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authorLaurent Bercot <ska-skaware@skarnet.org>2014-09-18 18:55:44 +0000
committerLaurent Bercot <ska-skaware@skarnet.org>2014-09-18 18:55:44 +0000
commit3534b428629be185e096be99e3bd5fdfe32d5544 (patch)
tree210ef3198ed66bc7f7b7bf6a85e4579f455e5a36 /src/librandom/surf.c
downloadskalibs-3534b428629be185e096be99e3bd5fdfe32d5544.tar.xz
initial commit with rc for skalibs-2.0.0.0
Diffstat (limited to 'src/librandom/surf.c')
-rw-r--r--src/librandom/surf.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/src/librandom/surf.c b/src/librandom/surf.c
new file mode 100644
index 0000000..1687df9
--- /dev/null
+++ b/src/librandom/surf.c
@@ -0,0 +1,54 @@
+/* ISC license. */
+
+#include <skalibs/uint32.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/surf.h>
+
+#define ROTATE(x, b) (((x) << (b)) | ((x) >> (32 - (b))))
+#define MUSH(i, b) x = t[i] += (((x ^ ctx->seed[i]) + sum) ^ ROTATE(x, b))
+
+static void surfit (SURFSchedule_ref ctx)
+{
+ uint32 t[12] ;
+ uint32 z[8] ;
+ uint32 x ;
+ uint32 sum = 0 ;
+ unsigned int i = 0, loop = 0 ; ;
+
+ if (!++ctx->in[0] && !++ctx->in[1] && !++ctx->in[2]) ++ctx->in[3] ;
+ for (; i < 12 ; i++) t[i] = ctx->in[i] ^ ctx->seed[12+i] ;
+ for (i = 0 ; i < 8 ; i++) z[i] = ctx->seed[24+i] ;
+ x = t[11] ;
+ for (; loop < 2 ; loop++)
+ {
+ for (i = 0 ; i < 16 ; i++)
+ {
+ sum += 0x9e3779b9 ;
+ MUSH(0, 5) ; MUSH(1, 7) ; MUSH(2, 9) ; MUSH(3, 13) ;
+ MUSH(4, 5) ; MUSH(5, 7) ; MUSH(6, 9) ; MUSH(7, 13) ;
+ MUSH(8, 5) ; MUSH(9, 7) ; MUSH(10, 9) ; MUSH(11, 13) ;
+ }
+ for (i = 0 ; i < 8 ; i++) z[i] ^= t[i+4] ;
+ }
+ for (i = 0 ; i < 8 ; i++) uint32_pack(ctx->out + (i<<2), z[i]) ;
+}
+
+void surf (SURFSchedule_ref ctx, char *s, unsigned int n)
+{
+ {
+ register unsigned int i = 32 - ctx->pos ;
+ if (n < i) i = n ;
+ byte_copy(s, i, ctx->out + ctx->pos) ;
+ s += i ; n -= i ; ctx->pos += i ;
+ }
+ while (n > 32)
+ {
+ surfit(ctx) ;
+ byte_copy(s, 32, ctx->out) ;
+ s += 32 ; n -= 32 ;
+ }
+ if (!n) return ;
+ surfit(ctx) ;
+ byte_copy(s, n, ctx->out) ;
+ ctx->pos = n ;
+}