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/* | |
These functions provide integer arithmetic with integer checking. They do not | |
actually raise an exception when an overflow is detected, but rather set a bit | |
in the overflow parameter. (This parameter may be re-used across several | |
arithmetic operations, so should be or-ed rather than assigned to.) | |
The implementation is divided into two parts, the signed and unsigned basecases, | |
which is where the magic happens, and a generic template matching a specific | |
type to an implementation based on its (c-compile-time) size and signedness. | |
When possible, branching is avoided, and preference is given to speed over | |
accuracy (a low rate of falsely "detected" overflows are acceptable, | |
undetected overflows are not). | |
TODO: Hook up checking. | |
TODO: Conditionally support 128-bit with intmax_t? | |
*/ | |
/////////////// Common.proto /////////////// | |
static int __Pyx_check_twos_complement(void) { | |
if ((-1) != (~0)) { | |
PyErr_SetString(PyExc_RuntimeError, "Two's complement required for overflow checks."); | |
return 1; | |
} else if ((sizeof(short) == sizeof(int))) { | |
PyErr_SetString(PyExc_RuntimeError, "sizeof(short) < sizeof(int) required for overflow checks."); | |
return 1; | |
} else { | |
return 0; | |
} | |
} | |
/////////////// Common.init /////////////// | |
if (likely(__Pyx_check_twos_complement() == 0)); else | |
// error propagation code is appended automatically | |
/////////////// BaseCaseUnsigned.proto /////////////// | |
{{if UINT == "long long"}} | |
static CYTHON_INLINE {{UINT}} __Pyx_add_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} b, int *overflow); | |
static CYTHON_INLINE {{UINT}} __Pyx_sub_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} b, int *overflow); | |
static CYTHON_INLINE {{UINT}} __Pyx_mul_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} b, int *overflow); | |
static CYTHON_INLINE {{UINT}} __Pyx_div_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} b, int *overflow); | |
// Use these when b is known at compile time. | |
static CYTHON_INLINE {{UINT}} __Pyx_mul_const_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} constant, int *overflow); | |
{{if UINT == "long long"}} | |
/////////////// BaseCaseUnsigned /////////////// | |
{{if UINT == "long long"}} | |
static CYTHON_INLINE {{UINT}} __Pyx_add_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} b, int *overflow) { | |
{{UINT}} result; | |
*overflow |= __builtin_add_overflow(a, b, &result); | |
return result; | |
} | |
static CYTHON_INLINE {{UINT}} __Pyx_sub_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} b, int *overflow) { | |
{{UINT}} result; | |
*overflow |= __builtin_sub_overflow(a, b, &result); | |
return result; | |
} | |
static CYTHON_INLINE {{UINT}} __Pyx_mul_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} b, int *overflow) { | |
{{UINT}} result; | |
*overflow |= __builtin_mul_overflow(a, b, &result); | |
return result; | |
} | |
static CYTHON_INLINE {{UINT}} __Pyx_add_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} b, int *overflow) { | |
{{UINT}} r = a + b; | |
*overflow |= r < a; | |
return r; | |
} | |
static CYTHON_INLINE {{UINT}} __Pyx_sub_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} b, int *overflow) { | |
{{UINT}} r = a - b; | |
*overflow |= r > a; | |
return r; | |
} | |
static CYTHON_INLINE {{UINT}} __Pyx_mul_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} b, int *overflow) { | |
// if we have a constant, use the constant version | |
if (__Pyx_is_constant(b)) { | |
return __Pyx_mul_const_{{NAME}}_checking_overflow(a, b, overflow); | |
} else if (__Pyx_is_constant(a)) { | |
return __Pyx_mul_const_{{NAME}}_checking_overflow(b, a, overflow); | |
} else if ((sizeof({{UINT}}) < sizeof(unsigned long))) { | |
unsigned long big_r = ((unsigned long) a) * ((unsigned long) b); | |
{{UINT}} r = ({{UINT}}) big_r; | |
*overflow |= big_r != r; | |
return r; | |
} else if ((sizeof({{UINT}}) < sizeof(unsigned PY_LONG_LONG))) { | |
unsigned PY_LONG_LONG big_r = ((unsigned PY_LONG_LONG) a) * ((unsigned PY_LONG_LONG) b); | |
{{UINT}} r = ({{UINT}}) big_r; | |
*overflow |= big_r != r; | |
return r; | |
} else { | |
return __Pyx_mul_const_{{NAME}}_checking_overflow(a, b, overflow); | |
} | |
} | |
static CYTHON_INLINE {{UINT}} __Pyx_mul_const_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} b, int *overflow) { | |
// note that deliberately the overflow check is written such that it divides by b; this | |
// function is used when b is a constant thus the compiler should be able to eliminate the | |
// (very slow on most CPUs!) division operation | |
{{UINT}} prod; | |
if (__Pyx_is_constant(a) && !__Pyx_is_constant(b)) { | |
// if a is a compile-time constant and b isn't, swap them | |
{{UINT}} temp = b; | |
b = a; | |
a = temp; | |
} | |
prod = a * b; | |
if (b != 0) | |
*overflow |= a > (__PYX_MAX({{UINT}}) / b); | |
return prod; | |
} | |
static CYTHON_INLINE {{UINT}} __Pyx_div_{{NAME}}_checking_overflow({{UINT}} a, {{UINT}} b, int *overflow) { | |
if (b == 0) { | |
*overflow |= 1; | |
return 0; | |
} | |
return a / b; | |
} | |
{{if UINT == "long long"}} | |
/////////////// BaseCaseSigned.proto /////////////// | |
{{if INT == "long long"}} | |
static CYTHON_INLINE {{INT}} __Pyx_add_{{NAME}}_checking_overflow({{INT}} a, {{INT}} b, int *overflow); | |
static CYTHON_INLINE {{INT}} __Pyx_sub_{{NAME}}_checking_overflow({{INT}} a, {{INT}} b, int *overflow); | |
static CYTHON_INLINE {{INT}} __Pyx_mul_{{NAME}}_checking_overflow({{INT}} a, {{INT}} b, int *overflow); | |
static CYTHON_INLINE {{INT}} __Pyx_div_{{NAME}}_checking_overflow({{INT}} a, {{INT}} b, int *overflow); | |
// Use when b is known at compile time. | |
static CYTHON_INLINE {{INT}} __Pyx_mul_const_{{NAME}}_checking_overflow({{INT}} a, {{INT}} constant, int *overflow); | |
{{if INT == "long long"}} | |
/////////////// BaseCaseSigned /////////////// | |
{{if INT == "long long"}} | |
static CYTHON_INLINE {{INT}} __Pyx_add_{{NAME}}_checking_overflow({{INT}} a, {{INT}} b, int *overflow) { | |
{{INT}} result; | |
*overflow |= __builtin_add_overflow(a, b, &result); | |
return result; | |
} | |
static CYTHON_INLINE {{INT}} __Pyx_sub_{{NAME}}_checking_overflow({{INT}} a, {{INT}} b, int *overflow) { | |
{{INT}} result; | |
*overflow |= __builtin_sub_overflow(a, b, &result); | |
return result; | |
} | |
static CYTHON_INLINE {{INT}} __Pyx_mul_{{NAME}}_checking_overflow({{INT}} a, {{INT}} b, int *overflow) { | |
{{INT}} result; | |
*overflow |= __builtin_mul_overflow(a, b, &result); | |
return result; | |
} | |
static CYTHON_INLINE {{INT}} __Pyx_add_{{NAME}}_checking_overflow({{INT}} a, {{INT}} b, int *overflow) { | |
if ((sizeof({{INT}}) < sizeof(long))) { | |
long big_r = ((long) a) + ((long) b); | |
{{INT}} r = ({{INT}}) big_r; | |
*overflow |= big_r != r; | |
return r; | |
} else if ((sizeof({{INT}}) < sizeof(PY_LONG_LONG))) { | |
PY_LONG_LONG big_r = ((PY_LONG_LONG) a) + ((PY_LONG_LONG) b); | |
{{INT}} r = ({{INT}}) big_r; | |
*overflow |= big_r != r; | |
return r; | |
} else { | |
// Signed overflow undefined, but unsigned overflow is well defined. Casting is | |
// implementation-defined, but we assume two's complement (see __Pyx_check_twos_complement | |
// above), and arithmetic in two's-complement is the same as unsigned arithmetic. | |
unsigned {{INT}} r = (unsigned {{INT}}) a + (unsigned {{INT}}) b; | |
// Overflow happened if the operands have the same sign, but the result | |
// has opposite sign. | |
*overflow |= (((unsigned {{INT}})a ^ r) & ((unsigned {{INT}})b ^ r)) >> (8 * sizeof({{INT}}) - 1); | |
return ({{INT}}) r; | |
} | |
} | |
static CYTHON_INLINE {{INT}} __Pyx_sub_{{NAME}}_checking_overflow({{INT}} a, {{INT}} b, int *overflow) { | |
// Compilers don't handle widening as well in the subtraction case, so don't bother | |
unsigned {{INT}} r = (unsigned {{INT}}) a - (unsigned {{INT}}) b; | |
// Overflow happened if the operands differing signs, and the result | |
// has opposite sign to a. | |
*overflow |= (((unsigned {{INT}})a ^ (unsigned {{INT}})b) & ((unsigned {{INT}})a ^ r)) >> (8 * sizeof({{INT}}) - 1); | |
return ({{INT}}) r; | |
} | |
static CYTHON_INLINE {{INT}} __Pyx_mul_{{NAME}}_checking_overflow({{INT}} a, {{INT}} b, int *overflow) { | |
// if we have a constant, use the constant version | |
if (__Pyx_is_constant(b)) { | |
return __Pyx_mul_const_{{NAME}}_checking_overflow(a, b, overflow); | |
} else if (__Pyx_is_constant(a)) { | |
return __Pyx_mul_const_{{NAME}}_checking_overflow(b, a, overflow); | |
} else if ((sizeof({{INT}}) < sizeof(long))) { | |
long big_r = ((long) a) * ((long) b); | |
{{INT}} r = ({{INT}}) big_r; | |
*overflow |= big_r != r; | |
return ({{INT}}) r; | |
} else if ((sizeof({{INT}}) < sizeof(PY_LONG_LONG))) { | |
PY_LONG_LONG big_r = ((PY_LONG_LONG) a) * ((PY_LONG_LONG) b); | |
{{INT}} r = ({{INT}}) big_r; | |
*overflow |= big_r != r; | |
return ({{INT}}) r; | |
} else { | |
return __Pyx_mul_const_{{NAME}}_checking_overflow(a, b, overflow); | |
} | |
} | |
static CYTHON_INLINE {{INT}} __Pyx_mul_const_{{NAME}}_checking_overflow({{INT}} a, {{INT}} b, int *overflow) { | |
// note that deliberately all these comparisons are written such that they divide by b; this | |
// function is used when b is a constant thus the compiler should be able to eliminate the | |
// (very slow on most CPUs!) division operations | |
if (__Pyx_is_constant(a) && !__Pyx_is_constant(b)) { | |
// if a is a compile-time constant and b isn't, swap them | |
{{INT}} temp = b; | |
b = a; | |
a = temp; | |
} | |
if (b > 1) { | |
*overflow |= a > __PYX_MAX({{INT}}) / b; | |
*overflow |= a < __PYX_MIN({{INT}}) / b; | |
} else if (b == -1) { | |
*overflow |= a == __PYX_MIN({{INT}}); | |
} else if (b < -1) { | |
*overflow |= a > __PYX_MIN({{INT}}) / b; | |
*overflow |= a < __PYX_MAX({{INT}}) / b; | |
} | |
return ({{INT}}) (((unsigned {{INT}})a) * ((unsigned {{INT}}) b)); | |
} | |
static CYTHON_INLINE {{INT}} __Pyx_div_{{NAME}}_checking_overflow({{INT}} a, {{INT}} b, int *overflow) { | |
if (b == 0) { | |
*overflow |= 1; | |
return 0; | |
} | |
*overflow |= a == __PYX_MIN({{INT}}) && b == -1; | |
return ({{INT}}) ((unsigned {{INT}}) a / (unsigned {{INT}}) b); | |
} | |
{{if INT == "long long"}} | |
/////////////// SizeCheck.init /////////////// | |
if (likely(__Pyx_check_sane_{{NAME}}() == 0)); else | |
// error propagation code is appended automatically | |
/////////////// SizeCheck.proto /////////////// | |
static int __Pyx_check_sane_{{NAME}}(void) { | |
if (((sizeof({{TYPE}}) <= sizeof(int)) || | |
(sizeof({{TYPE}}) == sizeof(PY_LONG_LONG)) || | |
(sizeof({{TYPE}}) == sizeof(long)))) { | |
return 0; | |
} else { | |
PyErr_Format(PyExc_RuntimeError, \ | |
"Bad size for int type %.{{max(60, len(TYPE))}}s: %d", "{{TYPE}}", (int) sizeof({{TYPE}})); | |
return 1; | |
} | |
} | |
/////////////// Binop.proto /////////////// | |
static CYTHON_INLINE {{TYPE}} __Pyx_{{BINOP}}_{{NAME}}_checking_overflow({{TYPE}} a, {{TYPE}} b, int *overflow); | |
/////////////// Binop /////////////// | |
static CYTHON_INLINE {{TYPE}} __Pyx_{{BINOP}}_{{NAME}}_checking_overflow({{TYPE}} a, {{TYPE}} b, int *overflow) { | |
if ((sizeof({{TYPE}}) < sizeof(int))) { | |
return __Pyx_{{BINOP}}_no_overflow(a, b, overflow); | |
} else if (__PYX_IS_UNSIGNED({{TYPE}})) { | |
if ((sizeof({{TYPE}}) == sizeof(unsigned int))) { | |
return ({{TYPE}}) __Pyx_{{BINOP}}_unsigned_int_checking_overflow(a, b, overflow); | |
} else if ((sizeof({{TYPE}}) == sizeof(unsigned long))) { | |
return ({{TYPE}}) __Pyx_{{BINOP}}_unsigned_long_checking_overflow(a, b, overflow); | |
} else if ((sizeof({{TYPE}}) == sizeof(unsigned PY_LONG_LONG))) { | |
return ({{TYPE}}) __Pyx_{{BINOP}}_unsigned_long_long_checking_overflow(a, b, overflow); | |
} else { | |
abort(); return 0; /* handled elsewhere */ | |
} | |
} else { | |
if ((sizeof({{TYPE}}) == sizeof(int))) { | |
return ({{TYPE}}) __Pyx_{{BINOP}}_int_checking_overflow(a, b, overflow); | |
} else if ((sizeof({{TYPE}}) == sizeof(long))) { | |
return ({{TYPE}}) __Pyx_{{BINOP}}_long_checking_overflow(a, b, overflow); | |
} else if ((sizeof({{TYPE}}) == sizeof(PY_LONG_LONG))) { | |
return ({{TYPE}}) __Pyx_{{BINOP}}_long_long_checking_overflow(a, b, overflow); | |
} else { | |
abort(); return 0; /* handled elsewhere */ | |
} | |
} | |
} | |
/////////////// LeftShift.proto /////////////// | |
static CYTHON_INLINE {{TYPE}} __Pyx_lshift_{{NAME}}_checking_overflow({{TYPE}} a, {{TYPE}} b, int *overflow) { | |
int overflow_check = | |
(a < 0) || (b < 0) || | |
// the following must be a _logical_ OR as the RHS is undefined if the LHS is true | |
(b >= ({{TYPE}}) (8 * sizeof({{TYPE}}))) || (a > (__PYX_MAX({{TYPE}}) >> b)); | |
if (overflow_check) { | |
*overflow |= 1; | |
return 0; | |
} else { | |
return a << b; | |
} | |
} | |
/////////////// UnaryNegOverflows.proto /////////////// | |
// from intobject.c | |