mirror of
https://github.com/python/cpython.git
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291 lines
8.1 KiB
C
291 lines
8.1 KiB
C
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#include "Python.h"
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#if defined(__sgi) && !defined(_SGI_MP_SOURCE)
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#define _SGI_MP_SOURCE
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#endif
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/* strtol and strtoul, renamed to avoid conflicts */
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#include <ctype.h>
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#ifdef HAVE_ERRNO_H
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#include <errno.h>
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#endif
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/* Static overflow check values for bases 2 through 36.
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* smallmax[base] is the largest unsigned long i such that
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* i * base doesn't overflow unsigned long.
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*/
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static const unsigned long smallmax[] = {
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0, /* bases 0 and 1 are invalid */
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0,
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ULONG_MAX / 2,
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ULONG_MAX / 3,
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ULONG_MAX / 4,
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ULONG_MAX / 5,
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ULONG_MAX / 6,
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ULONG_MAX / 7,
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ULONG_MAX / 8,
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ULONG_MAX / 9,
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ULONG_MAX / 10,
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ULONG_MAX / 11,
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ULONG_MAX / 12,
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ULONG_MAX / 13,
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ULONG_MAX / 14,
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ULONG_MAX / 15,
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ULONG_MAX / 16,
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ULONG_MAX / 17,
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ULONG_MAX / 18,
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ULONG_MAX / 19,
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ULONG_MAX / 20,
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ULONG_MAX / 21,
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ULONG_MAX / 22,
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ULONG_MAX / 23,
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ULONG_MAX / 24,
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ULONG_MAX / 25,
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ULONG_MAX / 26,
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ULONG_MAX / 27,
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ULONG_MAX / 28,
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ULONG_MAX / 29,
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ULONG_MAX / 30,
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ULONG_MAX / 31,
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ULONG_MAX / 32,
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ULONG_MAX / 33,
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ULONG_MAX / 34,
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ULONG_MAX / 35,
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ULONG_MAX / 36,
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};
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/* maximum digits that can't ever overflow for bases 2 through 36,
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* calculated by [int(math.floor(math.log(2**32, i))) for i in range(2, 37)].
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* Note that this is pessimistic if sizeof(long) > 4.
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*/
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#if SIZEOF_LONG == 4
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static const int digitlimit[] = {
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0, 0, 32, 20, 16, 13, 12, 11, 10, 10, /* 0 - 9 */
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9, 9, 8, 8, 8, 8, 8, 7, 7, 7, /* 10 - 19 */
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7, 7, 7, 7, 6, 6, 6, 6, 6, 6, /* 20 - 29 */
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6, 6, 6, 6, 6, 6, 6}; /* 30 - 36 */
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#elif SIZEOF_LONG == 8
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/* [int(math.floor(math.log(2**64, i))) for i in range(2, 37)] */
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static const int digitlimit[] = {
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0, 0, 64, 40, 32, 27, 24, 22, 21, 20, /* 0 - 9 */
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19, 18, 17, 17, 16, 16, 16, 15, 15, 15, /* 10 - 19 */
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14, 14, 14, 14, 13, 13, 13, 13, 13, 13, /* 20 - 29 */
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13, 12, 12, 12, 12, 12, 12}; /* 30 - 36 */
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#else
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#error "Need table for SIZEOF_LONG"
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#endif
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/*
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** strtoul
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** This is a general purpose routine for converting
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** an ascii string to an integer in an arbitrary base.
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** Leading white space is ignored. If 'base' is zero
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** it looks for a leading 0b, 0o or 0x to tell which
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** base. If these are absent it defaults to 10.
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** Base must be 0 or between 2 and 36 (inclusive).
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** If 'ptr' is non-NULL it will contain a pointer to
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** the end of the scan.
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** Errors due to bad pointers will probably result in
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** exceptions - we don't check for them.
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*/
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unsigned long
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PyOS_strtoul(const char *str, char **ptr, int base)
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{
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unsigned long result = 0; /* return value of the function */
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int c; /* current input character */
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int ovlimit; /* required digits to overflow */
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/* skip leading white space */
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while (*str && Py_ISSPACE(Py_CHARMASK(*str)))
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++str;
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/* check for leading 0b, 0o or 0x for auto-base or base 16 */
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switch (base) {
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case 0: /* look for leading 0b, 0o or 0x */
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if (*str == '0') {
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++str;
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if (*str == 'x' || *str == 'X') {
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/* there must be at least one digit after 0x */
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if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 16) {
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if (ptr)
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*ptr = (char *)str;
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return 0;
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}
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++str;
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base = 16;
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} else if (*str == 'o' || *str == 'O') {
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/* there must be at least one digit after 0o */
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if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 8) {
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if (ptr)
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*ptr = (char *)str;
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return 0;
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}
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++str;
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base = 8;
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} else if (*str == 'b' || *str == 'B') {
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/* there must be at least one digit after 0b */
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if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 2) {
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if (ptr)
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*ptr = (char *)str;
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return 0;
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}
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++str;
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base = 2;
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} else {
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/* skip all zeroes... */
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while (*str == '0')
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++str;
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while (Py_ISSPACE(Py_CHARMASK(*str)))
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++str;
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if (ptr)
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*ptr = (char *)str;
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return 0;
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}
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}
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else
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base = 10;
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break;
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/* even with explicit base, skip leading 0? prefix */
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case 16:
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if (*str == '0') {
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++str;
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if (*str == 'x' || *str == 'X') {
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/* there must be at least one digit after 0x */
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if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 16) {
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if (ptr)
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*ptr = (char *)str;
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return 0;
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}
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++str;
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}
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}
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break;
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case 8:
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if (*str == '0') {
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++str;
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if (*str == 'o' || *str == 'O') {
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/* there must be at least one digit after 0o */
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if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 8) {
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if (ptr)
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*ptr = (char *)str;
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return 0;
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}
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++str;
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}
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}
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break;
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case 2:
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if(*str == '0') {
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++str;
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if (*str == 'b' || *str == 'B') {
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/* there must be at least one digit after 0b */
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if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 2) {
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if (ptr)
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*ptr = (char *)str;
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return 0;
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}
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++str;
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}
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}
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break;
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}
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/* catch silly bases */
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if (base < 2 || base > 36) {
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if (ptr)
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*ptr = (char *)str;
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return 0;
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}
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/* skip leading zeroes */
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while (*str == '0')
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++str;
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/* base is guaranteed to be in [2, 36] at this point */
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ovlimit = digitlimit[base];
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/* do the conversion until non-digit character encountered */
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while ((c = _PyLong_DigitValue[Py_CHARMASK(*str)]) < base) {
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if (ovlimit > 0) /* no overflow check required */
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result = result * base + c;
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else { /* requires overflow check */
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unsigned long temp_result;
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if (ovlimit < 0) /* guaranteed overflow */
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goto overflowed;
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/* there could be an overflow */
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/* check overflow just from shifting */
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if (result > smallmax[base])
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goto overflowed;
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result *= base;
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/* check overflow from the digit's value */
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temp_result = result + c;
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if (temp_result < result)
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goto overflowed;
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result = temp_result;
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}
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++str;
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--ovlimit;
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}
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/* set pointer to point to the last character scanned */
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if (ptr)
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*ptr = (char *)str;
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return result;
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overflowed:
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if (ptr) {
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/* spool through remaining digit characters */
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while (_PyLong_DigitValue[Py_CHARMASK(*str)] < base)
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++str;
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*ptr = (char *)str;
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}
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errno = ERANGE;
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return (unsigned long)-1;
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}
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/* Checking for overflow in PyOS_strtol is a PITA; see comments
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* about PY_ABS_LONG_MIN in longobject.c.
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*/
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#define PY_ABS_LONG_MIN (0-(unsigned long)LONG_MIN)
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long
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PyOS_strtol(const char *str, char **ptr, int base)
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{
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long result;
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unsigned long uresult;
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char sign;
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while (*str && Py_ISSPACE(Py_CHARMASK(*str)))
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str++;
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sign = *str;
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if (sign == '+' || sign == '-')
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str++;
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uresult = PyOS_strtoul(str, ptr, base);
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if (uresult <= (unsigned long)LONG_MAX) {
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result = (long)uresult;
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if (sign == '-')
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result = -result;
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}
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else if (sign == '-' && uresult == PY_ABS_LONG_MIN) {
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result = LONG_MIN;
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}
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else {
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errno = ERANGE;
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result = LONG_MAX;
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}
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return result;
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}
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