I've patched original crc32 PHP function to allow incremental crc32
counting.
It touches only a few lines of original code.
New crc32 function signature is
int crc32(string str [,int prev_sum])
With this patch you can generate crc32 checksum for even large files
without reading it contents to single variable.
Fe. instead of doing
| $file_string = file_get_contents($file);
$crc = crc32($file_string);
|
you can do
$crc=0;
$f =fopen($file,'r');
while ( $data=fread($f,1024)) $crc = crc32($data,$crc);
fclose($f);
Icremental processing has less memory requirements.
I'd like also change base64_* functions to allow incremental processing.
Any chances apply such changes ?
Regards,
Wojtek
Index: crc32.c
===================================================================
RCS file: /repository/php-src/ext/standard/crc32.c,v
retrieving revision 1.16
diff -u -r1.16 crc32.c
--- crc32.c 3 Aug 2005 14:07:57 -0000 1.16
+++ crc32.c 5 Sep 2005 11:02:00 -0000
@@ -1,13 +1,13 @@
/*
+----------------------------------------------------------------------+
- | PHP Version 5 |
+ | PHP Version 4 |
+----------------------------------------------------------------------+
- | Copyright (c) 1997-2005 The PHP Group |
+ | Copyright (c) 1997-2003 The PHP Group |
+----------------------------------------------------------------------+
- | This source file is subject to version 3.0 of the PHP license, |
+ | This source file is subject to version 2.02 of the PHP license, |
| that is bundled with this package in the file LICENSE, and is |
- | available through the world-wide-web at the following url: |
- | http://www.php.net/license/3_0.txt. |
+ | available at through the world-wide-web at |
+ | http://www.php.net/license/2_02.txt. |
| If you did not receive a copy of the PHP license and are unable to |
| obtain it through the world-wide-web, please send a note to |
| [EMAIL PROTECTED] so we can mail you a copy immediately. |
@@ -22,20 +22,19 @@
#include "basic_functions.h"
#include "crc32.h"
-/* {{{ proto string crc32(string str)
+/* {{{ proto int crc32(string str[,int prev_crc])
Calculate the crc32 polynomial of a string */
PHP_NAMED_FUNCTION(php_if_crc32)
{
- unsigned int crc = ~0;
+ unsigned int crc = 0;
char *p;
- int len, nr;
+ int len;
- if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &p, &nr) == FAILURE) {
+ if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s|l", &p, &len, &crc) == FAILURE) {
return;
}
-
- len = 0 ;
- for (len += nr; nr--; ++p) {
+ crc = ~crc;
+ for (; len--; ++p) {
CRC32(crc, *p);
}
RETVAL_LONG(~crc);
--
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