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/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% SSSSS IIIII GGGG N N AAA TTTTT U U RRRR EEEEE %
% SS I G NN N A A T U U R R E %
% SSS I G GG N N N AAAAA T U U RRRR EEE %
% SS I G G N NN A A T U U R R E %
% SSSSS IIIII GGG N N A A T UUU R R EEEEE %
% %
% %
% Compute a Digital Signature for a Image Colormap %
% %
% %
% %
% Software Design %
% John Cristy %
% December 1992 %
% %
% Copyright 1994 E. I. du Pont de Nemours and Company %
% %
% Permission to use, copy, modify, distribute, and sell this software and %
% its documentation for any purpose is hereby granted without fee, %
% provided that the above Copyright notice appear in all copies and that %
% both that Copyright notice and this permission notice appear in %
% supporting documentation, and that the name of E. I. du Pont de Nemours %
% and Company not be used in advertising or publicity pertaining to %
% distribution of the software without specific, written prior %
% permission. E. I. du Pont de Nemours and Company makes no representations %
% about the suitability of this software for any purpose. It is provided %
% "as is" without express or implied warranty. %
% %
% E. I. du Pont de Nemours and Company disclaims all warranties with regard %
% to this software, including all implied warranties of merchantability %
% and fitness, in no event shall E. I. du Pont de Nemours and Company be %
% liable for any special, indirect or consequential damages or any %
% damages whatsoever resulting from loss of use, data or profits, whether %
% in an action of contract, negligence or other tortuous action, arising %
% out of or in connection with the use or performance of this software. %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Routine ColormapSignature computes a digital signature from the image
% colormap. This signature uniquely identifies the colormap and is convenient
% for determining if the colormap of a sequence of images is identical when
% animating. The digital signature is from RSA Data Security MD5 Digest
% Algorithm described in Internet draft [MD5], July 1992.
%
%
*/
/*
Include declarations.
*/
#include "combine.h"
#include "defines.h"
/*
Typedef declarations.
*/
typedef struct _MessageDigest
{
unsigned long
number_bits[2],
accumulator[4];
unsigned char
message[64],
digest[16];
} MessageDigest;
/*
Forward declarations.
*/
static void
TransformMessageDigest _FD((MessageDigest *,unsigned long *)),
UpdateMessageDigest _FD((MessageDigest *,unsigned char *,unsigned long));
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
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% C o m p u t e M e s s a g e D i g e s t %
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Function ComputeMessageDigest computes the message digest.
%
% The format of the ComputeMessageDigest routine is:
%
% ComputeMessageDigest(message_digest,input_message,message_length)
%
% A description of each parameter follows:
%
% o message_digest: The address of a structure of type MessageDigest.
%
%
*/
static void ComputeMessageDigest(message_digest)
MessageDigest
*message_digest;
{
int
number_bytes;
register unsigned char
*p;
register unsigned int
i;
unsigned char
padding[64];
unsigned long
message[16],
padding_length;
/*
Save number of bits.
*/
message[14]=message_digest->number_bits[0];
message[15]=message_digest->number_bits[1];
/*
Compute number of bytes mod 64.
*/
number_bytes=(int) ((message_digest->number_bits[0] >> 3) & 0x3F);
/*
Pad message to 56 mod 64.
*/
padding_length=(number_bytes < 56) ? (56-number_bytes) : (120-number_bytes);
padding[0]=0x80;
for (i=1; i < padding_length; i++)
padding[i]=(char) 0;
UpdateMessageDigest(message_digest,padding,padding_length);
/*
Append length in bits and transform.
*/
p=message_digest->message;
for (i=0; i < 14; i++)
{
message[i]=(unsigned long) (*p++);
message[i]|=((unsigned long) (*p++)) << 8;
message[i]|=((unsigned long) (*p++)) << 16;
message[i]|=((unsigned long) (*p++)) << 24;
}
TransformMessageDigest(message_digest,message);
/*
Store message in digest.
*/
p=message_digest->digest;
for (i=0; i < 4; i++)
{
*p++=(unsigned char) (message_digest->accumulator[i] & 0xff);
*p++=(unsigned char) ((message_digest->accumulator[i] >> 8) & 0xff);
*p++=(unsigned char) ((message_digest->accumulator[i] >> 16) & 0xff);
*p++=(unsigned char) ((message_digest->accumulator[i] >> 24) & 0xff);
}
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
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% %
% I n i t i a l i z e M e s s a g e D i g e s t %
% %
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% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Function InitializeMessageDigest initializes the message digest structure.
%
% The format of the InitializeMessageDigest routine is:
%
% InitializeMessageDigest(message_digest)
%
% A description of each parameter follows:
%
% o message_digest: The address of a structure of type MessageDigest.
%
%
*/
static void InitializeMessageDigest(message_digest)
MessageDigest
*message_digest;
{
message_digest->number_bits[0]=(unsigned long) 0;
message_digest->number_bits[1]=(unsigned long) 0;
/*
Load magic initialization constants.
*/
message_digest->accumulator[0]=(unsigned long) 0x67452301;
message_digest->accumulator[1]=(unsigned long) 0xefcdab89;
message_digest->accumulator[2]=(unsigned long) 0x98badcfe;
message_digest->accumulator[3]=(unsigned long) 0x10325476;
}
/*
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% T r a n s f o r m M e s s a g e D i g e s t %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Function TransformMessageDigest updates the message digest.
%
% The format of the TransformMessageDigest routine is:
%
% TransformMessageDigest(message_digest,message)
%
% A description of each parameter follows:
%
% o message_digest: The address of a structure of type MessageDigest.
%
%
*/
static void TransformMessageDigest(message_digest,message)
MessageDigest
*message_digest;
unsigned long
*message;
{
#define F(x,y,z) (((x) & (y)) | ((~x) & (z)))
#define G(x,y,z) (((x) & (z)) | ((y) & (~z)))
#define H(x,y,z) ((x) ^ (y) ^ (z))
#define I(x,y,z) ((y) ^ ((x) | (~z)))
#define RotateLeft(x,n) (((x) << (n)) | (((x) & 0xffffffff) >> (32-(n))))
static unsigned long
additive_constant[64]= /* 4294967296*abs(sin(i)), i in radians */
{
0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf,
0x4787c62a, 0xa8304613, 0xfd469501, 0x698098d8, 0x8b44f7af,
0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193, 0xa679438e,
0x49b40821, 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
0xd62f105d, 0x2441453, 0xd8a1e681, 0xe7d3fbc8, 0x21e1cde6,
0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8,
0x676f02d9, 0x8d2a4c8a, 0xfffa3942, 0x8771f681, 0x6d9d6122,
0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x4881d05, 0xd9d4d039,
0xe6db99e5, 0x1fa27cf8, 0xc4ac5665, 0xf4292244, 0x432aff97,
0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92, 0xffeff47d,
0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391,
};
register int
i;
register unsigned int
j;
register unsigned long
a,
b,
c,
d,
*p;
/*
Save accumulator.
*/
a=message_digest->accumulator[0];
b=message_digest->accumulator[1];
c=message_digest->accumulator[2];
d=message_digest->accumulator[3];
/*
a=b+((a+F(b,c,d)+X[k]+t) <<< s).
*/
p=additive_constant;
j=0;
for (i=0; i < 4; i++)
{
a+=F(b,c,d)+message[j & 0x0f]+(*p++);
a=RotateLeft(a,7)+b;
j++;
d+=F(a,b,c)+message[j & 0x0f]+(*p++);
d=RotateLeft(d,12)+a;
j++;
c+=F(d,a,b)+message[j & 0x0f]+(*p++);
c=RotateLeft(c,17)+d;
j++;
b+=F(c,d,a)+message[j & 0x0f]+(*p++);
b=RotateLeft(b,22)+c;
j++;
}
/*
a=b+((a+G(b,c,d)+X[k]+t) <<< s).
*/
j=1;
for (i=0; i < 4; i++)
{
a+=G(b,c,d)+message[j & 0x0f]+(*p++);
a=RotateLeft(a,5)+b;
j+=5;
d+=G(a,b,c)+message[j & 0x0f]+(*p++);
d=RotateLeft(d,9)+a;
j+=5;
c+=G(d,a,b)+message[j & 0x0f]+(*p++);
c=RotateLeft(c,14)+d;
j+=5;
b+=G(c,d,a)+message[j & 0x0f]+(*p++);
b=RotateLeft(b,20)+c;
j+=5;
}
/*
a=b+((a+H(b,c,d)+X[k]+t) <<< s).
*/
j=5;
for (i=0; i < 4; i++)
{
a+=H(b,c,d)+message[j & 0x0f]+(*p++);
a=RotateLeft(a,4)+b;
j+=3;
d+=H(a,b,c)+message[j & 0x0f]+(*p++);
d=RotateLeft(d,11)+a;
j+=3;
c+=H(d,a,b)+message[j & 0x0f]+(*p++);
c=RotateLeft(c,16)+d;
j+=3;
b+=H(c,d,a)+message[j & 0x0f]+(*p++);
b=RotateLeft(b,23)+c;
j+=3;
}
/*
a=b+((a+I(b,c,d)+X[k]+t) <<< s).
*/
j=0;
for (i=0; i < 4; i++)
{
a+=I(b,c,d)+message[j & 0x0f]+(*p++);
a=RotateLeft(a,6)+b;
j+=7;
d+=I(a,b,c)+message[j & 0x0f]+(*p++);
d=RotateLeft(d,10)+a;
j+=7;
c+=I(d,a,b)+message[j & 0x0f]+(*p++);
c=RotateLeft(c,15)+d;
j+=7;
b+=I(c,d,a)+message[j & 0x0f]+(*p++);
b=RotateLeft(b,21)+c;
j+=7;
}
/*
Increment accumulator.
*/
message_digest->accumulator[0]+=a;
message_digest->accumulator[1]+=b;
message_digest->accumulator[2]+=c;
message_digest->accumulator[3]+=d;
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% U p d a t e M e s s a g e D i g e s t %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Function UpdateMessageDigest updates the message digest.
%
% The format of the UpdateMessageDigest routine is:
%
% UpdateMessageDigest(message_digest,input_message,message_length)
%
% A description of each parameter follows:
%
% o message_digest: The address of a structure of type MessageDigest.
%
%
*/
static void UpdateMessageDigest(message_digest,input_message,message_length)
MessageDigest
*message_digest;
unsigned char
*input_message;
unsigned long
message_length;
{
int
number_bytes;
register unsigned char
*p;
register unsigned int
i;
unsigned long
message[16];
/*
Compute number of bytes mod 64.
*/
number_bytes=(int) ((message_digest->number_bits[0] >> 3) & 0x3F);
/*
Update number of bits.
*/
if (((message_digest->number_bits[0]+(message_length << 3)) & 0xffffffff) <
message_digest->number_bits[0])
message_digest->number_bits[1]++;
message_digest->number_bits[0]+=message_length << 3;
message_digest->number_bits[1]+=message_length >> 29;
while (message_length--)
{
/*
Add new character to message.
*/
message_digest->message[number_bytes++]=(*input_message++);
if (number_bytes == 0x40)
{
/*
Transform message digest 64 bytes at a time.
*/
p=message_digest->message;
for (i=0; i < 16; i++)
{
message[i]=(unsigned long) (*p++);
message[i]|=((unsigned long) (*p++)) << 8;
message[i]|=((unsigned long) (*p++)) << 16;
message[i]|=((unsigned long) (*p++)) << 24;
}
TransformMessageDigest(message_digest,message);
number_bytes=0;
}
}
}
/*
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% %
% %
% %
% C o l o r m a p S i g n a t u r e %
% %
% %
% %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
% Fucntion ColormapSignature computes a digital signature from the image
% colormap. This signature uniquely identifies the colormap and is convenient
% for determining if the colormap of a sequence of images is identical when
% animating. The digital signature is from RSA Data Security MD5 Digest
% Algorithm described in Internet draft [MD5], July 1992.
%
% The format of the ColormapSignature routine is:
%
% ColormapSignature(image)
%
% A description of each parameter follows:
%
% o image: The address of a structure of type Image.
%
%
%
*/
void ColormapSignature(image)
Image
*image;
{
char
*hex;
MessageDigest
message_digest;
register int
i;
register unsigned char
*p;
unsigned char
*colormap;
if (image->class != PseudoClass)
return;
/*
Allocate colormap.
*/
colormap=(unsigned char *) malloc(3*image->colors*sizeof(unsigned char));
if (colormap == (unsigned char *) NULL)
{
(void) fprintf (stderr,
"Unable to compute colormap signature, Memory allocation failed\n");
return;
}
p=colormap;
for (i=0; i < image->colors; i++)
{
*p++=image->colormap[i].red;
*p++=image->colormap[i].green;
*p++=image->colormap[i].blue;
}
/*
Compute program colormap signature.
*/
InitializeMessageDigest(&message_digest);
UpdateMessageDigest(&message_digest,colormap,
(unsigned long) (image->colors*3));
ComputeMessageDigest(&message_digest);
(void) free((char *) colormap);
/*
Allocate memory for signature.
*/
if (image->signature != (char *) NULL)
(void) free((char *) image->signature);
image->signature=(char *) malloc(33*sizeof(char));
if (image->signature == (char *) NULL)
{
(void) fprintf (stderr,
"Unable to compute colormap signature, Memory allocation failed\n");
return;
}
/*
Convert digital signature to a 32 character hex string.
*/
p=(unsigned char *) image->signature;
hex="0123456789abcdef";
for (i=0; i < 16; i++)
{
*p++=hex[(message_digest.digest[i] >> 4) & 0xf];
*p++=hex[message_digest.digest[i] & 0xf];
}
*p='\0';
}
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