diff options
Diffstat (limited to 'py/parsenum.c')
| -rw-r--r-- | py/parsenum.c | 56 |
1 files changed, 46 insertions, 10 deletions
diff --git a/py/parsenum.c b/py/parsenum.c index bacf4f442..e3644b171 100644 --- a/py/parsenum.c +++ b/py/parsenum.c @@ -83,6 +83,8 @@ mp_obj_t mp_parse_num_integer(const char *restrict str_, size_t len, int base, m mp_uint_t dig = *str; if ('0' <= dig && dig <= '9') { dig -= '0'; + } else if (dig == '_') { + continue; } else { dig |= 0x20; // make digit lower-case if ('a' <= dig && dig <= 'z') { @@ -170,6 +172,19 @@ typedef enum { mp_obj_t mp_parse_num_decimal(const char *str, size_t len, bool allow_imag, bool force_complex, mp_lexer_t *lex) { #if MICROPY_PY_BUILTINS_FLOAT + +// DEC_VAL_MAX only needs to be rough and is used to retain precision while not overflowing +// SMALL_NORMAL_VAL is the smallest power of 10 that is still a normal float +#if MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_FLOAT +#define DEC_VAL_MAX 1e20F +#define SMALL_NORMAL_VAL (1e-37F) +#define SMALL_NORMAL_EXP (-37) +#elif MICROPY_FLOAT_IMPL == MICROPY_FLOAT_IMPL_DOUBLE +#define DEC_VAL_MAX 1e200 +#define SMALL_NORMAL_VAL (1e-307) +#define SMALL_NORMAL_EXP (-307) +#endif + const char *top = str + len; mp_float_t dec_val = 0; bool dec_neg = false; @@ -214,20 +229,32 @@ mp_obj_t mp_parse_num_decimal(const char *str, size_t len, bool allow_imag, bool // string should be a decimal number parse_dec_in_t in = PARSE_DEC_IN_INTG; bool exp_neg = false; - mp_float_t frac_mult = 0.1; - mp_int_t exp_val = 0; + int exp_val = 0; + int exp_extra = 0; while (str < top) { - mp_uint_t dig = *str++; + unsigned int dig = *str++; if ('0' <= dig && dig <= '9') { dig -= '0'; if (in == PARSE_DEC_IN_EXP) { - exp_val = 10 * exp_val + dig; + // don't overflow exp_val when adding next digit, instead just truncate + // it and the resulting float will still be correct, either inf or 0.0 + // (use INT_MAX/2 to allow adding exp_extra at the end without overflow) + if (exp_val < (INT_MAX / 2 - 9) / 10) { + exp_val = 10 * exp_val + dig; + } } else { - if (in == PARSE_DEC_IN_FRAC) { - dec_val += dig * frac_mult; - frac_mult *= MICROPY_FLOAT_CONST(0.1); - } else { + if (dec_val < DEC_VAL_MAX) { + // dec_val won't overflow so keep accumulating dec_val = 10 * dec_val + dig; + if (in == PARSE_DEC_IN_FRAC) { + --exp_extra; + } + } else { + // dec_val might overflow and we anyway can't represent more digits + // of precision, so ignore the digit and just adjust the exponent + if (in == PARSE_DEC_IN_INTG) { + ++exp_extra; + } } } } else if (in == PARSE_DEC_IN_INTG && dig == '.') { @@ -248,6 +275,8 @@ mp_obj_t mp_parse_num_decimal(const char *str, size_t len, bool allow_imag, bool } else if (allow_imag && (dig | 0x20) == 'j') { imag = true; break; + } else if (dig == '_') { + continue; } else { // unknown character str--; @@ -260,7 +289,12 @@ mp_obj_t mp_parse_num_decimal(const char *str, size_t len, bool allow_imag, bool exp_val = -exp_val; } - // apply the exponent + // apply the exponent, making sure it's not a subnormal value + exp_val += exp_extra; + if (exp_val < SMALL_NORMAL_EXP) { + exp_val -= SMALL_NORMAL_EXP; + dec_val *= SMALL_NORMAL_VAL; + } dec_val *= MICROPY_FLOAT_C_FUN(pow)(10, exp_val); } @@ -289,11 +323,13 @@ mp_obj_t mp_parse_num_decimal(const char *str, size_t len, bool allow_imag, bool return mp_obj_new_complex(0, dec_val); } else if (force_complex) { return mp_obj_new_complex(dec_val, 0); + } #else if (imag || force_complex) { raise_exc(mp_obj_new_exception_msg(&mp_type_ValueError, "complex values not supported"), lex); + } #endif - } else { + else { return mp_obj_new_float(dec_val); } |