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73b44c9429
mame/src/lib/util/chd.cpp
Vas Crabb 73b44c9429 Turn core_file into a proper class that gets cleaned up safely using unique_ptr 
Subverted somewhat by chd_file class
2016-03-06 21:49:56 +11:00

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// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/***************************************************************************
chd.c
MAME Compressed Hunks of Data file format
***************************************************************************/
#include <assert.h>
#include "chd.h"
#include "avhuff.h"
#include "hashing.h"
#include "flac.h"
#include "cdrom.h"
#include "coretmpl.h"
#include <zlib.h>
#include <time.h>
#include <stddef.h>
#include <stdlib.h>
#include <new>
#include "eminline.h"
//**************************************************************************
// CONSTANTS
//**************************************************************************
// standard metadata formats
const char *HARD_DISK_METADATA_FORMAT = "CYLS:%d,HEADS:%d,SECS:%d,BPS:%d";
const char *CDROM_TRACK_METADATA_FORMAT = "TRACK:%d TYPE:%s SUBTYPE:%s FRAMES:%d";
const char *CDROM_TRACK_METADATA2_FORMAT = "TRACK:%d TYPE:%s SUBTYPE:%s FRAMES:%d PREGAP:%d PGTYPE:%s PGSUB:%s POSTGAP:%d";
const char *GDROM_TRACK_METADATA_FORMAT = "TRACK:%d TYPE:%s SUBTYPE:%s FRAMES:%d PAD:%d PREGAP:%d PGTYPE:%s PGSUB:%s POSTGAP:%d";
const char *AV_METADATA_FORMAT = "FPS:%d.%06d WIDTH:%d HEIGHT:%d INTERLACED:%d CHANNELS:%d SAMPLERATE:%d";
static const UINT32 METADATA_HEADER_SIZE = 16; // metadata header size
static const UINT8 V34_MAP_ENTRY_FLAG_TYPE_MASK = 0x0f; // what type of hunk
static const UINT8 V34_MAP_ENTRY_FLAG_NO_CRC = 0x10; // no CRC is present
// V3-V4 entry types
enum
{
V34_MAP_ENTRY_TYPE_INVALID = 0, // invalid type
V34_MAP_ENTRY_TYPE_COMPRESSED = 1, // standard compression
V34_MAP_ENTRY_TYPE_UNCOMPRESSED = 2, // uncompressed data
V34_MAP_ENTRY_TYPE_MINI = 3, // mini: use offset as raw data
V34_MAP_ENTRY_TYPE_SELF_HUNK = 4, // same as another hunk in this file
V34_MAP_ENTRY_TYPE_PARENT_HUNK = 5, // same as a hunk in the parent file
V34_MAP_ENTRY_TYPE_2ND_COMPRESSED = 6 // compressed with secondary algorithm (usually FLAC CDDA)
};
// V5 compression types
enum
{
///< codec #0
// these types are live when running
COMPRESSION_TYPE_0 = 0,
///< codec #1
COMPRESSION_TYPE_1 = 1,
///< codec #2
COMPRESSION_TYPE_2 = 2,
///< codec #3
COMPRESSION_TYPE_3 = 3,
///< no compression; implicit length = hunkbytes
COMPRESSION_NONE = 4,
///< same as another block in this chd
COMPRESSION_SELF = 5,
///< same as a hunk's worth of units in the parent chd
COMPRESSION_PARENT = 6,
///< start of small RLE run (4-bit length)
// these additional pseudo-types are used for compressed encodings:
COMPRESSION_RLE_SMALL,
///< start of large RLE run (8-bit length)
COMPRESSION_RLE_LARGE,
///< same as the last COMPRESSION_SELF block
COMPRESSION_SELF_0,
///< same as the last COMPRESSION_SELF block + 1
COMPRESSION_SELF_1,
///< same block in the parent
COMPRESSION_PARENT_SELF,
///< same as the last COMPRESSION_PARENT block
COMPRESSION_PARENT_0,
///< same as the last COMPRESSION_PARENT block + 1
COMPRESSION_PARENT_1
};
//**************************************************************************
// TYPE DEFINITIONS
//**************************************************************************
// ======================> metadata_entry
// description of where a metadata entry lives within the file
struct chd_file::metadata_entry
{
UINT64 offset; // offset within the file of the header
UINT64 next; // offset within the file of the next header
UINT64 prev; // offset within the file of the previous header
UINT32 length; // length of the metadata
UINT32 metatag; // metadata tag
UINT8 flags; // flag bits
};
// ======================> metadata_hash
struct chd_file::metadata_hash
{
UINT8 tag[4]; // tag of the metadata in big-endian
sha1_t sha1; // hash data
};
//**************************************************************************
// INLINE FUNCTIONS
//**************************************************************************
//-------------------------------------------------
// be_read - extract a big-endian number from
// a byte buffer
//-------------------------------------------------
inline UINT64 chd_file::be_read(const UINT8 *base, int numbytes)
{
UINT64 result = 0;
while (numbytes--)
result = (result << 8) | *base++;
return result;
}
//-------------------------------------------------
// be_write - write a big-endian number to a byte
// buffer
//-------------------------------------------------
inline void chd_file::be_write(UINT8 *base, UINT64 value, int numbytes)
{
base += numbytes;
while (numbytes--)
{
*--base = value;
value >>= 8;
}
}
//-------------------------------------------------
// be_read_sha1 - fetch a sha1_t from a data
// stream in bigendian order
//-------------------------------------------------
inline sha1_t chd_file::be_read_sha1(const UINT8 *base)
{
sha1_t result;
memcpy(&result.m_raw[0], base, sizeof(result.m_raw));
return result;
}
//-------------------------------------------------
// be_write_sha1 - write a sha1_t to a data
// stream in bigendian order
//-------------------------------------------------
inline void chd_file::be_write_sha1(UINT8 *base, sha1_t value)
{
memcpy(base, &value.m_raw[0], sizeof(value.m_raw));
}
//-------------------------------------------------
// file_read - read from the file at the given
// offset; on failure throw an error
//-------------------------------------------------
inline void chd_file::file_read(UINT64 offset, void *dest, UINT32 length)
{
// no file = failure
if (m_file == nullptr)
throw CHDERR_NOT_OPEN;
// seek and read
m_file->seek(offset, SEEK_SET);
UINT32 count = m_file->read(dest, length);
if (count != length)
throw CHDERR_READ_ERROR;
}
//-------------------------------------------------
// file_write - write to the file at the given
// offset; on failure throw an error
//-------------------------------------------------
inline void chd_file::file_write(UINT64 offset, const void *source, UINT32 length)
{
// no file = failure
if (m_file == nullptr)
throw CHDERR_NOT_OPEN;
// seek and write
m_file->seek(offset, SEEK_SET);
UINT32 count = m_file->write(source, length);
if (count != length)
throw CHDERR_WRITE_ERROR;
}
//-------------------------------------------------
// file_append - append to the file at the given
// offset, ensuring we start at the given
// alignment; on failure throw an error
//-------------------------------------------------
inline UINT64 chd_file::file_append(const void *source, UINT32 length, UINT32 alignment)
{
// no file = failure
if (m_file == nullptr)
throw CHDERR_NOT_OPEN;
// seek to the end and align if necessary
m_file->seek(0, SEEK_END);
if (alignment != 0)
{
UINT64 offset = m_file->tell();
UINT32 delta = offset % alignment;
if (delta != 0)
{
// pad with 0's from a local buffer
UINT8 buffer[1024];
memset(buffer, 0, sizeof(buffer));
delta = alignment - delta;
while (delta != 0)
{
UINT32 bytes_to_write = MIN(sizeof(buffer), delta);
UINT32 count = m_file->write(buffer, bytes_to_write);
if (count != bytes_to_write)
throw CHDERR_WRITE_ERROR;
delta -= bytes_to_write;
}
}
}
// write the real data
UINT64 offset = m_file->tell();
UINT32 count = m_file->write(source, length);
if (count != length)
throw CHDERR_READ_ERROR;
return offset;
}
//-------------------------------------------------
// bits_for_value - return the number of bits
// necessary to represent all numbers 0..value
//-------------------------------------------------
inline UINT8 chd_file::bits_for_value(UINT64 value)
{
UINT8 result = 0;
while (value != 0)
value >>= 1, result++;
return result;
}
//**************************************************************************
// CHD FILE MANAGEMENT
//**************************************************************************
/**
* @fn chd_file::chd_file()
*
* @brief -------------------------------------------------
* chd_file - constructor
* -------------------------------------------------.
*/
chd_file::chd_file()
: m_file(nullptr),
m_owns_file(false)
{
// reset state
memset(m_decompressor, 0, sizeof(m_decompressor));
close();
}
/**
* @fn chd_file::~chd_file()
*
* @brief -------------------------------------------------
* ~chd_file - destructor
* -------------------------------------------------.
*/
chd_file::~chd_file()
{
// close any open files
close();
}
/**
* @fn sha1_t chd_file::sha1()
*
* @brief -------------------------------------------------
* sha1 - return our SHA1 value
* -------------------------------------------------.
*
* @return A sha1_t.
*/
sha1_t chd_file::sha1()
{
try
{
// read the big-endian version
UINT8 rawbuf[sizeof(sha1_t)];
file_read(m_sha1_offset, rawbuf, sizeof(rawbuf));
return be_read_sha1(rawbuf);
}
catch (chd_error &)
{
// on failure, return NULL
return sha1_t::null;
}
}
/**
* @fn sha1_t chd_file::raw_sha1()
*
* @brief -------------------------------------------------
* raw_sha1 - return our raw SHA1 value
* -------------------------------------------------.
*
* @exception CHDERR_UNSUPPORTED_VERSION Thrown when a chderr unsupported version error
* condition occurs.
*
* @return A sha1_t.
*/
sha1_t chd_file::raw_sha1()
{
try
{
// determine offset within the file for data-only
if (m_rawsha1_offset == 0)
throw CHDERR_UNSUPPORTED_VERSION;
// read the big-endian version
UINT8 rawbuf[sizeof(sha1_t)];
file_read(m_rawsha1_offset, rawbuf, sizeof(rawbuf));
return be_read_sha1(rawbuf);
}
catch (chd_error &)
{
// on failure, return NULL
return sha1_t::null;
}
}
/**
* @fn sha1_t chd_file::parent_sha1()
*
* @brief -------------------------------------------------
* parent_sha1 - return our parent's SHA1 value
* -------------------------------------------------.
*
* @exception CHDERR_UNSUPPORTED_VERSION Thrown when a chderr unsupported version error
* condition occurs.
*
* @return A sha1_t.
*/
sha1_t chd_file::parent_sha1()
{
try
{
// determine offset within the file
if (m_parentsha1_offset == 0)
throw CHDERR_UNSUPPORTED_VERSION;
// read the big-endian version
UINT8 rawbuf[sizeof(sha1_t)];
file_read(m_parentsha1_offset, rawbuf, sizeof(rawbuf));
return be_read_sha1(rawbuf);
}
catch (chd_error &)
{
// on failure, return NULL
return sha1_t::null;
}
}
/**
* @fn chd_error chd_file::hunk_info(UINT32 hunknum, chd_codec_type &compressor, UINT32 &compbytes)
*
* @brief -------------------------------------------------
* hunk_info - return information about this hunk
* -------------------------------------------------.
*
* @param hunknum The hunknum.
* @param [in,out] compressor The compressor.
* @param [in,out] compbytes The compbytes.
*
* @return A chd_error.
*/
chd_error chd_file::hunk_info(UINT32 hunknum, chd_codec_type &compressor, UINT32 &compbytes)
{
// error if invalid
if (hunknum >= m_hunkcount)
return CHDERR_HUNK_OUT_OF_RANGE;
// get the map pointer
UINT8 *rawmap;
switch (m_version)
{
// v3/v4 map entries
case 3:
case 4:
rawmap = &m_rawmap[16 * hunknum];
switch (rawmap[15] & V34_MAP_ENTRY_FLAG_TYPE_MASK)
{
case V34_MAP_ENTRY_TYPE_COMPRESSED:
compressor = CHD_CODEC_ZLIB;
compbytes = be_read(&rawmap[12], 2) + (rawmap[14] << 16);
break;
case V34_MAP_ENTRY_TYPE_UNCOMPRESSED:
compressor = CHD_CODEC_NONE;
compbytes = m_hunkbytes;
break;
case V34_MAP_ENTRY_TYPE_MINI:
compressor = CHD_CODEC_MINI;
compbytes = 0;
break;
case V34_MAP_ENTRY_TYPE_SELF_HUNK:
compressor = CHD_CODEC_SELF;
compbytes = 0;
break;
case V34_MAP_ENTRY_TYPE_PARENT_HUNK:
compressor = CHD_CODEC_PARENT;
compbytes = 0;
break;
}
break;
// v5 map entries
case 5:
rawmap = &m_rawmap[m_mapentrybytes * hunknum];
// uncompressed case
if (!compressed())
{
if (be_read(&rawmap[0], 4) == 0)
{
compressor = CHD_CODEC_PARENT;
compbytes = 0;
}
else
{
compressor = CHD_CODEC_NONE;
compbytes = m_hunkbytes;
}
break;
}
// compressed case
switch (rawmap[0])
{
case COMPRESSION_TYPE_0:
case COMPRESSION_TYPE_1:
case COMPRESSION_TYPE_2:
case COMPRESSION_TYPE_3:
compressor = m_compression[rawmap[0]];
compbytes = be_read(&rawmap[1], 3);
break;
case COMPRESSION_NONE:
compressor = CHD_CODEC_NONE;
compbytes = m_hunkbytes;
break;
case COMPRESSION_SELF:
compressor = CHD_CODEC_SELF;
compbytes = 0;
break;
case COMPRESSION_PARENT:
compressor = CHD_CODEC_PARENT;
compbytes = 0;
break;
default:
return CHDERR_UNKNOWN_COMPRESSION;
}
break;
}
return CHDERR_NONE;
}
/**
* @fn void chd_file::set_raw_sha1(sha1_t rawdata)
*
* @brief -------------------------------------------------
* set_raw_sha1 - set our SHA1 values
* -------------------------------------------------.
*
* @param rawdata The rawdata.
*/
void chd_file::set_raw_sha1(sha1_t rawdata)
{
// create a big-endian version
UINT8 rawbuf[sizeof(sha1_t)];
be_write_sha1(rawbuf, rawdata);
// write to the header
UINT64 offset = (m_rawsha1_offset != 0) ? m_rawsha1_offset : m_sha1_offset;
assert(offset != 0);
file_write(offset, rawbuf, sizeof(rawbuf));
// if we have a separate rawsha1_offset, update the full sha1 as well
if (m_rawsha1_offset != 0)
metadata_update_hash();
}
/**
* @fn void chd_file::set_parent_sha1(sha1_t parent)
*
* @brief -------------------------------------------------
* set_parent_sha1 - set the parent SHA1 value
* -------------------------------------------------.
*
* @exception CHDERR_INVALID_FILE Thrown when a chderr invalid file error condition occurs.
*
* @param parent The parent.
*/
void chd_file::set_parent_sha1(sha1_t parent)
{
// if no file, fail
if (m_file == nullptr)
throw CHDERR_INVALID_FILE;
// create a big-endian version
UINT8 rawbuf[sizeof(sha1_t)];
be_write_sha1(rawbuf, parent);
// write to the header
assert(m_parentsha1_offset != 0);
file_write(m_parentsha1_offset, rawbuf, sizeof(rawbuf));
}
/**
* @fn chd_error chd_file::create(util::core_file &file, UINT64 logicalbytes, UINT32 hunkbytes, UINT32 unitbytes, chd_codec_type compression[4])
*
* @brief -------------------------------------------------
* create - create a new file with no parent using an existing opened file handle
* -------------------------------------------------.
*
* @param [in,out] file The file.
* @param logicalbytes The logicalbytes.
* @param hunkbytes The hunkbytes.
* @param unitbytes The unitbytes.
* @param compression The compression.
*
* @return A chd_error.
*/
chd_error chd_file::create(util::core_file &file, UINT64 logicalbytes, UINT32 hunkbytes, UINT32 unitbytes, chd_codec_type compression[4])
{
// make sure we don't already have a file open
if (m_file != nullptr)
return CHDERR_ALREADY_OPEN;
// set the header parameters
m_logicalbytes = logicalbytes;
m_hunkbytes = hunkbytes;
m_unitbytes = unitbytes;
memcpy(m_compression, compression, sizeof(m_compression));
m_parent = nullptr;
// take ownership of the file
m_file = &file;
m_owns_file = false;
return create_common();
}
/**
* @fn chd_error chd_file::create(util::core_file &file, UINT64 logicalbytes, UINT32 hunkbytes, chd_codec_type compression[4], chd_file &parent)
*
* @brief -------------------------------------------------
* create - create a new file with a parent using an existing opened file handle
* -------------------------------------------------.
*
* @param [in,out] file The file.
* @param logicalbytes The logicalbytes.
* @param hunkbytes The hunkbytes.
* @param compression The compression.
* @param [in,out] parent The parent.
*
* @return A chd_error.
*/
chd_error chd_file::create(util::core_file &file, UINT64 logicalbytes, UINT32 hunkbytes, chd_codec_type compression[4], chd_file &parent)
{
// make sure we don't already have a file open
if (m_file != nullptr)
return CHDERR_ALREADY_OPEN;
// set the header parameters
m_logicalbytes = logicalbytes;
m_hunkbytes = hunkbytes;
m_unitbytes = parent.unit_bytes();
memcpy(m_compression, compression, sizeof(m_compression));
m_parent = &parent;
// take ownership of the file
m_file = &file;
m_owns_file = false;
return create_common();
}
/**
* @fn chd_error chd_file::create(const char *filename, UINT64 logicalbytes, UINT32 hunkbytes, UINT32 unitbytes, chd_codec_type compression[4])
*
* @brief -------------------------------------------------
* create - create a new file with no parent using a filename
* -------------------------------------------------.
*
* @param filename Filename of the file.
* @param logicalbytes The logicalbytes.
* @param hunkbytes The hunkbytes.
* @param unitbytes The unitbytes.
* @param compression The compression.
*
* @return A chd_error.
*/
chd_error chd_file::create(const char *filename, UINT64 logicalbytes, UINT32 hunkbytes, UINT32 unitbytes, chd_codec_type compression[4])
{
// make sure we don't already have a file open
if (m_file != nullptr)
return CHDERR_ALREADY_OPEN;
// create the new file
util::core_file::ptr file;
const file_error filerr = util::core_file::open(filename, OPEN_FLAG_READ | OPEN_FLAG_WRITE | OPEN_FLAG_CREATE, file);
if (filerr != FILERR_NONE)
return CHDERR_FILE_NOT_FOUND;
// create the file normally, then claim the file
const chd_error chderr = create(*file, logicalbytes, hunkbytes, unitbytes, compression);
m_owns_file = true;
// if an error happened, close and delete the file
if (chderr != CHDERR_NONE)
{
file.reset();
osd_rmfile(filename);
}
else
{
file.release();
}
return chderr;
}
/**
* @fn chd_error chd_file::create(const char *filename, UINT64 logicalbytes, UINT32 hunkbytes, chd_codec_type compression[4], chd_file &parent)
*
* @brief -------------------------------------------------
* create - create a new file with a parent using a filename
* -------------------------------------------------.
*
* @param filename Filename of the file.
* @param logicalbytes The logicalbytes.
* @param hunkbytes The hunkbytes.
* @param compression The compression.
* @param [in,out] parent The parent.
*
* @return A chd_error.
*/
chd_error chd_file::create(const char *filename, UINT64 logicalbytes, UINT32 hunkbytes, chd_codec_type compression[4], chd_file &parent)
{
// make sure we don't already have a file open
if (m_file != nullptr)
return CHDERR_ALREADY_OPEN;
// create the new file
util::core_file::ptr file;
const file_error filerr = util::core_file::open(filename, OPEN_FLAG_READ | OPEN_FLAG_WRITE | OPEN_FLAG_CREATE, file);
if (filerr != FILERR_NONE)
return CHDERR_FILE_NOT_FOUND;
// create the file normally, then claim the file
const chd_error chderr = create(*file, logicalbytes, hunkbytes, compression, parent);
m_owns_file = true;
// if an error happened, close and delete the file
if (chderr != CHDERR_NONE)
{
file.reset();
osd_rmfile(filename);
}
else
{
file.release();
}
return chderr;
}
/**
* @fn chd_error chd_file::open(const char *filename, bool writeable, chd_file *parent)
*
* @brief -------------------------------------------------
* open - open an existing file for read or read/write
* -------------------------------------------------.
*
* @param filename Filename of the file.
* @param writeable true if writeable.
* @param [in,out] parent If non-null, the parent.
*
* @return A chd_error.
*/
chd_error chd_file::open(const char *filename, bool writeable, chd_file *parent)
{
// make sure we don't already have a file open
if (m_file != nullptr)
return CHDERR_ALREADY_OPEN;
// open the file
const UINT32 openflags = writeable ? (OPEN_FLAG_READ | OPEN_FLAG_WRITE) : OPEN_FLAG_READ;
util::core_file::ptr file;
const file_error filerr = util::core_file::open(filename, openflags, file);
if (filerr != FILERR_NONE)
return CHDERR_FILE_NOT_FOUND;
// now open the CHD
chd_error err = open(*file, writeable, parent);
if (err != CHDERR_NONE)
return err;
// we now own this file
file.release();
m_owns_file = true;
return err;
}
/**
* @fn chd_error chd_file::open(util::core_file &file, bool writeable, chd_file *parent)
*
* @brief -------------------------------------------------
* open - open an existing file for read or read/write
* -------------------------------------------------.
*
* @param [in,out] file The file.
* @param writeable true if writeable.
* @param [in,out] parent If non-null, the parent.
*
* @return A chd_error.
*/
chd_error chd_file::open(util::core_file &file, bool writeable, chd_file *parent)
{
// make sure we don't already have a file open
if (m_file != nullptr)
return CHDERR_ALREADY_OPEN;
// open the file
m_file = &file;
m_owns_file = false;
m_parent = parent;
return open_common(writeable);
}
/**
* @fn void chd_file::close()
*
* @brief -------------------------------------------------
* close - close a CHD file for access
* -------------------------------------------------.
*/
void chd_file::close()
{
// reset file characteristics
if (m_owns_file && m_file)
delete m_file;
m_file = nullptr;
m_owns_file = false;
m_allow_reads = false;
m_allow_writes = false;
// reset core parameters from the header
m_version = HEADER_VERSION;
m_logicalbytes = 0;
m_mapoffset = 0;
m_metaoffset = 0;
m_hunkbytes = 0;
m_hunkcount = 0;
m_unitbytes = 0;
m_unitcount = 0;
memset(m_compression, 0, sizeof(m_compression));
m_parent = nullptr;
m_parent_missing = false;
// reset key offsets within the header
m_mapoffset_offset = 0;
m_metaoffset_offset = 0;
m_sha1_offset = 0;
m_rawsha1_offset = 0;
m_parentsha1_offset = 0;
// reset map information
m_mapentrybytes = 0;
m_rawmap.clear();
// reset compression management
for (auto & elem : m_decompressor)
{
delete elem;
elem = nullptr;
}
m_compressed.clear();
// reset caching
m_cache.clear();
m_cachehunk = ~0;
}
/**
* @fn chd_error chd_file::read_hunk(UINT32 hunknum, void *buffer)
*
* @brief -------------------------------------------------
* read - read a single hunk from the CHD file
* -------------------------------------------------.
*
* @exception CHDERR_NOT_OPEN Thrown when a chderr not open error condition occurs.
* @exception CHDERR_HUNK_OUT_OF_RANGE Thrown when a chderr hunk out of range error
* condition occurs.
* @exception CHDERR_DECOMPRESSION_ERROR Thrown when a chderr decompression error error
* condition occurs.
* @exception CHDERR_REQUIRES_PARENT Thrown when a chderr requires parent error condition
* occurs.
* @exception CHDERR_READ_ERROR Thrown when a chderr read error error condition
* occurs.
*
* @param hunknum The hunknum.
* @param [in,out] buffer If non-null, the buffer.
*
* @return The hunk.
*/
chd_error chd_file::read_hunk(UINT32 hunknum, void *buffer)
{
// wrap this for clean reporting
try
{
// punt if no file
if (m_file == nullptr)
throw CHDERR_NOT_OPEN;
// return an error if out of range
if (hunknum >= m_hunkcount)
throw CHDERR_HUNK_OUT_OF_RANGE;
// get a pointer to the map entry
UINT64 blockoffs;
UINT32 blocklen;
UINT32 blockcrc;
UINT8 *rawmap;
UINT8 *dest = reinterpret_cast<UINT8 *>(buffer);
switch (m_version)
{
// v3/v4 map entries
case 3:
case 4:
rawmap = &m_rawmap[16 * hunknum];
blockoffs = be_read(&rawmap[0], 8);
blockcrc = be_read(&rawmap[8], 4);
switch (rawmap[15] & V34_MAP_ENTRY_FLAG_TYPE_MASK)
{
case V34_MAP_ENTRY_TYPE_COMPRESSED:
blocklen = be_read(&rawmap[12], 2) + (rawmap[14] << 16);
file_read(blockoffs, &m_compressed[0], blocklen);
m_decompressor[0]->decompress(&m_compressed[0], blocklen, dest, m_hunkbytes);
if (!(rawmap[15] & V34_MAP_ENTRY_FLAG_NO_CRC) && dest != nullptr && crc32_creator::simple(dest, m_hunkbytes) != blockcrc)
throw CHDERR_DECOMPRESSION_ERROR;
return CHDERR_NONE;
case V34_MAP_ENTRY_TYPE_UNCOMPRESSED:
file_read(blockoffs, dest, m_hunkbytes);
if (!(rawmap[15] & V34_MAP_ENTRY_FLAG_NO_CRC) && crc32_creator::simple(dest, m_hunkbytes) != blockcrc)
throw CHDERR_DECOMPRESSION_ERROR;
return CHDERR_NONE;
case V34_MAP_ENTRY_TYPE_MINI:
be_write(dest, blockoffs, 8);
for (UINT32 bytes = 8; bytes < m_hunkbytes; bytes++)
dest[bytes] = dest[bytes - 8];
if (!(rawmap[15] & V34_MAP_ENTRY_FLAG_NO_CRC) && crc32_creator::simple(dest, m_hunkbytes) != blockcrc)
throw CHDERR_DECOMPRESSION_ERROR;
return CHDERR_NONE;
case V34_MAP_ENTRY_TYPE_SELF_HUNK:
return read_hunk(blockoffs, dest);
case V34_MAP_ENTRY_TYPE_PARENT_HUNK:
if (m_parent_missing)
throw CHDERR_REQUIRES_PARENT;
return m_parent->read_hunk(blockoffs, dest);
}
break;
// v5 map entries
case 5:
rawmap = &m_rawmap[m_mapentrybytes * hunknum];
// uncompressed case
if (!compressed())
{
blockoffs = UINT64(be_read(rawmap, 4)) * UINT64(m_hunkbytes);
if (blockoffs != 0)
file_read(blockoffs, dest, m_hunkbytes);
else if (m_parent_missing)
throw CHDERR_REQUIRES_PARENT;
else if (m_parent != nullptr)
m_parent->read_hunk(hunknum, dest);
else
memset(dest, 0, m_hunkbytes);
return CHDERR_NONE;
}
// compressed case
blocklen = be_read(&rawmap[1], 3);
blockoffs = be_read(&rawmap[4], 6);
blockcrc = be_read(&rawmap[10], 2);
switch (rawmap[0])
{
case COMPRESSION_TYPE_0:
case COMPRESSION_TYPE_1:
case COMPRESSION_TYPE_2:
case COMPRESSION_TYPE_3:
file_read(blockoffs, &m_compressed[0], blocklen);
m_decompressor[rawmap[0]]->decompress(&m_compressed[0], blocklen, dest, m_hunkbytes);
if (!m_decompressor[rawmap[0]]->lossy() && dest != nullptr && crc16_creator::simple(dest, m_hunkbytes) != blockcrc)
throw CHDERR_DECOMPRESSION_ERROR;
if (m_decompressor[rawmap[0]]->lossy() && crc16_creator::simple(&m_compressed[0], blocklen) != blockcrc)
throw CHDERR_DECOMPRESSION_ERROR;
return CHDERR_NONE;
case COMPRESSION_NONE:
file_read(blockoffs, dest, m_hunkbytes);
if (crc16_creator::simple(dest, m_hunkbytes) != blockcrc)
throw CHDERR_DECOMPRESSION_ERROR;
return CHDERR_NONE;
case COMPRESSION_SELF:
return read_hunk(blockoffs, dest);
case COMPRESSION_PARENT:
if (m_parent_missing)
throw CHDERR_REQUIRES_PARENT;
return m_parent->read_bytes(UINT64(blockoffs) * UINT64(m_parent->unit_bytes()), dest, m_hunkbytes);
}
break;
}
// if we get here, something was wrong
throw CHDERR_READ_ERROR;
}
// just return errors
catch (chd_error &err)
{
return err;
}
}
/**
* @fn chd_error chd_file::write_hunk(UINT32 hunknum, const void *buffer)
*
* @brief -------------------------------------------------
* write - write a single hunk to the CHD file
* -------------------------------------------------.
*
* @exception CHDERR_NOT_OPEN Thrown when a chderr not open error condition occurs.
* @exception CHDERR_HUNK_OUT_OF_RANGE Thrown when a chderr hunk out of range error
* condition occurs.
* @exception CHDERR_FILE_NOT_WRITEABLE Thrown when a chderr file not writeable error
* condition occurs.
*
* @param hunknum The hunknum.
* @param buffer The buffer.
*
* @return A chd_error.
*/
chd_error chd_file::write_hunk(UINT32 hunknum, const void *buffer)
{
// wrap this for clean reporting
try
{
// punt if no file
if (m_file == nullptr)
throw CHDERR_NOT_OPEN;
// return an error if out of range
if (hunknum >= m_hunkcount)
throw CHDERR_HUNK_OUT_OF_RANGE;
// if not writeable, fail
if (!m_allow_writes)
throw CHDERR_FILE_NOT_WRITEABLE;
// uncompressed writes only via this interface
if (compressed())
throw CHDERR_FILE_NOT_WRITEABLE;
// see if we have allocated the space on disk for this hunk
UINT8 *rawmap = &m_rawmap[hunknum * 4];
UINT32 rawentry = be_read(rawmap, 4);
// if not, allocate one now
if (rawentry == 0)
{
// first make sure we need to allocate it
bool all_zeros = true;
const UINT32 *scan = reinterpret_cast<const UINT32 *>(buffer);
for (UINT32 index = 0; index < m_hunkbytes / 4; index++)
if (scan[index] != 0)
{
all_zeros = false;
break;
}
// if it's all zeros, do nothing more
if (all_zeros)
return CHDERR_NONE;
// append new data to the end of the file, aligning the first chunk
rawentry = file_append(buffer, m_hunkbytes, m_hunkbytes) / m_hunkbytes;
// write the map entry back
be_write(rawmap, rawentry, 4);
file_write(m_mapoffset + hunknum * 4, rawmap, 4);
// update the cached hunk if we just wrote it
if (hunknum == m_cachehunk && buffer != &m_cache[0])
memcpy(&m_cache[0], buffer, m_hunkbytes);
}
// otherwise, just overwrite
else
file_write(UINT64(rawentry) * UINT64(m_hunkbytes), buffer, m_hunkbytes);
return CHDERR_NONE;
}
// just return errors
catch (chd_error &err)
{
return err;
}
}
/**
* @fn chd_error chd_file::read_units(UINT64 unitnum, void *buffer, UINT32 count)
*
* @brief -------------------------------------------------
* read_units - read the given number of units from the CHD
* -------------------------------------------------.
*
* @param unitnum The unitnum.
* @param [in,out] buffer If non-null, the buffer.
* @param count Number of.
*
* @return The units.
*/
chd_error chd_file::read_units(UINT64 unitnum, void *buffer, UINT32 count)
{
return read_bytes(unitnum * UINT64(m_unitbytes), buffer, count * m_unitbytes);
}
/**
* @fn chd_error chd_file::write_units(UINT64 unitnum, const void *buffer, UINT32 count)
*
* @brief -------------------------------------------------
* write_units - write the given number of units to the CHD
* -------------------------------------------------.
*
* @param unitnum The unitnum.
* @param buffer The buffer.
* @param count Number of.
*
* @return A chd_error.
*/
chd_error chd_file::write_units(UINT64 unitnum, const void *buffer, UINT32 count)
{
return write_bytes(unitnum * UINT64(m_unitbytes), buffer, count * m_unitbytes);
}
/**
* @fn chd_error chd_file::read_bytes(UINT64 offset, void *buffer, UINT32 bytes)
*
* @brief -------------------------------------------------
* read_bytes - read from the CHD at a byte level, using the cache to handle partial
* hunks
* -------------------------------------------------.
*
* @param offset The offset.
* @param [in,out] buffer If non-null, the buffer.
* @param bytes The bytes.
*
* @return The bytes.
*/
chd_error chd_file::read_bytes(UINT64 offset, void *buffer, UINT32 bytes)
{
// iterate over hunks
UINT32 first_hunk = offset / m_hunkbytes;
UINT32 last_hunk = (offset + bytes - 1) / m_hunkbytes;
UINT8 *dest = reinterpret_cast<UINT8 *>(buffer);
for (UINT32 curhunk = first_hunk; curhunk <= last_hunk; curhunk++)
{
// determine start/end boundaries
UINT32 startoffs = (curhunk == first_hunk) ? (offset % m_hunkbytes) : 0;
UINT32 endoffs = (curhunk == last_hunk) ? ((offset + bytes - 1) % m_hunkbytes) : (m_hunkbytes - 1);
// if it's a full block, just read directly from disk unless it's the cached hunk
chd_error err = CHDERR_NONE;
if (startoffs == 0 && endoffs == m_hunkbytes - 1 && curhunk != m_cachehunk)
err = read_hunk(curhunk, dest);
// otherwise, read from the cache
else
{
if (curhunk != m_cachehunk)
{
err = read_hunk(curhunk, &m_cache[0]);
if (err != CHDERR_NONE)
return err;
m_cachehunk = curhunk;
}
memcpy(dest, &m_cache[startoffs], endoffs + 1 - startoffs);
}
// handle errors and advance
if (err != CHDERR_NONE)
return err;
dest += endoffs + 1 - startoffs;
}
return CHDERR_NONE;
}
/**
* @fn chd_error chd_file::write_bytes(UINT64 offset, const void *buffer, UINT32 bytes)
*
* @brief -------------------------------------------------
* write_bytes - write to the CHD at a byte level, using the cache to handle partial
* hunks
* -------------------------------------------------.
*
* @param offset The offset.
* @param buffer The buffer.
* @param bytes The bytes.
*
* @return A chd_error.
*/
chd_error chd_file::write_bytes(UINT64 offset, const void *buffer, UINT32 bytes)
{
// iterate over hunks
UINT32 first_hunk = offset / m_hunkbytes;
UINT32 last_hunk = (offset + bytes - 1) / m_hunkbytes;
const UINT8 *source = reinterpret_cast<const UINT8 *>(buffer);
for (UINT32 curhunk = first_hunk; curhunk <= last_hunk; curhunk++)
{
// determine start/end boundaries
UINT32 startoffs = (curhunk == first_hunk) ? (offset % m_hunkbytes) : 0;
UINT32 endoffs = (curhunk == last_hunk) ? ((offset + bytes - 1) % m_hunkbytes) : (m_hunkbytes - 1);
// if it's a full block, just write directly to disk unless it's the cached hunk
chd_error err = CHDERR_NONE;
if (startoffs == 0 && endoffs == m_hunkbytes - 1 && curhunk != m_cachehunk)
err = write_hunk(curhunk, source);
// otherwise, write from the cache
else
{
if (curhunk != m_cachehunk)
{
err = read_hunk(curhunk, &m_cache[0]);
if (err != CHDERR_NONE)
return err;
m_cachehunk = curhunk;
}
memcpy(&m_cache[startoffs], source, endoffs + 1 - startoffs);
err = write_hunk(curhunk, &m_cache[0]);
}
// handle errors and advance
if (err != CHDERR_NONE)
return err;
source += endoffs + 1 - startoffs;
}
return CHDERR_NONE;
}
/**
* @fn chd_error chd_file::read_metadata(chd_metadata_tag searchtag, UINT32 searchindex, std::string &output)
*
* @brief -------------------------------------------------
* read_metadata - read the indexed metadata of the given type
* -------------------------------------------------.
*
* @exception CHDERR_METADATA_NOT_FOUND Thrown when a chderr metadata not found error
* condition occurs.
*
* @param searchtag The searchtag.
* @param searchindex The searchindex.
* @param [in,out] output The output.
*
* @return The metadata.
*/
chd_error chd_file::read_metadata(chd_metadata_tag searchtag, UINT32 searchindex, std::string &output)
{
// wrap this for clean reporting
try
{
// if we didn't find it, just return
metadata_entry metaentry;
if (!metadata_find(searchtag, searchindex, metaentry))
throw CHDERR_METADATA_NOT_FOUND;
// read the metadata
// TODO: how to properly allocate a dynamic char buffer?
auto metabuf = new char[metaentry.length+1];
memset(metabuf, 0x00, metaentry.length+1);
file_read(metaentry.offset + METADATA_HEADER_SIZE, metabuf, metaentry.length);
output.assign(metabuf);
delete[] metabuf;
return CHDERR_NONE;
}
// just return errors
catch (chd_error &err)
{
return err;
}
}
/**
* @fn chd_error chd_file::read_metadata(chd_metadata_tag searchtag, UINT32 searchindex, dynamic_buffer &output)
*
* @brief Reads a metadata.
*
* @exception CHDERR_METADATA_NOT_FOUND Thrown when a chderr metadata not found error
* condition occurs.
*
* @param searchtag The searchtag.
* @param searchindex The searchindex.
* @param [in,out] output The output.
*
* @return The metadata.
*/
chd_error chd_file::read_metadata(chd_metadata_tag searchtag, UINT32 searchindex, dynamic_buffer &output)
{
// wrap this for clean reporting
try
{
// if we didn't find it, just return
metadata_entry metaentry;
if (!metadata_find(searchtag, searchindex, metaentry))
throw CHDERR_METADATA_NOT_FOUND;
// read the metadata
output.resize(metaentry.length);
file_read(metaentry.offset + METADATA_HEADER_SIZE, &output[0], metaentry.length);
return CHDERR_NONE;
}
// just return errors
catch (chd_error &err)
{
return err;
}
}
/**
* @fn chd_error chd_file::read_metadata(chd_metadata_tag searchtag, UINT32 searchindex, void *output, UINT32 outputlen, UINT32 &resultlen)
*
* @brief Reads a metadata.
*
* @exception CHDERR_METADATA_NOT_FOUND Thrown when a chderr metadata not found error
* condition occurs.
*
* @param searchtag The searchtag.
* @param searchindex The searchindex.
* @param [in,out] output If non-null, the output.
* @param outputlen The outputlen.
* @param [in,out] resultlen The resultlen.
*
* @return The metadata.
*/
chd_error chd_file::read_metadata(chd_metadata_tag searchtag, UINT32 searchindex, void *output, UINT32 outputlen, UINT32 &resultlen)
{
// wrap this for clean reporting
try
{
// if we didn't find it, just return
metadata_entry metaentry;
if (!metadata_find(searchtag, searchindex, metaentry))
throw CHDERR_METADATA_NOT_FOUND;
// read the metadata
resultlen = metaentry.length;
file_read(metaentry.offset + METADATA_HEADER_SIZE, output, MIN(outputlen, resultlen));
return CHDERR_NONE;
}
// just return errors
catch (chd_error &err)
{
return err;
}
}
/**
* @fn chd_error chd_file::read_metadata(chd_metadata_tag searchtag, UINT32 searchindex, dynamic_buffer &output, chd_metadata_tag &resulttag, UINT8 &resultflags)
*
* @brief Reads a metadata.
*
* @exception CHDERR_METADATA_NOT_FOUND Thrown when a chderr metadata not found error
* condition occurs.
*
* @param searchtag The searchtag.
* @param searchindex The searchindex.
* @param [in,out] output The output.
* @param [in,out] resulttag The resulttag.
* @param [in,out] resultflags The resultflags.
*
* @return The metadata.
*/
chd_error chd_file::read_metadata(chd_metadata_tag searchtag, UINT32 searchindex, dynamic_buffer &output, chd_metadata_tag &resulttag, UINT8 &resultflags)
{
// wrap this for clean reporting
try
{
// if we didn't find it, just return
metadata_entry metaentry;
if (!metadata_find(searchtag, searchindex, metaentry))
throw CHDERR_METADATA_NOT_FOUND;
// read the metadata
output.resize(metaentry.length);
file_read(metaentry.offset + METADATA_HEADER_SIZE, &output[0], metaentry.length);
resulttag = metaentry.metatag;
resultflags = metaentry.flags;
return CHDERR_NONE;
}
// just return errors
catch (chd_error &err)
{
return err;
}
}
/**
* @fn chd_error chd_file::write_metadata(chd_metadata_tag metatag, UINT32 metaindex, const void *inputbuf, UINT32 inputlen, UINT8 flags)
*
* @brief -------------------------------------------------
* write_metadata - write the indexed metadata of the given type
* -------------------------------------------------.
*
* @param metatag The metatag.
* @param metaindex The metaindex.
* @param inputbuf The inputbuf.
* @param inputlen The inputlen.
* @param flags The flags.
*
* @return A chd_error.
*/
chd_error chd_file::write_metadata(chd_metadata_tag metatag, UINT32 metaindex, const void *inputbuf, UINT32 inputlen, UINT8 flags)
{
// wrap this for clean reporting
try
{
// must write at least 1 byte and no more than 16MB
if (inputlen < 1 || inputlen >= 16 * 1024 * 1024)
return CHDERR_INVALID_PARAMETER;
// find the entry if it already exists
metadata_entry metaentry;
bool finished = false;
if (metadata_find(metatag, metaindex, metaentry))
{
// if the new data fits over the old data, just overwrite
if (inputlen <= metaentry.length)
{
file_write(metaentry.offset + METADATA_HEADER_SIZE, inputbuf, inputlen);
// if the lengths don't match, we need to update the length in our header
if (inputlen != metaentry.length)
{
UINT8 length[3];
be_write(length, inputlen, 3);
file_write(metaentry.offset + 5, length, sizeof(length));
}
// indicate we did everything
finished = true;
}
// if it doesn't fit, unlink the current entry
else
metadata_set_previous_next(metaentry.prev, metaentry.next);
}
// if not yet done, create a new entry and append
if (!finished)
{
// now build us a new entry
UINT8 raw_meta_header[METADATA_HEADER_SIZE];
be_write(&raw_meta_header[0], metatag, 4);
raw_meta_header[4] = flags;
be_write(&raw_meta_header[5], (inputlen & 0x00ffffff) | (flags << 24), 3);
be_write(&raw_meta_header[8], 0, 8);
// append the new header, then the data
UINT64 offset = file_append(raw_meta_header, sizeof(raw_meta_header));
file_append(inputbuf, inputlen);
// set the previous entry to point to us
metadata_set_previous_next(metaentry.prev, offset);
}
// update the hash
metadata_update_hash();
return CHDERR_NONE;
}
// return any errors
catch (chd_error &err)
{
return err;
}
}
/**
* @fn chd_error chd_file::delete_metadata(chd_metadata_tag metatag, UINT32 metaindex)
*
* @brief -------------------------------------------------
* delete_metadata - remove the given metadata from the list
* -------------------------------------------------.
*
* @exception CHDERR_METADATA_NOT_FOUND Thrown when a chderr metadata not found error
* condition occurs.
*
* @param metatag The metatag.
* @param metaindex The metaindex.
*
* @return A chd_error.
*/
chd_error chd_file::delete_metadata(chd_metadata_tag metatag, UINT32 metaindex)
{
// wrap this for clean reporting
try
{
// find the entry
metadata_entry metaentry;
if (!metadata_find(metatag, metaindex, metaentry))
throw CHDERR_METADATA_NOT_FOUND;
// point the previous to the next, unlinking us
metadata_set_previous_next(metaentry.prev, metaentry.next);
return CHDERR_NONE;
}
// return any errors
catch (chd_error &err)
{
return err;
}
}
/**
* @fn chd_error chd_file::clone_all_metadata(chd_file &source)
*
* @brief -------------------------------------------------
* clone_all_metadata - clone the metadata from one CHD to a second
* -------------------------------------------------.
*
* @exception err Thrown when an error error condition occurs.
*
* @param [in,out] source Another instance to copy.
*
* @return A chd_error.
*/
chd_error chd_file::clone_all_metadata(chd_file &source)
{
// wrap this for clean reporting
try
{
// iterate over metadata entries in the source
dynamic_buffer filedata;
metadata_entry metaentry;
metaentry.metatag = 0;
metaentry.length = 0;
metaentry.next = 0;
metaentry.flags = 0;
for (bool has_data = source.metadata_find(CHDMETATAG_WILDCARD, 0, metaentry); has_data; has_data = source.metadata_find(CHDMETATAG_WILDCARD, 0, metaentry, true))
{
// read the metadata item
filedata.resize(metaentry.length);
source.file_read(metaentry.offset + METADATA_HEADER_SIZE, &filedata[0], metaentry.length);
// write it to the destination
chd_error err = write_metadata(metaentry.metatag, (UINT32)-1, &filedata[0], metaentry.length, metaentry.flags);
if (err != CHDERR_NONE)
throw err;
}
return CHDERR_NONE;
}
// return any errors
catch (chd_error &err)
{
return err;
}
}
/**
* @fn sha1_t chd_file::compute_overall_sha1(sha1_t rawsha1)
*
* @brief -------------------------------------------------
* compute_overall_sha1 - iterate through the metadata and compute the overall hash of
* the CHD file
* -------------------------------------------------.
*
* @param rawsha1 The first rawsha.
*
* @return The calculated overall sha 1.
*/
sha1_t chd_file::compute_overall_sha1(sha1_t rawsha1)
{
// only works for v4 and above
if (m_version < 4)
return rawsha1;
// iterate over metadata
dynamic_buffer filedata;
std::vector<metadata_hash> hasharray;
metadata_entry metaentry;
for (bool has_data = metadata_find(CHDMETATAG_WILDCARD, 0, metaentry); has_data; has_data = metadata_find(CHDMETATAG_WILDCARD, 0, metaentry, true))
{
// if not checksumming, continue
if ((metaentry.flags & CHD_MDFLAGS_CHECKSUM) == 0)
continue;
// allocate memory and read the data
filedata.resize(metaentry.length);
file_read(metaentry.offset + METADATA_HEADER_SIZE, &filedata[0], metaentry.length);
// create an entry for this metadata and add it
metadata_hash hashentry;
be_write(hashentry.tag, metaentry.metatag, 4);
hashentry.sha1 = sha1_creator::simple(&filedata[0], metaentry.length);
hasharray.push_back(hashentry);
}
// sort the array
if (!hasharray.empty())
qsort(&hasharray[0], hasharray.size(), sizeof(hasharray[0]), metadata_hash_compare);
// read the raw data hash from our header and start a new SHA1 with that data
sha1_creator overall_sha1;
overall_sha1.append(&rawsha1, sizeof(rawsha1));
if (!hasharray.empty())
overall_sha1.append(&hasharray[0], hasharray.size() * sizeof(hasharray[0]));
return overall_sha1.finish();
}
/**
* @fn chd_error chd_file::codec_configure(chd_codec_type codec, int param, void *config)
*
* @brief -------------------------------------------------
* codec_config - set internal codec parameters
* -------------------------------------------------.
*
* @param codec The codec.
* @param param The parameter.
* @param [in,out] config If non-null, the configuration.
*
* @return A chd_error.
*/
chd_error chd_file::codec_configure(chd_codec_type codec, int param, void *config)
{
// wrap this for clean reporting
try
{
// find the codec and call its configuration
for (int codecnum = 0; codecnum < ARRAY_LENGTH(m_compression); codecnum++)
if (m_compression[codecnum] == codec)
{
m_decompressor[codecnum]->configure(param, config);
return CHDERR_NONE;
}
return CHDERR_INVALID_PARAMETER;
}
// return any errors
catch (chd_error &err)
{
return err;
}
}
/**
* @fn const char *chd_file::error_string(chd_error err)
*
* @brief -------------------------------------------------
* error_string - return an error string for the given CHD error
* -------------------------------------------------.
*
* @param err The error.
*
* @return null if it fails, else a char*.
*/
const char *chd_file::error_string(chd_error err)
{
switch (err)
{
case CHDERR_NONE: return "no error";
case CHDERR_NO_INTERFACE: return "no drive interface";
case CHDERR_OUT_OF_MEMORY: return "out of memory";
case CHDERR_NOT_OPEN: return "file not open";
case CHDERR_ALREADY_OPEN: return "file already open";
case CHDERR_INVALID_FILE: return "invalid file";
case CHDERR_INVALID_PARAMETER: return "invalid parameter";
case CHDERR_INVALID_DATA: return "invalid data";
case CHDERR_FILE_NOT_FOUND: return "file not found";
case CHDERR_REQUIRES_PARENT: return "requires parent";
case CHDERR_FILE_NOT_WRITEABLE: return "file not writeable";
case CHDERR_READ_ERROR: return "read error";
case CHDERR_WRITE_ERROR: return "write error";
case CHDERR_CODEC_ERROR: return "codec error";
case CHDERR_INVALID_PARENT: return "invalid parent";
case CHDERR_HUNK_OUT_OF_RANGE: return "hunk out of range";
case CHDERR_DECOMPRESSION_ERROR: return "decompression error";
case CHDERR_COMPRESSION_ERROR: return "compression error";
case CHDERR_CANT_CREATE_FILE: return "can't create file";
case CHDERR_CANT_VERIFY: return "can't verify file";
case CHDERR_NOT_SUPPORTED: return "operation not supported";
case CHDERR_METADATA_NOT_FOUND: return "can't find metadata";
case CHDERR_INVALID_METADATA_SIZE: return "invalid metadata size";
case CHDERR_UNSUPPORTED_VERSION: return "mismatched DIFF and CHD or unsupported CHD version";
case CHDERR_VERIFY_INCOMPLETE: return "incomplete verify";
case CHDERR_INVALID_METADATA: return "invalid metadata";
case CHDERR_INVALID_STATE: return "invalid state";
case CHDERR_OPERATION_PENDING: return "operation pending";
case CHDERR_UNSUPPORTED_FORMAT: return "unsupported format";
case CHDERR_UNKNOWN_COMPRESSION: return "unknown compression type";
case CHDERR_WALKING_PARENT: return "currently examining parent";
case CHDERR_COMPRESSING: return "currently compressing";
default: return "undocumented error";
}
}
//**************************************************************************
// INTERNAL HELPERS
//**************************************************************************
/**
* @fn UINT32 chd_file::guess_unitbytes()
*
* @brief -------------------------------------------------
* guess_unitbytes - for older CHD formats, take a guess at the bytes/unit based on
* metadata
* -------------------------------------------------.
*
* @return An UINT32.
*/
UINT32 chd_file::guess_unitbytes()
{
// look for hard disk metadata; if found, then the unit size == sector size
std::string metadata;
int i0, i1, i2, i3;
if (read_metadata(HARD_DISK_METADATA_TAG, 0, metadata) == CHDERR_NONE && sscanf(metadata.c_str(), HARD_DISK_METADATA_FORMAT, &i0, &i1, &i2, &i3) == 4)
return i3;
// look for CD-ROM metadata; if found, then the unit size == CD frame size
if (read_metadata(CDROM_OLD_METADATA_TAG, 0, metadata) == CHDERR_NONE ||
read_metadata(CDROM_TRACK_METADATA_TAG, 0, metadata) == CHDERR_NONE ||
read_metadata(CDROM_TRACK_METADATA2_TAG, 0, metadata) == CHDERR_NONE ||
read_metadata(GDROM_OLD_METADATA_TAG, 0, metadata) == CHDERR_NONE ||
read_metadata(GDROM_TRACK_METADATA_TAG, 0, metadata) == CHDERR_NONE)
return CD_FRAME_SIZE;
// otherwise, just map 1:1 with the hunk size
return m_hunkbytes;
}
/**
* @fn void chd_file::parse_v3_header(UINT8 *rawheader, sha1_t &parentsha1)
*
* @brief -------------------------------------------------
* parse_v3_header - parse the header from a v3 file and configure core parameters
* -------------------------------------------------.
*
* @exception CHDERR_INVALID_FILE Thrown when a chderr invalid file error condition
* occurs.
* @exception CHDERR_UNKNOWN_COMPRESSION Thrown when a chderr unknown compression error
* condition occurs.
*
* @param [in,out] rawheader If non-null, the rawheader.
* @param [in,out] parentsha1 The first parentsha.
*/
void chd_file::parse_v3_header(UINT8 *rawheader, sha1_t &parentsha1)
{
// verify header length
if (be_read(&rawheader[8], 4) != V3_HEADER_SIZE)
throw CHDERR_INVALID_FILE;
// extract core info
m_logicalbytes = be_read(&rawheader[28], 8);
m_mapoffset = 120;
m_metaoffset = be_read(&rawheader[36], 8);
m_hunkbytes = be_read(&rawheader[76], 4);
m_hunkcount = be_read(&rawheader[24], 4);
// extract parent SHA-1
UINT32 flags = be_read(&rawheader[16], 4);
m_allow_writes = (flags & 2) == 0;
// determine compression
switch (be_read(&rawheader[20], 4))
{
case 0: m_compression[0] = CHD_CODEC_NONE; break;
case 1: m_compression[0] = CHD_CODEC_ZLIB; break;
case 2: m_compression[0] = CHD_CODEC_ZLIB; break;
case 3: m_compression[0] = CHD_CODEC_AVHUFF; break;
default: throw CHDERR_UNKNOWN_COMPRESSION;
}
m_compression[1] = m_compression[2] = m_compression[3] = CHD_CODEC_NONE;
// describe the format
m_mapoffset_offset = 0;
m_metaoffset_offset = 36;
m_sha1_offset = 80;
m_rawsha1_offset = 0;
m_parentsha1_offset = 100;
// determine properties of map entries
m_mapentrybytes = 16;
// extract parent SHA-1
if (flags & 1)
parentsha1 = be_read_sha1(&rawheader[m_parentsha1_offset]);
// guess at the units based on snooping the metadata
m_unitbytes = guess_unitbytes();
m_unitcount = (m_logicalbytes + m_unitbytes - 1) / m_unitbytes;
}
/**
* @fn void chd_file::parse_v4_header(UINT8 *rawheader, sha1_t &parentsha1)
*
* @brief -------------------------------------------------
* parse_v4_header - parse the header from a v4 file and configure core parameters
* -------------------------------------------------.
*
* @exception CHDERR_INVALID_FILE Thrown when a chderr invalid file error condition
* occurs.
* @exception CHDERR_UNKNOWN_COMPRESSION Thrown when a chderr unknown compression error
* condition occurs.
*
* @param [in,out] rawheader If non-null, the rawheader.
* @param [in,out] parentsha1 The first parentsha.
*/
void chd_file::parse_v4_header(UINT8 *rawheader, sha1_t &parentsha1)
{
// verify header length
if (be_read(&rawheader[8], 4) != V4_HEADER_SIZE)
throw CHDERR_INVALID_FILE;
// extract core info
m_logicalbytes = be_read(&rawheader[28], 8);
m_mapoffset = 108;
m_metaoffset = be_read(&rawheader[36], 8);
m_hunkbytes = be_read(&rawheader[44], 4);
m_hunkcount = be_read(&rawheader[24], 4);
// extract parent SHA-1
UINT32 flags = be_read(&rawheader[16], 4);
m_allow_writes = (flags & 2) == 0;
// determine compression
switch (be_read(&rawheader[20], 4))
{
case 0: m_compression[0] = CHD_CODEC_NONE; break;
case 1: m_compression[0] = CHD_CODEC_ZLIB; break;
case 2: m_compression[0] = CHD_CODEC_ZLIB; break;
case 3: m_compression[0] = CHD_CODEC_AVHUFF; break;
default: throw CHDERR_UNKNOWN_COMPRESSION;
}
m_compression[1] = m_compression[2] = m_compression[3] = CHD_CODEC_NONE;
// describe the format
m_mapoffset_offset = 0;
m_metaoffset_offset = 36;
m_sha1_offset = 48;
m_rawsha1_offset = 88;
m_parentsha1_offset = 68;
// determine properties of map entries
m_mapentrybytes = 16;
// extract parent SHA-1
if (flags & 1)
parentsha1 = be_read_sha1(&rawheader[m_parentsha1_offset]);
// guess at the units based on snooping the metadata
m_unitbytes = guess_unitbytes();
m_unitcount = (m_logicalbytes + m_unitbytes - 1) / m_unitbytes;
}
/**
* @fn void chd_file::parse_v5_header(UINT8 *rawheader, sha1_t &parentsha1)
*
* @brief -------------------------------------------------
* parse_v5_header - read the header from a v5 file and configure core parameters
* -------------------------------------------------.
*
* @exception CHDERR_INVALID_FILE Thrown when a chderr invalid file error condition occurs.
*
* @param [in,out] rawheader If non-null, the rawheader.
* @param [in,out] parentsha1 The first parentsha.
*/
void chd_file::parse_v5_header(UINT8 *rawheader, sha1_t &parentsha1)
{
// verify header length
if (be_read(&rawheader[8], 4) != V5_HEADER_SIZE)
throw CHDERR_INVALID_FILE;
// extract core info
m_logicalbytes = be_read(&rawheader[32], 8);
m_mapoffset = be_read(&rawheader[40], 8);
m_metaoffset = be_read(&rawheader[48], 8);
m_hunkbytes = be_read(&rawheader[56], 4);
m_hunkcount = (m_logicalbytes + m_hunkbytes - 1) / m_hunkbytes;
m_unitbytes = be_read(&rawheader[60], 4);
m_unitcount = (m_logicalbytes + m_unitbytes - 1) / m_unitbytes;
// determine compression
m_compression[0] = be_read(&rawheader[16], 4);
m_compression[1] = be_read(&rawheader[20], 4);
m_compression[2] = be_read(&rawheader[24], 4);
m_compression[3] = be_read(&rawheader[28], 4);
m_allow_writes = !compressed();
// describe the format
m_mapoffset_offset = 40;
m_metaoffset_offset = 48;
m_sha1_offset = 84;
m_rawsha1_offset = 64;
m_parentsha1_offset = 104;
// determine properties of map entries
m_mapentrybytes = compressed() ? 12 : 4;
// extract parent SHA-1
parentsha1 = be_read_sha1(&rawheader[m_parentsha1_offset]);
}
/**
* @fn chd_error chd_file::compress_v5_map()
*
* @brief -------------------------------------------------
* compress_v5_map - compress the v5 map and write it to the end of the file
* -------------------------------------------------.
*
* @exception CHDERR_COMPRESSION_ERROR Thrown when a chderr compression error error
* condition occurs.
*
* @return A chd_error.
*/
chd_error chd_file::compress_v5_map()
{
try
{
// first get a CRC-16 of the original rawmap
crc16_t mapcrc = crc16_creator::simple(&m_rawmap[0], m_hunkcount * 12);
// create a buffer to hold the RLE data
dynamic_buffer compression_rle(m_hunkcount);
UINT8 *dest = &compression_rle[0];
// use a huffman encoder for 16 different codes, maximum length is 8 bits
huffman_encoder<16, 8> encoder;
encoder.histo_reset();
// RLE-compress the compression type since we expect runs of the same
UINT32 max_self = 0;
UINT32 last_self = 0;
UINT64 max_parent = 0;
UINT64 last_parent = 0;
UINT32 max_complen = 0;
UINT8 lastcomp = 0;
int count = 0;
for (int hunknum = 0; hunknum < m_hunkcount; hunknum++)
{
UINT8 curcomp = m_rawmap[hunknum * 12 + 0];
// promote self block references to more compact forms
if (curcomp == COMPRESSION_SELF)
{
UINT32 refhunk = be_read(&m_rawmap[hunknum * 12 + 4], 6);
if (refhunk == last_self)
curcomp = COMPRESSION_SELF_0;
else if (refhunk == last_self + 1)
curcomp = COMPRESSION_SELF_1;
else
max_self = MAX(max_self, refhunk);
last_self = refhunk;
}
// promote parent block references to more compact forms
else if (curcomp == COMPRESSION_PARENT)
{
UINT32 refunit = be_read(&m_rawmap[hunknum * 12 + 4], 6);
if (refunit == (UINT64(hunknum) * UINT64(m_hunkbytes)) / m_unitbytes)
curcomp = COMPRESSION_PARENT_SELF;
else if (refunit == last_parent)
curcomp = COMPRESSION_PARENT_0;
else if (refunit == last_parent + m_hunkbytes / m_unitbytes)
curcomp = COMPRESSION_PARENT_1;
else
max_parent = MAX(max_parent, refunit);
last_parent = refunit;
}
// track maximum compressed length
else //if (curcomp >= COMPRESSION_TYPE_0 && curcomp <= COMPRESSION_TYPE_3)
max_complen = MAX(max_complen, be_read(&m_rawmap[hunknum * 12 + 1], 3));
// track repeats
if (curcomp == lastcomp)
count++;
// if no repeat, or we're at the end, flush it
if (curcomp != lastcomp || hunknum == m_hunkcount - 1)
{
while (count != 0)
{
if (count < 3)
encoder.histo_one(*dest++ = lastcomp), count--;
else if (count <= 3+15)
{
encoder.histo_one(*dest++ = COMPRESSION_RLE_SMALL);
encoder.histo_one(*dest++ = count - 3);
count = 0;
}
else
{
int this_count = MIN(count, 3+16+255);
encoder.histo_one(*dest++ = COMPRESSION_RLE_LARGE);
encoder.histo_one(*dest++ = (this_count - 3 - 16) >> 4);
encoder.histo_one(*dest++ = (this_count - 3 - 16) & 15);
count -= this_count;
}
}
if (curcomp != lastcomp)
encoder.histo_one(*dest++ = lastcomp = curcomp);
}
}
// compute a tree and export it to the buffer
dynamic_buffer compressed(m_hunkcount * 6);
bitstream_out bitbuf(&compressed[16], compressed.size() - 16);
huffman_error err = encoder.compute_tree_from_histo();
if (err != HUFFERR_NONE)
throw CHDERR_COMPRESSION_ERROR;
err = encoder.export_tree_rle(bitbuf);
if (err != HUFFERR_NONE)
throw CHDERR_COMPRESSION_ERROR;
// encode the data
for (UINT8 *src = &compression_rle[0]; src < dest; src++)
encoder.encode_one(bitbuf, *src);
// determine the number of bits we need to hold the a length
// and a hunk index
UINT8 lengthbits = bits_for_value(max_complen);
UINT8 selfbits = bits_for_value(max_self);
UINT8 parentbits = bits_for_value(max_parent);
// for each compression type, output the relevant data
lastcomp = 0;
count = 0;
UINT8 *src = &compression_rle[0];
UINT64 firstoffs = 0;
for (int hunknum = 0; hunknum < m_hunkcount; hunknum++)
{
UINT8 *rawmap = &m_rawmap[hunknum * 12];
UINT32 length = be_read(&rawmap[1], 3);
UINT64 offset = be_read(&rawmap[4], 6);
UINT16 crc = be_read(&rawmap[10], 2);
// if no count remaining, fetch the next entry
if (count == 0)
{
UINT8 val = *src++;
if (val == COMPRESSION_RLE_SMALL)
count = 2 + *src++;
else if (val == COMPRESSION_RLE_LARGE)
count = 2 + 16 + (*src++ << 4), count += *src++;
else
lastcomp = val;
}
else
count--;
// output additional data needed for this entry
switch (lastcomp)
{
case COMPRESSION_TYPE_0:
case COMPRESSION_TYPE_1:
case COMPRESSION_TYPE_2:
case COMPRESSION_TYPE_3:
assert(length < (1 << lengthbits));
bitbuf.write(length, lengthbits);
bitbuf.write(crc, 16);
if (firstoffs == 0)
firstoffs = offset;
break;
case COMPRESSION_NONE:
bitbuf.write(crc, 16);
if (firstoffs == 0)
firstoffs = offset;
break;
case COMPRESSION_SELF:
assert(offset < (UINT64(1) << selfbits));
bitbuf.write(offset, selfbits);
break;
case COMPRESSION_PARENT:
assert(offset < (UINT64(1) << parentbits));
bitbuf.write(offset, parentbits);
break;
case COMPRESSION_SELF_0:
case COMPRESSION_SELF_1:
case COMPRESSION_PARENT_SELF:
case COMPRESSION_PARENT_0:
case COMPRESSION_PARENT_1:
break;
}
}
// write the map header
UINT32 complen = bitbuf.flush();
assert(!bitbuf.overflow());
be_write(&compressed[0], complen, 4);
be_write(&compressed[4], firstoffs, 6);
be_write(&compressed[10], mapcrc, 2);
compressed[12] = lengthbits;
compressed[13] = selfbits;
compressed[14] = parentbits;
compressed[15] = 0;
// write the result
m_mapoffset = file_append(&compressed[0], complen + 16);
// then write the map offset
UINT8 rawbuf[sizeof(UINT64)];
be_write(rawbuf, m_mapoffset, 8);
file_write(m_mapoffset_offset, rawbuf, sizeof(rawbuf));
return CHDERR_NONE;
}
catch (chd_error &err)
{
return err;
}
}
/**
* @fn void chd_file::decompress_v5_map()
*
* @brief -------------------------------------------------
* decompress_v5_map - decompress the v5 map
* -------------------------------------------------.
*
* @exception CHDERR_DECOMPRESSION_ERROR Thrown when a chderr decompression error error
* condition occurs.
*/
void chd_file::decompress_v5_map()
{
// if no offset, we haven't written it yet
if (m_mapoffset == 0)
{
memset(&m_rawmap[0], 0xff, m_rawmap.size());
return;
}
// read the reader
UINT8 rawbuf[16];
file_read(m_mapoffset, rawbuf, sizeof(rawbuf));
UINT32 mapbytes = be_read(&rawbuf[0], 4);
UINT64 firstoffs = be_read(&rawbuf[4], 6);
UINT16 mapcrc = be_read(&rawbuf[10], 2);
UINT8 lengthbits = rawbuf[12];
UINT8 selfbits = rawbuf[13];
UINT8 parentbits = rawbuf[14];
// now read the map
dynamic_buffer compressed(mapbytes);
file_read(m_mapoffset + 16, &compressed[0], mapbytes);
bitstream_in bitbuf(&compressed[0], compressed.size());
// first decode the compression types
huffman_decoder<16, 8> decoder;
huffman_error err = decoder.import_tree_rle(bitbuf);
if (err != HUFFERR_NONE)
throw CHDERR_DECOMPRESSION_ERROR;
UINT8 lastcomp = 0;
int repcount = 0;
for (int hunknum = 0; hunknum < m_hunkcount; hunknum++)
{
UINT8 *rawmap = &m_rawmap[hunknum * 12];
if (repcount > 0)
rawmap[0] = lastcomp, repcount--;
else
{
UINT8 val = decoder.decode_one(bitbuf);
if (val == COMPRESSION_RLE_SMALL)
rawmap[0] = lastcomp, repcount = 2 + decoder.decode_one(bitbuf);
else if (val == COMPRESSION_RLE_LARGE)
rawmap[0] = lastcomp, repcount = 2 + 16 + (decoder.decode_one(bitbuf) << 4), repcount += decoder.decode_one(bitbuf);
else
rawmap[0] = lastcomp = val;
}
}
// then iterate through the hunks and extract the needed data
UINT64 curoffset = firstoffs;
UINT32 last_self = 0;
UINT64 last_parent = 0;
for (int hunknum = 0; hunknum < m_hunkcount; hunknum++)
{
UINT8 *rawmap = &m_rawmap[hunknum * 12];
UINT64 offset = curoffset;
UINT32 length = 0;
UINT16 crc = 0;
switch (rawmap[0])
{
// base types
case COMPRESSION_TYPE_0:
case COMPRESSION_TYPE_1:
case COMPRESSION_TYPE_2:
case COMPRESSION_TYPE_3:
curoffset += length = bitbuf.read(lengthbits);
crc = bitbuf.read(16);
break;
case COMPRESSION_NONE:
curoffset += length = m_hunkbytes;
crc = bitbuf.read(16);
break;
case COMPRESSION_SELF:
last_self = offset = bitbuf.read(selfbits);
break;
case COMPRESSION_PARENT:
offset = bitbuf.read(parentbits);
last_parent = offset;
break;
// pseudo-types; convert into base types
case COMPRESSION_SELF_1:
last_self++;
case COMPRESSION_SELF_0:
rawmap[0] = COMPRESSION_SELF;
offset = last_self;
break;
case COMPRESSION_PARENT_SELF:
rawmap[0] = COMPRESSION_PARENT;
last_parent = offset = (UINT64(hunknum) * UINT64(m_hunkbytes)) / m_unitbytes;
break;
case COMPRESSION_PARENT_1:
last_parent += m_hunkbytes / m_unitbytes;
case COMPRESSION_PARENT_0:
rawmap[0] = COMPRESSION_PARENT;
offset = last_parent;
break;
}
be_write(&rawmap[1], length, 3);
be_write(&rawmap[4], offset, 6);
be_write(&rawmap[10], crc, 2);
}
// verify the final CRC
if (crc16_creator::simple(&m_rawmap[0], m_hunkcount * 12) != mapcrc)
throw CHDERR_DECOMPRESSION_ERROR;
}
/**
* @fn chd_error chd_file::create_common()
*
* @brief -------------------------------------------------
* create_common - command path when creating a new CHD file
* -------------------------------------------------.
*
* @exception CHDERR_UNSUPPORTED_VERSION Thrown when a chderr unsupported version error
* condition occurs.
* @exception CHDERR_INVALID_PARAMETER Thrown when a chderr invalid parameter error
* condition occurs.
* @exception CHDERR_UNKNOWN_COMPRESSION Thrown when a chderr unknown compression error
* condition occurs.
*
* @return The new common.
*/
chd_error chd_file::create_common()
{
// wrap in try for proper error handling
try
{
m_version = HEADER_VERSION;
m_metaoffset = 0;
// if we have a parent, it must be V3 or later
if (m_parent != nullptr && m_parent->version() < 3)
throw CHDERR_UNSUPPORTED_VERSION;
// must be an even number of units per hunk
if (m_hunkbytes % m_unitbytes != 0)
throw CHDERR_INVALID_PARAMETER;
if (m_parent != nullptr && m_unitbytes != m_parent->unit_bytes())
throw CHDERR_INVALID_PARAMETER;
// verify the compression types
bool found_zero = false;
for (auto & elem : m_compression)
{
// once we hit an empty slot, all later slots must be empty as well
if (elem == CHD_CODEC_NONE)
found_zero = true;
else if (found_zero)
throw CHDERR_INVALID_PARAMETER;
else if (!chd_codec_list::codec_exists(elem))
throw CHDERR_UNKNOWN_COMPRESSION;
}
// create our V5 header
UINT8 rawheader[V5_HEADER_SIZE];
memcpy(&rawheader[0], "MComprHD", 8);
be_write(&rawheader[8], V5_HEADER_SIZE, 4);
be_write(&rawheader[12], m_version, 4);
be_write(&rawheader[16], m_compression[0], 4);
be_write(&rawheader[20], m_compression[1], 4);
be_write(&rawheader[24], m_compression[2], 4);
be_write(&rawheader[28], m_compression[3], 4);
be_write(&rawheader[32], m_logicalbytes, 8);
be_write(&rawheader[40], compressed() ? 0 : V5_HEADER_SIZE, 8);
be_write(&rawheader[48], m_metaoffset, 8);
be_write(&rawheader[56], m_hunkbytes, 4);
be_write(&rawheader[60], m_unitbytes, 4);
be_write_sha1(&rawheader[64], sha1_t::null);
be_write_sha1(&rawheader[84], sha1_t::null);
be_write_sha1(&rawheader[104], (m_parent != nullptr) ? m_parent->sha1() : sha1_t::null);
// write the resulting header
file_write(0, rawheader, sizeof(rawheader));
// parse it back out to set up fields appropriately
sha1_t parentsha1;
parse_v5_header(rawheader, parentsha1);
// writes are obviously permitted; reads only if uncompressed
m_allow_writes = true;
m_allow_reads = !compressed();
// write out the map (if not compressed)
if (!compressed())
{
UINT32 mapsize = m_mapentrybytes * m_hunkcount;
UINT8 buffer[4096] = { 0 };
UINT64 offset = m_mapoffset;
while (mapsize != 0)
{
UINT32 bytes_to_write = MIN(mapsize, sizeof(buffer));
file_write(offset, buffer, bytes_to_write);
offset += bytes_to_write;
mapsize -= bytes_to_write;
}
}
// finish opening the file
create_open_common();
}
// handle errors by closing ourself
catch (chd_error &err)
{
close();
return err;
}
catch (...)
{
close();
throw;
}
return CHDERR_NONE;
}
/**
* @fn chd_error chd_file::open_common(bool writeable)
*
* @brief -------------------------------------------------
* open_common - common path when opening an existing CHD file for input
* -------------------------------------------------.
*
* @exception CHDERR_INVALID_FILE Thrown when a chderr invalid file error condition
* occurs.
* @exception CHDERR_UNSUPPORTED_VERSION Thrown when a chderr unsupported version error
* condition occurs.
* @exception CHDERR_FILE_NOT_WRITEABLE Thrown when a chderr file not writeable error
* condition occurs.
* @exception CHDERR_INVALID_PARENT Thrown when a chderr invalid parent error condition
* occurs.
* @exception CHDERR_INVALID_PARAMETER Thrown when a chderr invalid parameter error
* condition occurs.
*
* @param writeable true if writeable.
*
* @return A chd_error.
*/
chd_error chd_file::open_common(bool writeable)
{
// wrap in try for proper error handling
try
{
// reads are always permitted
m_allow_reads = true;
// read the raw header
UINT8 rawheader[MAX_HEADER_SIZE];
file_read(0, rawheader, sizeof(rawheader));
// verify the signature
if (memcmp(rawheader, "MComprHD", 8) != 0)
throw CHDERR_INVALID_FILE;
// only allow writes to the most recent version
m_version = be_read(&rawheader[12], 4);
if (writeable && m_version < HEADER_VERSION)
throw CHDERR_UNSUPPORTED_VERSION;
// read the header if we support it
sha1_t parentsha1 = sha1_t::null;
switch (m_version)
{
case 3: parse_v3_header(rawheader, parentsha1); break;
case 4: parse_v4_header(rawheader, parentsha1); break;
case 5: parse_v5_header(rawheader, parentsha1); break;
default: throw CHDERR_UNSUPPORTED_VERSION;
}
if (writeable && !m_allow_writes)
throw CHDERR_FILE_NOT_WRITEABLE;
// make sure we have a parent if we need one (and don't if we don't)
if (parentsha1 != sha1_t::null)
{
if (m_parent == nullptr)
m_parent_missing = true;
else if (m_parent->sha1() != parentsha1)
throw CHDERR_INVALID_PARENT;
}
else if (m_parent != nullptr)
throw CHDERR_INVALID_PARAMETER;
// finish opening the file
create_open_common();
return CHDERR_NONE;
}
// handle errors by closing ourself
catch (chd_error &err)
{
close();
return err;
}
}
/**
* @fn void chd_file::create_open_common()
*
* @brief -------------------------------------------------
* create_open_common - common code for handling creation and opening of a file
* -------------------------------------------------.
*
* @exception CHDERR_UNKNOWN_COMPRESSION Thrown when a chderr unknown compression error
* condition occurs.
*/
void chd_file::create_open_common()
{
// verify the compression types and initialize the codecs
for (int decompnum = 0; decompnum < ARRAY_LENGTH(m_compression); decompnum++)
{
m_decompressor[decompnum] = chd_codec_list::new_decompressor(m_compression[decompnum], *this);
if (m_decompressor[decompnum] == nullptr && m_compression[decompnum] != 0)
throw CHDERR_UNKNOWN_COMPRESSION;
}
// read the map; v5+ compressed drives need to read and decompress their map
m_rawmap.resize(m_hunkcount * m_mapentrybytes);
if (m_version >= 5 && compressed())
decompress_v5_map();
else
file_read(m_mapoffset, &m_rawmap[0], m_rawmap.size());
// allocate the temporary compressed buffer and a buffer for caching
m_compressed.resize(m_hunkbytes);
m_cache.resize(m_hunkbytes);
}
/**
* @fn void chd_file::verify_proper_compression_append(UINT32 hunknum)
*
* @brief -------------------------------------------------
* verify_proper_compression_append - verify that the given hunk is a proper candidate
* for appending to a compressed CHD
* -------------------------------------------------.
*
* @exception CHDERR_NOT_OPEN Thrown when a chderr not open error condition occurs.
* @exception CHDERR_HUNK_OUT_OF_RANGE Thrown when a chderr hunk out of range error
* condition occurs.
* @exception CHDERR_FILE_NOT_WRITEABLE Thrown when a chderr file not writeable error
* condition occurs.
* @exception CHDERR_COMPRESSION_ERROR Thrown when a chderr compression error error
* condition occurs.
*
* @param hunknum The hunknum.
*/
void chd_file::verify_proper_compression_append(UINT32 hunknum)
{
// punt if no file
if (m_file == nullptr)
throw CHDERR_NOT_OPEN;
// return an error if out of range
if (hunknum >= m_hunkcount)
throw CHDERR_HUNK_OUT_OF_RANGE;
// if not writeable, fail
if (!m_allow_writes)
throw CHDERR_FILE_NOT_WRITEABLE;
// compressed writes only via this interface
if (!compressed())
throw CHDERR_FILE_NOT_WRITEABLE;
// only permitted to write new blocks
UINT8 *rawmap = &m_rawmap[hunknum * 12];
if (rawmap[0] != 0xff)
throw CHDERR_COMPRESSION_ERROR;
// if this isn't the first block, only permitted to write immediately
// after the previous one
if (hunknum != 0 && rawmap[-12] == 0xff)
throw CHDERR_COMPRESSION_ERROR;
}
/**
* @fn void chd_file::hunk_write_compressed(UINT32 hunknum, INT8 compression, const UINT8 *compressed, UINT32 complength, crc16_t crc16)
*
* @brief -------------------------------------------------
* hunk_write_compressed - write a hunk to a compressed CHD, discovering the best
* technique
* -------------------------------------------------.
*
* @param hunknum The hunknum.
* @param compression The compression.
* @param compressed The compressed.
* @param complength The complength.
* @param crc16 The CRC 16.
*/
void chd_file::hunk_write_compressed(UINT32 hunknum, INT8 compression, const UINT8 *compressed, UINT32 complength, crc16_t crc16)
{
// verify that we are appending properly to a compressed file
verify_proper_compression_append(hunknum);
// write the final result
UINT64 offset = file_append(compressed, complength);
// update the map entry
UINT8 *rawmap = &m_rawmap[hunknum * 12];
rawmap[0] = (compression == -1) ? COMPRESSION_NONE : compression;
be_write(&rawmap[1], complength, 3);
be_write(&rawmap[4], offset, 6);
be_write(&rawmap[10], crc16, 2);
}
/**
* @fn void chd_file::hunk_copy_from_self(UINT32 hunknum, UINT32 otherhunk)
*
* @brief -------------------------------------------------
* hunk_copy_from_self - mark a hunk as being a copy of another hunk in the same CHD
* -------------------------------------------------.
*
* @exception CHDERR_INVALID_PARAMETER Thrown when a chderr invalid parameter error
* condition occurs.
*
* @param hunknum The hunknum.
* @param otherhunk The otherhunk.
*/
void chd_file::hunk_copy_from_self(UINT32 hunknum, UINT32 otherhunk)
{
// verify that we are appending properly to a compressed file
verify_proper_compression_append(hunknum);
// only permitted to reference prior hunks
if (otherhunk >= hunknum)
throw CHDERR_INVALID_PARAMETER;
// update the map entry
UINT8 *rawmap = &m_rawmap[hunknum * 12];
rawmap[0] = COMPRESSION_SELF;
be_write(&rawmap[1], 0, 3);
be_write(&rawmap[4], otherhunk, 6);
be_write(&rawmap[10], 0, 2);
}
/**
* @fn void chd_file::hunk_copy_from_parent(UINT32 hunknum, UINT64 parentunit)
*
* @brief -------------------------------------------------
* hunk_copy_from_parent - mark a hunk as being a copy of a hunk from a parent CHD
* -------------------------------------------------.
*
* @param hunknum The hunknum.
* @param parentunit The parentunit.
*/
void chd_file::hunk_copy_from_parent(UINT32 hunknum, UINT64 parentunit)
{
// verify that we are appending properly to a compressed file
verify_proper_compression_append(hunknum);
// update the map entry
UINT8 *rawmap = &m_rawmap[hunknum * 12];
rawmap[0] = COMPRESSION_PARENT;
be_write(&rawmap[1], 0, 3);
be_write(&rawmap[4], parentunit, 6);
be_write(&rawmap[10], 0, 2);
}
/**
* @fn bool chd_file::metadata_find(chd_metadata_tag metatag, INT32 metaindex, metadata_entry &metaentry, bool resume)
*
* @brief -------------------------------------------------
* metadata_find - find a metadata entry
* -------------------------------------------------.
*
* @param metatag The metatag.
* @param metaindex The metaindex.
* @param [in,out] metaentry The metaentry.
* @param resume true to resume.
*
* @return true if it succeeds, false if it fails.
*/
bool chd_file::metadata_find(chd_metadata_tag metatag, INT32 metaindex, metadata_entry &metaentry, bool resume)
{
// start at the beginning unless we're resuming a previous search
if (!resume)
{
metaentry.offset = m_metaoffset;
metaentry.prev = 0;
}
else
{
metaentry.prev = metaentry.offset;
metaentry.offset = metaentry.next;
}
// loop until we run out of options
while (metaentry.offset != 0)
{
// read the raw header
UINT8 raw_meta_header[METADATA_HEADER_SIZE];
file_read(metaentry.offset, raw_meta_header, sizeof(raw_meta_header));
// extract the data
metaentry.metatag = be_read(&raw_meta_header[0], 4);
metaentry.flags = raw_meta_header[4];
metaentry.length = be_read(&raw_meta_header[5], 3);
metaentry.next = be_read(&raw_meta_header[8], 8);
// if we got a match, proceed
if (metatag == CHDMETATAG_WILDCARD || metaentry.metatag == metatag)
if (metaindex-- == 0)
return true;
// no match, fetch the next link
metaentry.prev = metaentry.offset;
metaentry.offset = metaentry.next;
}
// if we get here, we didn't find it
return false;
}
/**
* @fn void chd_file::metadata_set_previous_next(UINT64 prevoffset, UINT64 nextoffset)
*
* @brief -------------------------------------------------
* metadata_set_previous_next - set the 'next' offset of a piece of metadata
* -------------------------------------------------.
*
* @param prevoffset The prevoffset.
* @param nextoffset The nextoffset.
*/
void chd_file::metadata_set_previous_next(UINT64 prevoffset, UINT64 nextoffset)
{
UINT64 offset = 0;
// if we were the first entry, make the next entry the first
if (prevoffset == 0)
{
offset = m_metaoffset_offset;
m_metaoffset = nextoffset;
}
// otherwise, update the link in the previous header
else
offset = prevoffset + 8;
// create a big-endian version
UINT8 rawbuf[sizeof(UINT64)];
be_write(rawbuf, nextoffset, 8);
// write to the header and update our local copy
file_write(offset, rawbuf, sizeof(rawbuf));
}
/**
* @fn void chd_file::metadata_update_hash()
*
* @brief -------------------------------------------------
* metadata_update_hash - compute the SHA1 hash of all metadata that requests it
* -------------------------------------------------.
*/
void chd_file::metadata_update_hash()
{
// only works for V4 and above, and only for compressed CHDs
if (m_version < 4 || !compressed())
return;
// compute the new overall hash
sha1_t fullsha1 = compute_overall_sha1(raw_sha1());
// create a big-endian version
UINT8 rawbuf[sizeof(sha1_t)];
be_write_sha1(&rawbuf[0], fullsha1);
// write to the header
file_write(m_sha1_offset, rawbuf, sizeof(rawbuf));
}
/**
* @fn int CLIB_DECL chd_file::metadata_hash_compare(const void *elem1, const void *elem2)
*
* @brief -------------------------------------------------
* metadata_hash_compare - compare two hash entries
* -------------------------------------------------.
*
* @param elem1 The first element.
* @param elem2 The second element.
*
* @return A CLIB_DECL.
*/
int CLIB_DECL chd_file::metadata_hash_compare(const void *elem1, const void *elem2)
{
return memcmp(elem1, elem2, sizeof(metadata_hash));
}
//**************************************************************************
// CHD COMPRESSOR
//**************************************************************************
/**
* @fn chd_file_compressor::chd_file_compressor()
*
* @brief -------------------------------------------------
* chd_file_compressor - constructor
* -------------------------------------------------.
*/
chd_file_compressor::chd_file_compressor()
: m_walking_parent(false),
m_total_in(0),
m_total_out(0),
m_read_queue(nullptr),
m_read_queue_offset(0),
m_read_done_offset(0),
m_read_error(false),
m_work_queue(nullptr),
m_write_hunk(0)
{
// zap arrays
memset(m_codecs, 0, sizeof(m_codecs));
// allocate work queues
m_read_queue = osd_work_queue_alloc(WORK_QUEUE_FLAG_IO);
m_work_queue = osd_work_queue_alloc(WORK_QUEUE_FLAG_MULTI);
}
/**
* @fn chd_file_compressor::~chd_file_compressor()
*
* @brief -------------------------------------------------
* ~chd_file_compressor - destructor
* -------------------------------------------------.
*/
chd_file_compressor::~chd_file_compressor()
{
// free the work queues
osd_work_queue_free(m_read_queue);
osd_work_queue_free(m_work_queue);
// delete allocated arrays
for (auto & elem : m_codecs)
delete elem;
}
/**
* @fn void chd_file_compressor::compress_begin()
*
* @brief -------------------------------------------------
* compress_begin - initiate compression
* -------------------------------------------------.
*/
void chd_file_compressor::compress_begin()
{
// reset state
m_walking_parent = (m_parent != nullptr);
m_total_in = 0;
m_total_out = 0;
m_compsha1.reset();
// reset our maps
m_parent_map.reset();
m_current_map.reset();
// reset read state
m_read_queue_offset = 0;
m_read_done_offset = 0;
m_read_error = false;
// reset work item state
m_work_buffer.resize(hunk_bytes() * (WORK_BUFFER_HUNKS + 1));
memset(&m_work_buffer[0], 0, m_work_buffer.size());
m_compressed_buffer.resize(hunk_bytes() * WORK_BUFFER_HUNKS);
for (int itemnum = 0; itemnum < WORK_BUFFER_HUNKS; itemnum++)
{
work_item &item = m_work_item[itemnum];
item.m_compressor = this;
item.m_data = &m_work_buffer[hunk_bytes() * itemnum];
item.m_compressed = &m_compressed_buffer[hunk_bytes() * itemnum];
item.m_hash.resize(hunk_bytes() / unit_bytes());
}
// initialize codec instances
for (auto & elem : m_codecs)
{
delete elem;
elem = new chd_compressor_group(*this, m_compression);
}
// reset write state
m_write_hunk = 0;
}
/**
* @fn chd_error chd_file_compressor::compress_continue(double &progress, double &ratio)
*
* @brief -------------------------------------------------
* compress_continue - continue compression
* -------------------------------------------------.
*
* @param [in,out] progress The progress.
* @param [in,out] ratio The ratio.
*
* @return A chd_error.
*/
chd_error chd_file_compressor::compress_continue(double &progress, double &ratio)
{
// if we got an error, return an error
if (m_read_error)
return CHDERR_READ_ERROR;
// if done reading, queue some more
while (m_read_queue_offset < m_logicalbytes && osd_work_queue_items(m_read_queue) < 2)
{
// see if we have enough free work items to read the next half of a buffer
UINT32 startitem = m_read_queue_offset / hunk_bytes();
UINT32 enditem = startitem + WORK_BUFFER_HUNKS / 2;
UINT32 curitem;
for (curitem = startitem; curitem < enditem; curitem++)
if (m_work_item[curitem % WORK_BUFFER_HUNKS].m_status != WS_READY)
break;
// if it's not all clear, defer
if (curitem != enditem)
break;
// if we're walking the parent, we want one more item to have cleared so we
// can read an extra hunk there
if (m_walking_parent && m_work_item[curitem % WORK_BUFFER_HUNKS].m_status != WS_READY)
break;
// queue the next read
for (curitem = startitem; curitem < enditem; curitem++)
m_work_item[curitem % WORK_BUFFER_HUNKS].m_status = WS_READING;
osd_work_item_queue(m_read_queue, async_read_static, this, WORK_ITEM_FLAG_AUTO_RELEASE);
m_read_queue_offset += WORK_BUFFER_HUNKS * hunk_bytes() / 2;
}
// flush out any finished items
while (m_work_item[m_write_hunk % WORK_BUFFER_HUNKS].m_status == WS_COMPLETE)
{
work_item &item = m_work_item[m_write_hunk % WORK_BUFFER_HUNKS];
// free any OSD work item
if (item.m_osd != nullptr)
osd_work_item_release(item.m_osd);
item.m_osd = nullptr;
// for parent walking, just add to the hashmap
if (m_walking_parent)
{
UINT32 uph = hunk_bytes() / unit_bytes();
UINT32 units = uph;
if (item.m_hunknum == hunk_count() - 1 || !compressed())
units = 1;
for (UINT32 unit = 0; unit < units; unit++)
if (m_parent_map.find(item.m_hash[unit].m_crc16, item.m_hash[unit].m_sha1) == hashmap::NOT_FOUND)
m_parent_map.add(item.m_hunknum * uph + unit, item.m_hash[unit].m_crc16, item.m_hash[unit].m_sha1);
}
// if we're uncompressed, use regular writes
else if (!compressed())
{
chd_error err = write_hunk(item.m_hunknum, item.m_data);
if (err != CHDERR_NONE)
return err;
// writes of all-0 data don't actually take space, so see if we count this
chd_codec_type codec = CHD_CODEC_NONE;
UINT32 complen;
hunk_info(item.m_hunknum, codec, complen);
if (codec == CHD_CODEC_NONE)
m_total_out += m_hunkbytes;
}
// for compressing, process the result
else do
{
// first see if the hunk is in the parent or self maps
UINT64 selfhunk = m_current_map.find(item.m_hash[0].m_crc16, item.m_hash[0].m_sha1);
if (selfhunk != hashmap::NOT_FOUND)
{
hunk_copy_from_self(item.m_hunknum, selfhunk);
break;
}
// if not, see if it's in the parent map
if (m_parent != nullptr)
{
UINT64 parentunit = m_parent_map.find(item.m_hash[0].m_crc16, item.m_hash[0].m_sha1);
if (parentunit != hashmap::NOT_FOUND)
{
hunk_copy_from_parent(item.m_hunknum, parentunit);
break;
}
}
// otherwise, append it compressed and add to the self map
hunk_write_compressed(item.m_hunknum, item.m_compression, item.m_compressed, item.m_complen, item.m_hash[0].m_crc16);
m_total_out += item.m_complen;
m_current_map.add(item.m_hunknum, item.m_hash[0].m_crc16, item.m_hash[0].m_sha1);
} while (0);
// reset the item and advance
item.m_status = WS_READY;
m_write_hunk++;
// if we hit the end, finalize
if (m_write_hunk == m_hunkcount)
{
// if this is just walking the parent, reset and get ready for compression
if (m_walking_parent)
{
m_walking_parent = false;
m_read_queue_offset = m_read_done_offset = 0;
m_write_hunk = 0;
for (auto & elem : m_work_item)
elem.m_status = WS_READY;
}
// wait for all reads to finish and if we're compressed, write the final SHA1 and map
else
{
osd_work_queue_wait(m_read_queue, 30 * osd_ticks_per_second());
if (!compressed())
return CHDERR_NONE;
set_raw_sha1(m_compsha1.finish());
return compress_v5_map();
}
}
}
// update progress and ratio
if (m_walking_parent)
progress = double(m_read_done_offset) / double(logical_bytes());
else
progress = double(m_write_hunk) / double(m_hunkcount);
ratio = (m_total_in == 0) ? 1.0 : double(m_total_out) / double(m_total_in);
// if we're waiting for work, wait
while (m_work_item[m_write_hunk % WORK_BUFFER_HUNKS].m_status != WS_COMPLETE && m_work_item[m_write_hunk % WORK_BUFFER_HUNKS].m_osd != nullptr)
osd_work_item_wait(m_work_item[m_write_hunk % WORK_BUFFER_HUNKS].m_osd, osd_ticks_per_second());
return m_walking_parent ? CHDERR_WALKING_PARENT : CHDERR_COMPRESSING;
}
/**
* @fn void *chd_file_compressor::async_walk_parent_static(void *param, int threadid)
*
* @brief -------------------------------------------------
* async_walk_parent - handle asynchronous parent walking operations
* -------------------------------------------------.
*
* @param [in,out] param If non-null, the parameter.
* @param threadid The threadid.
*
* @return null if it fails, else a void*.
*/
void *chd_file_compressor::async_walk_parent_static(void *param, int threadid)
{
work_item *item = reinterpret_cast<work_item *>(param);
item->m_compressor->async_walk_parent(*item);
return nullptr;
}
/**
* @fn void chd_file_compressor::async_walk_parent(work_item &item)
*
* @brief Asynchronous walk parent.
*
* @param [in,out] item The item.
*/
void chd_file_compressor::async_walk_parent(work_item &item)
{
// compute CRC-16 and SHA-1 hashes for each unit, unless we're the last one or we're uncompressed
UINT32 units = hunk_bytes() / unit_bytes();
if (item.m_hunknum == m_hunkcount - 1 || !compressed())
units = 1;
for (UINT32 unit = 0; unit < units; unit++)
{
item.m_hash[unit].m_crc16 = crc16_creator::simple(item.m_data + unit * unit_bytes(), hunk_bytes());
item.m_hash[unit].m_sha1 = sha1_creator::simple(item.m_data + unit * unit_bytes(), hunk_bytes());
}
item.m_status = WS_COMPLETE;
}
/**
* @fn void *chd_file_compressor::async_compress_hunk_static(void *param, int threadid)
*
* @brief -------------------------------------------------
* async_compress_hunk - handle asynchronous hunk compression
* -------------------------------------------------.
*
* @param [in,out] param If non-null, the parameter.
* @param threadid The threadid.
*
* @return null if it fails, else a void*.
*/
void *chd_file_compressor::async_compress_hunk_static(void *param, int threadid)
{
work_item *item = reinterpret_cast<work_item *>(param);
item->m_compressor->async_compress_hunk(*item, threadid);
return nullptr;
}
/**
* @fn void chd_file_compressor::async_compress_hunk(work_item &item, int threadid)
*
* @brief Asynchronous compress hunk.
*
* @param [in,out] item The item.
* @param threadid The threadid.
*/
void chd_file_compressor::async_compress_hunk(work_item &item, int threadid)
{
// use our thread's codec
assert(threadid < ARRAY_LENGTH(m_codecs));
item.m_codecs = m_codecs[threadid];
// compute CRC-16 and SHA-1 hashes
item.m_hash[0].m_crc16 = crc16_creator::simple(item.m_data, hunk_bytes());
item.m_hash[0].m_sha1 = sha1_creator::simple(item.m_data, hunk_bytes());
// find the best compression scheme, unless we already have a self or parent match
// (note we may miss a self match from blocks not yet added, but this just results in extra work)
// TODO: data race
if (m_current_map.find(item.m_hash[0].m_crc16, item.m_hash[0].m_sha1) == hashmap::NOT_FOUND &&
m_parent_map.find(item.m_hash[0].m_crc16, item.m_hash[0].m_sha1) == hashmap::NOT_FOUND)
item.m_compression = item.m_codecs->find_best_compressor(item.m_data, item.m_compressed, item.m_complen);
// mark us complete
item.m_status = WS_COMPLETE;
}
/**
* @fn void *chd_file_compressor::async_read_static(void *param, int threadid)
*
* @brief -------------------------------------------------
* async_read - handle asynchronous source file reading
* -------------------------------------------------.
*
* @param [in,out] param If non-null, the parameter.
* @param threadid The threadid.
*
* @return null if it fails, else a void*.
*/
void *chd_file_compressor::async_read_static(void *param, int threadid)
{
reinterpret_cast<chd_file_compressor *>(param)->async_read();
return nullptr;
}
/**
* @fn void chd_file_compressor::async_read()
*
* @brief Asynchronous read.
*/
void chd_file_compressor::async_read()
{
// if in the error or complete state, stop
if (m_read_error)
return;
// determine parameters for the read
UINT32 work_buffer_bytes = WORK_BUFFER_HUNKS * hunk_bytes();
UINT32 numbytes = work_buffer_bytes / 2;
if (m_read_done_offset + numbytes > logical_bytes())
numbytes = logical_bytes() - m_read_done_offset;
// catch any exceptions coming out of here
try
{
// do the read
UINT8 *dest = &m_work_buffer[0] + (m_read_done_offset % work_buffer_bytes);
assert(dest == &m_work_buffer[0] || dest == &m_work_buffer[work_buffer_bytes/2]);
UINT64 end_offset = m_read_done_offset + numbytes;
// if walking the parent, read in hunks from the parent CHD
if (m_walking_parent)
{
UINT8 *curdest = dest;
for (UINT64 curoffs = m_read_done_offset; curoffs < end_offset + 1; curoffs += hunk_bytes())
{
m_parent->read_hunk(curoffs / hunk_bytes(), curdest);
curdest += hunk_bytes();
}
}
// otherwise, call the virtual function
else
read_data(dest, m_read_done_offset, numbytes);
// spawn off work for each hunk
for (UINT64 curoffs = m_read_done_offset; curoffs < end_offset; curoffs += hunk_bytes())
{
UINT32 hunknum = curoffs / hunk_bytes();
work_item &item = m_work_item[hunknum % WORK_BUFFER_HUNKS];
assert(item.m_status == WS_READING);
item.m_status = WS_QUEUED;
item.m_hunknum = hunknum;
item.m_osd = osd_work_item_queue(m_work_queue, m_walking_parent ? async_walk_parent_static : async_compress_hunk_static, &item, 0);
}
// continue the running SHA-1
if (!m_walking_parent)
{
if (compressed())
m_compsha1.append(dest, numbytes);
m_total_in += numbytes;
}
// advance the read pointer
m_read_done_offset += numbytes;
}
catch (chd_error& err)
{
fprintf(stderr, "CHD error occurred: %s\n", chd_file::error_string(err));
m_read_error = true;
}
catch (std::exception& ex)
{
fprintf(stderr, "exception occurred: %s\n", ex.what());
m_read_error = true;
}
}
//**************************************************************************
// CHD COMPRESSOR HASHMAP
//**************************************************************************
/**
* @fn chd_file_compressor::hashmap::hashmap()
*
* @brief -------------------------------------------------
* hashmap - constructor
* -------------------------------------------------.
*/
chd_file_compressor::hashmap::hashmap()
: m_block_list(new entry_block(nullptr))
{
// initialize the map to empty
memset(m_map, 0, sizeof(m_map));
}
/**
* @fn chd_file_compressor::hashmap::~hashmap()
*
* @brief -------------------------------------------------
* ~hashmap - destructor
* -------------------------------------------------.
*/
chd_file_compressor::hashmap::~hashmap()
{
reset();
delete m_block_list;
}
/**
* @fn void chd_file_compressor::hashmap::reset()
*
* @brief -------------------------------------------------
* reset - reset the state of the map
* -------------------------------------------------.
*/
void chd_file_compressor::hashmap::reset()
{
// delete all the blocks
while (m_block_list->m_next != nullptr)
{
entry_block *block = m_block_list;
m_block_list = block->m_next;
delete block;
}
m_block_list->m_nextalloc = 0;
// reset the hash
memset(m_map, 0, sizeof(m_map));
}
/**
* @fn UINT64 chd_file_compressor::hashmap::find(crc16_t crc16, sha1_t sha1)
*
* @brief -------------------------------------------------
* find - find an item in the CRC map
* -------------------------------------------------.
*
* @param crc16 The CRC 16.
* @param sha1 The first sha.
*
* @return An UINT64.
*/
UINT64 chd_file_compressor::hashmap::find(crc16_t crc16, sha1_t sha1)
{
// look up the entry in the map
for (entry_t *entry = m_map[crc16]; entry != nullptr; entry = entry->m_next)
if (entry->m_sha1 == sha1)
return entry->m_itemnum;
return NOT_FOUND;
}
/**
* @fn void chd_file_compressor::hashmap::add(UINT64 itemnum, crc16_t crc16, sha1_t sha1)
*
* @brief -------------------------------------------------
* add - add an item to the CRC map
* -------------------------------------------------.
*
* @param itemnum The itemnum.
* @param crc16 The CRC 16.
* @param sha1 The first sha.
*/
void chd_file_compressor::hashmap::add(UINT64 itemnum, crc16_t crc16, sha1_t sha1)
{
// add to the appropriate map
if (m_block_list->m_nextalloc == ARRAY_LENGTH(m_block_list->m_array))
m_block_list = new entry_block(m_block_list);
entry_t *entry = &m_block_list->m_array[m_block_list->m_nextalloc++];
entry->m_itemnum = itemnum;
entry->m_sha1 = sha1;
entry->m_next = m_map[crc16];
m_map[crc16] = entry;
}
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