diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/m_string.h | 37 |
1 files changed, 34 insertions, 3 deletions
diff --git a/include/m_string.h b/include/m_string.h index f1c42b0cda4..83622a5523e 100644 --- a/include/m_string.h +++ b/include/m_string.h @@ -92,9 +92,6 @@ extern char *stpcpy(char *, const char *); /* For AIX with gcc 2.95.3 */ extern char NEAR _dig_vec_upper[]; extern char NEAR _dig_vec_lower[]; -/* Defined in strtod.c */ -extern const double log_10[309]; - #ifdef BAD_STRING_COMPILER #define strmov(A,B) (memccpy(A,B,0,INT_MAX)-1) #else @@ -199,8 +196,42 @@ extern char *strstr(const char *, const char *); extern int is_prefix(const char *, const char *); /* Conversion routines */ +typedef enum { + MY_GCVT_ARG_FLOAT, + MY_GCVT_ARG_DOUBLE +} my_gcvt_arg_type; + double my_strtod(const char *str, char **end, int *error); double my_atof(const char *nptr); +size_t my_fcvt(double x, int precision, char *to, my_bool *error); +size_t my_gcvt(double x, my_gcvt_arg_type type, int width, char *to, + my_bool *error); + +#define NOT_FIXED_DEC 31 + +/* + The longest string my_fcvt can return is 311 + "precision" bytes. + Here we assume that we never cal my_fcvt() with precision >= NOT_FIXED_DEC + (+ 1 byte for the terminating '\0'). +*/ +#define FLOATING_POINT_BUFFER (311 + NOT_FIXED_DEC) + +/* + We want to use the 'e' format in some cases even if we have enough space + for the 'f' one just to mimic sprintf("%.15g") behavior for large integers, + and to improve it for numbers < 10^(-4). + That is, for |x| < 1 we require |x| >= 10^(-15), and for |x| > 1 we require + it to be integer and be <= 10^DBL_DIG for the 'f' format to be used. + We don't lose precision, but make cases like "1e200" or "0.00001" look nicer. +*/ +#define MAX_DECPT_FOR_F_FORMAT DBL_DIG + +/* + The maximum possible field width for my_gcvt() conversion. + (DBL_DIG + 2) significant digits + sign + "." + ("e-NNN" or + MAX_DECPT_FOR_F_FORMAT zeros for cases when |x|<1 and the 'f' format is used). +*/ +#define MY_GCVT_MAX_FIELD_WIDTH (DBL_DIG + 4 + max(5, MAX_DECPT_FOR_F_FORMAT)) \ extern char *llstr(longlong value,char *buff); extern char *ullstr(longlong value,char *buff); |