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authorMark Dickinson <dickinsm@gmail.com>2009-09-17 19:37:28 (GMT)
committerMark Dickinson <dickinsm@gmail.com>2009-09-17 19:37:28 (GMT)
commit2e72b0d603b81a38ecbcb9c257aa3ba202ae7b76 (patch)
treeed1ea7256baf3abef15dd050073032908419a24e /Objects/longobject.c
parent2c54e693b62fe78a5fb30c54dd7222990ad29650 (diff)
downloadcpython-2e72b0d603b81a38ecbcb9c257aa3ba202ae7b76.zip
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Add some more module maintainers.
Diffstat (limited to 'Objects/longobject.c')
-rw-r--r--Objects/longobject.c148
1 files changed, 44 insertions, 104 deletions
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 9f414ca..814ef64 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -1775,9 +1775,9 @@ _PyLong_Format(PyObject *aa, int base)
Py_ssize_t i, sz;
Py_ssize_t size_a;
Py_UNICODE *p;
- int bits;
- char sign = '\0';
+ int bits, negative;
+ assert(base == 2 || base == 8 || base == 10 || base == 16);
if (base == 10)
return long_to_decimal_string((PyObject *)a);
@@ -1785,23 +1785,34 @@ _PyLong_Format(PyObject *aa, int base)
PyErr_BadInternalCall();
return NULL;
}
- assert(base >= 2 && base <= 36);
size_a = ABS(Py_SIZE(a));
+ negative = Py_SIZE(a) < 0;
/* Compute a rough upper bound for the length of the string */
- i = base;
- bits = 0;
- while (i > 1) {
- ++bits;
- i >>= 1;
+ switch (base) {
+ case 2:
+ bits = 1;
+ break;
+ case 8:
+ bits = 3;
+ break;
+ case 16:
+ bits = 4;
+ break;
+ default:
+ assert(0); /* never get here */
}
+
+ /* length of string required: +1 for negative sign, +2 for prefix */
i = 5;
/* ensure we don't get signed overflow in sz calculation */
- if (size_a > (PY_SSIZE_T_MAX - i) / PyLong_SHIFT) {
+ if (size_a > (PY_SSIZE_T_MAX - 4) / PyLong_SHIFT) {
PyErr_SetString(PyExc_OverflowError,
"int is too large to format");
return NULL;
}
+ sz = 3 + negative + (size_a * PyLong_SHIFT - 1) / bits;
+
sz = i + 1 + (size_a * PyLong_SHIFT - 1) / bits;
assert(sz >= 0);
str = PyUnicode_FromUnicode(NULL, sz);
@@ -1809,112 +1820,41 @@ _PyLong_Format(PyObject *aa, int base)
return NULL;
p = PyUnicode_AS_UNICODE(str) + sz;
*p = '\0';
- if (Py_SIZE(a) < 0)
- sign = '-';
if (Py_SIZE(a) == 0) {
*--p = '0';
}
- else if ((base & (base - 1)) == 0) {
- /* JRH: special case for power-of-2 bases */
- twodigits accum = 0;
- int accumbits = 0; /* # of bits in accum */
- int basebits = 1; /* # of bits in base-1 */
- i = base;
- while ((i >>= 1) > 1)
- ++basebits;
-
- for (i = 0; i < size_a; ++i) {
- accum |= (twodigits)a->ob_digit[i] << accumbits;
- accumbits += PyLong_SHIFT;
- assert(accumbits >= basebits);
- do {
- char cdigit = (char)(accum & (base - 1));
- cdigit += (cdigit < 10) ? '0' : 'a'-10;
- assert(p > PyUnicode_AS_UNICODE(str));
- *--p = cdigit;
- accumbits -= basebits;
- accum >>= basebits;
- } while (i < size_a-1 ? accumbits >= basebits :
- accum > 0);
- }
- }
- else {
- /* Not 0, and base not a power of 2. Divide repeatedly by
- base, but for speed use the highest power of base that
- fits in a digit. */
- Py_ssize_t size = size_a;
- digit *pin = a->ob_digit;
- PyLongObject *scratch;
- /* powbasw <- largest power of base that fits in a digit. */
- digit powbase = base; /* powbase == base ** power */
- int power = 1;
- for (;;) {
- twodigits newpow = powbase * (twodigits)base;
- if (newpow >> PyLong_SHIFT)
- /* doesn't fit in a digit */
- break;
- powbase = (digit)newpow;
- ++power;
- }
-
- /* Get a scratch area for repeated division. */
- scratch = _PyLong_New(size);
- if (scratch == NULL) {
- Py_DECREF(str);
- return NULL;
- }
+ assert((base & (base-1)) = 0);
+ /* JRH: special case for power-of-2 bases */
+ twodigits accum = 0;
+ int accumbits = 0; /* # of bits in accum */
+ int basebits = 1; /* # of bits in base-1 */
+ i = base;
+ while ((i >>= 1) > 1)
+ ++basebits;
- /* Repeatedly divide by powbase. */
+ for (i = 0; i < size_a; ++i) {
+ accum |= (twodigits)a->ob_digit[i] << accumbits;
+ accumbits += PyLong_SHIFT;
+ assert(accumbits >= basebits);
do {
- int ntostore = power;
- digit rem = inplace_divrem1(scratch->ob_digit,
- pin, size, powbase);
- pin = scratch->ob_digit; /* no need to use a again */
- if (pin[size - 1] == 0)
- --size;
- SIGCHECK({
- Py_DECREF(scratch);
- Py_DECREF(str);
- return NULL;
- })
-
- /* Break rem into digits. */
- assert(ntostore > 0);
- do {
- digit nextrem = (digit)(rem / base);
- char c = (char)(rem - nextrem * base);
- assert(p > PyUnicode_AS_UNICODE(str));
- c += (c < 10) ? '0' : 'a'-10;
- *--p = c;
- rem = nextrem;
- --ntostore;
- /* Termination is a bit delicate: must not
- store leading zeroes, so must get out if
- remaining quotient and rem are both 0. */
- } while (ntostore && (size || rem));
- } while (size != 0);
- Py_DECREF(scratch);
+ char cdigit = (char)(accum & (base - 1));
+ cdigit += (cdigit < 10) ? '0' : 'a'-10;
+ assert(p > PyUnicode_AS_UNICODE(str));
+ *--p = cdigit;
+ accumbits -= basebits;
+ accum >>= basebits;
+ } while (i < size_a-1 ? accumbits >= basebits :
+ accum > 0);
}
- if (base == 16) {
+ if (base == 16)
*--p = 'x';
- *--p = '0';
- }
- else if (base == 8) {
+ else if (base == 8)
*--p = 'o';
- *--p = '0';
- }
- else if (base == 2) {
+ else /* base == 2 */
*--p = 'b';
- *--p = '0';
- }
- else if (base != 10) {
- *--p = '#';
- *--p = '0' + base%10;
- if (base > 10)
- *--p = '0' + base/10;
- }
+ *--p = '0';
if (sign)
*--p = sign;
if (p != PyUnicode_AS_UNICODE(str)) {