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package com.oracle.graal.python.builtins.modules;

import static com.oracle.graal.python.builtins.PythonBuiltinClassType.BinasciiError;
import static com.oracle.graal.python.builtins.PythonBuiltinClassType.NotImplementedError;
import static com.oracle.graal.python.builtins.PythonBuiltinClassType.TypeError;
import static com.oracle.graal.python.builtins.PythonBuiltinClassType.ValueError;
import static com.oracle.graal.python.nodes.PGuards.isAscii;
import static com.oracle.graal.python.util.PythonUtils.TS_ENCODING;

import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.Base64;
import java.util.List;
import java.util.zip.CRC32;

import com.oracle.graal.python.annotations.ArgumentClinic;
import com.oracle.graal.python.annotations.ClinicConverterFactory;
import com.oracle.graal.python.builtins.Builtin;
import com.oracle.graal.python.builtins.CoreFunctions;
import com.oracle.graal.python.builtins.PythonBuiltins;
import com.oracle.graal.python.builtins.objects.PNone;
import com.oracle.graal.python.builtins.objects.buffer.PythonBufferAccessLibrary;
import com.oracle.graal.python.builtins.objects.buffer.PythonBufferAcquireLibrary;
import com.oracle.graal.python.builtins.objects.bytes.PBytes;
import com.oracle.graal.python.builtins.objects.str.PString;
import com.oracle.graal.python.nodes.ErrorMessages;
import com.oracle.graal.python.nodes.PRaiseNode;
import com.oracle.graal.python.nodes.function.PythonBuiltinBaseNode;
import com.oracle.graal.python.nodes.function.builtins.PythonBinaryClinicBuiltinNode;
import com.oracle.graal.python.nodes.function.builtins.PythonClinicBuiltinNode;
import com.oracle.graal.python.nodes.function.builtins.PythonTernaryClinicBuiltinNode;
import com.oracle.graal.python.nodes.function.builtins.PythonUnaryClinicBuiltinNode;
import com.oracle.graal.python.nodes.function.builtins.clinic.ArgumentCastNode.ArgumentCastNodeWithRaiseAndIndirectCall;
import com.oracle.graal.python.nodes.function.builtins.clinic.ArgumentClinicProvider;
import com.oracle.graal.python.nodes.util.CastToTruffleStringNode;
import com.oracle.graal.python.runtime.sequence.storage.ByteSequenceStorage;
import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Cached.Shared;
import com.oracle.truffle.api.dsl.Fallback;
import com.oracle.truffle.api.dsl.GenerateNodeFactory;
import com.oracle.truffle.api.dsl.NodeFactory;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.library.CachedLibrary;
import com.oracle.truffle.api.library.ExportLibrary;
import com.oracle.truffle.api.library.ExportMessage;
import com.oracle.truffle.api.profiles.ConditionProfile;
import com.oracle.truffle.api.strings.TruffleString;
import com.oracle.truffle.api.strings.TruffleString.CodeRange;

@CoreFunctions(defineModule = "binascii")
public class BinasciiModuleBuiltins extends PythonBuiltins {

    @Override
    protected List<? extends NodeFactory<? extends PythonBuiltinBaseNode>> getNodeFactories() {
        return BinasciiModuleBuiltinsFactory.getFactories();
    }

    abstract static class AsciiBufferConverter extends ArgumentCastNodeWithRaiseAndIndirectCall {
        @Specialization(guards = "acquireLib.hasBuffer(value)", limit = "getCallSiteInlineCacheMaxDepth()")
        Object doObject(VirtualFrame frame, Object value,
                        @CachedLibrary("value") PythonBufferAcquireLibrary acquireLib) {
            return acquireLib.acquireReadonly(value, frame, getContext(), getLanguage(), this);
        }

        @ExportLibrary(PythonBufferAccessLibrary.class)
        static final class AsciiStringBuffer {
            private final TruffleString str;

            AsciiStringBuffer(TruffleString str) {
                assert str.getCodeRangeUncached(TS_ENCODING) == CodeRange.ASCII;
                this.str = str;
            }

            @ExportMessage
            @SuppressWarnings("static-method")
            boolean isBuffer() {
                return true;
            }

            @ExportMessage
            int getBufferLength(
                            @Cached TruffleString.CodePointLengthNode codePointLengthNode) {
                return codePointLengthNode.execute(str, TS_ENCODING);
            }

            @ExportMessage
            byte readByte(int byteOffset,
                            @Cached TruffleString.CodePointAtIndexNode codePointAtIndexNode) {
                int ch = codePointAtIndexNode.execute(str, byteOffset, TS_ENCODING);
                assert 0 <= ch && ch < 128;    // guaranteed because str is ASCII
                return (byte) ch;
            }
        }

        @Specialization(guards = "isAscii(value, getCodeRangeNode)", limit = "1")
        Object asciiString(TruffleString value,
                        @Shared("getCodeRange") @Cached @SuppressWarnings("unused") TruffleString.GetCodeRangeNode getCodeRangeNode) {
            return new AsciiStringBuffer(value);
        }

        @Specialization(guards = "!isAscii(value, getCodeRangeNode)", limit = "1")
        Object nonAsciiString(TruffleString value,
                        @Shared("getCodeRange") @Cached @SuppressWarnings("unused") TruffleString.GetCodeRangeNode getCodeRangeNode) {
            throw raise(ValueError, ErrorMessages.STRING_ARG_SHOULD_CONTAIN_ONLY_ASCII);
        }

        @Specialization
        Object string(PString value,
                        @Cached CastToTruffleStringNode cast,
                        @Shared("getCodeRange") @Cached @SuppressWarnings("unused") TruffleString.GetCodeRangeNode getCodeRangeNode,
                        @Cached ConditionProfile asciiProfile) {
            TruffleString ts = cast.execute(value);
            if (asciiProfile.profile(isAscii(ts, getCodeRangeNode))) {
                return asciiString(ts, getCodeRangeNode);
            } else {
                return nonAsciiString(ts, getCodeRangeNode);
            }
        }

        @Fallback
        Object error(@SuppressWarnings("unused") Object value) {
            throw raise(TypeError, ErrorMessages.ARG_SHOULD_BE_BYTES_BUFFER_OR_ASCII_NOT_P, value);
        }

        @ClinicConverterFactory
        public static AsciiBufferConverter create() {
            return BinasciiModuleBuiltinsFactory.AsciiBufferConverterNodeGen.create();
        }
    }

    @Builtin(name = "a2b_base64", minNumOfPositionalArgs = 1, numOfPositionalOnlyArgs = 1, parameterNames = {"data"})
    @ArgumentClinic(name = "data", conversionClass = AsciiBufferConverter.class)
    @GenerateNodeFactory
    abstract static class A2bBase64Node extends PythonUnaryClinicBuiltinNode {
        @Specialization(limit = "3")
        PBytes doConvert(VirtualFrame frame, Object buffer,
                        @CachedLibrary("buffer") PythonBufferAccessLibrary bufferLib) {
            try {
                ByteSequenceStorage storage = b64decode(bufferLib.getInternalOrCopiedByteArray(buffer), bufferLib.getBufferLength(buffer));
                return factory().createBytes(storage);
            } finally {
                bufferLib.release(buffer, frame, this);
            }
        }

        @TruffleBoundary
        private ByteSequenceStorage b64decode(byte[] data, int dataLen) {
            try {
                /*
                 * The JDK decoder behaves differently in some corner cases. It is more restrictive
                 * regarding superfluous padding. On the other hand, it's more permissive when it
                 * comes to lack of padding. We compute the expected padding ourselves to cover
                 * these two cases manually.
                 */
                // Compute the expected and real padding
                int base64chars = 0;
                int lastBase64Char = -1;
                int padding = 0;
                for (int i = 0; i < dataLen; i++) {
                    byte c = data[i];
                    if (c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z' || c >= '0' && c <= '9' || c == '+' || c == '/') {
                        lastBase64Char = i;
                        base64chars++;
                        padding = 0;
                    }
                    if (c == '=') {
                        padding++;
                    }
                }
                int expectedPadding = 0;
                if (base64chars % 4 == 1) {
                    throw PRaiseNode.raiseUncached(this, BinasciiError, ErrorMessages.INVALID_BASE64_ENCODED_STRING);
                } else if (base64chars % 4 == 2) {
                    expectedPadding = 2;
                } else if (base64chars % 4 == 3) {
                    expectedPadding = 1;
                }
                if (padding < expectedPadding) {
                    throw PRaiseNode.raiseUncached(this, BinasciiError, ErrorMessages.INCORRECT_PADDING);
                }
                // Find the end of the expected padding, if any
                int decodeLen = lastBase64Char + 1;
                int correctedPadding = 0;
                for (int i = decodeLen; correctedPadding < expectedPadding && i < dataLen; i++) {
                    if (data[i] == '=') {
                        correctedPadding++;
                        decodeLen = i + 1;
                    }
                }
                // Using MIME decoder because that one skips over anything that is not the alphabet,
                // just like CPython does
                ByteBuffer result = Base64.getMimeDecoder().decode(ByteBuffer.wrap(data, 0, decodeLen));
                return new ByteSequenceStorage(result.array(), result.limit());
            } catch (IllegalArgumentException e) {
                throw PRaiseNode.raiseUncached(this, BinasciiError, e);
            }
        }

        @Override
        protected ArgumentClinicProvider getArgumentClinic() {
            return BinasciiModuleBuiltinsClinicProviders.A2bBase64NodeClinicProviderGen.INSTANCE;
        }
    }

    @Builtin(name = "a2b_hex", minNumOfPositionalArgs = 1, numOfPositionalOnlyArgs = 1, parameterNames = {"data"})
    @ArgumentClinic(name = "data", conversionClass = AsciiBufferConverter.class)
    @GenerateNodeFactory
    abstract static class A2bHexNode extends PythonUnaryClinicBuiltinNode {
        @Specialization(limit = "3")
        PBytes a2b(VirtualFrame frame, Object buffer,
                        @CachedLibrary("buffer") PythonBufferAccessLibrary bufferLib) {
            try {
                byte[] bytes = a2b(bufferLib.getInternalOrCopiedByteArray(buffer), bufferLib.getBufferLength(buffer));
                return factory().createBytes(bytes);
            } finally {
                bufferLib.release(buffer, frame, this);
            }
        }

        @TruffleBoundary
        private byte[] a2b(byte[] bytes, int length) {
            if (length % 2 != 0) {
                throw PRaiseNode.raiseUncached(this, BinasciiError, ErrorMessages.ODD_LENGTH_STRING);
            }
            byte[] output = new byte[length / 2];
            for (int i = 0; i < length / 2; i++) {
                output[i] = (byte) (digitValue((char) bytes[i * 2]) * 16 + digitValue((char) bytes[i * 2 + 1]));
            }
            return output;
        }

        private int digitValue(char b) {
            if (b >= '0' && b <= '9') {
                return b - '0';
            } else if (b >= 'a' && b <= 'f') {
                return b - 'a' + 10;
            } else if (b >= 'A' && b <= 'F') {
                return b - 'A' + 10;
            } else {
                throw PRaiseNode.raiseUncached(this, BinasciiError, ErrorMessages.NON_HEX_DIGIT_FOUND);
            }
        }

        @Override
        protected ArgumentClinicProvider getArgumentClinic() {
            return BinasciiModuleBuiltinsClinicProviders.A2bHexNodeClinicProviderGen.INSTANCE;
        }
    }

    @Builtin(name = "b2a_base64", minNumOfPositionalArgs = 1, numOfPositionalOnlyArgs = 1, parameterNames = {"data"}, keywordOnlyNames = {"newline"})
    @ArgumentClinic(name = "data", conversion = ArgumentClinic.ClinicConversion.ReadableBuffer)
    @ArgumentClinic(name = "newline", conversion = ArgumentClinic.ClinicConversion.Int, defaultValue = "1", useDefaultForNone = true)
    @GenerateNodeFactory
    abstract static class B2aBase64Node extends PythonClinicBuiltinNode {
        @TruffleBoundary
        private PBytes b2a(byte[] data, int lenght, int newline) {
            ByteBuffer encoded;
            try {
                encoded = Base64.getEncoder().encode(ByteBuffer.wrap(data, 0, lenght));
            } catch (IllegalArgumentException e) {
                throw raise(BinasciiError, e);
            }
            if (newline != 0) {
                byte[] encodedWithNL = Arrays.copyOf(encoded.array(), encoded.limit() + 1);
                encodedWithNL[encodedWithNL.length - 1] = '\n';
                return factory().createBytes(encodedWithNL);
            }
            return factory().createBytes(encoded.array(), encoded.limit());
        }

        @Specialization(limit = "3")
        PBytes b2aBuffer(VirtualFrame frame, Object buffer, int newline,
                        @CachedLibrary("buffer") PythonBufferAccessLibrary bufferLib) {
            try {
                return b2a(bufferLib.getInternalOrCopiedByteArray(buffer), bufferLib.getBufferLength(buffer), newline);
            } finally {
                bufferLib.release(buffer, frame, this);
            }
        }

        @Override
        protected ArgumentClinicProvider getArgumentClinic() {
            return BinasciiModuleBuiltinsClinicProviders.B2aBase64NodeClinicProviderGen.INSTANCE;
        }
    }

    @Builtin(name = "b2a_hex", minNumOfPositionalArgs = 1, parameterNames = {"data", "sep", "bytes_per_sep"})
    @ArgumentClinic(name = "data", conversion = ArgumentClinic.ClinicConversion.ReadableBuffer)
    @ArgumentClinic(name = "bytes_per_sep", conversion = ArgumentClinic.ClinicConversion.Int, defaultValue = "1")
    @GenerateNodeFactory
    abstract static class B2aHexNode extends PythonTernaryClinicBuiltinNode {

        @CompilationFinal(dimensions = 1) private static final byte[] HEX_DIGITS = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};

        @Specialization(limit = "3")
        PBytes b2a(VirtualFrame frame, Object buffer, Object sep, int bytesPerSep,
                        @CachedLibrary("buffer") PythonBufferAccessLibrary bufferLib) {
            if (sep != PNone.NO_VALUE || bytesPerSep != 1) {
                // TODO implement sep and bytes_per_sep
                throw raise(NotImplementedError);
            }
            try {
                return b2a(bufferLib.getInternalOrCopiedByteArray(buffer), bufferLib.getBufferLength(buffer));
            } finally {
                bufferLib.release(buffer, frame, this);
            }
        }

        @TruffleBoundary
        private PBytes b2a(byte[] bytes, int length) {
            byte[] output = new byte[length * 2];
            for (int i = 0; i < length; i++) {
                int v = bytes[i] & 0xff;
                output[i * 2] = HEX_DIGITS[v >> 4];
                output[i * 2 + 1] = HEX_DIGITS[v & 0xf];
            }
            return factory().createBytes(output);
        }

        @Override
        protected ArgumentClinicProvider getArgumentClinic() {
            return BinasciiModuleBuiltinsClinicProviders.B2aHexNodeClinicProviderGen.INSTANCE;
        }
    }

    @Builtin(name = "crc32", minNumOfPositionalArgs = 1, parameterNames = {"data", "crc"})
    @ArgumentClinic(name = "data", conversion = ArgumentClinic.ClinicConversion.ReadableBuffer)
    // TODO crc argument
    @GenerateNodeFactory
    abstract static class Crc32Node extends PythonBinaryClinicBuiltinNode {
        // TODO crc != NO_VALUE
        @Specialization(guards = "isNoValue(crc)", limit = "3")
        long b2a(VirtualFrame frame, Object buffer, @SuppressWarnings("unused") PNone crc,
                        @CachedLibrary("buffer") PythonBufferAccessLibrary bufferLib) {
            try {
                return getCrcValue(bufferLib.getInternalOrCopiedByteArray(buffer), bufferLib.getBufferLength(buffer));
            } finally {
                bufferLib.release(buffer, frame, this);
            }
        }

        @TruffleBoundary
        private static long getCrcValue(byte[] bytes, int length) {
            CRC32 crc32 = new CRC32();
            crc32.update(bytes, 0, length);
            return crc32.getValue();
        }

        @Override
        protected ArgumentClinicProvider getArgumentClinic() {
            return BinasciiModuleBuiltinsClinicProviders.Crc32NodeClinicProviderGen.INSTANCE;
        }
    }

    @Builtin(name = "hexlify", minNumOfPositionalArgs = 1, parameterNames = {"data", "sep", "bytes_per_sep"})
    @ArgumentClinic(name = "data", conversion = ArgumentClinic.ClinicConversion.ReadableBuffer)
    @ArgumentClinic(name = "bytes_per_sep", conversion = ArgumentClinic.ClinicConversion.Int, defaultValue = "1")
    @GenerateNodeFactory
    abstract static class HexlifyNode extends B2aHexNode {
        @Override
        protected ArgumentClinicProvider getArgumentClinic() {
            return BinasciiModuleBuiltinsClinicProviders.HexlifyNodeClinicProviderGen.INSTANCE;
        }
    }

    @Builtin(name = "unhexlify", minNumOfPositionalArgs = 1, numOfPositionalOnlyArgs = 1, parameterNames = {"data"})
    @ArgumentClinic(name = "data", conversionClass = AsciiBufferConverter.class)
    @GenerateNodeFactory
    abstract static class UnhexlifyNode extends A2bHexNode {
        @Override
        protected ArgumentClinicProvider getArgumentClinic() {
            return BinasciiModuleBuiltinsClinicProviders.UnhexlifyNodeClinicProviderGen.INSTANCE;
        }
    }
}
