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