diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/include/pg_config.h.in | 3 | ||||
| -rw-r--r-- | src/include/port.h | 4 | ||||
| -rw-r--r-- | src/port/fls.c | 64 |
3 files changed, 71 insertions, 0 deletions
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in index db84f494ef7..46c72245032 100644 --- a/src/include/pg_config.h.in +++ b/src/include/pg_config.h.in @@ -158,6 +158,9 @@ /* Define to 1 if you have the `fdatasync' function. */ #undef HAVE_FDATASYNC +/* Define to 1 if you have the `fls' function. */ +#undef HAVE_FLS + /* Define to 1 if you have the `fpclass' function. */ #undef HAVE_FPCLASS diff --git a/src/include/port.h b/src/include/port.h index bec40c11612..a5e80211b41 100644 --- a/src/include/port.h +++ b/src/include/port.h @@ -396,6 +396,10 @@ extern double pg_erand48(unsigned short xseed[3]); extern long pg_lrand48(void); extern void pg_srand48(long seed); +#ifndef HAVE_FLS +extern int fls(int mask); +#endif + #ifndef HAVE_FSEEKO #define fseeko(a, b, c) fseek(a, b, c) #define ftello(a) ftell(a) diff --git a/src/port/fls.c b/src/port/fls.c new file mode 100644 index 00000000000..6badc865c8e --- /dev/null +++ b/src/port/fls.c @@ -0,0 +1,64 @@ +/*------------------------------------------------------------------------- + * + * fls.c + * finds the last (most significant) bit that is set + * + * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group + * + * + * IDENTIFICATION + * src/port/fls.c + * + * This file was taken from FreeBSD to provide an implementation of fls() + * for platforms that lack it. Note that the operating system's version may + * be substantially more efficient thatn ours, since some platforms have an + * assembly instruction that does exactly this. + * + * The FreeBSD copyright terms follow. + */ + +/*- + * Copyright (c) 1990, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include "c.h" + +/* + * Find Last Set bit + */ +int +fls(int mask) +{ + int bit; + + if (mask == 0) + return (0); + for (bit = 1; mask != 1; bit++) + mask = (unsigned int)mask >> 1; + return (bit); +} |