Compatible numeric hashes - Code Review (original) (raw)

OLD

NEW

1 /* Long (arbitrary precision) integer object implementation */

3 /* XXX The functional organization of this file is terrible */

5 #include "Python.h"

6 #include "longintrepr.h"

7 #include "structseq.h"

9 #include <float.h>

10 #include <ctype.h>

(...skipping 2554 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading...

2565 case -1: return v->ob_digit[0]==1 ? -2 : -(sdigit)v->ob_digit[0];

2566 case 0: return 0;

2567 case 1: return v->ob_digit[0];

2568 }

2569 sign = 1;

2570 x = 0;

2571 if (i < 0) {

2572 sign = -1;

2573 i = -(i);

2574 }

2575 /* The following loop produces a C unsigned long x such that x is

2576 congruent to the absolute value of v modulo ULONG_MAX. The

2577 resulting x is nonzero if and only if v is. */

2578 while (--i >= 0) {

2575 while (--i >= 0) {

2579 » » /* Force a native long #-bits (32 or 64) circular shift */

2576 » » /* Rotate bottom 31 bits left by PyLong_SHIFT bits; in effect,

2580 » » x = (x >> (8*SIZEOF_LONG-PyLong_SHIFT)) | (x << PyLong_SHIFT);

2577 » » this multiplies by 2**PyLong_SHIFT modulo 2**31 - 1. */

2578 » » x = ((x << PyLong_SHIFT) & _PyHASH_MASK) |

2579 » » » (x >> (_PyHASH_BITS - PyLong_SHIFT));

2581 x += v->ob_digit[i];

2580 x += v->ob_digit[i];

2582 /* If the addition above overflowed we compensate by

2581 /* If the addition above overflowed we compensate by

2583 incrementing. This preserves the value modulo

2582 incrementing. This preserves the value modulo

2584 ULONG_MAX. */

2583 ULONG_MAX. */

2585 » » if (x < v->ob_digit[i])

2584 » » if (x > _PyHASH_MASK)

2586 » » » x++;

2585 » » » x -= _PyHASH_MASK;

2587 }

2586 }

2588 x = x * sign;

2587 x = x * sign;

2589 if (x == (unsigned long)-1)

2588 if (x == (unsigned long)-1)

2590 x = (unsigned long)-2;

2589 x = (unsigned long)-2;

2591 return (long)x;

2590 return (long)x;

2592 }

2591 }

2593

2592

2594

2593

2595 /* Add the absolute values of two long integers. */

2594 /* Add the absolute values of two long integers. */

2596

2595

(...skipping 2214 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading...

4811 reinitializations will fail. */

4810 reinitializations will fail. */

4812 #if NSMALLNEGINTS + NSMALLPOSINTS > 0

4811 #if NSMALLNEGINTS + NSMALLPOSINTS > 0

4813 int i;

4812 int i;

4814 PyLongObject *v = small_ints;

4813 PyLongObject *v = small_ints;

4815 for (i = 0; i < NSMALLNEGINTS + NSMALLPOSINTS; i++, v++) {

4814 for (i = 0; i < NSMALLNEGINTS + NSMALLPOSINTS; i++, v++) {

4816 _Py_DEC_REFTOTAL;

4815 _Py_DEC_REFTOTAL;

4817 _Py_ForgetReference((PyObject*)v);

4816 _Py_ForgetReference((PyObject*)v);

4818 }

4817 }

4819 #endif

4818 #endif

4820 }

4819 }

OLD

NEW