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(sha_stream) [BLOCKSIZE]: Move definition to top of file.

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Ensure that it is a multiple of 64.
Rearrange loop exit tests so as to avoid performing an
additional fread after encountering an error or EOF.
This commit is contained in:
Jim Meyering 2003-02-18 19:00:40 +00:00
parent 7496bc25b0
commit 714f398d7f
1 changed files with 31 additions and 12 deletions
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43
lib/sha.c
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@ -1,7 +1,7 @@
/* sha.c - Functions to compute the SHA1 hash (message-digest) of files
or blocks of memory. Complies to the NIST specification FIPS-180-1.
Copyright (C) 2000, 2001 Scott G. Miller
Copyright (C) 2000, 2001, 2003 Scott G. Miller
Credits:
Robert Klep <robert@ilse.nl> -- Expansion function fix
@ -41,6 +41,13 @@
# define SWAP(n) (n)
#endif
#define BLOCKSIZE 4096
/* Ensure that BLOCKSIZE is a multiple of 64. */
#if BLOCKSIZE % 64 != 0
/* FIXME-someday (soon?): use #error instead of this kludge. */
"invalid BLOCKSIZE"
#endif
/* This array contains the bytes used to pad the buffer to the next
64-byte boundary. (RFC 1321, 3.1: Step 1) */
static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
@ -118,8 +125,6 @@ sha_finish_ctx (struct sha_ctx *ctx, void *resbuf)
int
sha_stream (FILE *stream, void *resblock)
{
/* Important: BLOCKSIZE must be a multiple of 64. */
#define BLOCKSIZE 4096
struct sha_ctx ctx;
char buffer[BLOCKSIZE + 72];
size_t sum;
@ -137,19 +142,31 @@ sha_stream (FILE *stream, void *resblock)
sum = 0;
/* Read block. Take care for partial reads. */
do
while (1)
{
n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
sum += n;
}
while (sum < BLOCKSIZE && n != 0);
if (n == 0 && ferror (stream))
return 1;
/* If end of file is reached, end the loop. */
if (n == 0)
break;
if (sum == BLOCKSIZE)
break;
if (n == 0)
{
/* Check for the error flag IFF N == 0, so that we don't
exit the loop after a partial read due to e.g., EAGAIN
or EWOULDBLOCK. */
if (ferror (stream))
return 1;
goto process_partial_block;
}
/* We've read at least one byte, so ignore errors. But always
check for EOF, since feof may be true even though N > 0.
Otherwise, we could end up calling fread after EOF. */
if (feof (stream))
goto process_partial_block;
}
/* Process buffer with BLOCKSIZE bytes. Note that
BLOCKSIZE % 64 == 0
@ -157,7 +174,9 @@ sha_stream (FILE *stream, void *resblock)
sha_process_block (buffer, BLOCKSIZE, &ctx);
}
/* Add the last bytes if necessary. */
process_partial_block:;
/* Process any remaining bytes. */
if (sum > 0)
sha_process_bytes (buffer, sum, &ctx);