mirror of
https://github.com/JetSetIlly/Gopher2600.git
synced 2024-05-20 13:48:02 -04:00
16adef8e7b
looking beyond this limit is unlikely to reveal any data of value and it can only cause excess slowdown for very large files, which are unlikely to be cartridge files in any case
94 lines
3.3 KiB
Go
94 lines
3.3 KiB
Go
// This file is part of Gopher2600.
|
|
//
|
|
// Gopher2600 is free software: you can redistribute it and/or modify
|
|
// it under the terms of the gnu general public license as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// Gopher2600 is distributed in the hope that it will be useful,
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU General Public License
|
|
// along with Gopher2600. If not, see <https://www.gnu.org/licenses/>.
|
|
|
|
// Package cartridgeloader is used to load cartridge data so that it can be used
|
|
// with the cartridge pacakage
|
|
//
|
|
// # File Extensions
|
|
//
|
|
// The file extension of a file will specify the cartridge mapping and will
|
|
// cause the emulation to use that mapping.
|
|
//
|
|
// The following file extensions are recognised and force the use of the
|
|
// specified mapper:
|
|
//
|
|
// Atari 2k "2k"
|
|
// Atari 4k "4k"
|
|
// Atari 8k "F8"
|
|
// Atari 16k "F6"
|
|
// Atari 32k "F4"
|
|
// Atari 2k (RAM) "2k+"
|
|
// Atari 4k (RAM) "4k+"
|
|
// Atari 8k (RAM) "F8+"
|
|
// Atari 16k (RAM) "F6+"
|
|
// Atari 32k (RAM) "F4+"
|
|
// CBS "FA"
|
|
// Parker Bros "E0"
|
|
// M-Network "E7"
|
|
// Tigervision "3F"
|
|
// Supercharger "AR", "MP3, "WAV"
|
|
// DF "DF"
|
|
// 3E "3E"
|
|
// 3E+ "3E+"
|
|
// Superbank "SB"
|
|
// DPC (Pitfall2) "DPC"
|
|
// DPC+ "DP+"
|
|
// CDF "CDF" (including CDFJ)
|
|
// MovieCart "MVC"
|
|
//
|
|
// File extensions are case insensitive.
|
|
//
|
|
// A file extension of "BIN", "ROM", "A26" indicates that the data should be
|
|
// fingerprinted as normal.
|
|
//
|
|
// # Preloaded data
|
|
//
|
|
// Cartridges with lots of data wil be streamed off disk as required. For
|
|
// example, Moviecart or Supercharge audio tapes can be large and don't need to
|
|
// exist in memory for a very long time.
|
|
//
|
|
// However, for practical reasons the first 1MB of data of any file will be
|
|
// 'preloaded'. When reading cartridge data you don't need to worry about
|
|
// whether data has been preloaded or not, except that it does affect both
|
|
// hashing and fingerprinting.
|
|
//
|
|
// # Hashes
|
|
//
|
|
// The creation of a cartridge loader includes the creation of both a SHA1 and
|
|
// an MD5 hash. Hashes are useful for matching cartridges regardless of path
|
|
// or filename
|
|
//
|
|
// The data used to create the hash is limited to the data that has been
|
|
// preloaded (see above).
|
|
//
|
|
// # Fingerprinting
|
|
//
|
|
// Cartridge data can be checked for 'fingerprint' data that can be used to
|
|
// decide on the 'mapping' the cartridge uses. The three cartridge loader
|
|
// functions, Contains(), ContainsLimit() and Count() can be used to search the
|
|
// preloaded data (see above) for specific bytes sequences.
|
|
//
|
|
// More complex fingerprinting can be done with the Read() function. However,
|
|
// because the Read() function works with the complete cartridge and not just
|
|
// the preloaded data, care should be taken not to read too much of the data for
|
|
// reasons of computation time. The constant value FingerprintLimit is provided
|
|
// as a useful value to which a Read() loop can be limited.
|
|
//
|
|
// Once fingerprinting has been completed it is very important to remember to
|
|
// reset the Read() position with the Seek() command:
|
|
//
|
|
// cartridgeloader.Seek(0, io.SeekStart)
|
|
package cartridgeloader
|