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author | Giorgio Vazzana <mywing81@gmail.com> | 2012-06-15 17:21:36 +0200 |
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committer | Michael Niedermayer <michaelni@gmx.at> | 2012-06-16 12:47:46 +0200 |
commit | c78cf00bd8329dd339d2f73d1b43c366d0f46837 (patch) | |
tree | f59babae65188cb5e0314bfe4eaf09e5f5c04214 /libavfilter/vf_super2xsai.c | |
parent | c7bdfbe79f00eaa1ee9e34db1a38db1e15bbda8e (diff) | |
download | ffmpeg-c78cf00bd8329dd339d2f73d1b43c366d0f46837.tar.gz |
md5: consistently use uint32_t instead of unsigned int
Basically to make code clearer and adherent to the
standard. RFC 1321, on page 2 states
Let the symbol "+" denote addition of words (i.e., modulo-2^32
addition). Let X <<< s denote the 32-bit value obtained by circularly
shifting (rotating) X left by s bit positions.
on page 3, section 3.3 states:
A four-word buffer (A,B,C,D) is used to compute the message digest.
Here each of A, B, C, D is a 32-bit register.
so the algorithm needs to work with integers that are exactly 32bits
in length. And indeed in struct AVMD5 the MD buffer is declared as
"uint32_t ABCD[4];", while in the function that performs the block
transformation the state variables were "unsigned int"s. On
architectures where sizeof(unsigned int) != sizeof(uint32_t) this
could be a problem, although I can't name such an architecture from
the top of my head.
On a side note, both the reference implementation in RFC 1321 and the
gnulib implementation (used by md5sum program on GNU systems) use
uint32_t in the transform function.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Diffstat (limited to 'libavfilter/vf_super2xsai.c')
0 files changed, 0 insertions, 0 deletions