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py: Implement parsing of infinity and nan for floats.

This commit is contained in:
Damien George 2014-03-21 10:55:08 +00:00
parent 1609f85582
commit c06ea7abf2
4 changed files with 109 additions and 49 deletions
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2
py/objfloat.c
View File

@ -38,7 +38,7 @@ STATIC mp_obj_t float_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const m
// a string, parse it
uint l;
const char *s = mp_obj_str_get_data(args[0], &l);
return mp_parse_num_decimal(s, l);
return mp_parse_num_decimal(s, l, false);
} else if (MP_OBJ_IS_TYPE(args[0], &mp_type_float)) {
return args[0];
} else {

152
py/parsenum.c
View File

@ -9,6 +9,10 @@
#include "parsenumbase.h"
#include "parsenum.h"
#if MICROPY_ENABLE_FLOAT
#include <math.h>
#endif
#if defined(UNIX)
#include <ctype.h>
@ -84,64 +88,120 @@ mp_obj_t mp_parse_num_integer(const char *restrict str, uint len, int base) {
#define PARSE_DEC_IN_FRAC (2)
#define PARSE_DEC_IN_EXP (3)
mp_obj_t mp_parse_num_decimal(const char *str, uint len) {
mp_obj_t mp_parse_num_decimal(const char *str, uint len, bool allow_imag) {
#if MICROPY_ENABLE_FLOAT
int in = PARSE_DEC_IN_INTG;
mp_float_t dec_val = 0;
bool exp_neg = false;
int exp_val = 0;
int exp_extra = 0;
bool imag = false;
const char *top = str + len;
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 == 'E' || dig == 'e')) {
in = PARSE_DEC_IN_EXP;
if (str[1] == '+') {
str++;
} else if (str[1] == '-') {
str++;
exp_neg = true;
}
} else if (dig == 'J' || dig == 'j') {
mp_float_t dec_val = 0;
bool dec_neg = false;
bool imag = false;
// skip leading space
for (; str < top && isspace(*str); str++) {
}
// get optional sign
if (str < top) {
if (*str == '+') {
str++;
imag = true;
break;
} else {
// unknown character
break;
} else if (*str == '-') {
str++;
dec_neg = true;
}
}
if (*str != 0) {
// 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 {
// parse the digits
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 && isspace(*str); str++) {
}
// check we reached the end of the string
if (str != top) {
nlr_jump(mp_obj_new_exception_msg(&mp_type_SyntaxError, "invalid syntax for number"));
}
if (exp_neg) {
exp_val = -exp_val;
}
exp_val += exp_extra;
for (; exp_val > 0; exp_val--) {
dec_val *= 10;
}
for (; exp_val < 0; exp_val++) {
dec_val *= 0.1;
}
// return the object
if (imag) {
return mp_obj_new_complex(0, dec_val);
} else {
return mp_obj_new_float(dec_val);
}
#else
nlr_jump(mp_obj_new_exception_msg(&mp_type_SyntaxError, "decimal numbers not supported"));
#endif

2
py/parsenum.h
View File

@ -1,2 +1,2 @@
mp_obj_t mp_parse_num_integer(const char *restrict str, uint len, int base);
mp_obj_t mp_parse_num_decimal(const char *str, uint len);
mp_obj_t mp_parse_num_decimal(const char *str, uint len, bool allow_imag);

2
py/runtime.c
View File

@ -375,7 +375,7 @@ mp_obj_t rt_load_const_dec(qstr qstr) {
DEBUG_OP_printf("load '%s'\n", qstr_str(qstr));
uint len;
const byte* data = qstr_data(qstr, &len);
return mp_parse_num_decimal((const char*)data, len);
return mp_parse_num_decimal((const char*)data, len, true);
}
mp_obj_t rt_load_const_str(qstr qstr) {