GtkSharp/Source/Libs/GLibSharp/AbiField.cs

178 lines
4.1 KiB
C#

// AbiField.cs - Utility to handle complex C structure ABI.
//
// Authors: Thibault Saunier <thibault.saunier@osg.samsung.com>
//
// Copyright (c) 2017 Thibault Saunier
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of version 2 of the Lesser GNU General
// Public License as published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this program; if not, write to the
// Free Software Foundation, Inc., 59 Temple Place - Suite 330,
// Boston, MA 02111-1307, USA.
// Helper utility to build C structure ABI even when using complex
// packing with union and bit fields. It basically uses the same
// logic as what is done inside csharp implementation (marshal.c in
// the mono codebase) but handling more things.
namespace GLib {
using System;
using System.Collections.Generic;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Linq;
using System.Collections.Specialized;
using System.CodeDom.Compiler;
public class AbiField {
public string Prev_name;
public string Next_name;
public string Name;
public long Offset;
public long Align;
public uint Natural_size;
public AbiStruct container;
public OrderedDictionary Parent_fields; // field_name<string> -> AbiField<> dictionary.
List<List<string>> Union_fields;
long End;
long Size;
public uint Bits;
public AbiField(string name,
long offset,
uint natural_size,
string prev_fieldname,
string next_fieldname,
long align,
uint bits)
{
Name = name;
Offset = offset;
Natural_size = natural_size;
Prev_name = prev_fieldname;
Next_name = next_fieldname;
End = -1;
Size = -1;
Union_fields = null;
Align = (long) align;
Bits = bits;
if (Bits > 0) {
var nbytes = (uint) (Math.Ceiling((double) Bits / (double) 8));
if (nbytes < GetSize())
Align = 1;
else // Like if no bitfields were used.
Bits = 0;
}
}
public AbiField(string name,
OrderedDictionary parent_fields,
uint natural_size,
string prev_fieldname,
string next_fieldname,
long align,
uint bits): this (name, -1,
natural_size, prev_fieldname, next_fieldname, align, bits)
{
Parent_fields = parent_fields;
}
public AbiField(string name,
long offset,
List<List<string>> fields_lists,
string prev_fieldname,
string next_fieldname, uint bits): this(name,
offset, (uint) 0, prev_fieldname, next_fieldname,
-1, bits)
{
Union_fields = fields_lists;
}
public uint GetEnd() {
if (End == -1)
End = (long) GetOffset() + GetSize();
return (uint) End;
}
public uint GetOffset() {
return (uint) Offset;
}
public bool InUnion () {
return Name.Contains(".");
}
public uint GetAlign () {
if (Union_fields != null) {
uint align = 1;
foreach (var fieldnames in Union_fields) {
foreach (var fieldname in fieldnames) {
var field = (AbiField) container.Fields[fieldname];
align = Math.Max(align, field.GetAlign());
}
}
return align;
}
return (uint) Align;
}
public uint GetUnionSize() {
uint size = 0;
foreach (var fieldnames in Union_fields) {
foreach (var fieldname in fieldnames) {
var field = ((AbiField) container.Fields[fieldname]);
var align = field.GetAlign();
if (field.Prev_name != null) {
var prev = ((AbiField)container.Fields[field.Prev_name]);
if (!prev.InUnion())
field.Offset = Offset;
else
field.Offset = prev.GetEnd();
}
field.Offset += align - 1;
field.Offset &= ~(align - 1);
size = Math.Max(size, field.GetEnd() - (uint) Offset);
}
}
return size;
}
public uint GetSize() {
if (Size != -1)
return (uint) Size;
if (Union_fields != null) {
Size = GetUnionSize();
} else {
Size = Natural_size;
}
return (uint) Size;
}
}
}