[ViewVC] Diff of: cvs/libecb/ecb.pod

Comparing libecb/ecb.pod (file contents):
Revision 1.52 by root, Sun Sep 23 22:32:33 2012 UTC vs.
Revision 1.81 by root, Mon Jan 20 21:01:29 2020 UTC

…		…
58		58
59	=head2 TYPES / TYPE SUPPORT	59	=head2 TYPES / TYPE SUPPORT
60		60
61	ecb.h makes sure that the following types are defined (in the expected way):	61	ecb.h makes sure that the following types are defined (in the expected way):
62		62
63	int8_t uint8_t int16_t uint16_t	63	int8_t uint8_
64	int32_t uint32_t int64_t uint64_t	64	int16_t uint16_t
		65	int32_t uint32_
		66	int64_t uint64_t
		67	int_fast8_t uint_fast8_t
		68	int_fast16_t uint_fast16_t
		69	int_fast32_t uint_fast32_t
		70	int_fast64_t uint_fast64_t
65	intptr_t uintptr_t	71	intptr_t uintptr_t
66		72
67	The macro C<ECB_PTRSIZE> is defined to the size of a pointer on this	73	The macro C<ECB_PTRSIZE> is defined to the size of a pointer on this
68	platform (currently C<4> or C<8>) and can be used in preprocessor	74	platform (currently C<4> or C<8>) and can be used in preprocessor
69	expressions.	75	expressions.
70		76
71	For C<ptrdiff_t> and C<size_t> use C<stddef.h>.	77	For C<ptrdiff_t> and C<size_t> use C<stddef.h>/C<cstddef>.
72		78
73	=head2 LANGUAGE/COMPILER VERSIONS	79	=head2 LANGUAGE/ENVIRONMENT/COMPILER VERSIONS
74		80
75	All the following symbols expand to an expression that can be tested in	81	All the following symbols expand to an expression that can be tested in
76	preprocessor instructions as well as treated as a boolean (use C<!!> to	82	preprocessor instructions as well as treated as a boolean (use C<!!> to
77	ensure it's either C<0> or C<1> if you need that).	83	ensure it's either C<0> or C<1> if you need that).
78		84
79	=over 4	85	=over 4
80		86
81	=item ECB_C	87	=item ECB_C
82		88
83	True if the implementation defines the C<__STDC__> macro to a true value,	89	True if the implementation defines the C<__STDC__> macro to a true value,
84	which is typically true for both C and C++ compilers.	90	while not claiming to be C++.
85		91
86	=item ECB_C99	92	=item ECB_C99
87		93
88	True if the implementation claims to be compliant to C99 (ISO/IEC	94	True if the implementation claims to be compliant to C99 (ISO/IEC
89	9899:1999) or any later version.	95	9899:1999) or any later version, while not claiming to be C++.
90		96
91	Note that later versions (ECB_C11) remove core features again (for	97	Note that later versions (ECB_C11) remove core features again (for
92	example, variable length arrays).	98	example, variable length arrays).
93		99
94	=item ECB_C11	100	=item ECB_C11, ECB_C17
95		101
96	True if the implementation claims to be compliant to C11 (ISO/IEC	102	True if the implementation claims to be compliant to C11/C17 (ISO/IEC
97	9899:2011) or any later version.	103	9899:2011, :20187) or any later version, while not claiming to be C++.
98		104
99	=item ECB_CPP	105	=item ECB_CPP
100		106
101	True if the implementation defines the C<__cplusplus__> macro to a true	107	True if the implementation defines the C<__cplusplus__> macro to a true
102	value, which is typically true for C++ compilers.	108	value, which is typically true for C++ compilers.
103		109
104	=item ECB_CPP11	110	=item ECB_CPP11, ECB_CPP14, ECB_CPP17
105		111
106	True if the implementation claims to be compliant to ISO/IEC 14882:2011	112	True if the implementation claims to be compliant to C++11/C++14/C++17
107	(C++11) or any later version.	113	(ISO/IEC 14882:2011, :2014, :2017) or any later version.
108		114
		115	=item ECB_OPTIMIZE_SIZE
		116
		117	Is C<1> when the compiler optimizes for size, C<0> otherwise. This symbol
		118	can also be defined before including F<ecb.h>, in which case it will be
		119	unchanged.
		120
109	=item ECB_GCC_VERSION(major,minor)	121	=item ECB_GCC_VERSION (major, minor)
110		122
111	Expands to a true value (suitable for testing in by the preprocessor)	123	Expands to a true value (suitable for testing in by the preprocessor)
112	if the compiler used is GNU C and the version is the given version, or	124	if the compiler used is GNU C and the version is the given version, or
113	higher.	125	higher.
114		126
…		…
150		162
151	This is true for basically all modern platforms, although F<ecb.h> might	163	This is true for basically all modern platforms, although F<ecb.h> might
152	not be able to deduce this correctly everywhere and might err on the safe	164	not be able to deduce this correctly everywhere and might err on the safe
153	side.	165	side.
154		166
		167	=item ECB_AMD64, ECB_AMD64_X32
		168
		169	These two macros are defined to C<1> on the x86_64/amd64 ABI and the X32
		170	ABI, respectively, and undefined elsewhere.
		171
		172	The designers of the new X32 ABI for some inexplicable reason decided to
		173	make it look exactly like amd64, even though it's completely incompatible
		174	to that ABI, breaking about every piece of software that assumed that
		175	C<__x86_64> stands for, well, the x86-64 ABI, making these macros
		176	necessary.
		177
155	=back	178	=back
156		179
		180	=head2 MACRO TRICKERY
		181
		182	=over 4
		183
		184	=item ECB_CONCAT (a, b)
		185
		186	Expands any macros in C<a> and C<b>, then concatenates the result to form
		187	a single token. This is mainly useful to form identifiers from components,
		188	e.g.:
		189
		190	#define S1 str
		191	#define S2 cpy
		192
		193	ECB_CONCAT (S1, S2)(dst, src); // == strcpy (dst, src);
		194
		195	=item ECB_STRINGIFY (arg)
		196
		197	Expands any macros in C<arg> and returns the stringified version of
		198	it. This is mainly useful to get the contents of a macro in string form,
		199	e.g.:
		200
		201	#define SQL_LIMIT 100
		202	sql_exec ("select * from table limit " ECB_STRINGIFY (SQL_LIMIT));
		203
		204	=item ECB_STRINGIFY_EXPR (expr)
		205
		206	Like C<ECB_STRINGIFY>, but additionally evaluates C<expr> to make sure it
		207	is a valid expression. This is useful to catch typos or cases where the
		208	macro isn't available:
		209
		210	#include <errno.h>
		211
		212	ECB_STRINGIFY (EDOM); // "33" (on my system at least)
		213	ECB_STRINGIFY_EXPR (EDOM); // "33"
		214
		215	// now imagine we had a typo:
		216
		217	ECB_STRINGIFY (EDAM); // "EDAM"
		218	ECB_STRINGIFY_EXPR (EDAM); // error: EDAM undefined
		219
		220	=back
		221
157	=head2 GCC ATTRIBUTES	222	=head2 ATTRIBUTES
158		223
159	A major part of libecb deals with GCC attributes. These are additional	224	A major part of libecb deals with additional attributes that can be
160	attributes that you can assign to functions, variables and sometimes even	225	assigned to functions, variables and sometimes even types - much like
161	types - much like C<const> or C<volatile> in C.	226	C<const> or C<volatile> in C. They are implemented using either GCC
162		227	attributes or other compiler/language specific features. Attributes
163	While GCC allows declarations to show up in many surprising places,
164	but not in many expected places, the safest way is to put attribute
165	declarations before the whole declaration:	228	declarations must be put before the whole declaration:
166		229
167	ecb_const int mysqrt (int a);	230	ecb_const int mysqrt (int a);
168	ecb_unused int i;	231	ecb_unused int i;
169		232
170	For variables, it is often nicer to put the attribute after the name, and
171	avoid multiple declarations using commas:
172
173	int i ecb_unused;
174
175	=over 4	233	=over 4
176
177	=item ecb_attribute ((attrs...))
178
179	A simple wrapper that expands to C<__attribute__((attrs))> on GCC, and to
180	nothing on other compilers, so the effect is that only GCC sees these.
181
182	Example: use the C<deprecated> attribute on a function.
183
184	ecb_attribute((__deprecated__)) void
185	do_not_use_me_anymore (void);
186		234
187	=item ecb_unused	235	=item ecb_unused
188		236
189	Marks a function or a variable as "unused", which simply suppresses a	237	Marks a function or a variable as "unused", which simply suppresses a
190	warning by GCC when it detects it as unused. This is useful when you e.g.	238	warning by GCC when it detects it as unused. This is useful when you e.g.
191	declare a variable but do not always use it:	239	declare a variable but do not always use it:
192		240
193	{	241	{
194	int var ecb_unused;	242	ecb_unused int var;
195		243
196	#ifdef SOMECONDITION	244	#ifdef SOMECONDITION
197	var = ...;	245	var = ...;
198	return var;	246	return var;
199	#else	247	#else
200	return 0;	248	return 0;
201	#endif	249	#endif
202	}	250	}
203		251
		252	=item ecb_deprecated
		253
		254	Similar to C<ecb_unused>, but marks a function, variable or type as
		255	deprecated. This makes some compilers warn when the type is used.
		256
		257	=item ecb_deprecated_message (message)
		258
		259	Same as C<ecb_deprecated>, but if possible, the specified diagnostic is
		260	used instead of a generic depreciation message when the object is being
		261	used.
		262
204	=item ecb_inline	263	=item ecb_inline
205		264
206	This is not actually an attribute, but you use it like one. It expands	265	Expands either to (a compiler-specific equivalent of) C<static inline> or
207	either to C<static inline> or to just C<static>, if inline isn't	266	to just C<static>, if inline isn't supported. It should be used to declare
208	supported. It should be used to declare functions that should be inlined,	267	functions that should be inlined, for code size or speed reasons.
209	for code size or speed reasons.
210		268
211	Example: inline this function, it surely will reduce codesize.	269	Example: inline this function, it surely will reduce codesize.
212		270
213	ecb_inline int	271	ecb_inline int
214	negmul (int a, int b)	272	negmul (int a, int b)
…		…
216	return - (a * b);	274	return - (a * b);
217	}	275	}
218		276
219	=item ecb_noinline	277	=item ecb_noinline
220		278
221	Prevent a function from being inlined - it might be optimised away, but	279	Prevents a function from being inlined - it might be optimised away, but
222	not inlined into other functions. This is useful if you know your function	280	not inlined into other functions. This is useful if you know your function
223	is rarely called and large enough for inlining not to be helpful.	281	is rarely called and large enough for inlining not to be helpful.
224		282
225	=item ecb_noreturn	283	=item ecb_noreturn
226		284
…		…
236	}	294	}
237		295
238	In this case, the compiler would probably be smart enough to deduce it on	296	In this case, the compiler would probably be smart enough to deduce it on
239	its own, so this is mainly useful for declarations.	297	its own, so this is mainly useful for declarations.
240		298
		299	=item ecb_restrict
		300
		301	Expands to the C<restrict> keyword or equivalent on compilers that support
		302	them, and to nothing on others. Must be specified on a pointer type or
		303	an array index to indicate that the memory doesn't alias with any other
		304	restricted pointer in the same scope.
		305
		306	Example: multiply a vector, and allow the compiler to parallelise the
		307	loop, because it knows it doesn't overwrite input values.
		308
		309	void
		310	multiply (ecb_restrict float *src,
		311	ecb_restrict float *dst,
		312	int len, float factor)
		313	{
		314	int i;
		315
		316	for (i = 0; i < len; ++i)
		317	dst [i] = src [i] * factor;
		318	}
		319
241	=item ecb_const	320	=item ecb_const
242		321
243	Declares that the function only depends on the values of its arguments,	322	Declares that the function only depends on the values of its arguments,
244	much like a mathematical function. It specifically does not read or write	323	much like a mathematical function. It specifically does not read or write
245	any memory any arguments might point to, global variables, or call any	324	any memory any arguments might point to, global variables, or call any
…		…
335		414
336	=head2 OPTIMISATION HINTS	415	=head2 OPTIMISATION HINTS
337		416
338	=over 4	417	=over 4
339		418
340	=item bool ecb_is_constant(expr)	419	=item bool ecb_is_constant (expr)
341		420
342	Returns true iff the expression can be deduced to be a compile-time	421	Returns true iff the expression can be deduced to be a compile-time
343	constant, and false otherwise.	422	constant, and false otherwise.
344		423
345	For example, when you have a C<rndm16> function that returns a 16 bit	424	For example, when you have a C<rndm16> function that returns a 16 bit
…		…
363	return is_constant (n) && !(n & (n - 1))	442	return is_constant (n) && !(n & (n - 1))
364	? rndm16 () & (num - 1)	443	? rndm16 () & (num - 1)
365	: (n * (uint32_t)rndm16 ()) >> 16;	444	: (n * (uint32_t)rndm16 ()) >> 16;
366	}	445	}
367		446
368	=item bool ecb_expect (expr, value)	447	=item ecb_expect (expr, value)
369		448
370	Evaluates C<expr> and returns it. In addition, it tells the compiler that	449	Evaluates C<expr> and returns it. In addition, it tells the compiler that
371	the C<expr> evaluates to C<value> a lot, which can be used for static	450	the C<expr> evaluates to C<value> a lot, which can be used for static
372	branch optimisations.	451	branch optimisations.
373		452
…		…
420	{	499	{
421	if (ecb_expect_false (current + size > end))	500	if (ecb_expect_false (current + size > end))
422	real_reserve_method (size); /* presumably noinline */	501	real_reserve_method (size); /* presumably noinline */
423	}	502	}
424		503
425	=item bool ecb_assume (cond)	504	=item ecb_assume (cond)
426		505
427	Try to tell the compiler that some condition is true, even if it's not	506	Tries to tell the compiler that some condition is true, even if it's not
428	obvious.	507	obvious. This is not a function, but a statement: it cannot be used in
		508	another expression.
429		509
430	This can be used to teach the compiler about invariants or other	510	This can be used to teach the compiler about invariants or other
431	conditions that might improve code generation, but which are impossible to	511	conditions that might improve code generation, but which are impossible to
432	deduce form the code itself.	512	deduce form the code itself.
433		513
…		…
450		530
451	Then the compiler I<might> be able to optimise out the second call	531	Then the compiler I<might> be able to optimise out the second call
452	completely, as it knows that C<< current + 1 > end >> is false and the	532	completely, as it knows that C<< current + 1 > end >> is false and the
453	call will never be executed.	533	call will never be executed.
454		534
455	=item bool ecb_unreachable ()	535	=item ecb_unreachable ()
456		536
457	This function does nothing itself, except tell the compiler that it will	537	This function does nothing itself, except tell the compiler that it will
458	never be executed. Apart from suppressing a warning in some cases, this	538	never be executed. Apart from suppressing a warning in some cases, this
459	function can be used to implement C<ecb_assume> or similar functions.	539	function can be used to implement C<ecb_assume> or similar functionality.
460		540
461	=item bool ecb_prefetch (addr, rw, locality)	541	=item ecb_prefetch (addr, rw, locality)
462		542
463	Tells the compiler to try to prefetch memory at the given C<addr>ess	543	Tells the compiler to try to prefetch memory at the given C<addr>ess
464	for either reading (C<rw> = 0) or writing (C<rw> = 1). A C<locality> of	544	for either reading (C<rw> = 0) or writing (C<rw> = 1). A C<locality> of
465	C<0> means that there will only be one access later, C<3> means that	545	C<0> means that there will only be one access later, C<3> means that
466	the data will likely be accessed very often, and values in between mean	546	the data will likely be accessed very often, and values in between mean
467	something... in between. The memory pointed to by the address does not	547	something... in between. The memory pointed to by the address does not
468	need to be accessible (it could be a null pointer for example), but C<rw>	548	need to be accessible (it could be a null pointer for example), but C<rw>
469	and C<locality> must be compile-time constants.	549	and C<locality> must be compile-time constants.
470		550
		551	This is a statement, not a function: you cannot use it as part of an
		552	expression.
		553
471	An obvious way to use this is to prefetch some data far away, in a big	554	An obvious way to use this is to prefetch some data far away, in a big
472	array you loop over. This prefetches memory some 128 array elements later,	555	array you loop over. This prefetches memory some 128 array elements later,
473	in the hope that it will be ready when the CPU arrives at that location.	556	in the hope that it will be ready when the CPU arrives at that location.
474		557
475	int sum = 0;	558	int sum = 0;
…		…
512		595
513	=item int ecb_ctz32 (uint32_t x)	596	=item int ecb_ctz32 (uint32_t x)
514		597
515	=item int ecb_ctz64 (uint64_t x)	598	=item int ecb_ctz64 (uint64_t x)
516		599
		600	=item int ecb_ctz (T x) [C++]
		601
517	Returns the index of the least significant bit set in C<x> (or	602	Returns the index of the least significant bit set in C<x> (or
518	equivalently the number of bits set to 0 before the least significant bit	603	equivalently the number of bits set to 0 before the least significant bit
519	set), starting from 0. If C<x> is 0 the result is undefined.	604	set), starting from 0. If C<x> is 0 the result is undefined.
520		605
521	For smaller types than C<uint32_t> you can safely use C<ecb_ctz32>.	606	For smaller types than C<uint32_t> you can safely use C<ecb_ctz32>.
522		607
		608	The overloaded C++ C<ecb_ctz> function supports C<uint8_t>, C<uint16_t>,
		609	C<uint32_t> and C<uint64_t> types.
		610
523	For example:	611	For example:
524		612
525	ecb_ctz32 (3) = 0	613	ecb_ctz32 (3) = 0
526	ecb_ctz32 (6) = 1	614	ecb_ctz32 (6) = 1
527		615
528	=item bool ecb_is_pot32 (uint32_t x)	616	=item bool ecb_is_pot32 (uint32_t x)
529		617
530	=item bool ecb_is_pot64 (uint32_t x)	618	=item bool ecb_is_pot64 (uint32_t x)
531		619
		620	=item bool ecb_is_pot (T x) [C++]
		621
532	Return true iff C<x> is a power of two or C<x == 0>.	622	Returns true iff C<x> is a power of two or C<x == 0>.
533		623
534	For smaller types then C<uint32_t> you can safely use C<ecb_is_pot32>.	624	For smaller types than C<uint32_t> you can safely use C<ecb_is_pot32>.
		625
		626	The overloaded C++ C<ecb_is_pot> function supports C<uint8_t>, C<uint16_t>,
		627	C<uint32_t> and C<uint64_t> types.
535		628
536	=item int ecb_ld32 (uint32_t x)	629	=item int ecb_ld32 (uint32_t x)
537		630
538	=item int ecb_ld64 (uint64_t x)	631	=item int ecb_ld64 (uint64_t x)
		632
		633	=item int ecb_ld64 (T x) [C++]
539		634
540	Returns the index of the most significant bit set in C<x>, or the number	635	Returns the index of the most significant bit set in C<x>, or the number
541	of digits the number requires in binary (so that C<< 2**ld <= x <	636	of digits the number requires in binary (so that C<< 2**ld <= x <
542	2**(ld+1) >>). If C<x> is 0 the result is undefined. A common use case is	637	2**(ld+1) >>). If C<x> is 0 the result is undefined. A common use case is
543	to compute the integer binary logarithm, i.e. C<floor (log2 (n))>, for	638	to compute the integer binary logarithm, i.e. C<floor (log2 (n))>, for
…		…
548	the given data type), while C<ecb_ld> returns how many bits the number	643	the given data type), while C<ecb_ld> returns how many bits the number
549	itself requires.	644	itself requires.
550		645
551	For smaller types than C<uint32_t> you can safely use C<ecb_ld32>.	646	For smaller types than C<uint32_t> you can safely use C<ecb_ld32>.
552		647
		648	The overloaded C++ C<ecb_ld> function supports C<uint8_t>, C<uint16_t>,
		649	C<uint32_t> and C<uint64_t> types.
		650
553	=item int ecb_popcount32 (uint32_t x)	651	=item int ecb_popcount32 (uint32_t x)
554		652
555	=item int ecb_popcount64 (uint64_t x)	653	=item int ecb_popcount64 (uint64_t x)
556		654
		655	=item int ecb_popcount (T x) [C++]
		656
557	Returns the number of bits set to 1 in C<x>.	657	Returns the number of bits set to 1 in C<x>.
558		658
559	For smaller types than C<uint32_t> you can safely use C<ecb_popcount32>.	659	For smaller types than C<uint32_t> you can safely use C<ecb_popcount32>.
		660
		661	The overloaded C++ C<ecb_popcount> function supports C<uint8_t>, C<uint16_t>,
		662	C<uint32_t> and C<uint64_t> types.
560		663
561	For example:	664	For example:
562		665
563	ecb_popcount32 (7) = 3	666	ecb_popcount32 (7) = 3
564	ecb_popcount32 (255) = 8	667	ecb_popcount32 (255) = 8
…		…
567		670
568	=item uint16_t ecb_bitrev16 (uint16_t x)	671	=item uint16_t ecb_bitrev16 (uint16_t x)
569		672
570	=item uint32_t ecb_bitrev32 (uint32_t x)	673	=item uint32_t ecb_bitrev32 (uint32_t x)
571		674
		675	=item T ecb_bitrev (T x) [C++]
		676
572	Reverses the bits in x, i.e. the MSB becomes the LSB, MSB-1 becomes LSB+1	677	Reverses the bits in x, i.e. the MSB becomes the LSB, MSB-1 becomes LSB+1
573	and so on.	678	and so on.
574		679
		680	The overloaded C++ C<ecb_bitrev> function supports C<uint8_t>, C<uint16_t> and C<uint32_t> types.
		681
575	Example:	682	Example:
576		683
577	ecb_bitrev8 (0xa7) = 0xea	684	ecb_bitrev8 (0xa7) = 0xea
578	ecb_bitrev32 (0xffcc4411) = 0x882233ff	685	ecb_bitrev32 (0xffcc4411) = 0x882233ff
579		686
		687	=item T ecb_bitrev (T x) [C++]
		688
		689	Overloaded C++ bitrev function.
		690
		691	C<T> must be one of C<uint8_t>, C<uint16_t> or C<uint32_t>.
		692
580	=item uint32_t ecb_bswap16 (uint32_t x)	693	=item uint32_t ecb_bswap16 (uint32_t x)
581		694
582	=item uint32_t ecb_bswap32 (uint32_t x)	695	=item uint32_t ecb_bswap32 (uint32_t x)
583		696
584	=item uint64_t ecb_bswap64 (uint64_t x)	697	=item uint64_t ecb_bswap64 (uint64_t x)
		698
		699	=item T ecb_bswap (T x)
585		700
586	These functions return the value of the 16-bit (32-bit, 64-bit) value	701	These functions return the value of the 16-bit (32-bit, 64-bit) value
587	C<x> after reversing the order of bytes (0x11223344 becomes 0x44332211 in	702	C<x> after reversing the order of bytes (0x11223344 becomes 0x44332211 in
588	C<ecb_bswap32>).	703	C<ecb_bswap32>).
589		704
		705	The overloaded C++ C<ecb_bswap> function supports C<uint8_t>, C<uint16_t>,
		706	C<uint32_t> and C<uint64_t> types.
		707
590	=item uint8_t ecb_rotl8 (uint8_t x, unsigned int count)	708	=item uint8_t ecb_rotl8 (uint8_t x, unsigned int count)
591		709
592	=item uint16_t ecb_rotl16 (uint16_t x, unsigned int count)	710	=item uint16_t ecb_rotl16 (uint16_t x, unsigned int count)
593		711
594	=item uint32_t ecb_rotl32 (uint32_t x, unsigned int count)	712	=item uint32_t ecb_rotl32 (uint32_t x, unsigned int count)
…		…
609		727
610	Current GCC versions understand these functions and usually compile them	728	Current GCC versions understand these functions and usually compile them
611	to "optimal" code (e.g. a single C<rol> or a combination of C<shld> on	729	to "optimal" code (e.g. a single C<rol> or a combination of C<shld> on
612	x86).	730	x86).
613		731
		732	=item T ecb_rotl (T x, unsigned int count) [C++]
		733
		734	=item T ecb_rotr (T x, unsigned int count) [C++]
		735
		736	Overloaded C++ rotl/rotr functions.
		737
		738	C<T> must be one of C<uint8_t>, C<uint16_t>, C<uint32_t> or C<uint64_t>.
		739
614	=back	740	=back
615		741
		742	=head2 HOST ENDIANNESS CONVERSION
		743
		744	=over 4
		745
		746	=item uint_fast16_t ecb_be_u16_to_host (uint_fast16_t v)
		747
		748	=item uint_fast32_t ecb_be_u32_to_host (uint_fast32_t v)
		749
		750	=item uint_fast64_t ecb_be_u64_to_host (uint_fast64_t v)
		751
		752	=item uint_fast16_t ecb_le_u16_to_host (uint_fast16_t v)
		753
		754	=item uint_fast32_t ecb_le_u32_to_host (uint_fast32_t v)
		755
		756	=item uint_fast64_t ecb_le_u64_to_host (uint_fast64_t v)
		757
		758	Convert an unsigned 16, 32 or 64 bit value from big or little endian to host byte order.
		759
		760	The naming convention is C<ecb_>(C<be>\|C<le>)C<_u>C<16\|32\|64>C<_to_host>,
		761	where C<be> and C<le> stand for big endian and little endian, respectively.
		762
		763	=item uint_fast16_t ecb_host_to_be_u16 (uint_fast16_t v)
		764
		765	=item uint_fast32_t ecb_host_to_be_u32 (uint_fast32_t v)
		766
		767	=item uint_fast64_t ecb_host_to_be_u64 (uint_fast64_t v)
		768
		769	=item uint_fast16_t ecb_host_to_le_u16 (uint_fast16_t v)
		770
		771	=item uint_fast32_t ecb_host_to_le_u32 (uint_fast32_t v)
		772
		773	=item uint_fast64_t ecb_host_to_le_u64 (uint_fast64_t v)
		774
		775	Like above, but converts I<from> host byte order to the specified
		776	endianness.
		777
		778	=back
		779
		780	In C++ the following additional template functions are supported:
		781
		782	=over 4
		783
		784	=item T ecb_be_to_host (T v)
		785
		786	=item T ecb_le_to_host (T v)
		787
		788	=item T ecb_host_to_be (T v)
		789
		790	=item T ecb_host_to_le (T v)
		791
		792	These functions work like their C counterparts, above, but use templates,
		793	which make them useful in generic code.
		794
		795	C<T> must be one of C<uint8_t>, C<uint16_t>, C<uint32_t> or C<uint64_t>
		796	(so unlike their C counterparts, there is a version for C<uint8_t>, which
		797	again can be useful in generic code).
		798
		799	=head2 UNALIGNED LOAD/STORE
		800
		801	These function load or store unaligned multi-byte values.
		802
		803	=over 4
		804
		805	=item uint_fast16_t ecb_peek_u16_u (const void *ptr)
		806
		807	=item uint_fast32_t ecb_peek_u32_u (const void *ptr)
		808
		809	=item uint_fast64_t ecb_peek_u64_u (const void *ptr)
		810
		811	These functions load an unaligned, unsigned 16, 32 or 64 bit value from
		812	memory.
		813
		814	=item uint_fast16_t ecb_peek_be_u16_u (const void *ptr)
		815
		816	=item uint_fast32_t ecb_peek_be_u32_u (const void *ptr)
		817
		818	=item uint_fast64_t ecb_peek_be_u64_u (const void *ptr)
		819
		820	=item uint_fast16_t ecb_peek_le_u16_u (const void *ptr)
		821
		822	=item uint_fast32_t ecb_peek_le_u32_u (const void *ptr)
		823
		824	=item uint_fast64_t ecb_peek_le_u64_u (const void *ptr)
		825
		826	Like above, but additionally convert from big endian (C<be>) or little
		827	endian (C<le>) byte order to host byte order while doing so.
		828
		829	=item ecb_poke_u16_u (void *ptr, uint16_t v)
		830
		831	=item ecb_poke_u32_u (void *ptr, uint32_t v)
		832
		833	=item ecb_poke_u64_u (void *ptr, uint64_t v)
		834
		835	These functions store an unaligned, unsigned 16, 32 or 64 bit value to
		836	memory.
		837
		838	=item ecb_poke_be_u16_u (void *ptr, uint_fast16_t v)
		839
		840	=item ecb_poke_be_u32_u (void *ptr, uint_fast32_t v)
		841
		842	=item ecb_poke_be_u64_u (void *ptr, uint_fast64_t v)
		843
		844	=item ecb_poke_le_u16_u (void *ptr, uint_fast16_t v)
		845
		846	=item ecb_poke_le_u32_u (void *ptr, uint_fast32_t v)
		847
		848	=item ecb_poke_le_u64_u (void *ptr, uint_fast64_t v)
		849
		850	Like above, but additionally convert from host byte order to big endian
		851	(C<be>) or little endian (C<le>) byte order while doing so.
		852
		853	=back
		854
		855	In C++ the following additional template functions are supported:
		856
		857	=over 4
		858
		859	=item T ecb_peek<T> (const void *ptr)
		860
		861	=item T ecb_peek_be<T> (const void *ptr)
		862
		863	=item T ecb_peek_le<T> (const void *ptr)
		864
		865	=item T ecb_peek_u<T> (const void *ptr)
		866
		867	=item T ecb_peek_be_u<T> (const void *ptr)
		868
		869	=item T ecb_peek_le_u<T> (const void *ptr)
		870
		871	Similarly to their C counterparts, these functions load an unsigned 8, 16,
		872	32 or 64 bit value from memory, with optional conversion from big/little
		873	endian.
		874
		875	Since the type cannot be deduced, it has to be specified explicitly, e.g.
		876
		877	uint_fast16_t v = ecb_peek<uint16_t> (ptr);
		878
		879	C<T> must be one of C<uint8_t>, C<uint16_t>, C<uint32_t> or C<uint64_t>.
		880
		881	Unlike their C counterparts, these functions support 8 bit quantities
		882	(C<uint8_t>) and also have an aligned version (without the C<_u> prefix),
		883	all of which hopefully makes them more useful in generic code.
		884
		885	=item ecb_poke (void *ptr, T v)
		886
		887	=item ecb_poke_be (void *ptr, T v)
		888
		889	=item ecb_poke_le (void *ptr, T v)
		890
		891	=item ecb_poke_u (void *ptr, T v)
		892
		893	=item ecb_poke_be_u (void *ptr, T v)
		894
		895	=item ecb_poke_le_u (void *ptr, T v)
		896
		897	Again, similarly to their C counterparts, these functions store an
		898	unsigned 8, 16, 32 or z64 bit value to memory, with optional conversion to
		899	big/little endian.
		900
		901	C<T> must be one of C<uint8_t>, C<uint16_t>, C<uint32_t> or C<uint64_t>.
		902
		903	Unlike their C counterparts, these functions support 8 bit quantities
		904	(C<uint8_t>) and also have an aligned version (without the C<_u> prefix),
		905	all of which hopefully makes them more useful in generic code.
		906
		907	=back
		908
616	=head2 FLOATING POINT FIDDLING	909	=head2 FLOATING POINT FIDDLING
617		910
618	=over 4	911	=over 4
619		912
		913	=item ECB_INFINITY [-UECB_NO_LIBM]
		914
		915	Evaluates to positive infinity if supported by the platform, otherwise to
		916	a truly huge number.
		917
		918	=item ECB_NAN [-UECB_NO_LIBM]
		919
		920	Evaluates to a quiet NAN if supported by the platform, otherwise to
		921	C<ECB_INFINITY>.
		922
		923	=item float ecb_ldexpf (float x, int exp) [-UECB_NO_LIBM]
		924
		925	Same as C<ldexpf>, but always available.
		926
		927	=item uint32_t ecb_float_to_binary16 (float x) [-UECB_NO_LIBM]
		928
620	=item uint32_t ecb_float_to_binary32 (float x) [-UECB_NO_LIBM]	929	=item uint32_t ecb_float_to_binary32 (float x) [-UECB_NO_LIBM]
621		930
622	=item uint64_t ecb_double_to_binary64 (double x) [-UECB_NO_LIBM]	931	=item uint64_t ecb_double_to_binary64 (double x) [-UECB_NO_LIBM]
623		932
624	These functions each take an argument in the native C<float> or C<double>	933	These functions each take an argument in the native C<float> or C<double>
625	type and return the IEEE 754 bit representation of it.	934	type and return the IEEE 754 bit representation of it (binary16/half,
		935	binary32/single or binary64/double precision).
626		936
627	The bit representation is just as IEEE 754 defines it, i.e. the sign bit	937	The bit representation is just as IEEE 754 defines it, i.e. the sign bit
628	will be the most significant bit, followed by exponent and mantissa.	938	will be the most significant bit, followed by exponent and mantissa.
629		939
630	This function should work even when the native floating point format isn't	940	This function should work even when the native floating point format isn't
…		…
634		944
635	On all modern platforms (where C<ECB_STDFP> is true), the compiler should	945	On all modern platforms (where C<ECB_STDFP> is true), the compiler should
636	be able to optimise away this function completely.	946	be able to optimise away this function completely.
637		947
638	These functions can be helpful when serialising floats to the network - you	948	These functions can be helpful when serialising floats to the network - you
639	can serialise the return value like a normal uint32_t/uint64_t.	949	can serialise the return value like a normal uint16_t/uint32_t/uint64_t.
640		950
641	Another use for these functions is to manipulate floating point values	951	Another use for these functions is to manipulate floating point values
642	directly.	952	directly.
643		953
644	Silly example: toggle the sign bit of a float.	954	Silly example: toggle the sign bit of a float.
…		…
647	/* this results in a single add instruction to toggle the bit, and 4 extra */	957	/* this results in a single add instruction to toggle the bit, and 4 extra */
648	/* instructions to move the float value to an integer register and back. */	958	/* instructions to move the float value to an integer register and back. */
649		959
650	x = ecb_binary32_to_float (ecb_float_to_binary32 (x) ^ 0x80000000U)	960	x = ecb_binary32_to_float (ecb_float_to_binary32 (x) ^ 0x80000000U)
651		961
		962	=item float ecb_binary16_to_float (uint16_t x) [-UECB_NO_LIBM]
		963
652	=item float ecb_binary32_to_float (uint32_t x) [-UECB_NO_LIBM]	964	=item float ecb_binary32_to_float (uint32_t x) [-UECB_NO_LIBM]
653		965
654	=item double ecb_binary32_to_double (uint64_t x) [-UECB_NO_LIBM]	966	=item double ecb_binary64_to_double (uint64_t x) [-UECB_NO_LIBM]
655		967
656	The reverse operation of the previos function - takes the bit representation	968	The reverse operation of the previous function - takes the bit
657	of an IEEE binary32 or binary64 number and converts it to the native C<float>	969	representation of an IEEE binary16, binary32 or binary64 number (half,
		970	single or double precision) and converts it to the native C<float> or
658	or C<double> format.	971	C<double> format.
659		972
660	This function should work even when the native floating point format isn't	973	This function should work even when the native floating point format isn't
661	IEEE compliant, of course at a speed and code size penalty, and of course	974	IEEE compliant, of course at a speed and code size penalty, and of course
662	also within reasonable limits (it tries to convert normals and denormals,	975	also within reasonable limits (it tries to convert normals and denormals,
663	and might be lucky for infinities, and with extraordinary luck, also for	976	and might be lucky for infinities, and with extraordinary luck, also for
664	negative zero).	977	negative zero).
665		978
666	On all modern platforms (where C<ECB_STDFP> is true), the compiler should	979	On all modern platforms (where C<ECB_STDFP> is true), the compiler should
667	be able to optimise away this function completely.	980	be able to optimise away this function completely.
		981
		982	=item uint16_t ecb_binary32_to_binary16 (uint32_t x)
		983
		984	=item uint32_t ecb_binary16_to_binary32 (uint16_t x)
		985
		986	Convert a IEEE binary32/single precision to binary16/half format, and vice
		987	versa, handling all details (round-to-nearest-even, subnormals, infinity
		988	and NaNs) correctly.
		989
		990	These are functions are available under C<-DECB_NO_LIBM>, since
		991	they do not rely on the platform floating point format. The
		992	C<ecb_float_to_binary16> and C<ecb_binary16_to_float> functions are
		993	usually what you want.
668		994
669	=back	995	=back
670		996
671	=head2 ARITHMETIC	997	=head2 ARITHMETIC
672		998
…		…
753	dependencies on the math library (usually called F<-lm>) - these are	1079	dependencies on the math library (usually called F<-lm>) - these are
754	marked with [-UECB_NO_LIBM].	1080	marked with [-UECB_NO_LIBM].
755		1081
756	=back	1082	=back
757		1083
		1084	=head1 UNDOCUMENTED FUNCTIONALITY
758		1085
		1086	F<ecb.h> is full of undocumented functionality as well, some of which is
		1087	intended to be internal-use only, some of which we forgot to document, and
		1088	some of which we hide because we are not sure we will keep the interface
		1089	stable.
		1090
		1091	While you are welcome to rummage around and use whatever you find useful
		1092	(we can't stop you), keep in mind that we will change undocumented
		1093	functionality in incompatible ways without thinking twice, while we are
		1094	considerably more conservative with documented things.
		1095
		1096	=head1 AUTHORS
		1097
		1098	C<libecb> is designed and maintained by:
		1099
		1100	Emanuele Giaquinta <e.giaquinta@glauco.it>
		1101	Marc Alexander Lehmann <schmorp@schmorp.de>
		1102
		1103

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Comparing libecb/ecb.pod (file contents): Revision 1.52 by root, Sun Sep 23 22:32:33 2012 UTC vs. Revision 1.81 by root, Mon Jan 20 21:01:29 2020 UTC

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Comparing libecb/ecb.pod (file contents):
Revision 1.52 by root, Sun Sep 23 22:32:33 2012 UTC vs.
Revision 1.81 by root, Mon Jan 20 21:01:29 2020 UTC