mkxp/src/filesystem.cpp

/*
** filesystem.cpp
**
** This file is part of mkxp.
**
** Copyright (C) 2013 Jonas Kulla <Nyocurio@gmail.com>
**
** mkxp 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, either version 2 of the License, or
** (at your option) any later version.
**
** mkxp 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 for more details.
**
** You should have received a copy of the GNU General Public License
** along with mkxp.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "filesystem.h"

#include "util.h"
#include "exception.h"

#include "physfs.h"

#include <QHash>
#include <QSet>
#include <QByteArray>

#include "stdio.h"
#include "string.h"

#include <QDebug>

struct RGSS_entryData
{
	int64_t offset;
	uint64_t size;
	uint32_t startMagic;
};

struct RGSS_entryHandle
{
	RGSS_entryData data;
	uint32_t currentMagic;
	uint64_t currentOffset;
	PHYSFS_Io *io;

	RGSS_entryHandle(const RGSS_entryData &data, PHYSFS_Io *archIo)
	    : data(data),
	      currentMagic(data.startMagic),
	      currentOffset(0)
	{
		io = archIo->duplicate(archIo);
	}

	~RGSS_entryHandle()
	{
		io->destroy(io);
	}
};

typedef QList<QByteArray> QByteList;

struct RGSS_archiveData
{
	PHYSFS_Io *archiveIo;

	/* Maps: file path
	 * to:   entry data */
	QHash<QByteArray, RGSS_entryData> entryHash;

	/* Maps: directory path,
	 * to:   list of contained entries */
	QHash<QByteArray, QSet<QByteArray> > dirHash;
};

static bool
readUint32(PHYSFS_Io *io, uint32_t &result)
{
	char buff[4];
	PHYSFS_sint64 count = io->read(io, buff, 4);

	result = ((buff[0] << 0x00) & 0x000000FF) |
	         ((buff[1] << 0x08) & 0x0000FF00) |
	         ((buff[2] << 0x10) & 0x00FF0000) |
	         ((buff[3] << 0x18) & 0xFF000000) ;

	return (count == 4);
}

#define RGSS_HEADER_1 0x53534752
#define RGSS_HEADER_2 0x01004441

#define RGSS_MAGIC 0xDEADCAFE

#define PHYSFS_ALLOC(type) \
	static_cast<type*>(PHYSFS_getAllocator()->Malloc(sizeof(type)))

static inline uint32_t
advanceMagic(uint32_t &magic)
{
	uint32_t old = magic;

	magic = magic * 7 + 3;

	return old;
}

struct MagicState
{
	uint32_t magic;
	uint64_t offset;

	MagicState(uint64_t offset = 0)
	    : offset(offset)
	{
		magic = RGSS_MAGIC;

		for (uint i = 0; i < (offset/4); ++i)
			advanceBlock();
	}

	uint8_t advancePath()
	{
		uint8_t ret = magic & 0xFF;

		offset++;
		advanceBlock();

		return ret;
	}

	uint8_t advanceData()
	{
		uint8_t ret = magic & 0xFF;

		if (offset++ % 4 == 0)
			advanceBlock();

		return ret;
	}

private:
	void advanceBlock()
	{
		magic = magic * 7 + 3;
	}
};

static PHYSFS_sint64
RGSS_ioRead(PHYSFS_Io *self, void *buffer, PHYSFS_uint64 len)
{
	RGSS_entryHandle *entry = static_cast<RGSS_entryHandle*>(self->opaque);

	PHYSFS_Io *io = entry->io;

	uint64_t toRead = min<uint64_t>(entry->data.size - entry->currentOffset, len);
	uint64_t offs = entry->currentOffset;

	io->seek(io, entry->data.offset + offs);

	/* We divide up the bytes to be read in 3 categories:
	 *
	 * preAlign: If the current read address is not dword
	 *   aligned, this is the number of bytes to read til
	 *   we reach alignment again (therefore can only be
	 *   3 or less).
	 *
	 * align: The number of aligned dwords we can read
	 *   times 4 (= number of bytes).
	 *
	 * postAlign: The number of bytes to read after the
	 *   last aligned dword. Always 3 or less.
	 *
	 * Treating the pre- and post aligned reads specially,
	 * we can read all aligned dwords in one syscall directly
	 * into the write buffer and then run the xor chain on
	 * it afterwards. */

	uint8_t preAlign = 4 - (offs % 4);

	if (preAlign == 4)
		preAlign = 0;
	else
		preAlign = min<uint64_t>(preAlign, len);

	uint8_t postAlign = (len > preAlign) ? (offs + len) % 4 : 0;

	uint64_t align = len - (preAlign + postAlign);

	/* Byte buffer pointer */
	uint8_t *bBufferP = static_cast<uint8_t*>(buffer);

	if (preAlign > 0)
	{
		uint32_t dword;
		io->read(io, &dword, preAlign);

		/* Need to align the bytes with the
		 * magic before xoring */
		dword <<= 8 * (offs % 4);
		dword ^= entry->currentMagic;

		/* Shift them back to normal */
		dword >>= 8 * (offs % 4);
		memcpy(bBufferP, &dword, preAlign);

		bBufferP += preAlign;

		/* Only advance the magic if we actually
		 * reached the next alignment */
		if ((offs+preAlign) % 4 == 0)
			advanceMagic(entry->currentMagic);
	}

	if (align > 0)
	{
		/* Double word buffer pointer */
		uint32_t *dwBufferP = reinterpret_cast<uint32_t*>(bBufferP);

		/* Read aligned dwords in one go */
		io->read(io, bBufferP, align);

		/* Then xor them */
		for (uint64_t i = 0; i < (align / 4); ++i)
			dwBufferP[i] ^= advanceMagic(entry->currentMagic);

		bBufferP += align;
	}

	if (postAlign > 0)
	{
		uint32_t dword;
		io->read(io, &dword, postAlign);

		/* Bytes are already aligned with magic */
		dword ^= entry->currentMagic;
		memcpy(bBufferP, &dword, postAlign);
	}

	entry->currentOffset += toRead;

	return toRead;
}

static int
RGSS_ioSeek(PHYSFS_Io *self, PHYSFS_uint64 offset)
{
	RGSS_entryHandle *entry = static_cast<RGSS_entryHandle*>(self->opaque);

	if (offset == entry->currentOffset)
		return 1;

	if (offset > entry->data.size-1)
		return 0;

	/* If rewinding, we need to rewind to begining */
	if (offset < entry->currentOffset)
	{
		entry->currentOffset = 0;
		entry->currentMagic = entry->data.startMagic;
	}

	/* For each overstepped alignment, advance magic */
	uint64_t currentDword = entry->currentOffset / 4;
	uint64_t targetDword  = offset / 4;
	uint64_t dwordsSought = targetDword - currentDword;

	for (uint64_t i = 0; i < dwordsSought; ++i)
		advanceMagic(entry->currentMagic);

	entry->currentOffset = offset;
	entry->io->seek(entry->io, entry->data.offset + entry->currentOffset);

	return 1;
}

static PHYSFS_sint64
RGSS_ioTell(PHYSFS_Io *self)
{
	RGSS_entryHandle *entry = static_cast<RGSS_entryHandle*>(self->opaque);

	return entry->currentOffset;
}

static PHYSFS_sint64
RGSS_ioLength(PHYSFS_Io *self)
{
	RGSS_entryHandle *entry = static_cast<RGSS_entryHandle*>(self->opaque);

	return entry->data.size;
}

static PHYSFS_Io*
RGSS_ioDuplicate(PHYSFS_Io *self)
{
	RGSS_entryHandle *entry = static_cast<RGSS_entryHandle*>(self->opaque);
	RGSS_entryHandle *entryDup = new RGSS_entryHandle(*entry);

	PHYSFS_Io *dup = PHYSFS_ALLOC(PHYSFS_Io);
	*dup = *self;
	dup->opaque = entryDup;

	return dup;
}

static void
RGSS_ioDestroy(PHYSFS_Io *self)
{
	RGSS_entryHandle *entry = static_cast<RGSS_entryHandle*>(self->opaque);

	delete entry;

	PHYSFS_getAllocator()->Free(self);
}

static const PHYSFS_Io RGSS_IoTemplate =
{
    0, /* version */
    0, /* opaque */
    RGSS_ioRead,
    0, /* write */
    RGSS_ioSeek,
    RGSS_ioTell,
    RGSS_ioLength,
    RGSS_ioDuplicate,
    0, /* flush */
    RGSS_ioDestroy
};

static void*
RGSS_openArchive(PHYSFS_Io *io, const char *, int forWrite)
{
	if (forWrite)
		return 0;

	/* Check header */
	uint32_t header1, header2;
	readUint32(io, header1);
	readUint32(io, header2);

	if (header1 != RGSS_HEADER_1 || header2 != RGSS_HEADER_2)
		return 0;

	RGSS_archiveData *data = new RGSS_archiveData;
	data->archiveIo = io;

	uint32_t magic = RGSS_MAGIC;

	/* Top level entry list */
	QSet<QByteArray> &topLevel = data->dirHash["."];

	while (true)
	{
		/* Read filename length,
         * if nothing was read, no files remain */
		uint32_t nameLen;
		if (!readUint32(io, nameLen))
			break;

		nameLen ^= advanceMagic(magic);

		static char nameBuf[512];
		uint i;
		for (i = 0; i < nameLen; ++i)
		{
			char c;
			io->read(io, &c, 1);
			nameBuf[i] = c ^ (advanceMagic(magic) & 0xFF);
			if (nameBuf[i] == '\\')
				nameBuf[i] = '/';
		}
		nameBuf[i] = 0;

		uint32_t entrySize;
		readUint32(io, entrySize);
		entrySize ^= advanceMagic(magic);

		RGSS_entryData entry;
		entry.offset = io->tell(io);
		entry.size = entrySize;
		entry.startMagic = magic;

		data->entryHash.insert(nameBuf, entry);

		/* Check for top level entries */
		for (i = 0; i < nameLen; ++i)
		{
			bool slash = nameBuf[i] == '/';
			if (!slash && i+1 < nameLen)
				continue;

			if (slash)
				nameBuf[i] = '\0';

			topLevel.insert(nameBuf);

			if (slash)
				nameBuf[i] = '/';
		}

		/* Check for more entries */
		for (i = nameLen; i > 0; i--)
			if (nameBuf[i] == '/')
			{
				nameBuf[i] = '\0';

				const char *dir = nameBuf;
				const char *entry = &nameBuf[i+1];

				QSet<QByteArray> &entryList = data->dirHash[dir];
				entryList.insert(entry);
			}

		io->seek(io, entry.offset + entry.size);
	}

	return data;
}

static void
RGSS_enumerateFiles(void *opaque, const char *dirname,
                    PHYSFS_EnumFilesCallback cb,
                    const char *origdir, void *callbackdata)
{
	RGSS_archiveData *data = static_cast<RGSS_archiveData*>(opaque);

	QByteArray _dirname(dirname);

	if (!data->dirHash.contains(_dirname))
		return;

	const QSet<QByteArray> &entries = data->dirHash.value(_dirname);

	QSet<QByteArray>::const_iterator iter;
	for (iter = entries.begin(); iter != entries.end(); ++iter)
		cb(callbackdata, origdir, iter->constData());
}

static PHYSFS_Io*
RGSS_openRead(void *opaque, const char *filename)
{
	RGSS_archiveData *data = static_cast<RGSS_archiveData*>(opaque);

	if (!data->entryHash.contains(filename))
		return 0;

	RGSS_entryHandle *entry =
	        new RGSS_entryHandle(data->entryHash[filename], data->archiveIo);

	PHYSFS_Io *io = PHYSFS_ALLOC(PHYSFS_Io);

	*io = RGSS_IoTemplate;
	io->opaque = entry;

	return io;
}

static int
RGSS_stat(void *opaque, const char *filename, PHYSFS_Stat *stat)
{
	RGSS_archiveData *data = static_cast<RGSS_archiveData*>(opaque);

	bool hasFile = data->entryHash.contains(filename);
	bool hasDir  = data->dirHash.contains(filename);

	if (!hasFile && !hasDir)
	{
		PHYSFS_setErrorCode(PHYSFS_ERR_NOT_FOUND);
		return 0;
	}

	stat->modtime    =
	stat->createtime =
	stat->accesstime = 0;
	stat->readonly   = 1;

	if (hasFile)
	{
		RGSS_entryData &entry = data->entryHash[filename];

		stat->filesize = entry.size;
		stat->filetype = PHYSFS_FILETYPE_REGULAR;
	}
	else
	{
		stat->filesize = 0;
		stat->filetype = PHYSFS_FILETYPE_DIRECTORY;
	}

	return 1;
}

static void
RGSS_closeArchive(void *opaque)
{
	RGSS_archiveData *data = static_cast<RGSS_archiveData*>(opaque);

	delete data;
}

static PHYSFS_Io*
RGSS_noop1(void*, const char*)
{
	return 0;
}

static int
RGSS_noop2(void*, const char*)
{
	return 0;
}

static const PHYSFS_Archiver RGSS_Archiver =
{
	0,
    {
        "RGSSAD",
        "RGSS encrypted archive format",
        "Jonas Kulla <Nyocurio@gmail.com>",
        "http://k-du.de/rgss/rgss.html",
        0 /* symlinks not supported */
    },
    RGSS_openArchive,
    RGSS_enumerateFiles,
    RGSS_openRead,
    RGSS_noop1, /* openWrite */
    RGSS_noop1, /* openAppend */
    RGSS_noop2, /* remove */
    RGSS_noop2, /* mkdir */
    RGSS_stat,
    RGSS_closeArchive
};

FileStream::FileStream(PHYSFS_File *file)
{
	p = file;
}

FileStream::~FileStream()
{
//	if (p)
//		PHYSFS_close(p);
}

void FileStream::operator=(const FileStream &o)
{
	p = o.p;
}

sf::Int64 FileStream::read(void *data, sf::Int64 size)
{
	if (!p)
		return -1;

	return PHYSFS_readBytes(p, data, size);
}

sf::Int64 FileStream::seek(sf::Int64 position)
{
	if (!p)
		return -1;

	int success = PHYSFS_seek(p, (PHYSFS_uint64) position);

	return success ? position : -1;
}

sf::Int64 FileStream::tell()
{
	if (!p)
		return -1;

	return PHYSFS_tell(p);
}

sf::Int64 FileStream::getSize()
{
	if (!p)
		return -1;

	return PHYSFS_fileLength(p);
}

sf::Int64 FileStream::write(const void *data, sf::Int64 size)
{
	if (!p)
		return -1;

	return PHYSFS_writeBytes(p, data, size);
}

void FileStream::close()
{
	if (p)
	{
		PHYSFS_close(p);
		p = 0;
	}
}

static const char *imgExt[] =
{
	"jpg",
	"png"
};

static const char *audExt[] =
{
//	"mid",
//	"midi",
//	"mp3",
//	"wma",
	"ogg",
	"wav"
};

static const char *fonExt[] =
{
    "ttf"
};

struct FileExtensions
{
	const char **ext;
	int count;
} fileExtensions[] =
{
	{ imgExt, ARRAY_SIZE(imgExt) },
	{ audExt, ARRAY_SIZE(audExt) },
	{ fonExt, ARRAY_SIZE(fonExt) }
};

struct FileSystemPrivate
{
	/* All keys are lower case */
	QHash<QByteArray, QByteArray> pathCache;

	const char *completeFileName(const char *filename,
	                             FileSystem::FileType type)
	{
		char buff[512];
		size_t i;

		for (i = 0; i < sizeof(buff) && filename[i]; ++i)
			buff[i] = tolower(filename[i]);

		buff[i] = '\0';

		QByteArray key(buff);

		if (pathCache.contains(key))
			return pathCache[key].constData();

		char buff2[512];

		if (type != FileSystem::Undefined)
		{
			FileExtensions *extTest = &fileExtensions[type];
			for (int i = 0; i < extTest->count; ++i)
			{
				snprintf(buff2, sizeof(buff2), "%s.%s", buff, extTest->ext[i]);

				key = buff2;
				if (pathCache.contains(key))
					return pathCache[key].constData();
			}
		}

		return 0;
	}

	PHYSFS_File *openReadInt(const char *filename,
	                         FileSystem::FileType type)
	{
		const char *foundName = completeFileName(filename, type);

		if (!foundName)
			throw Exception(Exception::NoFileError,
		                "No such file or directory - %s", filename);

		PHYSFS_File *handle = PHYSFS_openRead(foundName);
		if (!handle)
			throw Exception(Exception::PHYSFSError, "PhysFS: %s", PHYSFS_getLastError());

		return handle;
	}
};

FileSystem::FileSystem(const char *argv0,
                       bool allowSymlinks)
{
	p = new FileSystemPrivate;

	PHYSFS_init(argv0);
	PHYSFS_registerArchiver(&RGSS_Archiver);

	if (allowSymlinks)
		PHYSFS_permitSymbolicLinks(1);
}

FileSystem::~FileSystem()
{
	delete p;

	if (PHYSFS_deinit() == 0)
		qDebug() << "PhyFS failed to deinit.";
}

void FileSystem::addPath(const char *path)
{
	PHYSFS_mount(path, 0, 1);
}

static void cacheEnumCB(void *d, const char *origdir,
                        const char *fname)
{
	FileSystemPrivate *p = static_cast<FileSystemPrivate*>(d);

	char buf[512];

	if (*origdir != '.')
		snprintf(buf, sizeof(buf), "%s/%s", origdir, fname);
	else
		strncpy(buf, fname, sizeof(buf));

	QByteArray mixedCase(buf);

	for (char *p = buf; *p; ++p)
		*p = tolower(*p);

	QByteArray lowerCase(buf);

	p->pathCache.insert(lowerCase, mixedCase);

	PHYSFS_enumerateFilesCallback(mixedCase.constData(), cacheEnumCB, p);
}

void FileSystem::createPathCache()
{
	PHYSFS_enumerateFilesCallback(".", cacheEnumCB, p);
}

FileStream FileSystem::openRead(const char *filename,
                                FileType type)
{
	PHYSFS_File *handle = p->openReadInt(filename, type);

	return FileStream(handle);
}

static inline PHYSFS_File *sdlPHYS(SDL_RWops *ops)
{
	return static_cast<PHYSFS_File*>(ops->hidden.unknown.data1);
}

static Sint64 SDL_RWopsSize(SDL_RWops *ops)
{
	PHYSFS_File *f = sdlPHYS(ops);

	if (!f)
		return -1;

	return PHYSFS_fileLength(f);
}

static Sint64 SDL_RWopsSeek(SDL_RWops *ops, Sint64 offset, int whence)
{
	PHYSFS_File *f = sdlPHYS(ops);

	if (!f)
		return -1;

	Sint64 base;
	switch (whence)
	{
	default:
	case RW_SEEK_SET :
		base = 0;
		break;
	case RW_SEEK_CUR :
		base = PHYSFS_tell(f);
		break;
	case RW_SEEK_END :
		base = PHYSFS_fileLength(f);
		break;
	}

	int result = PHYSFS_seek(f, base + offset);

	return (result != 0) ? PHYSFS_tell(f) : -1;
}

static size_t SDL_RWopsRead(SDL_RWops *ops, void *buffer, size_t size, size_t maxnum)
{
	PHYSFS_File *f = sdlPHYS(ops);

	if (!f)
		return 0;

	PHYSFS_sint64 result = PHYSFS_readBytes(f, buffer, size*maxnum);

	return (result != -1) ? (result / size) : 0;
}

static size_t SDL_RWopsWrite(SDL_RWops *ops, const void *buffer, size_t size, size_t num)
{
	PHYSFS_File *f = sdlPHYS(ops);

	if (!f)
		return 0;

	PHYSFS_sint64 result = PHYSFS_writeBytes(f, buffer, size*num);

	return (result != -1) ? (result / size) : 0;
}

static int SDL_RWopsClose(SDL_RWops *ops)
{
	PHYSFS_File *f = sdlPHYS(ops);

	if (!f)
		return -1;

	int result = PHYSFS_close(f);

	f = 0;

	return (result != 0) ? 0 : -1;
}

static int SDL_RWopsCloseFree(SDL_RWops *ops)
{
	int result = SDL_RWopsClose(ops);

	SDL_FreeRW(ops);

	return result;
}

const Uint32 SDL_RWOPS_PHYSFS = SDL_RWOPS_UNKNOWN+10;

void FileSystem::openRead(SDL_RWops &ops,
                          const char *filename,
                          FileType type,
                          bool freeOnClose)
{
	PHYSFS_File *handle = p->openReadInt(filename, type);

	ops.size  = SDL_RWopsSize;
	ops.seek  = SDL_RWopsSeek;
	ops.read  = SDL_RWopsRead;
	ops.write = SDL_RWopsWrite;

	if (freeOnClose)
		ops.close = SDL_RWopsCloseFree;
	else
		ops.close = SDL_RWopsClose;

	ops.type = SDL_RWOPS_PHYSFS;
	ops.hidden.unknown.data1 = handle;
}

bool FileSystem::exists(const char *filename, FileType type)
{
	const char *foundName = p->completeFileName(filename, type);

	return (foundName != 0);
}