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A fast Befunge93/98 interpreter in C
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VorpalBlade/cfunge
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This is cfunge - a fast Befunge93/98/108 interpreter in C. cfunge offers some features that many other standard conforming interpreters don't. For example: * Sandbox mode, prevents programs from harming system (more details below). * Advance tracing support, debugging protocol support system under development. * Passes mycology (of course other conforming interpreters does this, but most interpreters are, sadly, not conforming). * Tested using valgrind and similar tools. * Tested with fuzz testing to ensure cfunge does not segfault on random stuff. * Coded for maximum performance AND correctness. * Support for selecting either 64-bit or 32-bit integers as datatype in funge-space at compile time. Dependencies ------------ REQUIRED: * cmake (http://www.cmake.org/) to generate Makefile for cfunge. * A C99 compiler, or one that supports a large subset of C99, like GCC. + GCC 3.4.6, 4.1.2, 4.2.1 and 4.3.2 are known to work, other versions may or may not work. + ICC 10.1 is known to work too. - TCC 0.9.24 is known to fail at certain C99 constructs used in cfunge. Other compilers may or may not work. * cfunge requires IEC 60559 floating-point arithmetic (please see Annex F in ISO/IEC 9899 for more details.) * A POSIX system. Linux 2.6.24 is known to work, so is FreeBSD 7.0. Windows may or may not work, but I won't fix any bugs that can't be reproduced on a POSIX system, except if someone else provides a patch. Patches for Windows are welcome only if they don't mess up source too much (anything using Win32/64 specific API(s) counts as messing up). * Ncurses (http://www.gnu.org/software/ncurses/), used for the TERM fingerprint. This is most likely already installed. OPTIONAL: Boehm-GC (http://www.hpl.hp.com/personal/Hans_Boehm/gc/) version 7 or later. Configuring ----------- To build using cmake, you can run these commands in the top source directory: cmake . If you are on a 32-bit system you may want to use 32-bit integers (instead of 64-bit integers) for speed. To do that you could use this command instead of the above one: cmake -DUSE_64BIT=OFF . If you want to see a list of available options use ccmake. It will allow you to select options in a ncurses based user interface. Help is always shown at the bottom of the screen. ccmake . (press c) (change options - use t to show advanced options) (press c again) (press g to generate make file) For more information see: cmake --help and/or ccmake --help To enable garbage collector you can run cmake with -DUSE_GC=ON. However using a GC isn't as fast as not using one and it could also cause issues with certain fingerprints. Compiling --------- After having run cmake as described in the above section, just run: make Installing ---------- Not needed, cfunge can be run from build directory, but if you want to (after having compiled cfunge): make install Fingerprints ------------ It is planned to implement most or all of the existing fingerprints, with some exceptions: * FNGR - Contradicts with 98 standard. * IMAP - Too intrusive. * MODE - Intrusive into IP handling. * TRDS - Exceedingly complex and intrusive. * WIND - Too complex to implement and not portable. Short descriptions of implemented fingerprints: 3DSP 3D space manipulation extension BASE I/O for numbers in other bases CPLI Complex Integer extension DIRF Directory functions extension (not available in sandbox mode) FILE File I/O functions (not available in sandbox mode) FING Operate on single fingerprint semantics FIXP Some useful math functions FPDP Double precision floating point FPSP Single precision floating point FRTH Some common forth commands HRTI High-Resolution Timer Interface INDV Pointer functions JSTR Read and write strings in Funge-Space MODU Modulo Arithmetic Extension NULL Funge-98 Null Fingerprint ORTH Orthogonal Easement Library PERL Generic Interface to the Perl Language (not available in sandbox mode) PNTR Alias for INDV REFC Referenced Cells Extension REXP Regular Expression Matching ROMA Funge-98 Roman Numerals SCKE TCP/IP async socket and dns resolving extension STRN String functions SOCK TCP/IP socket extension SUBR Subroutine extension TERM Terminal control functions TIME Time and Date functions TOYS Funge-98 Standard Toys TURT Simple Turtle Graphics Library For more details please see the specs for each fingerprint. In cases of undefined behaviour in fingerprints, cfunge mostly tries to do the same thing as CCBI. Undefined behaviour ------------------- The Befunge98 standard leaves some things undefined, here is what we do for some of those cases: * y pushes time in UTC not local time. * k with a negative argument reflects. * # across edge of funge-space may or may not skip first char after wrapping depending on exact situation. * ( and ) with a negative count reflects and doesn't pop any fingerprint. * Loaded fingerprints are inherited to child IPs at split (t). * STDOUT is only flushed at: * Newline (line feed, ASCII 10) printed using , instruction. * Any input instructions. * End of program. * Input buffering works as in CCBI. Notes on different standards ---------------------------- The option -s 93 does not prevent the program from accessing outside the first 80x25 cells. Nor does it disallow instructions that didn't exist in 93. It does however change space behaviour to match 93 style. If a program depends on a instruction that is undefined in 93 to reflect, it should be easy to replace such instructions with a r for reflect or any in the range A-Z (and not load any fingerprint). Further division by zero always returns 0 in all modes, though the Befunge93 specs says the interpreter should ask the user what result he/she wants in that situation. Sandbox mode ------------ Sandbox mode prevents Funge programs from doing "harmful" things, this includes, but is not limited to: * Any file or filesystem IO is forbidden. * The environment variables it can see are restricted. * Non-safe fingerprints can not be loaded (this includes network and file system access as well as other things).
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A fast Befunge93/98 interpreter in C