//
// Image.cs
//
// Author:
//   Jb Evain (jbevain@gmail.com)
//
// Copyright (c) 2008 - 2011 Jb Evain
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

using System;

using Mono;
using Mono.Cecil.Cil;
using Mono.Cecil.Metadata;

using RVA = System.UInt32;

namespace Mono.Cecil.PE
{

    sealed class Image
    {

        public ModuleKind Kind;
        public TargetRuntime Runtime;
        public TargetArchitecture Architecture;
        public ModuleCharacteristics Characteristics;
        public string FileName;

        public Section[] Sections;

        public Section MetadataSection;

        public uint EntryPointToken;
        public ModuleAttributes Attributes;

        public DataDirectory Debug;
        public DataDirectory Resources;
        public DataDirectory StrongName;

        public StringHeap StringHeap;
        public BlobHeap BlobHeap;
        public UserStringHeap UserStringHeap;
        public GuidHeap GuidHeap;
        public TableHeap TableHeap;

        readonly int[] coded_index_sizes = new int[13];

        readonly Func<Table, int> counter;

        public Image()
        {
            counter = GetTableLength;
        }

        public bool HasTable(Table table)
        {
            return GetTableLength(table) > 0;
        }

        public int GetTableLength(Table table)
        {
            return (int)TableHeap[table].Length;
        }

        public int GetTableIndexSize(Table table)
        {
            return GetTableLength(table) < 65536 ? 2 : 4;
        }

        public int GetCodedIndexSize(CodedIndex coded_index)
        {
            var index = (int)coded_index;
            var size = coded_index_sizes[index];
            if (size != 0)
                return size;

            return coded_index_sizes[index] = Mixin.GetSize(coded_index, counter);
        }

        public uint ResolveVirtualAddress(RVA rva)
        {
            var section = GetSectionAtVirtualAddress(rva);
            if (section == null)
                throw new ArgumentOutOfRangeException();

            return ResolveVirtualAddressInSection(rva, section);
        }

        public uint ResolveVirtualAddressInSection(RVA rva, Section section)
        {
            return rva + section.PointerToRawData - section.VirtualAddress;
        }

        public Section GetSection(string name)
        {
            var sections = this.Sections;
            for (int i = 0; i < sections.Length; i++)
            {
                var section = sections[i];
                if (section.Name == name)
                    return section;
            }

            return null;
        }

        public Section GetSectionAtVirtualAddress(RVA rva)
        {
            var sections = this.Sections;
            for (int i = 0; i < sections.Length; i++)
            {
                var section = sections[i];
                if (rva >= section.VirtualAddress && rva < section.VirtualAddress + section.SizeOfRawData)
                    return section;
            }

            return null;
        }

        public ImageDebugDirectory GetDebugHeader(out byte[] header)
        {
            var section = GetSectionAtVirtualAddress(Debug.VirtualAddress);
            var buffer = new ByteBuffer(section.Data);
            buffer.position = (int)(Debug.VirtualAddress - section.VirtualAddress);

            var directory = new ImageDebugDirectory
            {
                Characteristics = buffer.ReadInt32(),
                TimeDateStamp = buffer.ReadInt32(),
                MajorVersion = buffer.ReadInt16(),
                MinorVersion = buffer.ReadInt16(),
                Type = buffer.ReadInt32(),
                SizeOfData = buffer.ReadInt32(),
                AddressOfRawData = buffer.ReadInt32(),
                PointerToRawData = buffer.ReadInt32(),
            };

            buffer.position = (int)(directory.PointerToRawData - section.PointerToRawData);

            header = new byte[directory.SizeOfData];
            Buffer.BlockCopy(buffer.buffer, buffer.position, header, 0, header.Length);

            return directory;
        }
    }
}