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mpv/libvo/md5sum.c
ivo a91f764096 New MD5 sum video output driver. For every frame, it calculates the MD5 sum 
and writes a list of those sums to an, optionally specified, output file.
It does not rely on external programs to be installed. The MD5 sum code is
borrowed from the uCIFS library, written by Christopher R. Hertel in 2004
and released under the LGPL license.

Note: This driver is not yet activated and will not be compiled and linked
to libvo. A separate patch will take care of that. This is just for adding
the files to the repository.


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@13396 b3059339-0415-0410-9bf9-f77b7e298cf2
2004-09-20 01:01:08 +00:00

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/* ========================================================================== **
*
* MD5.c
*
* Copyright:
* Copyright (C) 2003, 2004 by Christopher R. Hertel
*
* Email: crh@ubiqx.mn.org
*
* $Id$
*
* -------------------------------------------------------------------------- **
*
* Description:
* Implements the MD5 hash algorithm, as described in RFC 1321.
*
* -------------------------------------------------------------------------- **
*
* License:
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* -------------------------------------------------------------------------- **
*
* Notes:
*
* None of this will make any sense unless you're studying RFC 1321 as you
* read the code.
*
* MD5 is described in RFC 1321.
* The MD*4* algorithm is described in RFC 1320 (that's 1321 - 1).
* MD5 is very similar to MD4, but not quite similar enough to justify
* putting the two into a single module. Besides, I wanted to add a few
* extra functions to this one to expand its usability.
*
* There are three primary motivations for this particular implementation.
* 1) Programmer's pride. I wanted to be able to say I'd done it, and I
* wanted to learn from the experience.
* 2) Portability. I wanted an implementation that I knew to be portable
* to a reasonable number platforms. In particular, the algorithm is
* designed with little-endian platforms in mind, but I wanted an
* endian-agnostic implementation.
* 3) Compactness. While not an overriding goal, I thought it worth-while
* to see if I could reduce the overall size of the result. This is in
* keeping with my hopes that this library will be suitable for use in
* some embedded environments.
* Beyond that, cleanliness and clarity are always worth pursuing.
*
* As mentioned above, the code really only makes sense if you are familiar
* with the MD5 algorithm or are using RFC 1321 as a guide. This code is
* quirky, however, so you'll want to be reading carefully.
*
* Yeah...most of the comments are cut-and-paste from my MD4 implementation.
*
* -------------------------------------------------------------------------- **
*
* References:
* IETF RFC 1321: The MD5 Message-Digest Algorithm
* Ron Rivest. IETF, April, 1992
*
* ========================================================================== **
*/
/* #include "MD5.h" Line of original code */
#include "md5sum.h" /* Added this line */
/* -------------------------------------------------------------------------- **
* Static Constants:
*
* K[][] - In round one, the values of k (which are used to index
* particular four-byte sequences in the input) are simply
* sequential. In later rounds, however, they are a bit more
* varied. Rather than calculate the values of k (which may
* or may not be possible--I haven't though about it) the
* values are stored in this array.
*
* S[][] - In each round there is a left rotate operation performed as
* part of the 16 permutations. The number of bits varies in
* a repeating patter. This array keeps track of the patterns
* used in each round.
*
* T[][] - There are four rounds of 16 permutations for a total of 64.
* In each of these 64 permutation operations, a different
* constant value is added to the mix. The constants are
* based on the sine function...read RFC 1321 for more detail.
* In any case, the correct constants are stored in the T[][]
* array. They're divided up into four groups of 16.
*/
static const uint8_t K[3][16] =
{
/* Round 1: skipped (since it is simply sequential). */
{ 1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12 }, /* R2 */
{ 5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2 }, /* R3 */
{ 0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9 } /* R4 */
};
static const uint8_t S[4][4] =
{
{ 7, 12, 17, 22 }, /* Round 1 */
{ 5, 9, 14, 20 }, /* Round 2 */
{ 4, 11, 16, 23 }, /* Round 3 */
{ 6, 10, 15, 21 } /* Round 4 */
};
static const uint32_t T[4][16] =
{
{ 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, /* Round 1 */
0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821 },
{ 0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa, /* Round 2 */
0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a },
{ 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c, /* Round 3 */
0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05,
0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665 },
{ 0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, /* Round 4 */
0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391 },
};
/* -------------------------------------------------------------------------- **
* Macros:
* md5F(), md5G(), md5H(), and md5I() are described in RFC 1321.
* All of these operations are bitwise, and so not impacted by endian-ness.
*
* GetLongByte()
* Extract one byte from a (32-bit) longword. A value of 0 for <idx>
* indicates the lowest order byte, while 3 indicates the highest order
* byte.
*
*/
#define md5F( X, Y, Z ) ( ((X) & (Y)) | ((~(X)) & (Z)) )
#define md5G( X, Y, Z ) ( ((X) & (Z)) | ((Y) & (~(Z))) )
#define md5H( X, Y, Z ) ( (X) ^ (Y) ^ (Z) )
#define md5I( X, Y, Z ) ( (Y) ^ ((X) | (~(Z))) )
#define GetLongByte( L, idx ) ((uchar)(( L >> (((idx) & 0x03) << 3) ) & 0xFF))
/* -------------------------------------------------------------------------- **
* Static Functions:
*/
static void Permute( uint32_t ABCD[4], const uchar block[64] )
/* ------------------------------------------------------------------------ **
* Permute the ABCD "registers" using the 64-byte <block> as a driver.
*
* Input: ABCD - Pointer to an array of four unsigned longwords.
* block - An array of bytes, 64 bytes in size.
*
* Output: none.
*
* Notes: The MD5 algorithm operates on a set of four longwords stored
* (conceptually) in four "registers". It is easy to imagine a
* simple MD4/5 chip that would operate this way. In any case,
* the mangling of the contents of those registers is driven by
* the input message. The message is chopped and finally padded
* into 64-byte chunks and each chunk is used to manipulate the
* contents of the registers.
*
* The MD5 Algorithm calls for padding the input to ensure that
* it is a multiple of 64 bytes in length. The last 16 bytes
* of the padding space are used to store the message length
* (the length of the original message, before padding, expressed
* in terms of bits). If there is not enough room for 16 bytes
* worth of bitcount (eg., if the original message was 122 bytes
* long) then the block is padded to the end with zeros and
* passed to this function. Then *another* block is filled with
* zeros except for the last 16 bytes which contain the length.
*
* Oh... and the algorithm requires that there be at least one
* padding byte. The first padding byte has a value of 0x80,
* and any others are 0x00.
*
* ------------------------------------------------------------------------ **
*/
{
int round;
int i, j;
uint8_t s;
uint32_t a, b, c, d;
uint32_t KeepABCD[4];
uint32_t X[16];
/* Store the current ABCD values for later re-use.
*/
for( i = 0; i < 4; i++ )
KeepABCD[i] = ABCD[i];
/* Convert the input block into an array of unsigned longs, taking care
* to read the block in Little Endian order (the algorithm assumes this).
* The uint32_t values are then handled in host order.
*/
for( i = 0, j = 0; i < 16; i++ )
{
X[i] = (uint32_t)block[j++];
X[i] |= ((uint32_t)block[j++] << 8);
X[i] |= ((uint32_t)block[j++] << 16);
X[i] |= ((uint32_t)block[j++] << 24);
}
/* This loop performs the four rounds of permutations.
* The rounds are each very similar. The differences are in three areas:
* - The function (F, G, H, or I) used to perform bitwise permutations
* on the registers,
* - The order in which values from X[] are chosen.
* - Changes to the number of bits by which the registers are rotated.
* This implementation uses a switch statement to deal with some of the
* differences between rounds. Other differences are handled by storing
* values in arrays and using the round number to select the correct set
* of values.
*
* (My implementation appears to be a poor compromise between speed, size,
* and clarity. Ugh. [crh])
*/
for( round = 0; round < 4; round++ )
{
for( i = 0; i < 16; i++ )
{
j = (4 - (i % 4)) & 0x3; /* <j> handles the rotation of ABCD. */
s = S[round][i%4]; /* <s> is the bit shift for this iteration. */
b = ABCD[(j+1) & 0x3]; /* Copy the b,c,d values per ABCD rotation. */
c = ABCD[(j+2) & 0x3]; /* This isn't really necessary, it just looks */
d = ABCD[(j+3) & 0x3]; /* clean & will hopefully be optimized away. */
/* The actual perumation function.
* This is broken out to minimize the code within the switch().
*/
switch( round )
{
case 0:
/* round 1 */
a = md5F( b, c, d ) + X[i];
break;
case 1:
/* round 2 */
a = md5G( b, c, d ) + X[ K[0][i] ];
break;
case 2:
/* round 3 */
a = md5H( b, c, d ) + X[ K[1][i] ];
break;
default:
/* round 4 */
a = md5I( b, c, d ) + X[ K[2][i] ];
break;
}
a = 0xFFFFFFFF & ( ABCD[j] + a + T[round][i] );
ABCD[j] = b + (0xFFFFFFFF & (( a << s ) | ( a >> (32 - s) )));
}
}
/* Use the stored original A, B, C, D values to perform
* one last convolution.
*/
for( i = 0; i < 4; i++ )
ABCD[i] = 0xFFFFFFFF & ( ABCD[i] + KeepABCD[i] );
} /* Permute */
/* -------------------------------------------------------------------------- **
* Functions:
*/
auth_md5Ctx *auth_md5InitCtx( auth_md5Ctx *ctx )
/* ------------------------------------------------------------------------ **
* Initialize an MD5 context.
*
* Input: ctx - A pointer to the MD5 context structure to be initialized.
* Contexts are typically created thusly:
* ctx = (auth_md5Ctx *)malloc( sizeof(auth_md5Ctx) );
*
* Output: A pointer to the initialized context (same as <ctx>).
*
* Notes: The purpose of the context is to make it possible to generate
* an MD5 Message Digest in stages, rather than having to pass a
* single large block to a single MD5 function. The context
* structure keeps track of various bits of state information.
*
* Once the context is initialized, the blocks of message data
* are passed to the <auth_md5SumCtx()> function. Once the
* final bit of data has been handed to <auth_md5SumCtx()> the
* context can be closed out by calling <auth_md5CloseCtx()>,
* which also calculates the final MD5 result.
*
* Don't forget to free an allocated context structure when
* you've finished using it.
*
* See Also: <auth_md5SumCtx()>, <auth_md5CloseCtx()>
*
* ------------------------------------------------------------------------ **
*/
{
ctx->len = 0;
ctx->b_used = 0;
ctx->ABCD[0] = 0x67452301; /* The array ABCD[] contains the four 4-byte */
ctx->ABCD[1] = 0xefcdab89; /* "registers" that are manipulated to */
ctx->ABCD[2] = 0x98badcfe; /* produce the MD5 digest. The input acts */
ctx->ABCD[3] = 0x10325476; /* upon the registers, not the other way */
/* 'round. The initial values are those */
/* given in RFC 1321 (pg. 4). Note, however, that RFC 1321 */
/* provides these values as bytes, not as longwords, and the */
/* bytes are arranged in little-endian order as if they were */
/* the bytes of (little endian) 32-bit ints. That's */
/* confusing as all getout (to me, anyway). The values given */
/* here are provided as 32-bit values in C language format, */
/* so they are endian-agnostic. */
return( ctx );
} /* auth_md5InitCtx */
auth_md5Ctx *auth_md5SumCtx( auth_md5Ctx *ctx,
const uchar *src,
const int len )
/* ------------------------------------------------------------------------ **
* Build an MD5 Message Digest within the given context.
*
* Input: ctx - Pointer to the context in which the MD5 sum is being
* built.
* src - A chunk of source data. This will be used to drive
* the MD5 algorithm.
* len - The number of bytes in <src>.
*
* Output: A pointer to the updated context (same as <ctx>).
*
* See Also: <auth_md5InitCtx()>, <auth_md5CloseCtx()>, <auth_md5Sum()>
*
* ------------------------------------------------------------------------ **
*/
{
int i;
/* Add the new block's length to the total length.
*/
ctx->len += (uint32_t)len;
/* Copy the new block's data into the context block.
* Call the Permute() function whenever the context block is full.
*/
for( i = 0; i < len; i++ )
{
ctx->block[ ctx->b_used ] = src[i];
(ctx->b_used)++;
if( 64 == ctx->b_used )
{
Permute( ctx->ABCD, ctx->block );
ctx->b_used = 0;
}
}
/* Return the updated context.
*/
return( ctx );
} /* auth_md5SumCtx */
auth_md5Ctx *auth_md5CloseCtx( auth_md5Ctx *ctx, uchar *dst )
/* ------------------------------------------------------------------------ **
* Close an MD5 Message Digest context and generate the final MD5 sum.
*
* Input: ctx - Pointer to the context in which the MD5 sum is being
* built.
* dst - A pointer to at least 16 bytes of memory, which will
* receive the finished MD5 sum.
*
* Output: A pointer to the closed context (same as <ctx>).
* You might use this to free a malloc'd context structure. :)
*
* Notes: The context (<ctx>) is returned in an undefined state.
* It must be re-initialized before re-use.
*
* See Also: <auth_md5InitCtx()>, <auth_md5SumCtx()>
*
* ------------------------------------------------------------------------ **
*/
{
int i;
uint32_t l;
/* Add the required 0x80 padding initiator byte.
* The auth_md5SumCtx() function always permutes and resets the context
* block when it gets full, so we know that there must be at least one
* free byte in the context block.
*/
ctx->block[ctx->b_used] = 0x80;
(ctx->b_used)++;
/* Zero out any remaining free bytes in the context block.
*/
for( i = ctx->b_used; i < 64; i++ )
ctx->block[i] = 0;
/* We need 8 bytes to store the length field.
* If we don't have 8, call Permute() and reset the context block.
*/
if( 56 < ctx->b_used )
{
Permute( ctx->ABCD, ctx->block );
for( i = 0; i < 64; i++ )
ctx->block[i] = 0;
}
/* Add the total length and perform the final perumation.
* Note: The 60'th byte is read from the *original* <ctx->len> value
* and shifted to the correct position. This neatly avoids
* any MAXINT numeric overflow issues.
*/
l = ctx->len << 3;
for( i = 0; i < 4; i++ )
ctx->block[56+i] |= GetLongByte( l, i );
ctx->block[60] = ((GetLongByte( ctx->len, 3 ) & 0xE0) >> 5); /* See Above! */
Permute( ctx->ABCD, ctx->block );
/* Now copy the result into the output buffer and we're done.
*/
for( i = 0; i < 4; i++ )
{
dst[ 0+i] = GetLongByte( ctx->ABCD[0], i );
dst[ 4+i] = GetLongByte( ctx->ABCD[1], i );
dst[ 8+i] = GetLongByte( ctx->ABCD[2], i );
dst[12+i] = GetLongByte( ctx->ABCD[3], i );
}
/* Return the context.
* This is done for compatibility with the other auth_md5*Ctx() functions.
*/
return( ctx );
} /* auth_md5CloseCtx */
uchar *auth_md5Sum( uchar *dst, const uchar *src, const int len )
/* ------------------------------------------------------------------------ **
* Compute an MD5 message digest.
*
* Input: dst - Destination buffer into which the result will be written.
* Must be 16 bytes, minimum.
* src - Source data block to be MD5'd.
* len - The length, in bytes, of the source block.
* (Note that the length is given in bytes, not bits.)
*
* Output: A pointer to <dst>, which will contain the calculated 16-byte
* MD5 message digest.
*
* Notes: This function is a shortcut. It takes a single input block.
* For more drawn-out operations, see <auth_md5InitCtx()>.
*
* This function is interface-compatible with the
* <auth_md4Sum()> function in the MD4 module.
*
* The MD5 algorithm is designed to work on data with an
* arbitrary *bit* length. Most implementations, this one
* included, handle the input data in byte-sized chunks.
*
* The MD5 algorithm does much of its work using four-byte
* words, and so can be tuned for speed based on the endian-ness
* of the host. This implementation is intended to be
* endian-neutral, which may make it a teeny bit slower than
* others. ...maybe.
*
* See Also: <auth_md5InitCtx()>
*
* ------------------------------------------------------------------------ **
*/
{
auth_md5Ctx ctx[1];
(void)auth_md5InitCtx( ctx ); /* Open a context. */
(void)auth_md5SumCtx( ctx, src, len ); /* Pass only one block. */
(void)auth_md5CloseCtx( ctx, dst ); /* Close the context. */
return( dst ); /* Makes life easy. */
} /* auth_md5Sum */
/* ========================================================================== */
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