diff options
Diffstat (limited to 'lib')
-rw-r--r-- | lib/mpi/mpicoder.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c index f0fa65995800..3962b7f7fe3f 100644 --- a/lib/mpi/mpicoder.c +++ b/lib/mpi/mpicoder.c | |||
@@ -18,10 +18,65 @@ | |||
18 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA | 18 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA |
19 | */ | 19 | */ |
20 | 20 | ||
21 | #include <linux/bitops.h> | ||
22 | #include <asm-generic/bitops/count_zeros.h> | ||
21 | #include "mpi-internal.h" | 23 | #include "mpi-internal.h" |
22 | 24 | ||
23 | #define MAX_EXTERN_MPI_BITS 16384 | 25 | #define MAX_EXTERN_MPI_BITS 16384 |
24 | 26 | ||
27 | /** | ||
28 | * mpi_read_raw_data - Read a raw byte stream as a positive integer | ||
29 | * @xbuffer: The data to read | ||
30 | * @nbytes: The amount of data to read | ||
31 | */ | ||
32 | MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes) | ||
33 | { | ||
34 | const uint8_t *buffer = xbuffer; | ||
35 | int i, j; | ||
36 | unsigned nbits, nlimbs; | ||
37 | mpi_limb_t a; | ||
38 | MPI val = NULL; | ||
39 | |||
40 | while (nbytes >= 0 && buffer[0] == 0) { | ||
41 | buffer++; | ||
42 | nbytes--; | ||
43 | } | ||
44 | |||
45 | nbits = nbytes * 8; | ||
46 | if (nbits > MAX_EXTERN_MPI_BITS) { | ||
47 | pr_info("MPI: mpi too large (%u bits)\n", nbits); | ||
48 | return NULL; | ||
49 | } | ||
50 | if (nbytes > 0) | ||
51 | nbits -= count_leading_zeros(buffer[0]); | ||
52 | else | ||
53 | nbits = 0; | ||
54 | |||
55 | nlimbs = (nbytes + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB; | ||
56 | val = mpi_alloc(nlimbs); | ||
57 | if (!val) | ||
58 | return NULL; | ||
59 | val->nbits = nbits; | ||
60 | val->sign = 0; | ||
61 | val->nlimbs = nlimbs; | ||
62 | |||
63 | if (nbytes > 0) { | ||
64 | i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB; | ||
65 | i %= BYTES_PER_MPI_LIMB; | ||
66 | for (j = nlimbs; j > 0; j--) { | ||
67 | a = 0; | ||
68 | for (; i < BYTES_PER_MPI_LIMB; i++) { | ||
69 | a <<= 8; | ||
70 | a |= *buffer++; | ||
71 | } | ||
72 | i = 0; | ||
73 | val->d[j - 1] = a; | ||
74 | } | ||
75 | } | ||
76 | return val; | ||
77 | } | ||
78 | EXPORT_SYMBOL_GPL(mpi_read_raw_data); | ||
79 | |||
25 | MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread) | 80 | MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread) |
26 | { | 81 | { |
27 | const uint8_t *buffer = xbuffer; | 82 | const uint8_t *buffer = xbuffer; |