Chris@82: Code conventions used internally by fftw3 (not in API):
Chris@82: 
Chris@82: LEARN FROM THE MASTERS: read Ken Thompson's C compiler in Plan 9.
Chris@82:    Avoid learning from C++/Java programs.
Chris@82: 
Chris@82: INDENTATION: K&R, 5 spaces/tab.  In case of doubt, indent -kr -i5.
Chris@82: 
Chris@82: NAMES: keep them short.  Shorter than you think.  The Bible was written
Chris@82:    without vowels.  Don't outsmart the Bible.
Chris@82: 
Chris@82:    Common names:
Chris@82: 
Chris@82:    R       : real type, aka fftw_real
Chris@82:    E       : real type for local variables (possibly extra precision)
Chris@82:    C       : complex type
Chris@82:    sz      : size
Chris@82:    vecsz   : vector size
Chris@82:    is, os  : input/output stride
Chris@82:    ri, ii  : real/imag input (complex data)
Chris@82:    ro, io  : real/imag output (complex data)
Chris@82:    I, O    : real input/output (real data)
Chris@82:    A       : assert
Chris@82:    CK      : check
Chris@82:    S       : solver, defined internally to each solver file
Chris@82:    P       : plan, defined internally to each solver file
Chris@82:    k       : codelet
Chris@82:    X(...)  : used for mangling of external names (see below)
Chris@82:    K(...)  : floating-point constant, in E precision
Chris@82: 
Chris@82:    If a name is used often and must have the form fftw_foo to avoid
Chris@82:    namespace pollution, #define FOO fftw_foo and use the short name.
Chris@82: 
Chris@82:    Leave that hungarian crap to MS.  foo_t counts as hungarian: use
Chris@82:    foo instead.  foo is lowercase so that it does not look like a DOS
Chris@82:    program. Exception: typedef struct foo_s {...} foo;  instead of
Chris@82:    typedef struct foo {...} foo;  for C++ compatibility.
Chris@82: 
Chris@82: NAME MANGLING: use X(foo) for external names instead of fftw_foo.
Chris@82:     X(foo) expands to fftwf_foo or fftw_foo, depending on the
Chris@82:     precision.  (Unfortunately, this is a ugly form of hungarian
Chris@82:     notation.  Grrr...)  Names that are not exported do not need to be
Chris@82:     mangled.
Chris@82: 
Chris@82: REPEATED CODE: favor a table.  E.g., do not write
Chris@82: 
Chris@82:     foo("xxx", 1);
Chris@82:     foo("yyy", 2);
Chris@82:     foo("zzz", -1);
Chris@82: 
Chris@82:     Instead write
Chris@82: 
Chris@82:       struct { const char *nam, int arg } footab[] = {
Chris@82: 	{ "xxx", 1 },
Chris@82: 	{ "yyy", 2 },
Chris@82: 	{ "zzz", -1 }
Chris@82:       };
Chris@82: 
Chris@82:     and loop over footab.  Rationale: it saves code space.
Chris@82:     Similarly, replace a switch statement with a table whenever
Chris@82:     possible.
Chris@82: 
Chris@82: C++: The code should compile as a C++ program. Run the code through
Chris@82:     gcc -xc++ .  The extra C++ restrictions are unnecessary, of
Chris@82:     course, but this will save us from a flood of complaints when
Chris@82:     we release the code.