compat: stdckdint: handle signed cases

compat/stdckdint/stdckdint.h

@@ -45,8 +45,72 @@ static inline _Bool __ckd_mul_##suffix(type *r, type a, type b) \
     return b > 0 && a > (MAX / b); \
 }
 
+#  define __ckd_signed_common(suffix, type, MIN, MAX) \
+static inline _Bool __ckd_add_##suffix(type *r, type a, type b) \
+{ \
+    union suffix ua = { .v = a }; \
+    union suffix ub = { .v = b }; \
+    union suffix ur = { .uv = ua.uv + ub.uv }; \
+    *r = ur.v; \
+    if ((b > 0 && a > (MAX - b)) || (b < 0 && a < (MIN - b))) \
+        return 1; \
+    return 0; \
+} \
+\
+static inline _Bool __ckd_sub_##suffix(type *r, type a, type b) \
+{ \
+    union suffix ua = { .v = a }; \
+    union suffix ub = { .v = b }; \
+    union suffix ur = { .uv = ua.uv - ub.uv }; \
+    *r = ur.v; \
+    if ((b < 0 && a > (MAX + b)) || (b > 0 && a < (MIN + b))) \
+        return 1; \
+    return 0; \
+} \
+\
+static inline _Bool __ckd_mul_##suffix(type *r, type a, type b) \
+{ \
+    union suffix ua = { .v = a }; \
+    union suffix ub = { .v = b }; \
+    union suffix ur = { .uv = ua.uv * ub.uv }; \
+    *r = ur.v; \
+    if (a > 0) { \
+        if (b > 0) { \
+            if (a > (MAX / b)) return 1; \
+        } else if (b < 0) { \
+            if (b < (MIN / a)) return 1; \
+        } \
+    } else if (a < 0) { \
+        if (b > 0) { \
+            if (a < (MIN / b)) return 1; \
+        } else if (b < 0) { \
+            if (b < (MAX / a)) return 1; \
+        } \
+    } \
+    return 0; \
+}
+
+#  define __ckd_signed(suffix, type, MIN, MAX) \
+union suffix { \
+    unsigned type uv; \
+    type v; \
+}; \
+__ckd_signed_common(suffix, type, MIN, MAX)
+
+#  define __ckd_signed_forced(suffix, type, MIN, MAX) \
+union suffix { \
+    unsigned type uv; \
+    signed type v; \
+}; \
+__ckd_signed_common(suffix, signed type, MIN, MAX)
+
 #  define __ckd_func(op, r, a, b) \
     _Generic (*(r), \
+        signed char:        __ckd_##op##_sc((signed char *)(r), a, b), \
+        short:              __ckd_##op##_ss((short *)(r), a, b), \
+        int:                __ckd_##op##_si((int *)(r), a, b), \
+        long:               __ckd_##op##_sl((long *)(r), a, b), \
+        long long:          __ckd_##op##_sll((long long *)(r), a, b), \
         unsigned char:      __ckd_##op##_uc((unsigned char *)(r), a, b), \
         unsigned short:     __ckd_##op##_us((unsigned short *)(r), a, b), \
         unsigned int:       __ckd_##op##_ui((unsigned int *)(r), a, b), \
@@ -59,6 +123,12 @@ __ckd_unsigned(ui,  unsigned int,       UINT_MAX)
 __ckd_unsigned(ul,  unsigned long,      ULONG_MAX)
 __ckd_unsigned(ull, unsigned long long, ULLONG_MAX)
 
+__ckd_signed_forced(sc,  char, SCHAR_MIN, SCHAR_MAX)
+__ckd_signed(ss,  short,       SHRT_MIN,  SHRT_MAX)
+__ckd_signed(si,  int,         INT_MIN,   INT_MAX)
+__ckd_signed(sl,  long,        LONG_MIN,  LONG_MAX)
+__ckd_signed(sll, long long,   LLONG_MIN, LLONG_MAX)
+
 #  define ckd_add(r, a, b) __ckd_func(add, r, a, b)
 #  define ckd_sub(r, a, b) __ckd_func(sub, r, a, b)
 #  define ckd_mul(r, a, b) __ckd_func(mul, r, a, b)