Mercurial > hg > xemacs-beta
view src/gmalloc.c @ 665:fdefd0186b75
[xemacs-hg @ 2001-09-20 06:28:42 by ben]
The great integral types renaming.
The purpose of this is to rationalize the names used for various
integral types, so that they match their intended uses and follow
consist conventions, and eliminate types that were not semantically
different from each other.
The conventions are:
-- All integral types that measure quantities of anything are
signed. Some people disagree vociferously with this, but their
arguments are mostly theoretical, and are vastly outweighed by
the practical headaches of mixing signed and unsigned values,
and more importantly by the far increased likelihood of
inadvertent bugs: Because of the broken "viral" nature of
unsigned quantities in C (operations involving mixed
signed/unsigned are done unsigned, when exactly the opposite is
nearly always wanted), even a single error in declaring a
quantity unsigned that should be signed, or even the even more
subtle error of comparing signed and unsigned values and
forgetting the necessary cast, can be catastrophic, as
comparisons will yield wrong results. -Wsign-compare is turned
on specifically to catch this, but this tends to result in a
great number of warnings when mixing signed and unsigned, and
the casts are annoying. More has been written on this
elsewhere.
-- All such quantity types just mentioned boil down to EMACS_INT,
which is 32 bits on 32-bit machines and 64 bits on 64-bit
machines. This is guaranteed to be the same size as Lisp
objects of type `int', and (as far as I can tell) of size_t
(unsigned!) and ssize_t. The only type below that is not an
EMACS_INT is Hashcode, which is an unsigned value of the same
size as EMACS_INT.
-- Type names should be relatively short (no more than 10
characters or so), with the first letter capitalized and no
underscores if they can at all be avoided.
-- "count" == a zero-based measurement of some quantity. Includes
sizes, offsets, and indexes.
-- "bpos" == a one-based measurement of a position in a buffer.
"Charbpos" and "Bytebpos" count text in the buffer, rather than
bytes in memory; thus Bytebpos does not directly correspond to
the memory representation. Use "Membpos" for this.
-- "Char" refers to internal-format characters, not to the C type
"char", which is really a byte.
-- For the actual name changes, see the script below.
I ran the following script to do the conversion. (NOTE: This script
is idempotent. You can safely run it multiple times and it will
not screw up previous results -- in fact, it will do nothing if
nothing has changed. Thus, it can be run repeatedly as necessary
to handle patches coming in from old workspaces, or old branches.)
There are two tags, just before and just after the change:
`pre-integral-type-rename' and `post-integral-type-rename'. When
merging code from the main trunk into a branch, the best thing to
do is first merge up to `pre-integral-type-rename', then apply the
script and associated changes, then merge from
`post-integral-type-change' to the present. (Alternatively, just do
the merging in one operation; but you may then have a lot of
conflicts needing to be resolved by hand.)
Script `fixtypes.sh' follows:
----------------------------------- cut ------------------------------------
files="*.[ch] s/*.h m/*.h config.h.in ../configure.in Makefile.in.in ../lib-src/*.[ch] ../lwlib/*.[ch]"
gr Memory_Count Bytecount $files
gr Lstream_Data_Count Bytecount $files
gr Element_Count Elemcount $files
gr Hash_Code Hashcode $files
gr extcount bytecount $files
gr bufpos charbpos $files
gr bytind bytebpos $files
gr memind membpos $files
gr bufbyte intbyte $files
gr Extcount Bytecount $files
gr Bufpos Charbpos $files
gr Bytind Bytebpos $files
gr Memind Membpos $files
gr Bufbyte Intbyte $files
gr EXTCOUNT BYTECOUNT $files
gr BUFPOS CHARBPOS $files
gr BYTIND BYTEBPOS $files
gr MEMIND MEMBPOS $files
gr BUFBYTE INTBYTE $files
gr MEMORY_COUNT BYTECOUNT $files
gr LSTREAM_DATA_COUNT BYTECOUNT $files
gr ELEMENT_COUNT ELEMCOUNT $files
gr HASH_CODE HASHCODE $files
----------------------------------- cut ------------------------------------
`fixtypes.sh' is a Bourne-shell script; it uses 'gr':
----------------------------------- cut ------------------------------------
#!/bin/sh
# Usage is like this:
# gr FROM TO FILES ...
# globally replace FROM with TO in FILES. FROM and TO are regular expressions.
# backup files are stored in the `backup' directory.
from="$1"
to="$2"
shift 2
echo ${1+"$@"} | xargs global-replace "s/$from/$to/g"
----------------------------------- cut ------------------------------------
`gr' in turn uses a Perl script to do its real work,
`global-replace', which follows:
----------------------------------- cut ------------------------------------
: #-*- Perl -*-
### global-modify --- modify the contents of a file by a Perl expression
## Copyright (C) 1999 Martin Buchholz.
## Copyright (C) 2001 Ben Wing.
## Authors: Martin Buchholz <martin@xemacs.org>, Ben Wing <ben@xemacs.org>
## Maintainer: Ben Wing <ben@xemacs.org>
## Current Version: 1.0, May 5, 2001
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with XEmacs; see the file COPYING. If not, write to the Free
# Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, USA.
eval 'exec perl -w -S $0 ${1+"$@"}'
if 0;
use strict;
use FileHandle;
use Carp;
use Getopt::Long;
use File::Basename;
(my $myName = $0) =~ s@.*/@@; my $usage="
Usage: $myName [--help] [--backup-dir=DIR] [--line-mode] [--hunk-mode]
PERLEXPR FILE ...
Globally modify a file, either line by line or in one big hunk.
Typical usage is like this:
[with GNU print, GNU xargs: guaranteed to handle spaces, quotes, etc.
in file names]
find . -name '*.[ch]' -print0 | xargs -0 $0 's/\bCONST\b/const/g'\n
[with non-GNU print, xargs]
find . -name '*.[ch]' -print | xargs $0 's/\bCONST\b/const/g'\n
The file is read in, either line by line (with --line-mode specified)
or in one big hunk (with --hunk-mode specified; it's the default), and
the Perl expression is then evalled with \$_ set to the line or hunk of
text, including the terminating newline if there is one. It should
destructively modify the value there, storing the changed result in \$_.
Files in which any modifications are made are backed up to the directory
specified using --backup-dir, or to `backup' by default. To disable this,
use --backup-dir= with no argument.
Hunk mode is the default because it is MUCH MUCH faster than line-by-line.
Use line-by-line only when it matters, e.g. you want to do a replacement
only once per line (the default without the `g' argument). Conversely,
when using hunk mode, *ALWAYS* use `g'; otherwise, you will only make one
replacement in the entire file!
";
my %options = ();
$Getopt::Long::ignorecase = 0;
&GetOptions (
\%options,
'help', 'backup-dir=s', 'line-mode', 'hunk-mode',
);
die $usage if $options{"help"} or @ARGV <= 1;
my $code = shift;
die $usage if grep (-d || ! -w, @ARGV);
sub SafeOpen {
open ((my $fh = new FileHandle), $_[0]);
confess "Can't open $_[0]: $!" if ! defined $fh;
return $fh;
}
sub SafeClose {
close $_[0] or confess "Can't close $_[0]: $!";
}
sub FileContents {
my $fh = SafeOpen ("< $_[0]");
my $olddollarslash = $/;
local $/ = undef;
my $contents = <$fh>;
$/ = $olddollarslash;
return $contents;
}
sub WriteStringToFile {
my $fh = SafeOpen ("> $_[0]");
binmode $fh;
print $fh $_[1] or confess "$_[0]: $!\n";
SafeClose $fh;
}
foreach my $file (@ARGV) {
my $changed_p = 0;
my $new_contents = "";
if ($options{"line-mode"}) {
my $fh = SafeOpen $file;
while (<$fh>) {
my $save_line = $_;
eval $code;
$changed_p = 1 if $save_line ne $_;
$new_contents .= $_;
}
} else {
my $orig_contents = $_ = FileContents $file;
eval $code;
if ($_ ne $orig_contents) {
$changed_p = 1;
$new_contents = $_;
}
}
if ($changed_p) {
my $backdir = $options{"backup-dir"};
$backdir = "backup" if !defined ($backdir);
if ($backdir) {
my ($name, $path, $suffix) = fileparse ($file, "");
my $backfulldir = $path . $backdir;
my $backfile = "$backfulldir/$name";
mkdir $backfulldir, 0755 unless -d $backfulldir;
print "modifying $file (original saved in $backfile)\n";
rename $file, $backfile;
}
WriteStringToFile ($file, $new_contents);
}
}
----------------------------------- cut ------------------------------------
In addition to those programs, I needed to fix up a few other
things, particularly relating to the duplicate definitions of
types, now that some types merged with others. Specifically:
1. in lisp.h, removed duplicate declarations of Bytecount. The
changed code should now look like this: (In each code snippet
below, the first and last lines are the same as the original, as
are all lines outside of those lines. That allows you to locate
the section to be replaced, and replace the stuff in that
section, verifying that there isn't anything new added that
would need to be kept.)
--------------------------------- snip -------------------------------------
/* Counts of bytes or chars */
typedef EMACS_INT Bytecount;
typedef EMACS_INT Charcount;
/* Counts of elements */
typedef EMACS_INT Elemcount;
/* Hash codes */
typedef unsigned long Hashcode;
/* ------------------------ dynamic arrays ------------------- */
--------------------------------- snip -------------------------------------
2. in lstream.h, removed duplicate declaration of Bytecount.
Rewrote the comment about this type. The changed code should
now look like this:
--------------------------------- snip -------------------------------------
#endif
/* The have been some arguments over the what the type should be that
specifies a count of bytes in a data block to be written out or read in,
using Lstream_read(), Lstream_write(), and related functions.
Originally it was long, which worked fine; Martin "corrected" these to
size_t and ssize_t on the grounds that this is theoretically cleaner and
is in keeping with the C standards. Unfortunately, this practice is
horribly error-prone due to design flaws in the way that mixed
signed/unsigned arithmetic happens. In fact, by doing this change,
Martin introduced a subtle but fatal error that caused the operation of
sending large mail messages to the SMTP server under Windows to fail.
By putting all values back to be signed, avoiding any signed/unsigned
mixing, the bug immediately went away. The type then in use was
Lstream_Data_Count, so that it be reverted cleanly if a vote came to
that. Now it is Bytecount.
Some earlier comments about why the type must be signed: This MUST BE
SIGNED, since it also is used in functions that return the number of
bytes actually read to or written from in an operation, and these
functions can return -1 to signal error.
Note that the standard Unix read() and write() functions define the
count going in as a size_t, which is UNSIGNED, and the count going
out as an ssize_t, which is SIGNED. This is a horrible design
flaw. Not only is it highly likely to lead to logic errors when a
-1 gets interpreted as a large positive number, but operations are
bound to fail in all sorts of horrible ways when a number in the
upper-half of the size_t range is passed in -- this number is
unrepresentable as an ssize_t, so code that checks to see how many
bytes are actually written (which is mandatory if you are dealing
with certain types of devices) will get completely screwed up.
--ben
*/
typedef enum lstream_buffering
--------------------------------- snip -------------------------------------
3. in dumper.c, there are four places, all inside of switch()
statements, where XD_BYTECOUNT appears twice as a case tag. In
each case, the two case blocks contain identical code, and you
should *REMOVE THE SECOND* and leave the first.
| author | ben |
|---|---|
| date | Thu, 20 Sep 2001 06:31:11 +0000 |
| parents | b39c14581166 |
| children | 943eaba38521 |
line wrap: on
line source
/* Synched up with: Not synched up with FSF 19.28, even though I thought I did so. */ /* Get the configuration files if we're being compiled for Emacs. */ #ifdef emacs # include <config.h> # include "getpagesize.h" # ifndef HAVE_CONFIG_H # define HAVE_CONFIG_H # endif #endif #if defined (__STDC__) && !defined (STDC_HEADERS) /* The ANSI standard says that defining __STDC__ to a non-zero value means that the compiler conforms to that standard. The standard requires certain header files and library functions to be present. Therefore, if your compiler defines __STDC__ to non-0 but does not have ANSI headers and the ANSI library routines, then your compiler is buggy. Conversely, an ANSI-conforming environment (which has both the ANSI headers and library routines, i.e., stdlib.h and `memmove') does not necessarily define the STDC_HEADERS flag. Lucid Emacs requires an ANSI compiler. Therefore, there is no need to consult the abominable STDC_HEADERS flag. -- jwz */ # define STDC_HEADERS #endif /* DO NOT EDIT THIS FILE -- it is automagically generated. -*- C -*- */ /* Bwaa-haa-haa! Not a chance that this is actually true! */ #define _MALLOC_INTERNAL /* The malloc headers and source files from the C library follow here. */ /* Declarations for `malloc' and friends. Copyright 1990, 1991, 1992, 1993 Free Software Foundation, Inc. Written May 1989 by Mike Haertel. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU General Public License along with this library; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. The author may be reached (Email) at the address mike@ai.mit.edu, or (US mail) as Mike Haertel c/o Free Software Foundation, Inc. */ #ifndef _MALLOC_H #define _MALLOC_H 1 #ifdef _MALLOC_INTERNAL #ifdef HAVE_CONFIG_H #include <config.h> #endif #include <string.h> #include <limits.h> #ifdef HAVE_UNISTD_H #include <unistd.h> #endif #endif /* _MALLOC_INTERNAL. */ #ifdef __cplusplus extern "C" { #endif #undef __P #define __P(args) args #undef __ptr_t #define __ptr_t void * #include <stddef.h> #define __malloc_size_t size_t #ifndef NULL #define NULL 0 #endif /* XEmacs: I thought this should be int under SunOS, but that apparently fails. Curses on all this shit. */ #define __free_ret_t void #undef malloc #undef realloc #undef calloc #undef free /* XEmacs: I tried commenting these out and including stdlib.h, but that fails badly. Urk! This sucks. */ /* Allocate SIZE bytes of memory. */ extern __ptr_t malloc __P ((size_t __size)); /* Re-allocate the previously allocated block in __ptr_t, making the new block SIZE bytes long. */ extern __ptr_t realloc __P ((__ptr_t __ptr, size_t __size)); /* Allocate NMEMB elements of SIZE bytes each, all initialized to 0. */ extern __ptr_t calloc __P ((size_t __nmemb, size_t __size)); /* Free a block allocated by `malloc', `realloc' or `calloc'. */ extern __free_ret_t free __P ((__ptr_t __ptr)); /* Allocate SIZE bytes allocated to ALIGNMENT bytes. */ extern __ptr_t memalign __P ((size_t __alignment, size_t __size)); /* Allocate SIZE bytes on a page boundary. */ extern __ptr_t valloc __P ((size_t __size)); #ifdef _MALLOC_INTERNAL /* The allocator divides the heap into blocks of fixed size; large requests receive one or more whole blocks, and small requests receive a fragment of a block. Fragment sizes are powers of two, and all fragments of a block are the same size. When all the fragments in a block have been freed, the block itself is freed. */ #define INT_BIT (CHAR_BIT * sizeof(int)) #define BLOCKLOG (INT_BIT > 16 ? 12 : 9) #define BLOCKSIZE (1 << BLOCKLOG) #define BLOCKIFY(SIZE) (((SIZE) + BLOCKSIZE - 1) / BLOCKSIZE) /* Determine the amount of memory spanned by the initial heap table (not an absolute limit). */ #define HEAP (INT_BIT > 16 ? 4194304 : 65536) /* Number of contiguous free blocks allowed to build up at the end of memory before they will be returned to the system. */ #define FINAL_FREE_BLOCKS 8 /* Data structure giving per-block information. */ typedef union { /* Heap information for a busy block. */ struct { /* Zero for a large block, or positive giving the logarithm to the base two of the fragment size. */ int type; union { struct { __malloc_size_t nfree; /* Free frags in a fragmented block. */ __malloc_size_t first; /* First free fragment of the block. */ } frag; /* Size (in blocks) of a large cluster. */ __malloc_size_t size; } info; } busy; /* Heap information for a free block (that may be the first of a free cluster). */ struct { __malloc_size_t size; /* Size (in blocks) of a free cluster. */ __malloc_size_t next; /* Index of next free cluster. */ __malloc_size_t prev; /* Index of previous free cluster. */ } free; } malloc_info; /* Pointer to first block of the heap. */ extern char *_heapbase; /* Table indexed by block number giving per-block information. */ extern malloc_info *_heapinfo; /* Address to block number and vice versa. */ #define BLOCK(A) (((char *) (A) - _heapbase) / BLOCKSIZE + 1) #define ADDRESS(B) ((__ptr_t) (((B) - 1) * BLOCKSIZE + _heapbase)) /* Current search index for the heap table. */ extern __malloc_size_t _heapindex; /* Limit of valid info table indices. */ extern __malloc_size_t _heaplimit; /* Doubly linked lists of free fragments. */ struct list { struct list *next; struct list *prev; }; /* Free list headers for each fragment size. */ extern struct list _fraghead[]; /* List of blocks allocated with `memalign' (or `valloc'). */ struct alignlist { struct alignlist *next; __ptr_t aligned; /* The address that memaligned returned. */ __ptr_t exact; /* The address that malloc returned. */ }; extern struct alignlist *_aligned_blocks; /* Instrumentation. */ extern __malloc_size_t _chunks_used; extern __malloc_size_t _bytes_used; extern __malloc_size_t _chunks_free; extern __malloc_size_t _bytes_free; /* Internal version of `free' used in `morecore' (malloc.c). */ extern void _free_internal __P ((__ptr_t __ptr)); #endif /* _MALLOC_INTERNAL. */ /* Underlying allocation function; successive calls should return contiguous pieces of memory. */ extern __ptr_t (*__morecore) __P ((ptrdiff_t __size)); /* Default value of `__morecore'. */ extern __ptr_t __default_morecore __P ((ptrdiff_t __size)); /* If not NULL, this function is called after each time `__morecore' is called to increase the data size. */ extern void (*__after_morecore_hook) __P ((void)); /* Nonzero if `malloc' has been called and done its initialization. */ /* extern int __malloc_initialized; */ /* Hooks for debugging versions. */ extern void (*__free_hook) __P ((__ptr_t __ptr)); extern __ptr_t (*__malloc_hook) __P ((size_t __size)); extern __ptr_t (*__realloc_hook) __P ((__ptr_t __ptr, size_t __size)); /* Return values for `mprobe': these are the kinds of inconsistencies that `mcheck' enables detection of. */ enum mcheck_status { MCHECK_DISABLED = -1, /* Consistency checking is not turned on. */ MCHECK_OK, /* Block is fine. */ MCHECK_FREE, /* Block freed twice. */ MCHECK_HEAD, /* Memory before the block was clobbered. */ MCHECK_TAIL /* Memory after the block was clobbered. */ }; /* Activate a standard collection of debugging hooks. This must be called before `malloc' is ever called. ABORTFUNC is called with an error code (see enum above) when an inconsistency is detected. If ABORTFUNC is null, the standard function prints on stderr and then calls `abort'. */ extern int mcheck __P ((void (*__abortfunc) __P ((enum mcheck_status)))); /* Check for aberrations in a particular malloc'd block. You must have called `mcheck' already. These are the same checks that `mcheck' does when you free or reallocate a block. */ extern enum mcheck_status mprobe __P ((__ptr_t __ptr)); /* Activate a standard collection of tracing hooks. */ extern void mtrace __P ((void)); extern void muntrace __P ((void)); /* Statistics available to the user. */ struct mstats { __malloc_size_t bytes_total; /* Total size of the heap. */ __malloc_size_t chunks_used; /* Chunks allocated by the user. */ __malloc_size_t bytes_used; /* Byte total of user-allocated chunks. */ __malloc_size_t chunks_free; /* Chunks in the free list. */ __malloc_size_t bytes_free; /* Byte total of chunks in the free list. */ }; /* Pick up the current statistics. */ extern struct mstats mstats __P ((void)); /* Call WARNFUN with a warning message when memory usage is high. */ extern void memory_warnings __P ((__ptr_t __start, void (*__warnfun) __P ((const char *)))); #if 0 /* unused in this file, and conflicting prototypes anyway */ /* Relocating allocator. */ /* Allocate SIZE bytes, and store the address in *HANDLEPTR. */ extern __ptr_t r_alloc __P ((__ptr_t *__handleptr, size_t __size)); /* Free the storage allocated in HANDLEPTR. */ extern void r_alloc_free __P ((__ptr_t *__handleptr)); /* Adjust the block at HANDLEPTR to be SIZE bytes long. */ extern __ptr_t r_re_alloc __P ((__ptr_t *__handleptr, size_t __size)); #endif /* 0 */ #ifdef __cplusplus } #endif #endif /* malloc.h */ /* Allocate memory on a page boundary. Copyright (C) 1991, 1992, 1993, 1994 Free Software Foundation, Inc. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU General Public License along with this library; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. The author may be reached (Email) at the address mike@ai.mit.edu, or (US mail) as Mike Haertel c/o Free Software Foundation, Inc. */ #if defined (__GNU_LIBRARY__) || defined (_LIBC) #include <stddef.h> #include <sys/cdefs.h> #if ! (defined (__GLIBC__) && (__GLIBC__ >= 2)) extern size_t __getpagesize __P ((void)); #endif #else #include "getpagesize.h" #define __getpagesize() getpagesize() #endif #ifndef _MALLOC_INTERNAL #define _MALLOC_INTERNAL #include <malloc.h> #endif static __malloc_size_t pagesize; __ptr_t valloc (__malloc_size_t size) { if (pagesize == 0) pagesize = __getpagesize (); return memalign (pagesize, size); } /* Memory allocator `malloc'. Copyright 1990, 1991, 1992, 1993, 1994 Free Software Foundation Written May 1989 by Mike Haertel. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU General Public License along with this library; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. The author may be reached (Email) at the address mike@ai.mit.edu, or (US mail) as Mike Haertel c/o Free Software Foundation, Inc. */ #ifndef _MALLOC_INTERNAL #define _MALLOC_INTERNAL #include <malloc.h> #endif /* How to really get more memory. */ #if defined (HEAP_IN_DATA) && !defined(PDUMP) /* once dumped, free() & realloc() on static heap space will fail */ #define PURE_DATA(x) \ ((static_heap_dumped && (char*)x >= static_heap_base \ && (char*)x <= (static_heap_base + static_heap_size) ) ? 1 : 0) extern int initialized; extern int purify_flag; extern char* static_heap_base; extern char* static_heap_ptr; extern char* static_heap_dumped; extern unsigned long static_heap_size; extern __ptr_t more_static_core __P ((ptrdiff_t __size)); __ptr_t (*__morecore) __P ((ptrdiff_t __size)) = more_static_core; #else __ptr_t (*__morecore) __P ((ptrdiff_t __size)) = __default_morecore; #define PURE_DATA(x) 0 #endif /* Debugging hook for `malloc'. */ __ptr_t (*__malloc_hook) __P ((__malloc_size_t __size)); /* Pointer to the base of the first block. */ char *_heapbase; /* Block information table. Allocated with align/__free (not malloc/free). */ malloc_info *_heapinfo; /* Number of info entries. */ static __malloc_size_t heapsize; /* Search index in the info table. */ __malloc_size_t _heapindex; /* Limit of valid info table indices. */ __malloc_size_t _heaplimit; /* Free lists for each fragment size. */ struct list _fraghead[BLOCKLOG]; /* Instrumentation. */ __malloc_size_t _chunks_used; __malloc_size_t _bytes_used; __malloc_size_t _chunks_free; __malloc_size_t _bytes_free; /* Are you experienced? */ int __malloc_initialized; void (*__after_morecore_hook) __P ((void)); /* Aligned allocation. */ static __ptr_t align __P ((__malloc_size_t)); static __ptr_t align (__malloc_size_t size) { __ptr_t result; unsigned long int adj; result = (*__morecore) (size); adj = (unsigned long int) ((unsigned long int) ((char *) result - (char *) NULL)) % BLOCKSIZE; if (adj != 0) { adj = BLOCKSIZE - adj; (void) (*__morecore) (adj); result = (char *) result + adj; } if (__after_morecore_hook) (*__after_morecore_hook) (); return result; } /* Set everything up and remember that we have. */ static int initialize __P ((void)); static int initialize () { #if defined (HEAP_IN_DATA) && !defined(PDUMP) if (static_heap_dumped && __morecore == more_static_core) { __morecore = __default_morecore; } #endif heapsize = HEAP / BLOCKSIZE; _heapinfo = (malloc_info *) align (heapsize * sizeof (malloc_info)); if (_heapinfo == NULL) return 0; memset (_heapinfo, 0, heapsize * sizeof (malloc_info)); memset (_fraghead, 0, BLOCKLOG * sizeof (struct list)); _heapinfo[0].free.size = 0; _heapinfo[0].free.next = _heapinfo[0].free.prev = 0; _heapindex = 0; _heaplimit = 0; _heapbase = (char *) _heapinfo; /* Account for the _heapinfo block itself in the statistics. */ _bytes_used = heapsize * sizeof (malloc_info); _chunks_used = 1; _chunks_free=0; _bytes_free=0; _aligned_blocks=0; __malloc_initialized = 1; return 1; } /* Get neatly aligned memory, initializing or growing the heap info table as necessary. */ static __ptr_t morecore __P ((__malloc_size_t)); static __ptr_t morecore (__malloc_size_t size) { __ptr_t result; malloc_info *newinfo, *oldinfo; __malloc_size_t newsize; result = align (size); if (result == NULL) return NULL; /* Check if we need to grow the info table. */ if ((__malloc_size_t) BLOCK ((char *) result + size) > heapsize) { newsize = heapsize; while ((__malloc_size_t) BLOCK ((char *) result + size) > newsize) newsize *= 2; newinfo = (malloc_info *) align (newsize * sizeof (malloc_info)); if (newinfo == NULL) { (*__morecore) (-(int)size); return NULL; } memcpy (newinfo, _heapinfo, heapsize * sizeof (malloc_info)); memset (&newinfo[heapsize], 0, (newsize - heapsize) * sizeof (malloc_info)); oldinfo = _heapinfo; newinfo[BLOCK (oldinfo)].busy.type = 0; newinfo[BLOCK (oldinfo)].busy.info.size = BLOCKIFY (heapsize * sizeof (malloc_info)); _heapinfo = newinfo; /* Account for the _heapinfo block itself in the statistics. */ _bytes_used += newsize * sizeof (malloc_info); ++_chunks_used; _free_internal (oldinfo); heapsize = newsize; } _heaplimit = BLOCK ((char *) result + size); return result; } /* Allocate memory from the heap. */ __ptr_t malloc (__malloc_size_t size) { __ptr_t result; __malloc_size_t block, blocks, lastblocks, start; __malloc_size_t i; struct list *next; /* ANSI C allows `malloc (0)' to either return NULL, or to return a valid address you can realloc and free (though not dereference). It turns out that some extant code (sunrpc, at least Ultrix's version) expects `malloc (0)' to return non-NULL and breaks otherwise. Be compatible. */ #ifdef HAVE_X_WINDOWS /* there is at least one Xt bug where calloc(n,x) is blindly called where n can be 0, and yet if 0 is returned, Xt barfs */ if (size == 0) size = sizeof (struct list); #else if (size == 0) return NULL; #endif if (__malloc_hook != NULL) return (*__malloc_hook) (size); if (!__malloc_initialized) if (!initialize ()) return NULL; #ifdef SUNOS_LOCALTIME_BUG /* Workaround for localtime() allocating 8 bytes and writing 9 bug... */ if (size < 16) size = 16; #endif if (size < sizeof (struct list)) size = sizeof (struct list); /* Determine the allocation policy based on the request size. */ if (size <= BLOCKSIZE / 2) { /* Small allocation to receive a fragment of a block. Determine the logarithm to base two of the fragment size. */ __malloc_size_t log = 1; --size; while ((size /= 2) != 0) ++log; /* Look in the fragment lists for a free fragment of the desired size. */ next = _fraghead[log].next; if (next != NULL) { /* There are free fragments of this size. Pop a fragment out of the fragment list and return it. Update the block's nfree and first counters. */ result = (__ptr_t) next; next->prev->next = next->next; if (next->next != NULL) next->next->prev = next->prev; block = BLOCK (result); if (--_heapinfo[block].busy.info.frag.nfree != 0) _heapinfo[block].busy.info.frag.first = (unsigned long int) ((unsigned long int) ((char *) next->next - (char *) NULL) % BLOCKSIZE) >> log; /* Update the statistics. */ ++_chunks_used; _bytes_used += 1 << log; --_chunks_free; _bytes_free -= 1 << log; } else { /* No free fragments of the desired size, so get a new block and break it into fragments, returning the first. */ result = malloc (BLOCKSIZE); if (result == NULL) return NULL; /* Link all fragments but the first into the free list. */ for (i = 1; i < (__malloc_size_t) (BLOCKSIZE >> log); ++i) { next = (struct list *) ((char *) result + (i << log)); next->next = _fraghead[log].next; next->prev = &_fraghead[log]; next->prev->next = next; if (next->next != NULL) next->next->prev = next; } /* Initialize the nfree and first counters for this block. */ block = BLOCK (result); _heapinfo[block].busy.type = log; _heapinfo[block].busy.info.frag.nfree = i - 1; _heapinfo[block].busy.info.frag.first = i - 1; _chunks_free += (BLOCKSIZE >> log) - 1; _bytes_free += BLOCKSIZE - (1 << log); _bytes_used -= BLOCKSIZE - (1 << log); } } else { /* Large allocation to receive one or more blocks. Search the free list in a circle starting at the last place visited. If we loop completely around without finding a large enough space we will have to get more memory from the system. */ blocks = BLOCKIFY (size); start = block = _heapindex; while (_heapinfo[block].free.size < blocks) { block = _heapinfo[block].free.next; if (block == start) { /* Need to get more from the system. Check to see if the new core will be contiguous with the final free block; if so we don't need to get as much. */ block = _heapinfo[0].free.prev; lastblocks = _heapinfo[block].free.size; if (_heaplimit != 0 && block + lastblocks == _heaplimit && (*__morecore) (0) == ADDRESS (block + lastblocks) && (morecore ((blocks - lastblocks) * BLOCKSIZE)) != NULL) { /* Which block we are extending (the `final free block' referred to above) might have changed, if it got combined with a freed info table. */ block = _heapinfo[0].free.prev; _heapinfo[block].free.size += (blocks - lastblocks); _bytes_free += (blocks - lastblocks) * BLOCKSIZE; continue; } result = morecore (blocks * BLOCKSIZE); if (result == NULL) return NULL; block = BLOCK (result); _heapinfo[block].busy.type = 0; _heapinfo[block].busy.info.size = blocks; ++_chunks_used; _bytes_used += blocks * BLOCKSIZE; return result; } } /* At this point we have found a suitable free list entry. Figure out how to remove what we need from the list. */ result = ADDRESS (block); if (_heapinfo[block].free.size > blocks) { /* The block we found has a bit left over, so relink the tail end back into the free list. */ _heapinfo[block + blocks].free.size = _heapinfo[block].free.size - blocks; _heapinfo[block + blocks].free.next = _heapinfo[block].free.next; _heapinfo[block + blocks].free.prev = _heapinfo[block].free.prev; _heapinfo[_heapinfo[block].free.prev].free.next = _heapinfo[_heapinfo[block].free.next].free.prev = _heapindex = block + blocks; } else { /* The block exactly matches our requirements, so just remove it from the list. */ _heapinfo[_heapinfo[block].free.next].free.prev = _heapinfo[block].free.prev; _heapinfo[_heapinfo[block].free.prev].free.next = _heapindex = _heapinfo[block].free.next; --_chunks_free; } _heapinfo[block].busy.type = 0; _heapinfo[block].busy.info.size = blocks; ++_chunks_used; _bytes_used += blocks * BLOCKSIZE; _bytes_free -= blocks * BLOCKSIZE; } return result; } #ifndef _LIBC /* On some ANSI C systems, some libc functions call _malloc, _free and _realloc. Make them use the GNU functions. */ __ptr_t _malloc (__malloc_size_t size); __ptr_t _malloc (__malloc_size_t size) { return malloc (size); } void _free (__ptr_t ptr); void _free (__ptr_t ptr) { free (ptr); } __ptr_t _realloc (__ptr_t ptr, __malloc_size_t size); __ptr_t _realloc (__ptr_t ptr, __malloc_size_t size) { return realloc (ptr, size); } #endif /* Free a block of memory allocated by `malloc'. Copyright 1990, 1991, 1992, 1994 Free Software Foundation Written May 1989 by Mike Haertel. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU General Public License along with this library; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. The author may be reached (Email) at the address mike@ai.mit.edu, or (US mail) as Mike Haertel c/o Free Software Foundation, Inc. */ #ifndef _MALLOC_INTERNAL #define _MALLOC_INTERNAL #include <malloc.h> #endif /* Debugging hook for free. */ void (*__free_hook) __P ((__ptr_t __ptr)); /* List of blocks allocated by memalign. */ struct alignlist *_aligned_blocks = NULL; /* Return memory to the heap. Like `free' but don't call a __free_hook if there is one. */ void _free_internal (__ptr_t ptr) { int type; __malloc_size_t block, blocks; __malloc_size_t i; struct list *prev, *next; block = BLOCK (ptr); type = _heapinfo[block].busy.type; switch (type) { case 0: /* Get as many statistics as early as we can. */ --_chunks_used; _bytes_used -= _heapinfo[block].busy.info.size * BLOCKSIZE; _bytes_free += _heapinfo[block].busy.info.size * BLOCKSIZE; /* Find the free cluster previous to this one in the free list. Start searching at the last block referenced; this may benefit programs with locality of allocation. */ i = _heapindex; if (i > block) while (i > block) i = _heapinfo[i].free.prev; else { do i = _heapinfo[i].free.next; while (i > 0 && i < block); i = _heapinfo[i].free.prev; } /* Determine how to link this block into the free list. */ if (block == i + _heapinfo[i].free.size) { /* Coalesce this block with its predecessor. */ _heapinfo[i].free.size += _heapinfo[block].busy.info.size; block = i; } else { /* Really link this block back into the free list. */ _heapinfo[block].free.size = _heapinfo[block].busy.info.size; _heapinfo[block].free.next = _heapinfo[i].free.next; _heapinfo[block].free.prev = i; _heapinfo[i].free.next = block; _heapinfo[_heapinfo[block].free.next].free.prev = block; ++_chunks_free; } /* Now that the block is linked in, see if we can coalesce it with its successor (by deleting its successor from the list and adding in its size). */ if (block + _heapinfo[block].free.size == _heapinfo[block].free.next) { _heapinfo[block].free.size += _heapinfo[_heapinfo[block].free.next].free.size; _heapinfo[block].free.next = _heapinfo[_heapinfo[block].free.next].free.next; _heapinfo[_heapinfo[block].free.next].free.prev = block; --_chunks_free; } /* Now see if we can return stuff to the system. */ blocks = _heapinfo[block].free.size; if (blocks >= FINAL_FREE_BLOCKS && block + blocks == _heaplimit && (*__morecore) (0) == ADDRESS (block + blocks)) { __malloc_size_t bytes = blocks * BLOCKSIZE; _heaplimit -= blocks; (*__morecore) (-(int)bytes); _heapinfo[_heapinfo[block].free.prev].free.next = _heapinfo[block].free.next; _heapinfo[_heapinfo[block].free.next].free.prev = _heapinfo[block].free.prev; block = _heapinfo[block].free.prev; --_chunks_free; _bytes_free -= bytes; } /* Set the next search to begin at this block. */ _heapindex = block; break; default: /* Do some of the statistics. */ --_chunks_used; _bytes_used -= 1 << type; ++_chunks_free; _bytes_free += 1 << type; /* Get the address of the first free fragment in this block. */ prev = (struct list *) ((char *) ADDRESS (block) + (_heapinfo[block].busy.info.frag.first << type)); if (_heapinfo[block].busy.info.frag.nfree == (__malloc_size_t) ((BLOCKSIZE >> type) - 1)) { /* If all fragments of this block are free, remove them from the fragment list and free the whole block. */ next = prev; for (i = 1; i < (__malloc_size_t) (BLOCKSIZE >> type); ++i) next = next->next; prev->prev->next = next; if (next != NULL) next->prev = prev->prev; _heapinfo[block].busy.type = 0; _heapinfo[block].busy.info.size = 1; /* Keep the statistics accurate. */ ++_chunks_used; _bytes_used += BLOCKSIZE; _chunks_free -= BLOCKSIZE >> type; _bytes_free -= BLOCKSIZE; free (ADDRESS (block)); } else if (_heapinfo[block].busy.info.frag.nfree != 0) { /* If some fragments of this block are free, link this fragment into the fragment list after the first free fragment of this block. */ next = (struct list *) ptr; next->next = prev->next; next->prev = prev; prev->next = next; if (next->next != NULL) next->next->prev = next; ++_heapinfo[block].busy.info.frag.nfree; } else { /* No fragments of this block are free, so link this fragment into the fragment list and announce that it is the first free fragment of this block. */ prev = (struct list *) ptr; _heapinfo[block].busy.info.frag.nfree = 1; _heapinfo[block].busy.info.frag.first = (unsigned long int) ((unsigned long int) ((char *) ptr - (char *) NULL) % BLOCKSIZE >> type); prev->next = _fraghead[type].next; prev->prev = &_fraghead[type]; prev->prev->next = prev; if (prev->next != NULL) prev->next->prev = prev; } break; } } /* Return memory to the heap. */ __free_ret_t free (__ptr_t ptr) { struct alignlist *l; if (ptr == NULL) return; if (PURE_DATA(ptr)) { return; } for (l = _aligned_blocks; l != NULL; l = l->next) if (l->aligned == ptr) { l->aligned = NULL; /* Mark the slot in the list as free. */ ptr = l->exact; break; } if (__free_hook != NULL) (*__free_hook) (ptr); else _free_internal (ptr); } /* Copyright (C) 1991, 1993, 1994 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU General Public License along with this library; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifndef _MALLOC_INTERNAL #define _MALLOC_INTERNAL #include <malloc.h> #endif #ifdef _LIBC #include <ansidecl.h> #include <gnu-stabs.h> #undef cfree function_alias(cfree, free, void, (ptr), DEFUN(cfree, (ptr), PTR ptr)) #else void cfree (__ptr_t ptr); void cfree (__ptr_t ptr) { free (ptr); } #endif /* Change the size of a block allocated by `malloc'. Copyright 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc. Written May 1989 by Mike Haertel. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU General Public License along with this library; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. The author may be reached (Email) at the address mike@ai.mit.edu, or (US mail) as Mike Haertel c/o Free Software Foundation, Inc. */ #ifndef _MALLOC_INTERNAL #define _MALLOC_INTERNAL #include <malloc.h> #endif #ifndef min #define min(A, B) ((A) < (B) ? (A) : (B)) #endif /* Debugging hook for realloc. */ __ptr_t (*__realloc_hook) __P ((__ptr_t __ptr, __malloc_size_t __size)); /* Resize the given region to the new size, returning a pointer to the (possibly moved) region. This is optimized for speed; some benchmarks seem to indicate that greater compactness is achieved by unconditionally allocating and copying to a new region. This module has incestuous knowledge of the internals of both free and malloc. */ __ptr_t realloc (__ptr_t ptr, __malloc_size_t size) { __ptr_t result; int type; __malloc_size_t block, blocks, oldlimit; if (PURE_DATA (ptr)) { result = malloc (size); memcpy(result, ptr, size); return result; } else if (size == 0) { free (ptr); return malloc (0); } else if (ptr == NULL) return malloc (size); if (__realloc_hook != NULL) return (*__realloc_hook) (ptr, size); block = BLOCK (ptr); type = _heapinfo[block].busy.type; switch (type) { case 0: /* Maybe reallocate a large block to a small fragment. */ if (size <= BLOCKSIZE / 2) { result = malloc (size); if (result != NULL) { memcpy (result, ptr, size); _free_internal (ptr); return result; } } /* The new size is a large allocation as well; see if we can hold it in place. */ blocks = BLOCKIFY (size); if (blocks < _heapinfo[block].busy.info.size) { /* The new size is smaller; return excess memory to the free list. */ _heapinfo[block + blocks].busy.type = 0; _heapinfo[block + blocks].busy.info.size = _heapinfo[block].busy.info.size - blocks; _heapinfo[block].busy.info.size = blocks; /* We have just created a new chunk by splitting a chunk in two. Now we will free this chunk; increment the statistics counter so it doesn't become wrong when _free_internal decrements it. */ ++_chunks_used; _free_internal (ADDRESS (block + blocks)); result = ptr; } else if (blocks == _heapinfo[block].busy.info.size) /* No size change necessary. */ result = ptr; else { /* Won't fit, so allocate a new region that will. Free the old region first in case there is sufficient adjacent free space to grow without moving. */ blocks = _heapinfo[block].busy.info.size; /* Prevent free from actually returning memory to the system. */ oldlimit = _heaplimit; _heaplimit = 0; free (ptr); _heaplimit = oldlimit; result = malloc (size); if (result == NULL) { /* Now we're really in trouble. We have to unfree the thing we just freed. Unfortunately it might have been coalesced with its neighbors. */ if (_heapindex == block) (void) malloc (blocks * BLOCKSIZE); else { __ptr_t previous = malloc ((block - _heapindex) * BLOCKSIZE); (void) malloc (blocks * BLOCKSIZE); free (previous); } return NULL; } if (ptr != result) memmove (result, ptr, blocks * BLOCKSIZE); } break; default: /* Old size is a fragment; type is logarithm to base two of the fragment size. */ if (size > (__malloc_size_t) (1 << (type - 1)) && size <= (__malloc_size_t) (1 << type)) /* The new size is the same kind of fragment. */ result = ptr; else { /* The new size is different; allocate a new space, and copy the lesser of the new size and the old. */ result = malloc (size); if (result == NULL) return NULL; memcpy (result, ptr, min (size, (__malloc_size_t) 1 << type)); free (ptr); } break; } return result; } /* Copyright (C) 1991, 1992, 1994 Free Software Foundation, Inc. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU General Public License along with this library; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. The author may be reached (Email) at the address mike@ai.mit.edu, or (US mail) as Mike Haertel c/o Free Software Foundation, Inc. */ #ifndef _MALLOC_INTERNAL #define _MALLOC_INTERNAL #include <malloc.h> #endif /* Allocate an array of NMEMB elements each SIZE bytes long. The entire array is initialized to zeros. */ __ptr_t calloc (__malloc_size_t nmemb, __malloc_size_t size) { __ptr_t result = malloc (nmemb * size); if (result != NULL) (void) memset (result, 0, nmemb * size); return result; } /* Copyright (C) 1991, 1992, 1993, 1994 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with the GNU C Library; see the file COPYING. If not, write to the Free the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifndef _MALLOC_INTERNAL #define _MALLOC_INTERNAL #include <malloc.h> #endif /* #ifndef __GNU_LIBRARY__ */ #define __sbrk sbrk /* #endif */ #ifdef GMALLOC_NEEDS_SBRK_DECL /* some versions of OSF1 need this */ extern __ptr_t __sbrk __P ((ssize_t increment)); #else #ifdef __GNU_LIBRARY__ /* It is best not to declare this and cast its result on foreign operating systems with potentially hostile include files. */ #if !(defined(linux) && defined(sparc)) extern __ptr_t __sbrk __P ((int increment)); #endif #endif #endif #ifndef NULL #define NULL 0 #endif /* Allocate INCREMENT more bytes of data space, and return the start of data space, or NULL on errors. If INCREMENT is negative, shrink data space. */ __ptr_t __default_morecore (ptrdiff_t increment) { __ptr_t result = (__ptr_t) __sbrk (increment); if (result == (__ptr_t) -1) return NULL; return result; } /* Copyright (C) 1991, 1992, 1993, 1994 Free Software Foundation, Inc. This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU General Public License along with this library; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifndef _MALLOC_INTERNAL #define _MALLOC_INTERNAL #include <malloc.h> #endif __ptr_t memalign (__malloc_size_t alignment, __malloc_size_t size) { __ptr_t result; unsigned long int adj; size = ((size + alignment - 1) / alignment) * alignment; result = malloc (size); if (result == NULL) return NULL; adj = (unsigned long int) ((unsigned long int) ((char *) result - (char *) NULL)) % alignment; if (adj != 0) { struct alignlist *l; for (l = _aligned_blocks; l != NULL; l = l->next) if (l->aligned == NULL) /* This slot is free. Use it. */ break; if (l == NULL) { l = (struct alignlist *) malloc (sizeof (struct alignlist)); if (l == NULL) { free (result); return NULL; } l->next = _aligned_blocks; _aligned_blocks = l; } l->exact = result; result = l->aligned = (char *) result + alignment - adj; } return result; }