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- Cleaner math

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git-svn-id: file:///svn/phpbb/trunk@5903 89ea8834-ac86-4346-8a33-228a782c2dd0
This commit is contained in:
David M 2006-05-12 22:02:07 +00:00
parent a8d99f2228
commit 08e708f76b
1 changed files with 7 additions and 12 deletions
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19
phpBB/includes/captcha/captcha_non_gd.php
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@ -139,12 +139,9 @@ class captcha
*/ */
function png_chunk($length, $type, $data) function png_chunk($length, $type, $data)
{ {
$raw = $type; $raw = $type . $data;
$raw .= $data;
$crc = crc32($raw);
$raw .= pack('C4', ($crc >> 24) & 255, ($crc >> 16) & 255, ($crc >> 8) & 255, $crc & 255);
return pack('C4', ($length >> 24) & 255, ($length >> 16) & 255, ($length >> 8) & 255, $length & 255) . $raw; return pack('N', $length) . $raw . pack('N', crc32($raw));
} }
/** /**
@ -159,8 +156,7 @@ class captcha
$image = pack('C8', 137, 80, 78, 71, 13, 10, 26, 10); $image = pack('C8', 137, 80, 78, 71, 13, 10, 26, 10);
// IHDR // IHDR
$raw = pack('C4', ($width >> 24) & 255, ($width >> 16) & 255, ($width >> 8) & 255, $width & 255); $raw = pack('N2', $width, $height);
$raw .= pack('C4', ($height >> 24) & 255, ($height >> 16) & 255, ($height >> 8) & 255, $height & 255);
$raw .= pack('C5', 8, 0, 0, 0, 0); $raw .= pack('C5', 8, 0, 0, 0, 0);
$image .= $this->png_chunk(13, 'IHDR', $raw); $image .= $this->png_chunk(13, 'IHDR', $raw);
@ -180,11 +176,11 @@ class captcha
if (@extension_loaded('hash')) if (@extension_loaded('hash'))
{ {
$adler_hash = hash('adler32', $raw_image, true); $adler_hash = strrev(hash('adler32', $raw_image, true));
} }
else if (@extension_loaded('mhash')) else if (@extension_loaded('mhash'))
{ {
$adler_hash = mhash(MHASH_ADLER32, $raw_image); $adler_hash = strrev(mhash(MHASH_ADLER32, $raw_image));
} }
else else
{ {
@ -212,12 +208,11 @@ class captcha
$s1 %= 65521; $s1 %= 65521;
$s2 %= 65521; $s2 %= 65521;
} }
$adler = ($s2 << 16) | $s1; $adler_hash = pack('N', ($s2 << 16) | $s1);
$adler_hash = pack('C4', $adler & 255, ($adler >> 8) & 255, ($adler >> 16) & 255, ($adler >> 24) & 255);
} }
// This is the same thing as gzcompress($raw_image, 0) but does not need zlib // This is the same thing as gzcompress($raw_image, 0) but does not need zlib
$raw_image = pack('C7', 0x78, 0x01, 0x01, $length, ($length >> 8) & 255, ~$length & 255, ~($length >> 8)) . $raw_image . strrev($adler_hash); $raw_image = pack('C3v2', 0x78, 0x01, 0x01, $length, ~$length) . $raw_image . $adler_hash;
// The Zlib header + Adler hash make us add on 11 // The Zlib header + Adler hash make us add on 11
$length += 11; $length += 11;