter count: " + parameterCount);
    }

    final Class getInvokerIntType() {
        return int.class;
    }

    public boolean isSupported(JITSignature signature) {
        final int parameterCount = signature.getParameterCount();

        if (!signature.getCallingConvention().equals(CallingConvention.DEFAULT) || parameterCount > MAX_PARAMETERS) {
            return false;
        }

        final Platform platform = Platform.getPlatform();

        if (platform.getOS().equals(Platform.OS.WINDOWS)) {
            return false;
        }

        if (!platform.getCPU().equals(Platform.CPU.I386) && !platform.getCPU().equals(Platform.CPU.X86_64)) {
            return false;
        }

        for (int i = 0; i < parameterCount; i++) {
            if (!isFastIntParameter(platform, signature.getParameterType(i))) {
                return false;
            }
        }

        return isFastIntResult(platform, signature.getResultType());
    }


    final static int getMaximumFastIntParameters() {
        try {
            com.kenai.jffi.Invoker.class.getDeclaredMethod("invokeIIIIIIrI", com.kenai.jffi.Function.class,
                    int.class, int.class, int.class, int.class, int.class, int.class);
            return 6;
        } catch (NoSuchMethodException nex) {
            try {
                com.kenai.jffi.Invoker.class.getDeclaredMethod("invokeIIIrI", com.kenai.jffi.Function.class,
                        int.class, int.class, int.class);
                return 3;
            } catch (NoSuchMethodException nex2) {
                return -1;
            }
        } catch (Throwable t) {
            return -1;
        }
    }


    private static boolean isFastIntType(Platform platform, NativeType type) {
        switch (type) {
            case BOOL:
            case BYTE:
            case UBYTE:
            case SHORT:
            case USHORT:
            case INT:
            case UINT:
                return true;
                
            case LONG:
            case ULONG:
                return platform.longSize() == 32;
                
            default:
                return false;
        }
    }


    static boolean isFastIntResult(Platform platform, NativeType type) {
        switch (type) {
            case VOID:
                return true;

            case POINTER:
            case STRING:
                return platform.addressSize() == 32;

            default:
                return isFastIntType(platform, type);
        }
    }

    static boolean isFastIntParameter(Platform platform, NativeType type) {
        switch (type) {
            case POINTER:
            case BUFFER_IN:
            case BUFFER_OUT:
            case BUFFER_INOUT:
                return platform.addressSize() == 32;
            default:
                return isFastIntType(platform, type);
        }
    }
}