more explicit types mp_err, mp_ord, mp_bool, mp_sign

* MP_STRICT_TYPES enables enums
* Wc++-compat catches some implicit conversions if MP_STRICT_TYPES is defined
* 100% backwards compatible API/ABI if MP_STRICT_TYPES is not defined

Author: minad

.travis.yml

@@ -112,7 +112,8 @@ matrix:
             - gcc-4.9
 
     # clang for x86-64 architecture (64-bit longs and 64-bit pointers)
-    - env: CONV_WARNINGS=1 BUILDOPTIONS='--with-cc=clang-7 --with-m64 --with-valgrind'
+    - env: CONV_WARNINGS=strict BUILDOPTIONS='--with-cc=clang-7 --with-m64 --with-valgrind'
+    - env: CONV_WARNINGS=relaxed BUILDOPTIONS='--with-cc=clang-7 --with-m64 --with-valgrind'
     - env: BUILDOPTIONS='--with-cc=clang-6.0 --with-m64 --with-valgrind'
       addons:
         apt:

bn_deprecated.c

@@ -7,73 +7,73 @@
 /* SPDX-License-Identifier: Unlicense */
 #include <tommath_private.h>
 #ifdef BN_FAST_MP_INVMOD_C
-int fast_mp_invmod(const mp_int *a, const mp_int *b, mp_int *c)
+mp_err fast_mp_invmod(const mp_int *a, const mp_int *b, mp_int *c)
 {
    return s_mp_invmod_fast(a, b, c);
 }
 #endif
 #ifdef BN_FAST_MP_MONTGOMERY_REDUCE_C
-int fast_mp_montgomery_reduce(mp_int *x, const mp_int *n, mp_digit rho)
+mp_err fast_mp_montgomery_reduce(mp_int *x, const mp_int *n, mp_digit rho)
 {
    return s_mp_montgomery_reduce_fast(x, n, rho);
 }
 #endif
 #ifdef BN_FAST_S_MP_MUL_DIGS_C
-int fast_s_mp_mul_digs(const mp_int *a, const mp_int *b, mp_int *c, int digs)
+mp_err fast_s_mp_mul_digs(const mp_int *a, const mp_int *b, mp_int *c, int digs)
 {
    return s_mp_mul_digs_fast(a, b, c, digs);
 }
 #endif
 #ifdef BN_FAST_S_MP_MUL_HIGH_DIGS_C
-int fast_s_mp_mul_high_digs(const mp_int *a, const mp_int *b, mp_int *c, int digs)
+mp_err fast_s_mp_mul_high_digs(const mp_int *a, const mp_int *b, mp_int *c, int digs)
 {
    return s_mp_mul_high_digs_fast(a, b, c, digs);
 }
 #endif
 #ifdef BN_FAST_S_MP_SQR_C
-int fast_s_mp_sqr(const mp_int *a, mp_int *b)
+mp_err fast_s_mp_sqr(const mp_int *a, mp_int *b)
 {
    return s_mp_sqr_fast(a, b);
 }
 #endif
 #ifdef BN_MP_BALANCE_MUL_C
-int mp_balance_mul(const mp_int *a, const mp_int *b, mp_int *c)
+mp_err mp_balance_mul(const mp_int *a, const mp_int *b, mp_int *c)
 {
    return s_mp_balance_mul(a, b, c);
 }
 #endif
 #ifdef BN_MP_EXPTMOD_FAST_C
-int mp_exptmod_fast(const mp_int *G, const mp_int *X, const mp_int *P, mp_int *Y, int redmode)
+mp_err mp_exptmod_fast(const mp_int *G, const mp_int *X, const mp_int *P, mp_int *Y, int redmode)
 {
    return s_mp_exptmod_fast(G, X, P, Y, redmode);
 }
 #endif
 #ifdef BN_MP_INVMOD_SLOW_C
-int mp_invmod_slow(const mp_int *a, const mp_int *b, mp_int *c)
+mp_err mp_invmod_slow(const mp_int *a, const mp_int *b, mp_int *c)
 {
    return s_mp_invmod_slow(a, b, c);
 }
 #endif
 #ifdef BN_MP_KARATSUBA_MUL_C
-int mp_karatsuba_mul(const mp_int *a, const mp_int *b, mp_int *c)
+mp_err mp_karatsuba_mul(const mp_int *a, const mp_int *b, mp_int *c)
 {
    return s_mp_karatsuba_mul(a, b, c);
 }
 #endif
 #ifdef BN_MP_KARATSUBA_SQR_C
-int mp_karatsuba_sqr(const mp_int *a, mp_int *b)
+mp_err mp_karatsuba_sqr(const mp_int *a, mp_int *b)
 {
    return s_mp_karatsuba_sqr(a, b);
 }
 #endif
 #ifdef BN_MP_TOOM_MUL_C
-int mp_toom_mul(const mp_int *a, const mp_int *b, mp_int *c)
+mp_err mp_toom_mul(const mp_int *a, const mp_int *b, mp_int *c)
 {
    return s_mp_toom_mul(a, b, c);
 }
 #endif
 #ifdef BN_MP_TOOM_SQR_C
-int mp_toom_sqr(const mp_int *a, mp_int *b)
+mp_err mp_toom_sqr(const mp_int *a, mp_int *b)
 {
    return s_mp_toom_sqr(a, b);
 }

bn_mp_2expt.c

@@ -8,9 +8,9 @@
  * Simple algorithm which zeroes the int, grows it then just sets one bit
  * as required.
  */
-int mp_2expt(mp_int *a, int b)
+mp_err mp_2expt(mp_int *a, int b)
 {
-   int     res;
+   mp_err    res;
 
    /* zero a as per default */
    mp_zero(a);

bn_mp_abs.c

@@ -7,9 +7,9 @@
  *
  * Simple function copies the input and fixes the sign to positive
  */
-int mp_abs(const mp_int *a, mp_int *b)
+mp_err mp_abs(const mp_int *a, mp_int *b)
 {
-   int     res;
+   mp_err     res;
 
    /* copy a to b */
    if (a != b) {

bn_mp_add.c

@@ -4,9 +4,10 @@
 /* SPDX-License-Identifier: Unlicense */
 
 /* high level addition (handles signs) */
-int mp_add(const mp_int *a, const mp_int *b, mp_int *c)
+mp_err mp_add(const mp_int *a, const mp_int *b, mp_int *c)
 {
-   int     sa, sb, res;
+   mp_sign sa, sb;
+   mp_err res;
 
    /* get sign of both inputs */
    sa = a->sign;

bn_mp_add_d.c

@@ -4,9 +4,10 @@
 /* SPDX-License-Identifier: Unlicense */
 
 /* single digit addition */
-int mp_add_d(const mp_int *a, mp_digit b, mp_int *c)
+mp_err mp_add_d(const mp_int *a, mp_digit b, mp_int *c)
 {
-   int     res, ix, oldused;
+   mp_err     res;
+   int ix, oldused;
    mp_digit *tmpa, *tmpc, mu;
 
    /* grow c as required */

bn_mp_addmod.c

@@ -4,9 +4,9 @@
 /* SPDX-License-Identifier: Unlicense */
 
 /* d = a + b (mod c) */
-int mp_addmod(const mp_int *a, const mp_int *b, const mp_int *c, mp_int *d)
+mp_err mp_addmod(const mp_int *a, const mp_int *b, const mp_int *c, mp_int *d)
 {
-   int     res;
+   mp_err  res;
    mp_int  t;
 
    if ((res = mp_init(&t)) != MP_OKAY) {

bn_mp_and.c

@@ -4,9 +4,10 @@
 /* SPDX-License-Identifier: Unlicense */
 
 /* AND two ints together */
-int mp_and(const mp_int *a, const mp_int *b, mp_int *c)
+mp_err mp_and(const mp_int *a, const mp_int *b, mp_int *c)
 {
-   int     res, ix, px;
+   int ix, px;
+   mp_err res;
    mp_int  t;
    const mp_int *x;
 

bn_mp_cmp.c

@@ -4,7 +4,7 @@
 /* SPDX-License-Identifier: Unlicense */
 
 /* compare two ints (signed)*/
-int mp_cmp(const mp_int *a, const mp_int *b)
+mp_ord mp_cmp(const mp_int *a, const mp_int *b)
 {
    /* compare based on sign */
    if (a->sign != b->sign) {

bn_mp_cmp_d.c

@@ -4,7 +4,7 @@
 /* SPDX-License-Identifier: Unlicense */
 
 /* compare a digit */
-int mp_cmp_d(const mp_int *a, mp_digit b)
+mp_ord mp_cmp_d(const mp_int *a, mp_digit b)
 {
    /* compare based on sign */
    if (a->sign == MP_NEG) {