js/src/util/DoubleToString.h
author Calixte <cdenizet@mozilla.com>
Fri, 03 Feb 2023 10:01:34 +0000
changeset 651654 a356e2d3cf4646e614e3666509c7c3ee9474a96b
parent 621709 8c1cb9f3f85712050dc977872738eb0f3faf2854
permissions -rw-r--r--
Bug 1810761 - Add API to save a pdf file opened in pdf.js r=pdfjs-reviewers,geckoview-reviewers,marco,ohall,calu Differential Revision: https://phabricator.services.mozilla.com/D168413

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 * 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 util_DoubleToString_h
#define util_DoubleToString_h

/*
 * Public interface to portable double-precision floating point to string
 * and back conversion package.
 */

struct DtoaState;

namespace js {

extern DtoaState* NewDtoaState();

extern void DestroyDtoaState(DtoaState* state);

}  // namespace js

/* 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

/*
 * 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 /* util_DoubleToString_h */