Mercurial > hg > xemacs-beta
view src/dynarr.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
/* Simple 'n' stupid dynamic-array module. Copyright (C) 1993 Sun Microsystems, Inc. This file is part of XEmacs. XEmacs 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. XEmacs 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. */ /* Synched up with: Not in FSF. */ /* Written by Ben Wing, December 1993. */ /* A "dynamic array" is a contiguous array of fixed-size elements where there is no upper limit (except available memory) on the number of elements in the array. Because the elements are maintained contiguously, space is used efficiently (no per-element pointers necessary) and random access to a particular element is in constant time. At any one point, the block of memory that holds the array has an upper limit; if this limit is exceeded, the memory is realloc()ed into a new array that is twice as big. Assuming that the time to grow the array is on the order of the new size of the array block, this scheme has a provably constant amortized time (i.e. average time over all additions). When you add elements or retrieve elements, pointers are used. Note that the element itself (of whatever size it is), and not the pointer to it, is stored in the array; thus you do not have to allocate any heap memory on your own. Also, returned pointers are only guaranteed to be valid until the next operation that changes the length of the array. This is a container object. Declare a dynamic array of a specific type as follows: typedef struct { Dynarr_declare (mytype); } mytype_dynarr; Use the following functions/macros: void *Dynarr_new(type) [MACRO] Create a new dynamic-array object, with each element of the specified type. The return value is cast to (type##_dynarr). This requires following the convention that types are declared in such a way that this type concatenation works. In particular, TYPE must be a symbol, not an arbitrary C type. Dynarr_add(d, el) [MACRO] Add an element to the end of a dynamic array. EL is a pointer to the element; the element itself is stored in the array, however. No function call is performed unless the array needs to be resized. Dynarr_add_many(d, base, len) [MACRO] Add LEN elements to the end of the dynamic array. The elements should be contiguous in memory, starting at BASE. Dynarr_insert_many_at_start(d, base, len) [MACRO] Append LEN elements to the beginning of the dynamic array. The elements should be contiguous in memory, starting at BASE. Dynarr_insert_many(d, base, len, start) Insert LEN elements to the dynamic array starting at position START. The elements should be contiguous in memory, starting at BASE. int Dynarr_length(d) [MACRO] Return the number of elements currently in a dynamic array. int Dynarr_largest(d) [MACRO] Return the maximum value that Dynarr_length(d) would ever have returned. type Dynarr_at(d, i) [MACRO] Return the element at the specified index (no bounds checking done on the index). The element itself is returned, not a pointer to it. type *Dynarr_atp(d, i) [MACRO] Return a pointer to the element at the specified index (no bounds checking done on the index). The pointer may not be valid after an element is added to or removed from the array. Dynarr_reset(d) [MACRO] Reset the length of a dynamic array to 0. Dynarr_free(d) Destroy a dynamic array and the memory allocated to it. Use the following global variable: Dynarr_min_size Minimum allowable size for a dynamic array when it is resized. */ #include <config.h> #include "lisp.h" static int Dynarr_min_size = 8; static void Dynarr_realloc (Dynarr *dy, int new_size) { if (DUMPEDP (dy->base)) { void *new_base = malloc (new_size); memcpy (new_base, dy->base, dy->max > new_size ? new_size : dy->max); dy->base = new_base; } else dy->base = xrealloc (dy->base, new_size); } void * Dynarr_newf (int elsize) { Dynarr *d = xnew_and_zero (Dynarr); d->elsize = elsize; return d; } void Dynarr_resize (void *d, int size) { int newsize; double multiplier; Dynarr *dy = (Dynarr *) d; if (dy->max <= 8) multiplier = 2; else multiplier = 1.5; for (newsize = dy->max; newsize < size;) newsize = max (Dynarr_min_size, (int) (multiplier * newsize)); /* Don't do anything if the array is already big enough. */ if (newsize > dy->max) { Dynarr_realloc (dy, newsize*dy->elsize); dy->max = newsize; } } /* Add a number of contiguous elements to the array starting at START. */ void Dynarr_insert_many (void *d, const void *el, int len, int start) { Dynarr *dy = (Dynarr *) d; Dynarr_resize (dy, dy->cur+len); /* Silently adjust start to be valid. */ if (start > dy->cur) start = dy->cur; else if (start < 0) start = 0; if (start != dy->cur) { memmove ((char *) dy->base + (start + len)*dy->elsize, (char *) dy->base + start*dy->elsize, (dy->cur - start)*dy->elsize); } memcpy ((char *) dy->base + start*dy->elsize, el, len*dy->elsize); dy->cur += len; if (dy->cur > dy->largest) dy->largest = dy->cur; } void Dynarr_delete_many (void *d, int start, int len) { Dynarr *dy = (Dynarr *) d; assert (start >= 0 && len >= 0 && start + len <= dy->cur); memmove ((char *) dy->base + start*dy->elsize, (char *) dy->base + (start + len)*dy->elsize, (dy->cur - start - len)*dy->elsize); dy->cur -= len; } void Dynarr_free (void *d) { Dynarr *dy = (Dynarr *) d; if (dy->base && !DUMPEDP (dy->base)) xfree (dy->base); if(!DUMPEDP (dy)) xfree (dy); } #ifdef MEMORY_USAGE_STATS /* Return memory usage for Dynarr D. The returned value is the total amount of bytes actually being used for the Dynarr, including all overhead. The extra amount of space in the Dynarr that is allocated beyond what was requested is returned in DYNARR_OVERHEAD in STATS. The extra amount of space that malloc() allocates beyond what was requested of it is returned in MALLOC_OVERHEAD in STATS. See the comment above the definition of this structure. */ Bytecount Dynarr_memory_usage (void *d, struct overhead_stats *stats) { Bytecount total = 0; Dynarr *dy = (Dynarr *) d; /* We have to be a bit tricky here because not all of the memory that malloc() will claim as "requested" was actually requested. */ if (dy->base) { Bytecount malloc_used = malloced_storage_size (dy->base, dy->elsize * dy->max, 0); /* #### This may or may not be correct. Some Dynarrs would prefer that we use dy->cur instead of dy->largest here. */ int was_requested = dy->elsize * dy->largest; int dynarr_overhead = dy->elsize * (dy->max - dy->largest); total += malloc_used; stats->was_requested += was_requested; stats->dynarr_overhead += dynarr_overhead; /* And the remainder must be malloc overhead. */ stats->malloc_overhead += malloc_used - was_requested - dynarr_overhead; } total += malloced_storage_size (d, sizeof (*dy), stats); return total; } #endif /* MEMORY_USAGE_STATS */