//
// STORAGE.CPP
//
// Source file for ArchiveLib 1.0
//
// Copyright (c) Greenleaf Software, Inc. 1994
// All Rights Reserved
//
// CONTENTS
//
// ALStorage::operator new()
// ALStorage::ALStorage()
// ALStorage::~ALStorage()
// ALStorage::UpdateCrc()
// ALStorage::Open()
// ALStorage::Create()
// ALStorage::Close()
// ALStorage::GetCrc32()
// ALStorage::InitCrc32()
// ALStorage::ReadBuffer()
// ALStorage::WriteBuffer()
// ALStorage::WritePortableShort()
// ALStorage::WritePortableLong()
// ALStorage::ReadPortableShort()
// ALStorage::ReadPortableLong()
// ALStorage::WriteString()
// ALStorage::ReadString()
// ALStorage::Tell()
// ALStorage::YieldTime()
// ALStorage::WriteStorageObjectData()
// ALStorage::ReadStorageObjectData()
//
// DESCRIPTION
//
// This file contains all of the source code for the member functions
// of ALStorage. AlStorage has pure virtual functions, so you can't
// ever instantiate one of these guys.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
//
#include "arclib.h"
#pragma hdrstop
#include <string.h>
//
// void * ALStorage::operator new( size_t size )
//
// ARGUMENTS:
//
// size : The number of bytes needed to create a new ALStorage object.
//
// RETURNS
//
// A pointer to the newly allocated storage area, or 0 if no storage
// was available.
//
// DESCRIPTION
//
// When using a DLL, it is easy to get into a dangerous situation when
// creating objects whose ctor and dtor are both in the DLL. The problem
// arises because when you create an object using new, the memory for
// the object will be allocated from the EXE. However, when you destroy
// the object using delete, the memory is freed inside the DLL. Since
// the DLL doesn't really own that memory, bad things can happen.
//
// But, you say, won't the space just go back to the Windows heap regardless
// of who tries to free it? Maybe, but maybe not. If the DLL is using
// a subsegment allocation scheme, it might do some sort of local free
// before returning the space to the windows heap. That is the point where
// you could conceivably cook your heap.
//
// By providing our own version of operator new inside this class, we
// ensure that all memory allocation for the class will be done from
// inside the DLL, not the EXE calling the DLL.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
#if defined( AL_BUILDING_DLL )
void AL_DLL_FAR * AL_PROTO ALStorage::operator new( size_t size )
{
return ::new char[ size ];
}
#endif
//
// ALStorage::ALStorage( const char *file_name,
// size_t size,
// const enum ALStorageType object_type,
// ALCase name_case )
//
// ARGUMENTS:
//
// file_name : The name to assign to the mName data member of the
// newly created storage object.
//
// size : The size of the I/O buffer that is going to be used
// for the storage object. ALFile uses 4096 as a default.
//
// object_type : The type of object, as defined in ALDEFS.H. Good
// values include AL_FILE_OBJECT and AL_MEMORY_OBJECT.
//
// name_case : The case sensitivity of the object name. For objects
// such as ALFile, AL_MIXED is a no-no. Those objects
// need to be forced to convert names to all upper
// or all lower, because the operating system considers
// file names to be case insensitive.
//
// RETURNS
//
// Nothing, it is a constructor.
//
// DESCRIPTION
//
// The constructor for ALStorage gets called from the constructor of
// derived classes. It has to initialize all sorts of data members.
// First, in the initializer list, it sets up the mName data member,
// as well as muBufferSize and miStorageObjectType. The latter two
// data members are set to be const so I can make them public, which
// means we have to initialize them in the initializer list.
//
// In the body of the constructor, we initialize a bunch of data members,
// none of which mean anything at this point.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
AL_PROTO ALStorage::ALStorage( const char AL_DLL_FAR *file_name,
size_t size,
const enum ALStorageType object_type,
ALCase name_case )
: mName( file_name, name_case ),
miStorageObjectType( object_type ),
muBufferSize( size )
{
mpcBuffer = 0;
muBufferValidData = 0;
muWriteIndex = 0;
muReadIndex = 0;
mlFilePointer = 0;
miUpdateCrcFlag = 0;
mlCrc32 = 0xffffffffL;
mlSize = -1L;
mpMonitor = 0;
miCreated = 0;
if ( mName.GetName() == 0 )
mStatus.SetError( AL_CANT_OPEN_BUFFER,
"Allocation of buffer failed in "
"ALStorage constructor" );
}
//
// ALStorage::~ALStorage()
//
// ARGUMENTS:
//
// No arguments for destructors.
//
// RETURNS
//
// No returns from destructors.
//
// DESCRIPTION
//
// In debug mode, we first check to make sure we are destroying the
// right type of object.
//
// The only thing left to do is free up the I/O buffer if it is still
// allocated. This piece of work probably isn't necessary. Since this
// is a virtual destructor, we will be called after the destructors
// for the derived class. Any derived class that is doing its job
// will make sure that it calls Close() before destroying itself. If
// it doesn't, it will probably be leaving unfinished business behind
// that we aren't going to be able to deal with here. Even so, we will
// be diligent in our attention to detail.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
AL_PROTO ALStorage::~ALStorage()
{
AL_ASSERT( GoodTag(), "~ALStorage: attempting to delete invalid object" );
if ( mpcBuffer )
Close();
}
//
// This giant table is used by the CRC routines. These are the coefficients
// for calculating the CCITT 32 bit CRC. I typed these in from memory, so
// I hope they are correct.
//
static unsigned long ccitt_32[ 256 ] =
{
0x00000000L, 0x77073096L, 0xee0e612cL, 0x990951baL, 0x076dc419L, 0x706af48fL, 0xe963a535L, 0x9e6495a3L,
0x0edb8832L, 0x79dcb8a4L, 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, 0x90bf1d91L,
0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL, 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L,
0x136c9856L, 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L, 0xfa0f3d63L, 0x8d080df5L,
0x3b6e20c8L, 0x4c69105eL, 0xd56041e4L, 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, 0xa50ab56bL,
0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L, 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L,
0x26d930acL, 0x51de003aL, 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L, 0xb8bda50fL,
0x2802b89eL, 0x5f058808L, 0xc60cd9b2L, 0xb10be924L, 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, 0xb6662d3dL,
0x76dc4190L, 0x01db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, 0x06b6b51fL, 0x9fbfe4a5L, 0xe8b8d433L,
0x7807c9a2L, 0x0f00f934L, 0x9609a88eL, 0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL, 0x91646c97L, 0xe6635c01L,
0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL, 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L,
0x65b0d9c6L, 0x12b7e950L, 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, 0x15da2d49L, 0x8cd37cf3L, 0xfbd44c65L,
0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, 0xd4bb30e2L, 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL,
0x4369e96aL, 0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L, 0xaa0a4c5fL, 0xdd0d7cc9L,
0x5005713cL, 0x270241aaL, 0xbe0b1010L, 0xc90c2086L, 0x5768b525L, 0x206f85b3L, 0xb966d409L, 0xce61e49fL,
0x5edef90eL, 0x29d9c998L, 0xb0d09822L, 0xc7d7a8b4L, 0x59b33d17L, 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL,
0xedb88320L, 0x9abfb3b6L, 0x03b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x04db2615L, 0x73dc1683L,
0xe3630b12L, 0x94643b84L, 0x0d6d6a3eL, 0x7a6a5aa8L, 0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L, 0x7d079eb1L,
0xf00f9344L, 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL, 0xf762575dL, 0x806567cbL, 0x196c3671L, 0x6e6b06e7L,
0xfed41b76L, 0x89d32be0L, 0x10da7a5aL, 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, 0x60b08ed5L,
0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L, 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL,
0xd80d2bdaL, 0xaf0a1b4cL, 0x36034af6L, 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL, 0x4669be79L,
0xcb61b38cL, 0xbc66831aL, 0x256fd2a0L, 0x5268e236L, 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, 0x5505262fL,
0xc5ba3bbeL, 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, 0xb5d0cf31L, 0x2cd99e8bL, 0x5bdeae1dL,
0x9b64c2b0L, 0xec63f226L, 0x756aa39cL, 0x026d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x05005713L,
0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL, 0x0cb61b38L, 0x92d28e9bL, 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L,
0x86d3d2d4L, 0xf1d4e242L, 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, 0xf6b9265bL, 0x6fb077e1L, 0x18b74777L,
0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, 0x11010b5cL, 0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L,
0xa00ae278L, 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L, 0x4969474dL, 0x3e6e77dbL,
0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L, 0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L,
0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, 0x24b4a3a6L, 0xbad03605L, 0xcdd70693L, 0x54de5729L, 0x23d967bfL,
0xb3667a2eL, 0xc4614ab8L, 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, 0x2d02ef8dL
};
//
// void ALStorage::UpdateCrc( size_t count )
//
// ARGUMENTS:
//
// count : The number of characters to process in the I/O buffer.
//
// RETURNS
//
// Nothing.
//
// DESCRIPTION
//
// If CRC checking has been turned on for the storage object, this
// routine will be called every time LoadBuffer() or FlushBuffer()
// are called. It does CRC checking on a buffer full of data at
// a time. Hopefully this means the compiler can optimize the
// heck out of this code.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
void AL_PROTO ALStorage::UpdateCrc( size_t count )
{
unsigned char *p = (unsigned char *) mpcBuffer;
while ( count-- != 0 )
mlCrc32 = ( ( mlCrc32 >> 8 ) & 0x00FFFFFFL ) ^
( ccitt_32[ ( (int) mlCrc32 ^ *p++ ) & 0xff ] );
}
//
// int ALStorage::Open()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// AL_SUCCESS, or AL_CANT_OPEN_BUFFER on memory allocation failure.
// If the object was already in an error state, it is very possible to
// get some other error code < 0.
//
// DESCRIPTION
//
// Any derived class needs to have its own Open() function. However,
// the derived class can also call this Open() function in the base
// class to do some odds and ends for it. The most important thing it
// does is allocate the I/O buffer, which is what makes ALStorage a
// relatively fast way to read and write data. Although the buffer
// is in place, there is no data in it, so this guy also sets up the
// indices and pointers to reflect that.
//
// Upon exit, all you need to to is start reading or writing, and the
// whole thing should be ready to go.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
int AL_PROTO ALStorage::Open()
{
if ( mStatus < AL_SUCCESS )
return mStatus;
if ( muBufferSize != 0 )
mpcBuffer = new unsigned char[ muBufferSize ];
muBufferValidData = 0;
muWriteIndex = 0;
muReadIndex = 0;
mlFilePointer = 0;
miUpdateCrcFlag = 0;
mlCrc32 = 0xffffffffL;
if ( mpcBuffer == 0 )
return mStatus.SetError( AL_CANT_OPEN_BUFFER,
"Allocation of buffer failed in Open()" );
return AL_SUCCESS;
}
//
// int ALStorage::Create()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// AL_SUCCESS, or AL_CANT_OPEN_BUFFER on memory allocation failure.
// If the object was already in an error state, it is very possible to
// get some other error code < 0.
//
// DESCRIPTION
//
// This function is nearly identical to ALStorage::Open().
//
// Any derived class needs to have its own Create() function. However,
// the derived class can also call this Create() function in the base
// class to do some odds and ends for it. The most important thing it
// does is allocate the I/O buffer, which is what makes ALStorage a
// relatively fast way to read and write data. Although the buffer
// is in place, there is no data in it, so this guy also sets up the
// indices and pointers to reflect that.
//
// Upon exit, all you need to to is start writing, and the
// whole thing should be ready to go.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
int AL_PROTO ALStorage::Create()
{
if ( mStatus < AL_SUCCESS )
return mStatus;
mpcBuffer = new unsigned char[ muBufferSize ];
muBufferValidData = 0;
muWriteIndex = 0;
muReadIndex = 0;
mlFilePointer = 0;
miUpdateCrcFlag = 0;
mlCrc32 = 0xffffffffL;
miCreated = 1;
if ( mpcBuffer == 0 )
return mStatus.SetError( AL_CANT_OPEN_BUFFER,
"Allocation of buffer failed in Open()" );
return AL_SUCCESS;
}
//
// int ALStorage::Close()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// The current integer status of the object. Hopefully this will be
// AL_SUCCESS, but it could well be a value < AL_SUCCESS.
//
// DESCRIPTION
//
// Just like with Open(), must derived classes will have their own
// versions of Close(). They can call this version to delete the I/O
// buffer if they feel like it is too hard to do themselves.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
int AL_PROTO ALStorage::Close()
{
if ( mpcBuffer ) {
delete[] mpcBuffer;
mpcBuffer = 0;
}
return mStatus;
}
//
// long ALStorage::GetCrc32()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// The current value of the CRC-32.
//
// DESCRIPTION
//
// This function is used to get the CRC-32 of a storage object. But it
// does a little bit more than just give you the CRC. First, it makes
// sure the buffers have been flushed, so that the CRC is accurate. If
// we didn't do this we might try to get the CRC on an incompletely
// written file.
//
// Once we get the CRC,the miUpdateCrcFlag is set to 0, which means
// that from here on out the value will not be updated. So retrieving
// the CRC means you are no longer interested in further calculation.
// It also means you can trust the value you just read, because it
// will never be modified again.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
long AL_PROTO ALStorage::GetCrc32()
{
if ( IsOpen() && miUpdateCrcFlag )
FlushBuffer();
miUpdateCrcFlag = 0;
return mlCrc32;
}
//
// void ALStorage::InitCrc32( unsigned long seed = 0xffffffffL )
//
// ARGUMENTS:
//
// seed : The long value to start the CRC off at. There is probably
// no reason to change this from the default value, although
// I won't be surprised if someone comes up with one.
//
// RETURNS
//
// Nothing.
//
// DESCRIPTION
//
// Calling this function kicks off the CRC calculation for a given
// storage object should be done immediately after the object is
// opened. Once the miUpdateCrcFlag is set, the CRC will be updated
// every time a LoadBuffer() or FlushBuffer() is called.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
void AL_PROTO ALStorage::InitCrc32( unsigned long seed /* = 0xffffffffL */ )
{
miUpdateCrcFlag = 1;
mlCrc32 = seed;
}
//
// size_t ALStorage::ReadBuffer( unsigned char *buf, size_t length )
//
// ARGUMENTS:
//
// buf : The buffer that is going to receive input characters.
//
// length : The number of bytes you want to read.
//
// RETURNS
//
// The number of bytes read in, always. If this function generates an
// error, it will be found in the mStatus member.
//
// DESCRIPTION
//
// We could write a simple version of this function by just calling
// ReadChar() over and over, but it would be nice to do things
// a little more efficiently. Since we have this nice big buffer
// full of data ready to read, it makes sense to copy big chunks of
// it in one fell swoop. That is what this guy does. It sits in a loop
// doing a memcpy() followed by LoadBuffer() until all of the data
// that has been asked for got moved. As data is read in, we have to
// update the data member muReadIndex. Other data members will get
// updated by LoadBuffer().
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
size_t AL_PROTO ALStorage::ReadBuffer( unsigned char *buf,
size_t length )
{
size_t bytes_left_to_read = length;
size_t buffer_bytes_available;
while ( bytes_left_to_read ) {
buffer_bytes_available = muBufferValidData - muReadIndex;
if ( buffer_bytes_available == 0 ) {
if ( LoadBuffer( mlFilePointer ) < 0 )
return length - bytes_left_to_read;
buffer_bytes_available = muBufferValidData;
}
if ( bytes_left_to_read <= buffer_bytes_available ) {
memcpy( buf, mpcBuffer + muReadIndex, bytes_left_to_read );
muReadIndex += bytes_left_to_read;
return length;
} else {
memcpy( buf, mpcBuffer + muReadIndex, buffer_bytes_available );
buf += buffer_bytes_available;
bytes_left_to_read -= buffer_bytes_available;
muReadIndex += buffer_bytes_available;
if ( LoadBuffer( mlFilePointer ) < 0 )
return length - bytes_left_to_read;
}
}
return length;
}
//
// size_t ALStorage::WriteBuffer( const unsigned char *buf,
// size_t length )
//
// ARGUMENTS:
//
// buf : The buffer that is contains the output data.
//
// length : The number of bytes you want to write.
//
// RETURNS
//
// The number of bytes written, always. If this function generates an
// error, it will be found in the mStatus member.
//
// DESCRIPTION
//
// We could write a simple version of this function by just calling
// WriteChar() over and over, but it would be nice to do things
// a little more efficiently. Since we have this nice big buffer
// just waiting for data, it makes sense to copy big chunks to
// it in one fell swoop. That is what this guy does. It sits in a loop
// doing a memcpy() followed by FlushBuffer() until all of the data
// that was ready to go has been sent. As data is written, we have to
// update the data member muWriteIndex. Other data members will get
// updated by FlushBuffer().
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
size_t AL_PROTO ALStorage::WriteBuffer( const unsigned char *buf,
size_t length )
{
size_t buffer_bytes_free;
size_t write_bytes_left = length;
if ( mStatus < 0 )
return 0;
while ( write_bytes_left > 0 ) {
buffer_bytes_free = muBufferSize - muWriteIndex;
if ( buffer_bytes_free == 0 ) {
if ( FlushBuffer() < 0 )
return length - write_bytes_left;
buffer_bytes_free = muBufferSize;
}
if ( write_bytes_left <= buffer_bytes_free ) {
memcpy( mpcBuffer + muWriteIndex, buf, write_bytes_left );
muWriteIndex += write_bytes_left;
return length;
} else {
memcpy( mpcBuffer + muWriteIndex, buf, buffer_bytes_free );
muWriteIndex += buffer_bytes_free;
buf += buffer_bytes_free;
write_bytes_left -= buffer_bytes_free;
if ( FlushBuffer() < 0 )
return length - write_bytes_left;
}
}
return length;
}
//
// int ALStorage::WritePortableShort( short int short_data )
//
// ARGUMENTS:
//
// short_data : A 16 bit int that is going to be written out in
// little endian format.
//
// RETURNS
//
// AL_SUCCESS if all goes well. Otherwise, some error code < AL_STATUS.
//
// DESCRIPTION
//
// In order to make sure our archives can be read and written on all sorts
// of systems, we have a few functions that are used to write numerical
// data in a portable fashion. This function writes short integers in
// little endian format (which is not native Intel format). The complementary
// function, ReadPortableShort(), reads short integers back using the
// same format.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
int AL_PROTO ALStorage::WritePortableShort( short int short_data )
{
WriteChar( short_data >> 8 );
WriteChar( short_data );
return mStatus;
}
//
// int ALStorage::WritePortableLong( long int long_data )
//
// ARGUMENTS:
//
// long_data : A 32 bit long int that is going to be written out in
// little endian format.
//
// RETURNS
//
// AL_SUCCESS if all goes well. Otherwise, some error code < AL_STATUS.
//
// DESCRIPTION
//
// In order to make sure our archives can be read and written on all sorts
// of systems, we have a few functions that are used to write numerical
// data in a portable fashion. This function writes long integers in
// little endian format (which is not native Intel format). The
// complementary function, ReadPortableLong(), reads long integers back
// using the same format.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
int AL_PROTO ALStorage::WritePortableLong( long long_data )
{
WriteChar( (int) ( long_data >> 24 ) );
WriteChar( (int) ( long_data >> 16 ) );
WriteChar( (int) ( long_data >> 8 ) );
WriteChar( (int) long_data );
return mStatus;
}
//
// int ALStorage::ReadPortableShort( short int &short_data )
//
// ARGUMENTS:
//
// short_data : A reference to a 16 bit integer that is going to
// have data read in from this storage object.
//
// RETURNS
//
// AL_SUCCESS if all goes well. Otherwise, some error code < AL_STATUS.
//
// DESCRIPTION
//
// In order to make sure our archives can be read and written on all sorts
// of systems, we have a few functions that are used to read numerical
// data in a portable fashion. This function reads short integers in
// little endian format (which is not native Intel format). The
// complementary function, WritePortableShort(), writes short integers out
// using the same format.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
int AL_PROTO ALStorage::ReadPortableShort( short int & short_data )
{
short_data = (short int) ( ReadChar() << 8 );
short_data |= (short int) ReadChar();
return mStatus;
}
//
// int ALStorage::ReadPortableLong( long int &short_data )
//
// ARGUMENTS:
//
// long_data : A reference to a 32 bit integer that is going to
// have data read in from this storage object.
//
// RETURNS
//
// AL_SUCCESS if all goes well. Otherwise, some error code < AL_STATUS.
//
// DESCRIPTION
//
// In order to make sure our archives can be read and written on all sorts
// of systems, we have a few functions that are used to read numerical
// data in a portable fashion. This function reads long integers in
// little endian format (which is not native Intel format). The
// complementary function, WritePortableLong(), writes long integers out
// using the same format.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
int AL_PROTO ALStorage::ReadPortableLong( long & long_data )
{
long_data = (long) ReadChar() << 24;
long_data |= (long) ReadChar() << 16;
long_data |= (long) ReadChar() << 8;
long_data |= ReadChar();
return mStatus;
}
//
// int ALStorage::WriteString( const char *string_data )
//
// ARGUMENTS:
//
// string_data : A string to be written out in our portable format.
//
// RETURNS
//
// AL_SUCCESS if things work, or an error code < AL_SUCCESS if an error
// occurs writing the data out.
//
// DESCRIPTION
//
// We write random length data to archive directories using this special
// format, which is a 16 bit int describing the length of the data,
// followed by the data itself. All of the storage objects and compression
// engines write their own private data out using this format. This
// means that even if another class doesn't understand the content of data
// stored in this format, at least it knows how to read it in so as to
// move past it.
//
// This function won't write just any random data, it is specifically
// oriented towards C strings. This means it is mostly used to write
// file names and comments. Their are a few places where classes
// write private data that isn't kept in C strings, they just manually
// write the length with WritePortableShort(), followed by the data.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
int AL_PROTO ALStorage::WriteString( const char *string_data )
{
short unsigned int len;
if ( string_data != 0 )
len = (short unsigned int) strlen( string_data );
else
len = 0;
WritePortableShort( len );
if ( len )
WriteBuffer( (unsigned char *) string_data, len );
return mStatus;
}
// PROTECTED MEMBER FUNCTION
//
// char * ALStorage::ReadString()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// A pointer to a string. This string has been allocated by the library,
// which can cause a problem if you are using a DLL. If an EXE tried
// to free a string pointer allocated by the DLL, havoc would result.
// Because of this hassle, this is a protected function.
//
// The solution to this is to write a new version of this that returns
// an ALName object. I thought of that, but too late.
//
// DESCRIPTION
//
// This function is used internally by ArchiveLib. It is used to read
// random length blocks of data out of archives (or other storage objects).
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
char AL_DLL_FAR * AL_PROTO ALStorage::ReadString()
{
short int len;
if ( ReadPortableShort( len ) < 0 )
return 0;
char *new_string = new char[ len + 1 ];
if ( new_string ) {
ReadBuffer( (unsigned char *) new_string, len );
new_string[ len ] = '\0';
return new_string;
} else {
mStatus.SetError( AL_CANT_ALLOCATE_MEMORY,
"Error allocating buffer space in call "
"to ReadString() for object %s",
mName.GetSafeName() );
return 0;
}
}
//
// long ALStorage::Tell()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// A long integer indicating the current position of the read/write
// pointer for the file.
//
// DESCRIPTION
//
// Because we are using buffered I/O here, figuring out the current
// position of the read write pointer is just a tiny bit more complicated
// than just checking a pointer. We have to find the physical location of
// the file pointer, then add in any offset created by the presence of
// data in the I/O buffer.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
long AL_PROTO ALStorage::Tell()
{
if ( muWriteIndex )
return mlFilePointer + muWriteIndex;
else
return mlFilePointer - muBufferValidData + muReadIndex;
}
//
// void ALStorage::YieldTime()
//
// ARGUMENTS:
//
// None.
//
// RETURNS
//
// Nothing.
//
// DESCRIPTION
//
// This function has two important things to do. It gets called
// at a few different points in the process of reading or writing data
// from storage objects. During normal reading and writing, it
// will get called every time the buffer is loaded or flushed.
//
// If we are in Windows mode, we execute a PeekMessage() loop. This
// makes sure that we aren't hogging the CPU. By doing it this way,
// the programmer can be ensure that he/she is being a good citizen
// without any significant effort.
//
// The second important function is that of calling the monitor function.
// The user interface elements need to be updated regularly, and this
// is done via this call.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
void AL_PROTO ALStorage::YieldTime()
{
if ( mpMonitor )
mpMonitor->Progress( Tell(), *this );
/*
* For right now I am going to put the PeekMessage loop in the load
* buffer routine by default. Most Windows applications are going
* to want to use this, right?
*/
#if defined( AL_WINDOWS_GUI )
MSG msg;
while ( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) ) {
TranslateMessage( &msg );
DispatchMessage(&msg);
}
#endif
}
//
// int ALStorage::WriteStorageObjectData( ALStorage * archive )
//
// ARGUMENTS:
//
// archive : A pointer to the storage object where we are going to
// write the private data.
//
// RETURNS
//
// AL_SUCCESS if things went okay, otherwise an error code < AL_SUCCESS.
//
// DESCRIPTION
//
// All storage objects have the ability to create a private data block
// that will be stored along with the directory when creating an archive.
// None of the classes predefined in ArchiveLib use this data block, which
// means they use this function instead of providing their own virtual
// substitute. This function writes a private data block of exactly 0
// bytes in length. Our internal storage format means that a block
// of 0 bytes length takes 2 bytes to store.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
int AL_PROTO ALStorage::WriteStorageObjectData( ALStorage * archive )
{
return archive->WritePortableShort( 0 );
}
//
// int ALStorage::ReadStorageObjectData( ALStorage * archive )
//
// ARGUMENTS:
//
// archive : A pointer to the storage object where we are going to
// read in the private data..
//
// RETURNS
//
// AL_SUCCESS if things went okay, otherwise an error code < AL_SUCCESS.
//
// DESCRIPTION
//
// All storage objects have the ability to create a private data block
// that will be stored along with the directory when creating an archive.
// None of the classes predefined in ArchiveLib use this data block, which
// means they use this function instead of providing their own virtual
// substitute. This function reads a private data block of exactly 0
// bytes in length. Our internal storage format means that a block
// of 0 bytes length takes 2 bytes to store.
//
// In debug mode, we get really bent out of shape if this data block
// doesn't look exactly like we expect it to.
//
// REVISION HISTORY
//
// May 26, 1994 1.0A : First release
//
int AL_PROTO ALStorage::ReadStorageObjectData( ALStorage * archive )
{
short int temp;
int status = archive->ReadPortableShort( temp );
AL_ASSERT( temp == 0, "ReadStorageObjectData: stored data is not null" );
return status;
}