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Commit 6855b303 authored by Rusty Russell's avatar Rusty Russell
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ilog: rework to reduce interface. 

If you've not got gcc, this is a bit of a lose.  But for everyone else,
it's far simpler.
parent 9056c31b
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Showing with 212 additions and 205 deletions
ccan/alloc/_info
View file @ 6855b303
......@@ -104,6 +104,7 @@ int main(int argc, char *argv[])
printf("ccan/alignof\n");
printf("ccan/build_assert\n");
printf("ccan/compiler\n");
printf("ccan/ilog\n");
printf("ccan/likely\n");
printf("ccan/short_types\n");
return 0;
......
ccan/alloc/bitops.c
View file @ 6855b303
#include "bitops.h"
#include "config.h"
#include <ccan/build_assert/build_assert.h>
#include <ccan/short_types/short_types.h>
#include <ccan/ilog/ilog.h>
#include <limits.h>
unsigned int fls(unsigned long val)
{
#if HAVE_BUILTIN_CLZL
/* This is significantly faster! */
return val ? sizeof(long) * CHAR_BIT - __builtin_clzl(val) : 0;
#else
unsigned int r = 32;
if (!val)
return 0;
if (!(val & 0xffff0000u)) {
val <<= 16;
r -= 16;
}
if (!(val & 0xff000000u)) {
val <<= 8;
r -= 8;
}
if (!(val & 0xf0000000u)) {
val <<= 4;
r -= 4;
}
if (!(val & 0xc0000000u)) {
val <<= 2;
r -= 2;
}
if (!(val & 0x80000000u)) {
val <<= 1;
r -= 1;
}
return r;
#endif
BUILD_ASSERT(sizeof(val) == sizeof(u32) || sizeof(val) == sizeof(u64));
if (sizeof(val) == sizeof(u32))
return ilog32(val);
else
return ilog64(val);
}
/* FIXME: Move to bitops. */
......
ccan/ilog/_info
View file @ 6855b303
/**
* ilog - Integer logarithm.
*
* ILOG_32() and ILOG_64() compute the minimum number of bits required to store
* ilog_32() and ilog_64() compute the minimum number of bits required to store
* an unsigned 32-bit or 64-bit value without any leading zero bits.
* This can also be thought of as the location of the highest set bit, with
* counting starting from one (so that 0 returns 0, 1 returns 1, and 2**31
* returns 32).
* When the value is known to be non-zero ILOGNZ_32() and ILOGNZ_64() can
* When the value is known to be non-zero ilog32_nz() and ilog64_nz() can
* compile into as few as two instructions, one of which may get optimized out
* later.
* STATIC_ILOG_32 and STATIC_ILOG_64 allow computation on compile-time
......@@ -19,12 +19,12 @@
*
* int main(void){
* int i;
* printf("ILOG_32(0x%08X)=%i\n",0,ILOG_32(0));
* printf("ilog32(0x%08X)=%i\n",0,ilog32(0));
* for(i=1;i<=STATIC_ILOG_32(USHRT_MAX);i++){
* uint32_t v;
* v=(uint32_t)1U<<(i-1);
* //Here we know v is non-zero, so we can use ILOGNZ_32().
* printf("ILOG_32(0x%08X)=%i\n",v,ILOGNZ_32(v));
* //Here we know v is non-zero, so we can use ilog32_nz().
* printf("ilog32(0x%08X)=%i\n",v,ilog32_nz(v));
* }
* return 0;
* }
......@@ -32,13 +32,14 @@
* License: LGPL (v2 or later)
*/
#include <string.h>
#include <stdio.h>
#include "config.h"
int main(int _argc,const char *_argv[]){
/*Expect exactly one argument.*/
if(_argc!=2)return 1;
if(strcmp(_argv[1],"depends")==0){
/*PRINTF-CCAN-PACKAGES-YOU-NEED-ONE-PER-LINE-IF-ANY*/
printf("ccan/compiler\n");
return 0;
}
return 1;
......
ccan/ilog/ilog.c
View file @ 6855b303
......@@ -16,18 +16,18 @@
year=1998,
note="\url{http://supertech.csail.mit.edu/papers/debruijn.pdf}"
}*/
#if !defined(ILOG_NODEBRUIJN)&& \
!defined(CLZ32)||!defined(CLZ64)&&LONG_MAX<9223372036854775807LL
static const unsigned char DEBRUIJN_IDX32[32]={
static UNNEEDED_ATTRIBUTE const unsigned char DEBRUIJN_IDX32[32]={
0, 1,28, 2,29,14,24, 3,30,22,20,15,25,17, 4, 8,
31,27,13,23,21,19,16, 7,26,12,18, 6,11, 5,10, 9
};
#endif
/* We always compile these in, in case someone takes address of function. */
#undef ilog32_nz
#undef ilog32
#undef ilog64_nz
#undef ilog64
int ilog32(uint32_t _v){
#if defined(CLZ32)
return (CLZ32_OFFS-CLZ32(_v))&-!!_v;
#else
/*On a Pentium M, this branchless version tested as the fastest version without
multiplications on 1,000,000,000 random 32-bit integers, edging out a
similar version with branches, and a 256-entry LUT version.*/
......@@ -62,13 +62,14 @@ int ilog32(uint32_t _v){
ret+=DEBRUIJN_IDX32[_v*0x77CB531U>>27&0x1F];
return ret;
# endif
#endif
}
int ilog32_nz(uint32_t _v)
{
return ilog32(_v);
}
int ilog64(uint64_t _v){
#if defined(CLZ64)
return (CLZ64_OFFS-CLZ64(_v))&-!!_v;
#else
# if defined(ILOG_NODEBRUIJN)
uint32_t v;
int ret;
......@@ -130,5 +131,10 @@ int ilog64(uint64_t _v){
return ret;
# endif
# endif
#endif
}
int ilog64_nz(uint64_t _v)
{
return ilog64(_v);
}
ccan/ilog/ilog.h
View file @ 6855b303
......@@ -2,30 +2,8 @@
# define _ilog_H (1)
# include "config.h"
# include <stdint.h>
# include <ccan/compiler/compiler.h>
# include <limits.h>
/*Note the casts to (int) below: this prevents CLZ{32|64}_OFFS from "upgrading"
the type of an entire expression to an (unsigned) size_t.*/
# if HAVE_BUILTIN_CLZ && INT_MAX>=2147483647
# define CLZ32_OFFS ((int)sizeof(unsigned)*CHAR_BIT)
# define CLZ32(_x) (__builtin_clz(_x))
# elif HAVE_BUILTIN_CLZL && LONG_MAX>=2147483647L
# define CLZ32_OFFS ((int)sizeof(unsigned long)*CHAR_BIT)
# define CLZ32(_x) (__builtin_clzl(_x))
# endif
# if HAVE_BUILTIN_CLZ && INT_MAX>=9223372036854775807LL
# define CLZ64_OFFS ((int)sizeof(unsigned)*CHAR_BIT)
# define CLZ64(_x) (__builtin_clz(_x))
# elif HAVE_BUILTIN_CLZL && LONG_MAX>=9223372036854775807LL
# define CLZ64_OFFS ((int)sizeof(unsigned long)*CHAR_BIT)
# define CLZ64(_x) (__builtin_clzl(_x))
# elif HAVE_BUILTIN_CLZLL /* long long must be >= 64 bits according to ISO C */
# define CLZ64_OFFS ((int)sizeof(unsigned long long)*CHAR_BIT)
# define CLZ64(_x) (__builtin_clzll(_x))
# endif
# include <ccan/compiler/compiler.h>
/**
* ilog32 - Integer binary logarithm of a 32-bit value.
......@@ -33,68 +11,130 @@
* Returns floor(log2(_v))+1, or 0 if _v==0.
* This is the number of bits that would be required to represent _v in two's
* complement notation with all of the leading zeros stripped.
* The ILOG_32() or ILOGNZ_32() macros may be able to use a builtin function
* instead, which should be faster.
* Note that many uses will resolve to the fast macro version instead.
*
* See Also:
* ilog32_nz(), ilog64()
*
* Example:
* // Rounds up to next power of 2 (if not a power of 2).
* static uint32_t round_up32(uint32_t i)
* {
* assert(i != 0);
* return 1U << ilog32(i-1);
* }
*/
int ilog32(uint32_t _v) IDEMPOTENT_ATTRIBUTE;
/**
* ilog32_nz - Integer binary logarithm of a non-zero 32-bit value.
* @_v: A 32-bit value.
* Returns floor(log2(_v))+1, or undefined if _v==0.
* This is the number of bits that would be required to represent _v in two's
* complement notation with all of the leading zeros stripped.
* Note that many uses will resolve to the fast macro version instead.
* See Also:
* ilog32(), ilog64_nz()
* Example:
* // Find Last Set (ie. highest bit set, 0 to 31).
* static uint32_t fls32(uint32_t i)
* {
* assert(i != 0);
* return ilog32_nz(i) - 1;
* }
*/
int ilog32_nz(uint32_t _v) IDEMPOTENT_ATTRIBUTE;
/**
* ilog64 - Integer binary logarithm of a 64-bit value.
* @_v: A 64-bit value.
* Returns floor(log2(_v))+1, or 0 if _v==0.
* This is the number of bits that would be required to represent _v in two's
* complement notation with all of the leading zeros stripped.
* The ILOG_64() or ILOGNZ_64() macros may be able to use a builtin function
* instead, which should be faster.
* Note that many uses will resolve to the fast macro version instead.
* See Also:
* ilog64_nz(), ilog32()
*/
int ilog64(uint64_t _v) IDEMPOTENT_ATTRIBUTE;
# if defined(CLZ32)
/**
* ILOGNZ_32 - Integer binary logarithm of a non-zero 32-bit value.
* @_v: A non-zero 32-bit value.
* Returns floor(log2(_v))+1.
* ilog64_nz - Integer binary logarithm of a non-zero 64-bit value.
* @_v: A 64-bit value.
* Returns floor(log2(_v))+1, or undefined if _v==0.
* This is the number of bits that would be required to represent _v in two's
* complement notation with all of the leading zeros stripped.
* If _v is zero, the return value is undefined; use ILOG_32() instead.
* Note that many uses will resolve to the fast macro version instead.
* See Also:
* ilog64(), ilog32_nz()
*/
# define ILOGNZ_32(_v) (CLZ32_OFFS-CLZ32(_v))
int ilog64_nz(uint64_t _v) IDEMPOTENT_ATTRIBUTE;
/**
* ILOG_32 - Integer binary logarithm of a 32-bit value.
* @_v: A 32-bit value.
* STATIC_ILOG_32 - The integer logarithm of an (unsigned, 32-bit) constant.
* @_v: A non-negative 32-bit constant.
* Returns floor(log2(_v))+1, or 0 if _v==0.
* This is the number of bits that would be required to represent _v in two's
* complement notation with all of the leading zeros stripped.
* This macro should only be used when you need a compile-time constant,
* otherwise ilog32 or ilog32_nz are just as fast and more flexible.
*
* Example:
* #define MY_PAGE_SIZE 4096
* #define MY_PAGE_BITS (STATIC_ILOG_32(PAGE_SIZE) - 1)
*/
# define ILOG_32(_v) (ILOGNZ_32(_v)&-!!(_v))
# else
# define ILOGNZ_32(_v) (ilog32(_v))
# define ILOG_32(_v) (ilog32(_v))
# endif
#define STATIC_ILOG_32(_v) (STATIC_ILOG5((uint32_t)(_v)))
# if defined(CLZ64)
/**
* ILOGNZ_64 - Integer binary logarithm of a non-zero 64-bit value.
* @_v: A non-zero 64-bit value.
* Returns floor(log2(_v))+1.
* This is the number of bits that would be required to represent _v in two's
* complement notation with all of the leading zeros stripped.
* If _v is zero, the return value is undefined; use ILOG_64() instead.
*/
# define ILOGNZ_64(_v) (CLZ64_OFFS-CLZ64(_v))
/**
* ILOG_64 - Integer binary logarithm of a 64-bit value.
* @_v: A 64-bit value.
* STATIC_ILOG_64 - The integer logarithm of an (unsigned, 64-bit) constant.
* @_v: A non-negative 64-bit constant.
* Returns floor(log2(_v))+1, or 0 if _v==0.
* This is the number of bits that would be required to represent _v in two's
* complement notation with all of the leading zeros stripped.
* This macro should only be used when you need a compile-time constant,
* otherwise ilog64 or ilog64_nz are just as fast and more flexible.
*/
# define ILOG_64(_v) (ILOGNZ_64(_v)&-!!(_v))
# else
# define ILOGNZ_64(_v) (ilog64(_v))
# define ILOG_64(_v) (ilog64(_v))
# endif
#define STATIC_ILOG_64(_v) (STATIC_ILOG6((uint64_t)(_v)))
/* Private implementation details */
/*Note the casts to (int) below: this prevents "upgrading"
the type of an entire expression to an (unsigned) size_t.*/
#if INT_MAX>=2147483647 && HAVE_BUILTIN_CLZ
#define builtin_ilog32_nz(v) \
(((int)sizeof(unsigned)*CHAR_BIT) - __builtin_clz(v))
#elif LONG_MAX>=2147483647L && HAVE_BUILTIN_CLZL
#define builtin_ilog32_nz(v) \
(((int)sizeof(unsigned)*CHAR_BIT) - __builtin_clzl(v))
#endif
#if INT_MAX>=9223372036854775807LL && HAVE_BUILTIN_CLZ
#define builtin_ilog64_nz(v) \
(((int)sizeof(unsigned)*CHAR_BIT) - __builtin_clz(v))
#elif LONG_MAX>=9223372036854775807LL && HAVE_BUILTIN_CLZL
#define builtin_ilog64_nz(v) \
(((int)sizeof(unsigned long)*CHAR_BIT) - __builtin_clzl(v))
#elif HAVE_BUILTIN_CLZLL
#define builtin_ilog64_nz(v) \
(((int)sizeof(unsigned long long)*CHAR_BIT) - __builtin_clzll(v))
#endif
#ifdef builtin_ilog32_nz
#define ilog32(_v) (builtin_ilog32_nz(_v)&-!!(_v))
#define ilog32_nz(_v) builtin_ilog32_nz(_v)
#else
#define ilog32_nz(_v) ilog32(_v)
#define ilog32(_v) (IS_COMPILE_CONSTANT(_v) ? STATIC_ILOG_32(_v) : ilog32(_v))
#endif /* builtin_ilog32_nz */
#ifdef builtin_ilog64_nz
#define ilog64(_v) (builtin_ilog64_nz(_v)&-!!(_v))
#define ilog64_nz(_v) builtin_ilog64_nz(_v)
#else
#define ilog64_nz(_v) ilog64(_v)
#define ilog64(_v) (IS_COMPILE_CONSTANT(_v) ? STATIC_ILOG_64(_v) : ilog64(_v))
#endif /* builtin_ilog64_nz */
/* Macros for evaluating compile-time constant ilog. */
# define STATIC_ILOG0(_v) (!!(_v))
# define STATIC_ILOG1(_v) (((_v)&0x2)?2:STATIC_ILOG0(_v))
# define STATIC_ILOG2(_v) (((_v)&0xC)?2+STATIC_ILOG1((_v)>>2):STATIC_ILOG1(_v))
......@@ -106,27 +146,5 @@ int ilog64(uint64_t _v) IDEMPOTENT_ATTRIBUTE;
(((_v)&0xFFFF0000)?16+STATIC_ILOG4((_v)>>16):STATIC_ILOG4(_v))
# define STATIC_ILOG6(_v) \
(((_v)&0xFFFFFFFF00000000ULL)?32+STATIC_ILOG5((_v)>>32):STATIC_ILOG5(_v))
/**
* STATIC_ILOG_32 - The integer logarithm of an (unsigned, 32-bit) constant.
* @_v: A non-negative 32-bit constant.
* Returns floor(log2(_v))+1, or 0 if _v==0.
* This is the number of bits that would be required to represent _v in two's
* complement notation with all of the leading zeros stripped.
* This macro is suitable for evaluation at compile time, but it should not be
* used on values that can change at runtime, as it operates via exhaustive
* search.
*/
# define STATIC_ILOG_32(_v) (STATIC_ILOG5((uint32_t)(_v)))
/**
* STATIC_ILOG_64 - The integer logarithm of an (unsigned, 64-bit) constant.
* @_v: A non-negative 64-bit constant.
* Returns floor(log2(_v))+1, or 0 if _v==0.
* This is the number of bits that would be required to represent _v in two's
* complement notation with all of the leading zeros stripped.
* This macro is suitable for evaluation at compile time, but it should not be
* used on values that can change at runtime, as it operates via exhaustive
* search.
*/
# define STATIC_ILOG_64(_v) (STATIC_ILOG6((uint64_t)(_v)))
#endif
#endif /* _ilog_H */
ccan/ilog/test/run-out-of-line.c 0 → 100644
View file @ 6855b303
#include <ccan/ilog/ilog.h>
#include <ccan/ilog/ilog.c>
#include <stdio.h>
#include <ccan/tap/tap.h>
/*Dead simple (but slow) versions to compare against.*/
static int test_ilog32(uint32_t _v){
int ret;
for(ret=0;_v;ret++)_v>>=1;
return ret;
}
static int test_ilog64(uint64_t _v){
int ret;
for(ret=0;_v;ret++)_v>>=1;
return ret;
}
#define NTRIALS (64)
int main(int _argc,const char *_argv[]){
int i;
int j;
int (*il32)(uint32_t) = ilog32;
int (*il64)(uint64_t) = ilog64;
int (*il32_nz)(uint32_t) = ilog32_nz;
int (*il64_nz)(uint64_t) = ilog64_nz;
/*This is how many tests you plan to run.*/
plan_tests(33 * NTRIALS * 3 + 65 * NTRIALS * 3);
for(i=0;i<=32;i++){
uint32_t v;
/*Test each bit in turn (and 0).*/
v=i?(uint32_t)1U<<(i-1):0;
for(j=0;j<NTRIALS;j++){
int l;
l=test_ilog32(v);
ok1(STATIC_ILOG_32(v)==l);
ok1(il32(v)==l);
ok1(il32_nz(v) == l || v == 0);
/*Also try a few more pseudo-random values with at most the same number
of bits.*/
v=(1103515245U*v+12345U)&0xFFFFFFFFU>>((33-i)>>1)>>((32-i)>>1);
}
}
for(i=0;i<=64;i++){
uint64_t v;
/*Test each bit in turn (and 0).*/
v=i?(uint64_t)1U<<(i-1):0;
for(j=0;j<NTRIALS;j++){
int l;
l=test_ilog64(v);
ok1(STATIC_ILOG_64(v)==l);
ok1(il64(v)==l);
ok1(il64_nz(v) == l || v == 0);
/*Also try a few more pseudo-random values with at most the same number
of bits.*/
v=(uint64_t)((2862933555777941757ULL*v+3037000493ULL)
&0xFFFFFFFFFFFFFFFFULL>>((65-i)>>1)>>((64-i)>>1));
}
}
return exit_status();
}
ccan/ilog/test/run.c
View file @ 6855b303
......@@ -20,12 +20,10 @@ static int test_ilog64(uint64_t _v){
#define NTRIALS (64)
int main(int _argc,const char *_argv[]){
int nmatches;
int i;
int j;
/*This is how many tests you plan to run.*/
plan_tests(2);
nmatches=0;
plan_tests(33 * NTRIALS * 3 + 65 * NTRIALS * 3);
for(i=0;i<=32;i++){
uint32_t v;
/*Test each bit in turn (and 0).*/
......@@ -33,26 +31,15 @@ int main(int _argc,const char *_argv[]){
for(j=0;j<NTRIALS;j++){
int l;
l=test_ilog32(v);
if(ILOG_32(v)!=l){
fprintf(stderr,"ILOG_32(0x%08lX): %i != %i\n",(long)v,ILOG_32(v),l);
}
else nmatches++;
if(ilog32(v)!=l){
fprintf(stderr,"ilog32(0x%08lX): %i != %i\n",(long)v,ilog32(v),l);
}
else nmatches++;
if(STATIC_ILOG_32(v)!=l){
fprintf(stderr,"STATIC_ILOG_32(0x%08lX): %i != %i\n",
(long)v,STATIC_ILOG_32(v),l);
}
else nmatches++;
ok1(STATIC_ILOG_32(v)==l);
ok1(ilog32(v)==l);
ok1(ilog32_nz(v) == l || v == 0);
/*Also try a few more pseudo-random values with at most the same number
of bits.*/
v=(1103515245U*v+12345U)&0xFFFFFFFFU>>((33-i)>>1)>>((32-i)>>1);
}
}
ok1(nmatches==3*(32+1)*NTRIALS);
nmatches=0;
for(i=0;i<=64;i++){
uint64_t v;
/*Test each bit in turn (and 0).*/
......@@ -60,27 +47,14 @@ int main(int _argc,const char *_argv[]){
for(j=0;j<NTRIALS;j++){
int l;
l=test_ilog64(v);
if(ILOG_64(v)!=l){
fprintf(stderr,"ILOG_64(0x%016llX): %i != %i\n",
(long long)v,ILOG_64(v),l);
}
else nmatches++;
if(ilog64(v)!=l){
fprintf(stderr,"ilog64(0x%016llX): %i != %i\n",
(long long)v,ilog64(v),l);
}
else nmatches++;
if(STATIC_ILOG_64(v)!=l){
fprintf(stderr,"STATIC_ILOG_64(0x%016llX): %i != %i\n",
(long long)v,STATIC_ILOG_64(v),l);
}
else nmatches++;
ok1(STATIC_ILOG_64(v)==l);
ok1(ilog64(v)==l);
ok1(ilog64_nz(v) == l || v == 0);
/*Also try a few more pseudo-random values with at most the same number
of bits.*/
v=(uint64_t)((2862933555777941757ULL*v+3037000493ULL)
&0xFFFFFFFFFFFFFFFFULL>>((65-i)>>1)>>((64-i)>>1));
}
}
ok1(nmatches==3*(64+1)*NTRIALS);
return exit_status();
}
ccan/isaac/isaac.c
View file @ 6855b303
......@@ -170,7 +170,7 @@ static float isaac_float_bits(isaac_ctx *_ctx,uint32_t _bits,int _base){
FLT_MANT_DIG+1 consecutive one bits.
Even the fallback C implementation of ILOGNZ_32() yields an implementation
25% faster than the frexp() method.*/
nbits_needed=FLT_MANT_DIG-ILOGNZ_32(_bits);
nbits_needed=FLT_MANT_DIG-ilog32_nz(_bits);
#if FLT_MANT_DIG>32
ret=ldexpf((float)_bits,_base);
# if FLT_MANT_DIG>65
......@@ -221,7 +221,7 @@ static double isaac_double_bits(isaac_ctx *_ctx,uint32_t _bits,int _base){
_base-=32;
_bits=isaac_next_uint32(_ctx);
}
nbits_needed=DBL_MANT_DIG-ILOGNZ_32(_bits);
nbits_needed=DBL_MANT_DIG-ilog32_nz(_bits);
#if DBL_MANT_DIG>32
ret=ldexp((double)_bits,_base);
# if DBL_MANT_DIG>65
......
ccan/isaac/isaac64.c
View file @ 6855b303
......@@ -166,7 +166,7 @@ static float isaac64_float_bits(isaac64_ctx *_ctx,uint64_t _bits,int _base){
_base-=64;
_bits=isaac64_next_uint64(_ctx);
}
nbits_needed=FLT_MANT_DIG-ILOGNZ_64(_bits);
nbits_needed=FLT_MANT_DIG-ilog64_nz(_bits);
#if FLT_MANT_DIG>64
ret=ldexpf((float)_bits,_base);
# if FLT_MANT_DIG>129
......@@ -217,7 +217,7 @@ static double isaac64_double_bits(isaac64_ctx *_ctx,uint64_t _bits,int _base){
_base-=64;
_bits=isaac64_next_uint64(_ctx);
}
nbits_needed=DBL_MANT_DIG-ILOGNZ_64(_bits);
nbits_needed=DBL_MANT_DIG-ilog64_nz(_bits);
#if DBL_MANT_DIG>64
ret=ldexp((double)_bits,_base);
# if DBL_MANT_DIG>129
......
ccan/tdb2/_info
View file @ 6855b303
......@@ -78,6 +78,7 @@ int main(int argc, char *argv[])
printf("ccan/asearch\n");
printf("ccan/compiler\n");
printf("ccan/build_assert\n");
printf("ccan/ilog\n");
printf("ccan/tally\n");
return 0;
}
......
ccan/tdb2/free.c
View file @ 6855b303
......@@ -17,50 +17,14 @@
*/
#include "private.h"
#include <ccan/likely/likely.h>
#include <ccan/ilog/ilog.h>
#include <time.h>
#include <assert.h>
#include <limits.h>
static unsigned fls64(uint64_t val)
{
#if HAVE_BUILTIN_CLZL
if (val <= ULONG_MAX) {
/* This is significantly faster! */
return val ? sizeof(long) * CHAR_BIT - __builtin_clzl(val) : 0;
} else {
#endif
uint64_t r = 64;
if (!val)
return 0;
if (!(val & 0xffffffff00000000ull)) {
val <<= 32;
r -= 32;
}
if (!(val & 0xffff000000000000ull)) {
val <<= 16;
r -= 16;
}
if (!(val & 0xff00000000000000ull)) {
val <<= 8;
r -= 8;
}
if (!(val & 0xf000000000000000ull)) {
val <<= 4;
r -= 4;
}
if (!(val & 0xc000000000000000ull)) {
val <<= 2;
r -= 2;
}
if (!(val & 0x8000000000000000ull)) {
val <<= 1;
r -= 1;
}
return r;
#if HAVE_BUILTIN_CLZL
}
#endif
return ilog64(val);
}
/* In which bucket would we find a particular record size? (ignoring header) */
......
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