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 * 1. Redistributions of source code must retain the above copyright notice, this list of
 * conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided
 * with the distribution.
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 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific prior written
 * permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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package com.oracle.truffle.llvm.parser.macho;

import java.util.Arrays;
import java.util.List;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import com.oracle.truffle.llvm.parser.macho.MachOSegmentCommand.MachOSection;
import com.oracle.truffle.llvm.runtime.Magic;
import com.oracle.truffle.llvm.runtime.except.LLVMParserException;
import org.graalvm.polyglot.io.ByteSequence;

public final class MachOFile {

    private static final String INTERMEDIATE_SEGMENT = "";
    private static final String BITCODE_SECTION = "__bitcode";
    private static final String LLVM_SEGMENT = "__LLVM";
    private static final String BUNDLE_SECTION = "__bundle";

    private static final int MH_OBJECT = 0x1; /* relocatable object file */
    private static final int MH_EXECUTE = 0x2; /* demand paged executable file */
    private static final int MH_DYLIB = 0x6; /* dynamically bound shared library */
    private static final int MH_BUNDLE = 0x8; /* dynamicly bound bundle file */

    // currently unused types:
    @SuppressWarnings("unused") private static final int MH_FVMLIB = 0x3;
    @SuppressWarnings("unused") private static final int MH_CORE = 0x4;
    @SuppressWarnings("unused") private static final int MH_PRELOAD = 0x5;
    @SuppressWarnings("unused") private static final int MH_DYLINKER = 0x7;
    @SuppressWarnings("unused") private static final int MH_DYLIB_STUB = 0x9;

    private final MachOHeader header;
    private final MachOLoadCommandTable loadCommandTable;
    private final ByteSequence buffer;

    MachOFile(MachOHeader header, MachOLoadCommandTable loadCommandTable, ByteSequence buffer) {
        this.header = header;
        this.loadCommandTable = loadCommandTable;
        this.buffer = buffer;
    }

    public MachOSegmentCommand getSegment(String name) {
        return loadCommandTable.getSegment(name);
    }

    public MachOHeader getHeader() {
        return header;
    }

    private Stream<MachOLoadCommand> getLoadCommand(int cmdId) {
        return Arrays.stream(loadCommandTable.getLoadCommands()).filter(cmd -> cmd.getCmd() == cmdId);
    }

    public List<String> getDyLibs(String origin) {
        return getLoadCommand(MachOLoadCommand.LC_LOAD_DYLIB).map(MachODylibCommand.class::cast).map(e -> fixupRPath(origin, e.getName())).collect(Collectors.toList());
    }

    public List<String> getRPaths(String origin) {
        return getLoadCommand(MachOLoadCommand.LC_RPATH).map(MachORPathCommand.class::cast).map(e -> fixupRPath(origin, e.getName())).collect(Collectors.toList());
    }

    private static final Pattern RPATH_PATTERN = Pattern.compile("@loader_path");

    
Replaces special rpath tokens. Currently, only @loader_path is supported and will be replace by the directory containing executable or shared object. /**
     * Replaces special rpath tokens. Currently, only {@code @loader_path} is supported and will be
     * replace by the directory containing executable or shared object.
     */
    private static String fixupRPath(String origin, String path) {
        if (origin == null) {
            return path;
        }
        return RPATH_PATTERN.matcher(path).replaceAll(origin);
    }

    public ByteSequence extractBitcode() {
        switch (header.getFileType()) {
            case MH_OBJECT:
                return getSectionData(INTERMEDIATE_SEGMENT, BITCODE_SECTION);
            case MH_DYLIB:
            case MH_BUNDLE:
            case MH_EXECUTE:
                return getSectionData(LLVM_SEGMENT, BUNDLE_SECTION);
            default:
                throw new LLVMParserException("Mach-O file type not supported!");
        }
    }

    public ByteSequence getSectionData(String segment, String section) {
        MachOSegmentCommand seg = loadCommandTable.getSegment(segment);

        if (seg == null) {
            // Mach-O file does not contain the segment
            return null;
        }

        MachOSection sect = seg.getSection(section);

        if (sect == null) {
            // Mach-O file does not contain a section
            return null;
        }

        int offset = sect.getOffset();
        long size = sect.getSize();

        return buffer.subSequence(offset, offset + (int) size);
    }

    public static MachOFile create(ByteSequence data) {
        return MachOReader.create(data);
    }

    public static boolean isMachOMagicNumber(long magic) {
        return isMachO32MagicNumber(magic) || isMachO64MagicNumber(magic);
    }

    public static boolean isMachO32MagicNumber(long magic) {
        return magic == Magic.MH_MAGIC.magic || magic == Magic.MH_CIGAM.magic;
    }

    public static boolean isMachO64MagicNumber(long magic) {
        return magic == Magic.MH_MAGIC_64.magic || magic == Magic.MH_CIGAM_64.magic;
    }

}