gecko/js/src/jsdtoa.h

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code, released
 * March 31, 1998.
 *
 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
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 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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#ifndef jsdtoa_h___
#define jsdtoa_h___
/*
 * Public interface to portable double-precision floating point to string
 * and back conversion package.
 */

#include "jscompat.h"

JS_BEGIN_EXTERN_C

struct DtoaState;

DtoaState *
js_NewDtoaState();

void
js_DestroyDtoaState(DtoaState *state);

/*
 * 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 NULL, *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.
 *
 * *err is set to zero on success; it's set to JS_DTOA_ERANGE on range
 * errors and JS_DTOA_ENOMEM on memory failure.
 */
#define JS_DTOA_ERANGE 1
#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)

/*
 * Convert dval according to the given mode and return a pointer to the resulting ASCII string.
 * 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 NULL if out of memory.
 */
char *
js_dtostr(DtoaState *state, char *buffer, size_t bufferSize, JSDToStrMode mode, int precision,
          double dval);

/*
 * 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 NULL if out of memory.  If the result is not NULL, it must be released via free().
 */
char *
js_dtobasestr(DtoaState *state, int base, double d);

JS_END_EXTERN_C

#endif /* jsdtoa_h___ */