/* Process LEN bytes of BUFFER, accumulating context into CTX. */
void
md2_process_block (const void *buffer, size_t len, struct md2_ctx *ctx)
{
md2_process_bytes (buffer, len, ctx);
}
/* Compute MD2 message digest for bytes read from STREAM. The
resulting message digest number will be written into the 16 bytes
beginning at RESBLOCK. */
int
md2_stream (FILE *stream, void *resblock)
{
struct md2_ctx ctx;
size_t sum;
char *buffer = malloc (BLOCKSIZE + 72);
if (!buffer)
return 1;
/* Initialize the computation context. */
md2_init_ctx (&ctx);
/* Iterate over full file contents. */
while (1)
{
/* We read the file in blocks of BLOCKSIZE bytes. One call of the
computation function processes the whole buffer so that with the
next round of the loop another block can be read. */
size_t n;
sum = 0;
/* Read block. Take care for partial reads. */
while (1)
{
n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
sum += n;
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))
{
free (buffer);
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
*/
md2_process_block (buffer, BLOCKSIZE, &ctx);
}
process_partial_block:;
/* Process any remaining bytes. */
if (sum > 0)
md2_process_bytes (buffer, sum, &ctx);
/* Construct result in desired memory. */
md2_finish_ctx (&ctx, resblock);
free (buffer);
return 0;
}