Merge pull request #454 from libtom/better-use-of-isneg

Better use of isneg

Author: sjaeckel

etc/mersenne.c

@@ -43,7 +43,7 @@ static mp_err is_mersenne(long s, bool *pp)
       }
 
       /* make sure u is positive */
-      while (u.sign == MP_NEG) {
+      while (mp_isneg(&u)) {
          if ((res = mp_add(&u, &n, &u)) != MP_OKAY) {
             goto LBL_MU;
          }

mp_add_d.c

@@ -11,13 +11,13 @@ mp_err mp_add_d(const mp_int *a, mp_digit b, mp_int *c)
 
    /* fast path for a == c */
    if (a == c) {
-      if ((c->sign == MP_ZPOS) &&
+      if (!mp_isneg(c) &&
           !mp_iszero(c) &&
           ((c->dp[0] + b) < MP_DIGIT_MAX)) {
          c->dp[0] += b;
          return MP_OKAY;
       }
-      if ((c->sign == MP_NEG) &&
+      if (mp_isneg(c) &&
           (c->dp[0] > b)) {
          c->dp[0] -= b;
          return MP_OKAY;
@@ -30,7 +30,7 @@ mp_err mp_add_d(const mp_int *a, mp_digit b, mp_int *c)
    }
 
    /* if a is negative and |a| >= b, call c = |a| - b */
-   if ((a->sign == MP_NEG) && ((a->used > 1) || (a->dp[0] >= b))) {
+   if (mp_isneg(a) && ((a->used > 1) || (a->dp[0] >= b))) {
       mp_int a_ = *a;
       /* temporarily fix sign of a */
       a_.sign = MP_ZPOS;
@@ -51,7 +51,7 @@ mp_err mp_add_d(const mp_int *a, mp_digit b, mp_int *c)
    oldused = c->used;
 
    /* if a is positive */
-   if (a->sign == MP_ZPOS) {
+   if (!mp_isneg(a)) {
       /* add digits, mu is carry */
       int i;
       mp_digit mu = b;

mp_and.c

@@ -9,7 +9,7 @@ mp_err mp_and(const mp_int *a, const mp_int *b, mp_int *c)
    int used = MP_MAX(a->used, b->used) + 1, i;
    mp_err err;
    mp_digit ac = 1, bc = 1, cc = 1;
-   mp_sign csign = ((a->sign == MP_NEG) && (b->sign == MP_NEG)) ? MP_NEG : MP_ZPOS;
+   bool neg = (mp_isneg(a) && mp_isneg(b));
 
    if ((err = mp_grow(c, used)) != MP_OKAY) {
       return err;
@@ -19,7 +19,7 @@ mp_err mp_and(const mp_int *a, const mp_int *b, mp_int *c)
       mp_digit x, y;
 
       /* convert to two complement if negative */
-      if (a->sign == MP_NEG) {
+      if (mp_isneg(a)) {
          ac += (i >= a->used) ? MP_MASK : (~a->dp[i] & MP_MASK);
          x = ac & MP_MASK;
          ac >>= MP_DIGIT_BIT;
@@ -28,7 +28,7 @@ mp_err mp_and(const mp_int *a, const mp_int *b, mp_int *c)
       }
 
       /* convert to two complement if negative */
-      if (b->sign == MP_NEG) {
+      if (mp_isneg(b)) {
          bc += (i >= b->used) ? MP_MASK : (~b->dp[i] & MP_MASK);
          y = bc & MP_MASK;
          bc >>= MP_DIGIT_BIT;
@@ -39,15 +39,15 @@ mp_err mp_and(const mp_int *a, const mp_int *b, mp_int *c)
       c->dp[i] = x & y;
 
       /* convert to to sign-magnitude if negative */
-      if (csign == MP_NEG) {
+      if (neg) {
          cc += ~c->dp[i] & MP_MASK;
          c->dp[i] = cc & MP_MASK;
          cc >>= MP_DIGIT_BIT;
       }
    }
 
    c->used = used;
-   c->sign = csign;
+   c->sign = (neg ? MP_NEG : MP_ZPOS);
    mp_clamp(c);
    return MP_OKAY;
 }

mp_clamp.c

@@ -19,8 +19,8 @@ void mp_clamp(mp_int *a)
       --(a->used);
    }
 
-   /* reset the sign flag if used == 0 */
-   if (a->used == 0) {
+   /* reset the sign flag if zero */
+   if (mp_iszero(a)) {
       a->sign = MP_ZPOS;
    }
 }

mp_cmp.c

@@ -8,11 +8,11 @@ mp_ord mp_cmp(const mp_int *a, const mp_int *b)
 {
    /* compare based on sign */
    if (a->sign != b->sign) {
-      return a->sign == MP_NEG ? MP_LT : MP_GT;
+      return mp_isneg(a) ? MP_LT : MP_GT;
    }
 
    /* if negative compare opposite direction */
-   if (a->sign == MP_NEG) {
+   if (mp_isneg(a)) {
       MP_EXCH(const mp_int *, a, b);
    }
 

mp_cmp_d.c

@@ -7,7 +7,7 @@
 mp_ord mp_cmp_d(const mp_int *a, mp_digit b)
 {
    /* compare based on sign */
-   if (a->sign == MP_NEG) {
+   if (mp_isneg(a)) {
       return MP_LT;
    }
 

mp_exptmod.c

@@ -13,12 +13,12 @@ mp_err mp_exptmod(const mp_int *G, const mp_int *X, const mp_int *P, mp_int *Y)
    int dr;
 
    /* modulus P must be positive */
-   if (P->sign == MP_NEG) {
+   if (mp_isneg(P)) {
       return MP_VAL;
    }
 
    /* if exponent X is negative we have to recurse */
-   if (X->sign == MP_NEG) {
+   if (mp_isneg(X)) {
       mp_int tmpG, tmpX;
       mp_err err;
 

mp_exteuclid.c

@@ -48,7 +48,7 @@ mp_err mp_exteuclid(const mp_int *a, const mp_int *b, mp_int *U1, mp_int *U2, mp
    }
 
    /* make sure U3 >= 0 */
-   if (u3.sign == MP_NEG) {
+   if (mp_isneg(&u3)) {
       if ((err = mp_neg(&u1, &u1)) != MP_OKAY)                    goto LBL_ERR;
       if ((err = mp_neg(&u2, &u2)) != MP_OKAY)                    goto LBL_ERR;
       if ((err = mp_neg(&u3, &u3)) != MP_OKAY)                    goto LBL_ERR;

mp_fread.c

@@ -8,7 +8,7 @@
 mp_err mp_fread(mp_int *a, int radix, FILE *stream)
 {
    mp_err err;
-   mp_sign neg = MP_ZPOS;
+   mp_sign sign = MP_ZPOS;
    int ch;
 
    /* make sure the radix is ok */
@@ -19,7 +19,7 @@ mp_err mp_fread(mp_int *a, int radix, FILE *stream)
    /* if first digit is - then set negative */
    ch = fgetc(stream);
    if (ch == (int)'-') {
-      neg = MP_NEG;
+      sign = MP_NEG;
       ch = fgetc(stream);
    }
 
@@ -56,7 +56,7 @@ mp_err mp_fread(mp_int *a, int radix, FILE *stream)
    } while ((ch = fgetc(stream)) != EOF);
 
    if (!mp_iszero(a)) {
-      a->sign = neg;
+      a->sign = sign;
    }
 
    return MP_OKAY;

mp_from_sbin.c

@@ -14,7 +14,7 @@ mp_err mp_from_sbin(mp_int *a, const uint8_t *buf, size_t size)
    }
 
    /* first byte is 0 for positive, non-zero for negative */
-   a->sign = (buf[0] == (uint8_t)0) ? MP_ZPOS : MP_NEG;
+   a->sign = (buf[0] != (uint8_t)0) ? MP_NEG : MP_ZPOS;
 
    return MP_OKAY;
 }