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// Copyright (C) 2003-2008 Dolphin Project.
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 2.0.
// 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 General Public License 2.0 for more details.
// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/
// Official SVN repository and contact information can be found at
// http://code.google.com/p/dolphin-emu/
#include "Common.h"
#include "ChunkFile.h"
#include <stdio.h>
// Not using file mapping, just bog standard fopen and friends. We trust them to be fast
// enough to not be the bottleneck.
ChunkFile::ChunkFile(const char *filename, ChunkFileMode _mode)
{
mode = _mode;
data = 0;
didFail = false;
f = fopen(filename, mode == MODE_WRITE ? "wb" : "rb");
if (!f) {
didFail = true;
return;
}
fseek(f, 0, SEEK_END);
fsize = ftell(f);
eof = fsize;
stack_ptr = 0;
}
ChunkFile::~ChunkFile()
{
if (f)
fclose(f);
}
int ChunkFile::ReadInt()
{
int x;
fread(&x, 4, 1, f);
return x;
}
void ChunkFile::WriteInt(int x)
{
fwrite(&x, 4, 1, f);
}
bool ChunkFile::Do(void *ptr, int size)
{
int sz;
switch (mode) {
case MODE_READ:
sz = ReadInt();
if (sz != size)
return false;
fread(ptr, size, 1, f);
fseek(f, ((size + 3) & ~3) - size, SEEK_CUR);
break;
case MODE_WRITE:
WriteInt(size);
fwrite(ptr, size, 1, f);
fseek(f, ((size + 3) & ~3) - size, SEEK_CUR);
break;
case MODE_VERIFY:
sz = ReadInt();
if (sz != size)
return false;
fseek(f, (size + 3) & ~3, SEEK_CUR);
break;
}
return true;
}
// Do variable size array (probably heap-allocated)
bool ChunkFile::DoArray(void *ptr, int size, int arrSize) {
int sz;
if(ptr == NULL)
return false;
switch (mode) {
case MODE_READ:
sz = ReadInt();
if (sz != size)
return false;
sz = ReadInt();
if (sz != arrSize)
return false;
fread(ptr, arrSize * size, 1, f);
fseek(f, (((arrSize * size) + 3) & ~3) - (arrSize * size),
SEEK_CUR);
break;
case MODE_WRITE:
WriteInt(size);
WriteInt(arrSize);
fwrite(ptr, arrSize * size, 1, f);
fseek(f, (((arrSize * size) + 3) & ~3) - (arrSize * size),
SEEK_CUR);
break;
case MODE_VERIFY:
sz = ReadInt();
if (sz != size)
return false;
sz = ReadInt();
if (sz != arrSize)
return false;
for(int i = 0; i < arrSize; i++)
fseek(f, (size + 3) & ~3, SEEK_CUR);
break;
}
return true;
}
//let's get into the business
bool ChunkFile::Descend(const char *cid)
{
unsigned int id = *reinterpret_cast<const unsigned int*>(cid);
if (mode == MODE_READ)
{
bool found = false;
int startPos = ftell(f);
ChunkInfo temp = stack[stack_ptr];
//save information to restore after the next Ascend
stack[stack_ptr].parentStartLocation = startPos;
stack[stack_ptr].parentEOF = eof;
unsigned int firstID = 0;
//let's search through children..
while (ftell(f) < eof)
{
stack[stack_ptr].ID = ReadInt();
if (firstID == 0)
firstID = stack[stack_ptr].ID|1;
stack[stack_ptr].length = ReadInt();
stack[stack_ptr].startLocation = ftell(f);
if (stack[stack_ptr].ID == id)
{
found = true;
break;
}
else
{
fseek(f, stack[stack_ptr].length, SEEK_CUR); //try next block
}
}
//if we found nothing, return false so the caller can skip this
if (!found)
{
stack[stack_ptr] = temp;
fseek(f, stack[stack_ptr].parentStartLocation, SEEK_SET);
return false;
}
//descend into it
//pos was set inside the loop above
eof = stack[stack_ptr].startLocation + stack[stack_ptr].length;
stack_ptr++;
return true;
}
else
{
//write a chunk id, and prepare for filling in length later
WriteInt(id);
WriteInt(0); //will be filled in by Ascend
stack[stack_ptr].startLocation = ftell(f);
stack_ptr++;
return true;
}
}
//let's ascend out
void ChunkFile::Ascend()
{
if (mode == MODE_READ)
{
//ascend, and restore information
stack_ptr--;
fseek(f, stack[stack_ptr].parentStartLocation, SEEK_SET);
eof = stack[stack_ptr].parentEOF;
}
else
{
stack_ptr--;
//now fill in the written length automatically
int posNow = ftell(f);
fseek(f, stack[stack_ptr].startLocation - 4, SEEK_SET);
WriteInt(posNow - stack[stack_ptr].startLocation);
fseek(f, posNow, SEEK_SET);
}
}
int ChunkFile::GetCurrentChunkSize()
{
if (stack_ptr)
return stack[stack_ptr - 1].length;
else
return 0;
}
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