#ifndef UC_SATMATH_H_
#define UC_SATMATH_H_
#include <stdint.h>

/** @file
 * Implementation of saturated operation on uintxx_t. 
 *
 * Operations are clamped between 0 and UINTxx_MAX instead of
 * wrapping around.
 *
 * multiplication, subtraction and addition operations are provided.*/

//Use gcc builtins, supported since GCC 5
#if __GNUC__ >= 5

#define UC_SAT_ADD(a, b, type, max_val)\
({type res ;\
if (__builtin_add_overflow(a, b, &res)) {\
    res = max_val;}\
res;})


#define UC_SAT_SUB(a, b, type)\
({type res ;\
if (__builtin_sub_overflow(a, b, &res)) {\
    res = 0;}\
res;})

#define UC_SAT_MULT(a, b, type, max_val)\
({type res ;\
if (__builtin_mul_overflow(a, b, &res)) {\
    res = max_val;}\
res;})

#else

#define UC_SAT_ADD(a, b, type, max_val)\
((type)((a) + (b)) >= (a) ? (a) + (b) : (max_val))

#define UC_SAT_SUB(a, b, type)\
((a) >= (b) ? (a) - (b) : 0)

#define UC_SAT_MULT(a, b, type, max_val)\
((b) == 0 ? 0 :\
(a) <= (max_val) / (b) ? (type) (a) * (type) (b)  \
          : (max_val))

#endif

static inline uint8_t uc_sat_addu8(uint8_t a, uint8_t b)
{
    return UC_SAT_ADD(a, b, uint8_t, UINT8_MAX);
}

static inline uint8_t uc_sat_subu8(uint8_t a, uint8_t b)
{
    return UC_SAT_SUB(a, b, uint8_t);
}

static inline uint8_t uc_sat_multu8(uint8_t a, uint8_t b)
{
    return UC_SAT_MULT(a, b, uint8_t, UINT8_MAX);
}

static inline uint16_t uc_sat_addu16(uint16_t a, uint16_t b)
{
    return UC_SAT_ADD(a, b, uint16_t, UINT16_MAX);
}

static inline uint16_t uc_sat_subu16(uint16_t a, uint16_t b)
{
    return UC_SAT_SUB(a, b, uint16_t);
}

static inline uint16_t uc_sat_multu16(uint16_t a, uint16_t b)
{
    return UC_SAT_MULT(a, b, uint16_t, UINT16_MAX);
}

static inline uint32_t uc_sat_addu32(uint32_t a, uint32_t b)
{
    return UC_SAT_ADD(a, b, uint32_t, UINT32_MAX);
}

static inline uint32_t uc_sat_subu32(uint32_t a, uint32_t b)
{
    return UC_SAT_SUB(a, b, uint32_t);
}

static inline uint32_t uc_sat_multu32(uint32_t a, uint32_t b)
{
    return UC_SAT_MULT(a, b, uint32_t, UINT32_MAX);
}

static inline uint64_t uc_sat_addu64(uint64_t a, uint64_t b)
{
    return UC_SAT_ADD(a, b, uint64_t, UINT64_MAX);
}

static inline uint64_t uc_sat_subu64(uint64_t a, uint64_t b)
{
    return UC_SAT_SUB(a, b, uint64_t);
}

static inline uint64_t uc_sat_multu64(uint64_t a, uint64_t b)
{
    return UC_SAT_MULT(a, b, uint64_t, UINT64_MAX);
}

#endif