1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/jsdtoa.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,112 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + * vim: set ts=8 sts=4 et sw=4 tw=99:
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#ifndef jsdtoa_h
1.11 +#define jsdtoa_h
1.12 +
1.13 +/*
1.14 + * Public interface to portable double-precision floating point to string
1.15 + * and back conversion package.
1.16 + */
1.17 +
1.18 +#include <stddef.h>
1.19 +
1.20 +struct DtoaState;
1.21 +
1.22 +DtoaState *
1.23 +js_NewDtoaState();
1.24 +
1.25 +void
1.26 +js_DestroyDtoaState(DtoaState *state);
1.27 +
1.28 +/*
1.29 + * js_strtod_harder() returns as a double-precision floating-point number the
1.30 + * value represented by the character string pointed to by s00. The string is
1.31 + * scanned up to the first unrecognized character.
1.32 + *
1.33 + * If se is not nullptr, *se receives a pointer to the character terminating
1.34 + * the scan. If no number can be formed, *se receives a pointer to the first
1.35 + * unparseable character in s00, and zero is returned.
1.36 + *
1.37 + * On overflow, this function returns infinity and does not indicate an error.
1.38 + *
1.39 + * *err is set to zero on success; it's set to JS_DTOA_ENOMEM on memory failure.
1.40 + */
1.41 +#define JS_DTOA_ENOMEM 2
1.42 +double
1.43 +js_strtod_harder(DtoaState *state, const char *s00, char **se, int *err);
1.44 +
1.45 +/*
1.46 + * Modes for converting floating-point numbers to strings.
1.47 + *
1.48 + * Some of the modes can round-trip; this means that if the number is converted to
1.49 + * a string using one of these mode and then converted back to a number, the result
1.50 + * will be identical to the original number (except that, due to ECMA, -0 will get converted
1.51 + * to +0). These round-trip modes return the minimum number of significand digits that
1.52 + * permit the round trip.
1.53 + *
1.54 + * Some of the modes take an integer parameter <precision>.
1.55 + */
1.56 +/* NB: Keep this in sync with number_constants[]. */
1.57 +typedef enum JSDToStrMode {
1.58 + DTOSTR_STANDARD, /* Either fixed or exponential format; round-trip */
1.59 + DTOSTR_STANDARD_EXPONENTIAL, /* Always exponential format; round-trip */
1.60 + DTOSTR_FIXED, /* Round to <precision> digits after the decimal point; exponential if number is large */
1.61 + DTOSTR_EXPONENTIAL, /* Always exponential format; <precision> significant digits */
1.62 + DTOSTR_PRECISION /* Either fixed or exponential format; <precision> significant digits */
1.63 +} JSDToStrMode;
1.64 +
1.65 +
1.66 +/* Maximum number of characters (including trailing null) that a DTOSTR_STANDARD or DTOSTR_STANDARD_EXPONENTIAL
1.67 + * conversion can produce. This maximum is reached for a number like -0.0000012345678901234567. */
1.68 +#define DTOSTR_STANDARD_BUFFER_SIZE 26
1.69 +
1.70 +/* Maximum number of characters (including trailing null) that one of the other conversions
1.71 + * can produce. This maximum is reached for TO_FIXED, which can generate up to 21 digits before the decimal point. */
1.72 +#define DTOSTR_VARIABLE_BUFFER_SIZE(precision) ((precision)+24 > DTOSTR_STANDARD_BUFFER_SIZE ? (precision)+24 : DTOSTR_STANDARD_BUFFER_SIZE)
1.73 +
1.74 +/*
1.75 + * DO NOT USE THIS FUNCTION IF YOU CAN AVOID IT. js::NumberToCString() is a
1.76 + * better function to use.
1.77 + *
1.78 + * Convert dval according to the given mode and return a pointer to the
1.79 + * resulting ASCII string. If mode == DTOSTR_STANDARD and precision == 0 it's
1.80 + * equivalent to ToString() as specified by ECMA-262-5 section 9.8.1, but it
1.81 + * doesn't handle integers specially so should be avoided in that case (that's
1.82 + * why js::NumberToCString() is better).
1.83 + *
1.84 + * The result is held somewhere in buffer, but not necessarily at the
1.85 + * beginning. The size of buffer is given in bufferSize, and must be at least
1.86 + * as large as given by the above macros.
1.87 + *
1.88 + * Return nullptr if out of memory.
1.89 + */
1.90 +char *
1.91 +js_dtostr(DtoaState *state, char *buffer, size_t bufferSize, JSDToStrMode mode, int precision,
1.92 + double dval);
1.93 +
1.94 +/*
1.95 + * DO NOT USE THIS FUNCTION IF YOU CAN AVOID IT. js::NumberToCString() is a
1.96 + * better function to use.
1.97 + *
1.98 + * Convert d to a string in the given base. The integral part of d will be
1.99 + * printed exactly in that base, regardless of how large it is, because there
1.100 + * is no exponential notation for non-base-ten numbers. The fractional part
1.101 + * will be rounded to as few digits as possible while still preserving the
1.102 + * round-trip property (analogous to that of printing decimal numbers). In
1.103 + * other words, if one were to read the resulting string in via a hypothetical
1.104 + * base-number-reading routine that rounds to the nearest IEEE double (and to
1.105 + * an even significand if there are two equally near doubles), then the result
1.106 + * would equal d (except for -0.0, which converts to "0", and NaN, which is
1.107 + * not equal to itself).
1.108 + *
1.109 + * Return nullptr if out of memory. If the result is not nullptr, it must be
1.110 + * released via js_free().
1.111 + */
1.112 +char *
1.113 +js_dtobasestr(DtoaState *state, int base, double d);
1.114 +
1.115 +#endif /* jsdtoa_h */
