bc: move ^C check fro power calculation to multiplication

function                                             old     new   delta
bc_num_k                                             971     990     +19
bc_num_p                                             507     478     -29
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 19/-29)            Total: -10 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 14 insertions, 10 deletions

diff --git a/miscutils/bc.c b/miscutils/bc.c
index ea200ebda..07793e9d4 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -1676,6 +1676,10 @@ static BcStatus bc_num_k(BcNum *restrict a, BcNum *restrict b,
 
                         c->num[i + j] += (BcDig) carry;
                         len = BC_MAX(len, i + j + !!carry);
+
+                        // a=2^1000000
+                        // a*a <- without check below, this will not be interruptible
+                        if (G_interrupt) return BC_STATUS_FAILURE;
                 }
 
                 c->len = len;
@@ -1935,11 +1939,11 @@ static BcStatus bc_num_p(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale)
                 powrdx <<= 1;
                 s = bc_num_mul(&copy, &copy, &copy, powrdx);
                 if (s) goto err;
-                // It is too slow to handle ^C only after entire "2^1000000" completes
-                if (G_interrupt) {
-                        s = BC_STATUS_FAILURE;
-                        goto err;
-                }
+                // Not needed: bc_num_mul() has a check for ^C:
+                //if (G_interrupt) {
+                //      s = BC_STATUS_FAILURE;
+                //      goto err;
+                //}
         }
 
         bc_num_copy(c, &copy);
@@ -1955,11 +1959,11 @@ static BcStatus bc_num_p(BcNum *a, BcNum *b, BcNum *restrict c, size_t scale)
                         s = bc_num_mul(c, &copy, c, resrdx);
                         if (s) goto err;
                 }
-                // It is too slow to handle ^C only after entire "2^1000000" completes
-                if (G_interrupt) {
-                        s = BC_STATUS_FAILURE;
-                        goto err;
-                }
+                // Not needed: bc_num_mul() has a check for ^C:
+                //if (G_interrupt) {
+                //      s = BC_STATUS_FAILURE;
+                //      goto err;
+                //}
         }
 
         if (neg) {