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js/src/jsdtoa.h

author | Phil Ringnalda <philringnalda@gmail.com> |

Sat, 28 Mar 2015 10:39:56 -0700 | |

changeset 236377 | 5b892d8ef4538ea84378ebe4a352c49d8b9aa366 |

parent 236371 | 0c030f97a04f4e34c138b878c4352423f5e920f9 |

child 236396 | 02f2f4c75007651c63bbc0791d9a58dea88f545f |

permissions | -rw-r--r-- |

Backed out changeset 0c030f97a04f (bug 1144366) for being on top of patches being backed out
CLOSED TREE

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- * vim: set ts=8 sts=4 et sw=4 tw=99: * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #ifndef jsdtoa_h #define jsdtoa_h /* * Public interface to portable double-precision floating point to string * and back conversion package. */ #include <stddef.h> struct DtoaState; namespace js { extern DtoaState * NewDtoaState(); extern void DestroyDtoaState(DtoaState *state); } // namespace js /* * js_strtod_harder() returns as a double-precision floating-point number the * value represented by the character string pointed to by s00. The string is * scanned up to the first unrecognized character. * * If se is not nullptr, *se receives a pointer to the character terminating * the scan. If no number can be formed, *se receives a pointer to the first * unparseable character in s00, and zero is returned. * * On overflow, this function returns infinity and does not indicate an error. * * *err is set to zero on success; it's set to JS_DTOA_ENOMEM on memory failure. */ #define JS_DTOA_ENOMEM 2 double js_strtod_harder(DtoaState *state, const char *s00, char **se, int *err); /* * Modes for converting floating-point numbers to strings. * * Some of the modes can round-trip; this means that if the number is converted to * a string using one of these mode and then converted back to a number, the result * will be identical to the original number (except that, due to ECMA, -0 will get converted * to +0). These round-trip modes return the minimum number of significand digits that * permit the round trip. * * Some of the modes take an integer parameter <precision>. */ /* NB: Keep this in sync with number_constants[]. */ typedef enum JSDToStrMode { DTOSTR_STANDARD, /* Either fixed or exponential format; round-trip */ DTOSTR_STANDARD_EXPONENTIAL, /* Always exponential format; round-trip */ DTOSTR_FIXED, /* Round to <precision> digits after the decimal point; exponential if number is large */ DTOSTR_EXPONENTIAL, /* Always exponential format; <precision> significant digits */ DTOSTR_PRECISION /* Either fixed or exponential format; <precision> significant digits */ } JSDToStrMode; /* Maximum number of characters (including trailing null) that a DTOSTR_STANDARD or DTOSTR_STANDARD_EXPONENTIAL * conversion can produce. This maximum is reached for a number like -0.0000012345678901234567. */ #define DTOSTR_STANDARD_BUFFER_SIZE 26 /* Maximum number of characters (including trailing null) that one of the other conversions * can produce. This maximum is reached for TO_FIXED, which can generate up to 21 digits before the decimal point. */ #define DTOSTR_VARIABLE_BUFFER_SIZE(precision) ((precision)+24 > DTOSTR_STANDARD_BUFFER_SIZE ? (precision)+24 : DTOSTR_STANDARD_BUFFER_SIZE) /* * DO NOT USE THIS FUNCTION IF YOU CAN AVOID IT. js::NumberToCString() is a * better function to use. * * Convert dval according to the given mode and return a pointer to the * resulting ASCII string. If mode == DTOSTR_STANDARD and precision == 0 it's * equivalent to ToString() as specified by ECMA-262-5 section 9.8.1, but it * doesn't handle integers specially so should be avoided in that case (that's * why js::NumberToCString() is better). * * The result is held somewhere in buffer, but not necessarily at the * beginning. The size of buffer is given in bufferSize, and must be at least * as large as given by the above macros. * * Return nullptr if out of memory. */ char * js_dtostr(DtoaState *state, char *buffer, size_t bufferSize, JSDToStrMode mode, int precision, double dval); /* * DO NOT USE THIS FUNCTION IF YOU CAN AVOID IT. js::NumberToCString() is a * better function to use. * * Convert d to a string in the given base. The integral part of d will be * printed exactly in that base, regardless of how large it is, because there * is no exponential notation for non-base-ten numbers. The fractional part * will be rounded to as few digits as possible while still preserving the * round-trip property (analogous to that of printing decimal numbers). In * other words, if one were to read the resulting string in via a hypothetical * base-number-reading routine that rounds to the nearest IEEE double (and to * an even significand if there are two equally near doubles), then the result * would equal d (except for -0.0, which converts to "0", and NaN, which is * not equal to itself). * * Return nullptr if out of memory. If the result is not nullptr, it must be * released via js_free(). */ char * js_dtobasestr(DtoaState *state, int base, double d); #endif /* jsdtoa_h */