circuitpython/py/parsenum.c
Paul Sokolovsky 0294661da5 parsenum: Signedness issues.
char can be signedness, and using signedness types is dangerous - it can
lead to negative offsets when doing table lookups. We apparently should just
ban char usage.
2014-06-14 18:02:21 +03:00

267 lines
7.7 KiB
C

/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdbool.h>
#include <stdlib.h>
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "nlr.h"
#include "obj.h"
#include "parsenumbase.h"
#include "parsenum.h"
#include "smallint.h"
#if MICROPY_PY_BUILTINS_FLOAT
#include <math.h>
#endif
mp_obj_t mp_parse_num_integer(const char *restrict str_, uint len, int base) {
const byte *restrict str = (const byte *)str_;
const byte *restrict top = str + len;
bool neg = false;
mp_obj_t ret_val;
// check radix base
if ((base != 0 && base < 2) || base > 36) {
nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "int() arg 2 must be >= 2 and <= 36"));
}
// skip leading space
for (; str < top && unichar_isspace(*str); str++) {
}
// parse optional sign
if (str < top) {
if (*str == '+') {
str++;
} else if (*str == '-') {
str++;
neg = true;
}
}
// parse optional base prefix
str += mp_parse_num_base((const char*)str, top - str, &base);
// string should be an integer number
machine_int_t int_val = 0;
const byte *restrict str_val_start = str;
for (; str < top; str++) {
// get next digit as a value
int dig = *str;
if (unichar_isdigit(dig) && dig - '0' < base) {
// 0-9 digit
dig = dig - '0';
} else if (base == 16) {
dig |= 0x20;
if ('a' <= dig && dig <= 'f') {
// a-f hex digit
dig = dig - 'a' + 10;
} else {
// unknown character
break;
}
} else {
// unknown character
break;
}
// add next digi and check for overflow
if (mp_small_int_mul_overflow(int_val, base)) {
goto overflow;
}
int_val = int_val * base + dig;
if (!MP_SMALL_INT_FITS(int_val)) {
goto overflow;
}
}
// negate value if needed
if (neg) {
int_val = -int_val;
}
// create the small int
ret_val = MP_OBJ_NEW_SMALL_INT(int_val);
have_ret_val:
// check we parsed something
if (str == str_val_start) {
goto value_error;
}
// skip trailing space
for (; str < top && unichar_isspace(*str); str++) {
}
// check we reached the end of the string
if (str != top) {
goto value_error;
}
// return the object
return ret_val;
overflow:
// reparse using long int
{
const char *s2 = (const char*)str_val_start;
ret_val = mp_obj_new_int_from_str_len(&s2, top - str_val_start, neg, base);
str = (const byte*)s2;
goto have_ret_val;
}
value_error:
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "invalid syntax for integer with base %d: '%s'", base, str));
}
#define PARSE_DEC_IN_INTG (1)
#define PARSE_DEC_IN_FRAC (2)
#define PARSE_DEC_IN_EXP (3)
mp_obj_t mp_parse_num_decimal(const char *str, uint len, bool allow_imag, bool force_complex) {
#if MICROPY_PY_BUILTINS_FLOAT
const char *top = str + len;
mp_float_t dec_val = 0;
bool dec_neg = false;
bool imag = false;
// skip leading space
for (; str < top && unichar_isspace(*str); str++) {
}
// parse optional sign
if (str < top) {
if (*str == '+') {
str++;
} else if (*str == '-') {
str++;
dec_neg = true;
}
}
// determine what the string is
if (str < top && (str[0] | 0x20) == 'i') {
// string starts with 'i', should be 'inf' or 'infinity' (case insensitive)
if (str + 2 < top && (str[1] | 0x20) == 'n' && (str[2] | 0x20) == 'f') {
// inf
str += 3;
dec_val = INFINITY;
if (str + 4 < top && (str[0] | 0x20) == 'i' && (str[1] | 0x20) == 'n' && (str[2] | 0x20) == 'i' && (str[3] | 0x20) == 't' && (str[4] | 0x20) == 'y') {
// infinity
str += 5;
}
}
} else if (str < top && (str[0] | 0x20) == 'n') {
// string starts with 'n', should be 'nan' (case insensitive)
if (str + 2 < top && (str[1] | 0x20) == 'a' && (str[2] | 0x20) == 'n') {
// NaN
str += 3;
dec_val = MICROPY_FLOAT_C_FUN(nan)("");
}
} else {
// string should be a decimal number
int in = PARSE_DEC_IN_INTG;
bool exp_neg = false;
int exp_val = 0;
int exp_extra = 0;
for (; str < top; str++) {
int dig = *str;
if ('0' <= dig && dig <= '9') {
dig -= '0';
if (in == PARSE_DEC_IN_EXP) {
exp_val = 10 * exp_val + dig;
} else {
dec_val = 10 * dec_val + dig;
if (in == PARSE_DEC_IN_FRAC) {
exp_extra -= 1;
}
}
} else if (in == PARSE_DEC_IN_INTG && dig == '.') {
in = PARSE_DEC_IN_FRAC;
} else if (in != PARSE_DEC_IN_EXP && ((dig | 0x20) == 'e')) {
in = PARSE_DEC_IN_EXP;
if (str[1] == '+') {
str++;
} else if (str[1] == '-') {
str++;
exp_neg = true;
}
} else if (allow_imag && (dig | 0x20) == 'j') {
str++;
imag = true;
break;
} else {
// unknown character
break;
}
}
// work out the exponent
if (exp_neg) {
exp_val = -exp_val;
}
exp_val += exp_extra;
// apply the exponent
for (; exp_val > 0; exp_val--) {
dec_val *= 10;
}
for (; exp_val < 0; exp_val++) {
dec_val *= 0.1;
}
}
// negate value if needed
if (dec_neg) {
dec_val = -dec_val;
}
// skip trailing space
for (; str < top && unichar_isspace(*str); str++) {
}
// check we reached the end of the string
if (str != top) {
nlr_raise(mp_obj_new_exception_msg(&mp_type_SyntaxError, "invalid syntax for number"));
}
// return the object
if (imag) {
return mp_obj_new_complex(0, dec_val);
} else if (force_complex) {
return mp_obj_new_complex(dec_val, 0);
} else {
return mp_obj_new_float(dec_val);
}
#else
nlr_raise(mp_obj_new_exception_msg(&mp_type_SyntaxError, "decimal numbers not supported"));
#endif
}