bc: replace signed division / 10 by unsigned

function                                             old     new   delta
zbc_num_a                                            443     441      -2

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

diff --git a/miscutils/bc.c b/miscutils/bc.c
index eaab6cee633e891d50fa0320c97c570d2f9c2da6..6c63c17033196ac7476a76e2f10e6e6992188302 100644 (file)
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -1466,9 +1466,10 @@ static void bc_num_subArrays(BcDig *restrict a, BcDig *restrict b,
 {
        size_t i, j;
        for (i = 0; i < len; ++i) {
-               for (a[i] -= b[i], j = 0; a[i + j] < 0;) {
-                       a[i + j++] += 10;
-                       a[i + j] -= 1;
+               a[i] -= b[i];
+               for (j = i; a[j] < 0;) {
+                       a[j++] += 10;
+                       a[j] -= 1;
                }
        }
 }
@@ -1647,7 +1648,7 @@ static FAST_FUNC BC_STATUS zbc_num_a(BcNum *a, BcNum *b, BcNum *restrict c, size
 {
        BcDig *ptr, *ptr_a, *ptr_b, *ptr_c;
        size_t i, max, min_rdx, min_int, diff, a_int, b_int;
-       int carry, in;
+       unsigned carry;
 
        // Because this function doesn't need to use scale (per the bc spec),
        // I am hijacking it to say whether it's doing an add or a subtract.
@@ -1672,15 +1673,16 @@ static FAST_FUNC BC_STATUS zbc_num_a(BcNum *a, BcNum *b, BcNum *restrict c, size
                ptr = a->num;
                ptr_a = a->num + diff;
                ptr_b = b->num;
-       }
-       else {
+       } else {
                diff = b->rdx - a->rdx;
                ptr = b->num;
                ptr_a = a->num;
                ptr_b = b->num + diff;
        }
 
-       for (ptr_c = c->num, i = 0; i < diff; ++i, ++c->len) ptr_c[i] = ptr[i];
+       ptr_c = c->num;
+       for (i = 0; i < diff; ++i, ++c->len)
+               ptr_c[i] = ptr[i];
 
        ptr_c += diff;
        a_int = BC_NUM_INT(a);
@@ -1690,24 +1692,24 @@ static FAST_FUNC BC_STATUS zbc_num_a(BcNum *a, BcNum *b, BcNum *restrict c, size
                min_int = b_int;
                max = a_int;
                ptr = ptr_a;
-       }
-       else {
+       } else {
                min_int = a_int;
                max = b_int;
                ptr = ptr_b;
        }
 
-       for (carry = 0, i = 0; i < min_rdx + min_int; ++i, ++c->len) {
-               in = ((int) ptr_a[i]) + ((int) ptr_b[i]) + carry;
+       carry = 0;
+       for (i = 0; i < min_rdx + min_int; ++i) {
+               unsigned in = (unsigned)ptr_a[i] + (unsigned)ptr_b[i] + carry;
                carry = in / 10;
                ptr_c[i] = (BcDig)(in % 10);
        }
-
-       for (; i < max + min_rdx; ++i, ++c->len) {
-               in = ((int) ptr[i]) + carry;
+       for (; i < max + min_rdx; ++i) {
+               unsigned in = (unsigned)ptr[i] + carry;
                carry = in / 10;
                ptr_c[i] = (BcDig)(in % 10);
        }
+       c->len += i;
 
        if (carry != 0) c->num[c->len++] = (BcDig) carry;
 
@@ -1751,8 +1753,7 @@ static FAST_FUNC BC_STATUS zbc_num_s(BcNum *a, BcNum *b, BcNum *restrict c, size
                neg = a->neg;
                minuend = a;
                subtrahend = b;
-       }
-       else {
+       } else {
                neg = b->neg;
                if (sub) neg = !neg;
                minuend = b;
@@ -1765,8 +1766,7 @@ static FAST_FUNC BC_STATUS zbc_num_s(BcNum *a, BcNum *b, BcNum *restrict c, size
        if (c->rdx < subtrahend->rdx) {
                bc_num_extend(c, subtrahend->rdx - c->rdx);
                start = 0;
-       }
-       else
+       } else
                start = c->rdx - subtrahend->rdx;
 
        bc_num_subArrays(c->num + start, subtrahend->num, subtrahend->len);
@@ -1795,11 +1795,11 @@ static FAST_FUNC BC_STATUS zbc_num_k(BcNum *restrict a, BcNum *restrict b,
                RETURN_STATUS(BC_STATUS_SUCCESS);
        }
 
-       if (a->len + b->len < BC_NUM_KARATSUBA_LEN ||
-           a->len < BC_NUM_KARATSUBA_LEN || b->len < BC_NUM_KARATSUBA_LEN)
-       {
+       if (a->len + b->len < BC_NUM_KARATSUBA_LEN
+        || a->len < BC_NUM_KARATSUBA_LEN
+        || b->len < BC_NUM_KARATSUBA_LEN
+       ) {
                size_t i, j, len;
-               unsigned carry;
 
                bc_num_expand(c, a->len + b->len + 1);
 
@@ -1807,11 +1807,10 @@ static FAST_FUNC BC_STATUS zbc_num_k(BcNum *restrict a, BcNum *restrict b,
                c->len = len = 0;
 
                for (i = 0; i < b->len; ++i) {
-
-                       carry = 0;
+                       unsigned carry = 0;
                        for (j = 0; j < a->len; ++j) {
                                unsigned in = c->num[i + j];
-                               in += ((unsigned) a->num[j]) * ((unsigned) b->num[i]) + carry;
+                               in += (unsigned)a->num[j] * (unsigned)b->num[i] + carry;
                                // note: compilers prefer _unsigned_ div/const
                                carry = in / 10;
                                c->num[i + j] = (BcDig)(in % 10);
@@ -2158,8 +2157,7 @@ static BC_STATUS zbc_num_binary(BcNum *a, BcNum *b, BcNum *c, size_t scale,
                ptr_a = &num2;
                memcpy(ptr_a, c, sizeof(BcNum));
                init = true;
-       }
-       else
+       } else
                ptr_a = a;
 
        if (c == b) {
@@ -2168,8 +2166,7 @@ static BC_STATUS zbc_num_binary(BcNum *a, BcNum *b, BcNum *c, size_t scale,
                        memcpy(ptr_b, c, sizeof(BcNum));
                        init = true;
                }
-       }
-       else
+       } else
                ptr_b = b;
 
        if (init)
@@ -2350,10 +2347,9 @@ static BC_STATUS zbc_num_sqrt(BcNum *a, BcNum *restrict b, size_t scale)
        if (a->len == 0) {
                bc_num_setToZero(b, scale);
                RETURN_STATUS(BC_STATUS_SUCCESS);
-       }
-       else if (a->neg)
+       } else if (a->neg) {
                RETURN_STATUS(bc_error("negative number"));
-       else if (BC_NUM_ONE(a)) {
+       } else if (BC_NUM_ONE(a)) {
                bc_num_one(b);
                bc_num_extend(b, scale);
                RETURN_STATUS(BC_STATUS_SUCCESS);
@@ -2380,7 +2376,6 @@ static BC_STATUS zbc_num_sqrt(BcNum *a, BcNum *restrict b, size_t scale)
        pow = BC_NUM_INT(a);
 
        if (pow) {
-
                if (pow & 1)
                        x0->num[0] = 2;
                else
@@ -2399,7 +2394,6 @@ static BC_STATUS zbc_num_sqrt(BcNum *a, BcNum *restrict b, size_t scale)
        len = BC_NUM_INT(x0) + resrdx - 1;
 
        while (cmp != 0 || digs < len) {
-
                s = zbc_num_div(a, x0, &f, resrdx);
                if (s) goto err;
                s = zbc_num_add(x0, &f, &fprime, resrdx);
@@ -2429,8 +2423,7 @@ static BC_STATUS zbc_num_sqrt(BcNum *a, BcNum *restrict b, size_t scale)
        bc_num_copy(b, x0);
        scale -= 1;
        if (b->rdx > scale) bc_num_truncate(b, b->rdx - scale);
-
-err:
+ err:
        bc_num_free(&fprime);
        bc_num_free(&f);
        bc_num_free(&half);
@@ -2453,8 +2446,7 @@ static BC_STATUS zbc_num_divmod(BcNum *a, BcNum *b, BcNum *c, BcNum *d,
                ptr_a = &num2;
                bc_num_init(c, len);
                init = true;
-       }
-       else {
+       } else {
                ptr_a = a;
                bc_num_expand(c, len);
        }
@@ -2495,7 +2487,6 @@ static BC_STATUS zbc_num_modexp(BcNum *a, BcNum *b, BcNum *c, BcNum *restrict d)
        bc_num_copy(&exp, b);
 
        while (exp.len != 0) {
-
                s = zbc_num_divmod(&exp, &two, &exp, &temp, 0);
                if (s) goto err;
 
@@ -2511,8 +2502,7 @@ static BC_STATUS zbc_num_modexp(BcNum *a, BcNum *b, BcNum *c, BcNum *restrict d)
                s = zbc_num_rem(&temp, c, &base, 0);
                if (s) goto err;
        }
-
-err:
+ err:
        bc_num_free(&temp);
        bc_num_free(&two);
        bc_num_free(&exp);
@@ -2579,8 +2569,7 @@ static void bc_array_expand(BcVec *a, size_t len)
                        bc_num_init_DEF_SIZE(&data.n);
                        bc_vec_push(a, &data.n);
                }
-       }
-       else {
+       } else {
                while (len > a->len) {
                        bc_array_init(&data.v, true);
                        bc_vec_push(a, &data.v);
@@ -2614,33 +2603,24 @@ static void bc_result_copy(BcResult *d, BcResult *src)
        d->t = src->t;
 
        switch (d->t) {
-
                case BC_RESULT_TEMP:
                case BC_RESULT_IBASE:
                case BC_RESULT_SCALE:
                case BC_RESULT_OBASE:
-               {
                        bc_num_init(&d->d.n, src->d.n.len);
                        bc_num_copy(&d->d.n, &src->d.n);
                        break;
-               }
-
                case BC_RESULT_VAR:
                case BC_RESULT_ARRAY:
                case BC_RESULT_ARRAY_ELEM:
-               {
                        d->d.id.name = xstrdup(src->d.id.name);
                        break;
-               }
-
                case BC_RESULT_CONSTANT:
                case BC_RESULT_LAST:
                case BC_RESULT_ONE:
                case BC_RESULT_STR:
-               {
                        memcpy(&d->d.n, &src->d.n, sizeof(BcNum));
                        break;
-               }
        }
 }
 #endif // ENABLE_DC
@@ -2650,29 +2630,20 @@ static FAST_FUNC void bc_result_free(void *result)
        BcResult *r = (BcResult *) result;
 
        switch (r->t) {
-
                case BC_RESULT_TEMP:
                case BC_RESULT_IBASE:
                case BC_RESULT_SCALE:
                case BC_RESULT_OBASE:
-               {
                        bc_num_free(&r->d.n);
                        break;
-               }
-
                case BC_RESULT_VAR:
                case BC_RESULT_ARRAY:
                case BC_RESULT_ARRAY_ELEM:
-               {
                        free(r->d.id.name);
                        break;
-               }
-
                default:
-               {
                        // Do nothing.
                        break;
-               }
        }
 }