mirror of
https://gitlab.winehq.org/wine/wine-gecko.git
synced 2024-09-13 09:24:08 -07:00
512 lines
15 KiB
C++
512 lines
15 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* vim: set ts=8 sts=4 et sw=4 tw=99:
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/*
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* Portable double to alphanumeric string and back converters.
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*/
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#include "jsdtoa.h"
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#include "jsprf.h"
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#include "jstypes.h"
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#include "jsutil.h"
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using namespace js;
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#ifdef IS_LITTLE_ENDIAN
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#define IEEE_8087
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#else
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#define IEEE_MC68k
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#endif
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#ifndef Long
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#define Long int32_t
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#endif
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#ifndef ULong
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#define ULong uint32_t
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#endif
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/*
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#ifndef Llong
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#define Llong int64_t
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#endif
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#ifndef ULlong
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#define ULlong uint64_t
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#endif
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*/
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/*
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* MALLOC gets declared external, and that doesn't work for class members, so
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* wrap.
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*/
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static inline void* dtoa_malloc(size_t size) { return js_malloc(size); }
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static inline void dtoa_free(void* p) { return js_free(p); }
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#define NO_GLOBAL_STATE
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#define NO_ERRNO
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#define MALLOC dtoa_malloc
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#define FREE dtoa_free
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#include "dtoa.c"
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/* Mapping of JSDToStrMode -> js_dtoa mode */
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static const uint8_t dtoaModes[] = {
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0, /* DTOSTR_STANDARD */
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0, /* DTOSTR_STANDARD_EXPONENTIAL, */
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3, /* DTOSTR_FIXED, */
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2, /* DTOSTR_EXPONENTIAL, */
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2}; /* DTOSTR_PRECISION */
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double
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js_strtod_harder(DtoaState *state, const char *s00, char **se, int *err)
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{
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double retval;
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if (err)
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*err = 0;
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retval = _strtod(state, s00, se);
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return retval;
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}
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char *
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js_dtostr(DtoaState *state, char *buffer, size_t bufferSize, JSDToStrMode mode, int precision,
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double dinput)
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{
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U d;
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int decPt; /* Offset of decimal point from first digit */
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int sign; /* Nonzero if the sign bit was set in d */
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int nDigits; /* Number of significand digits returned by js_dtoa */
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char *numBegin; /* Pointer to the digits returned by js_dtoa */
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char *numEnd = 0; /* Pointer past the digits returned by js_dtoa */
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JS_ASSERT(bufferSize >= (size_t)(mode <= DTOSTR_STANDARD_EXPONENTIAL
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? DTOSTR_STANDARD_BUFFER_SIZE
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: DTOSTR_VARIABLE_BUFFER_SIZE(precision)));
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/*
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* Change mode here rather than below because the buffer may not be large
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* enough to hold a large integer.
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*/
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if (mode == DTOSTR_FIXED && (dinput >= 1e21 || dinput <= -1e21))
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mode = DTOSTR_STANDARD;
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dval(d) = dinput;
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numBegin = dtoa(PASS_STATE d, dtoaModes[mode], precision, &decPt, &sign, &numEnd);
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if (!numBegin) {
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return nullptr;
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}
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nDigits = numEnd - numBegin;
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JS_ASSERT((size_t) nDigits <= bufferSize - 2);
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if ((size_t) nDigits > bufferSize - 2) {
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return nullptr;
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}
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js_memcpy(buffer + 2, numBegin, nDigits);
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freedtoa(PASS_STATE numBegin);
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numBegin = buffer + 2; /* +2 leaves space for sign and/or decimal point */
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numEnd = numBegin + nDigits;
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*numEnd = '\0';
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/* If Infinity, -Infinity, or NaN, return the string regardless of mode. */
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if (decPt != 9999) {
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bool exponentialNotation = false;
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int minNDigits = 0; /* Min number of significant digits required */
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char *p;
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char *q;
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switch (mode) {
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case DTOSTR_STANDARD:
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if (decPt < -5 || decPt > 21)
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exponentialNotation = true;
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else
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minNDigits = decPt;
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break;
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case DTOSTR_FIXED:
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if (precision >= 0)
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minNDigits = decPt + precision;
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else
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minNDigits = decPt;
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break;
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case DTOSTR_EXPONENTIAL:
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JS_ASSERT(precision > 0);
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minNDigits = precision;
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/* Fall through */
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case DTOSTR_STANDARD_EXPONENTIAL:
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exponentialNotation = true;
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break;
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case DTOSTR_PRECISION:
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JS_ASSERT(precision > 0);
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minNDigits = precision;
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if (decPt < -5 || decPt > precision)
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exponentialNotation = true;
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break;
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}
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/* If the number has fewer than minNDigits, end-pad it with zeros. */
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if (nDigits < minNDigits) {
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p = numBegin + minNDigits;
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nDigits = minNDigits;
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do {
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*numEnd++ = '0';
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} while (numEnd != p);
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*numEnd = '\0';
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}
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if (exponentialNotation) {
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/* Insert a decimal point if more than one significand digit */
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if (nDigits != 1) {
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numBegin--;
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numBegin[0] = numBegin[1];
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numBegin[1] = '.';
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}
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JS_snprintf(numEnd, bufferSize - (numEnd - buffer), "e%+d", decPt-1);
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} else if (decPt != nDigits) {
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/* Some kind of a fraction in fixed notation */
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JS_ASSERT(decPt <= nDigits);
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if (decPt > 0) {
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/* dd...dd . dd...dd */
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p = --numBegin;
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do {
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*p = p[1];
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p++;
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} while (--decPt);
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*p = '.';
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} else {
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/* 0 . 00...00dd...dd */
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p = numEnd;
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numEnd += 1 - decPt;
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q = numEnd;
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JS_ASSERT(numEnd < buffer + bufferSize);
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*numEnd = '\0';
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while (p != numBegin)
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*--q = *--p;
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for (p = numBegin + 1; p != q; p++)
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*p = '0';
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*numBegin = '.';
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*--numBegin = '0';
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}
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}
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}
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/* If negative and neither -0.0 nor NaN, output a leading '-'. */
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if (sign &&
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!(word0(d) == Sign_bit && word1(d) == 0) &&
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!((word0(d) & Exp_mask) == Exp_mask &&
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(word1(d) || (word0(d) & Frac_mask)))) {
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*--numBegin = '-';
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}
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return numBegin;
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}
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/* Let b = floor(b / divisor), and return the remainder. b must be nonnegative.
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* divisor must be between 1 and 65536.
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* This function cannot run out of memory. */
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static uint32_t
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divrem(Bigint *b, uint32_t divisor)
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{
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int32_t n = b->wds;
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uint32_t remainder = 0;
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ULong *bx;
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ULong *bp;
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JS_ASSERT(divisor > 0 && divisor <= 65536);
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if (!n)
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return 0; /* b is zero */
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bx = b->x;
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bp = bx + n;
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do {
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ULong a = *--bp;
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ULong dividend = remainder << 16 | a >> 16;
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ULong quotientHi = dividend / divisor;
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ULong quotientLo;
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remainder = dividend - quotientHi*divisor;
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JS_ASSERT(quotientHi <= 0xFFFF && remainder < divisor);
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dividend = remainder << 16 | (a & 0xFFFF);
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quotientLo = dividend / divisor;
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remainder = dividend - quotientLo*divisor;
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JS_ASSERT(quotientLo <= 0xFFFF && remainder < divisor);
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*bp = quotientHi << 16 | quotientLo;
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} while (bp != bx);
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/* Decrease the size of the number if its most significant word is now zero. */
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if (bx[n-1] == 0)
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b->wds--;
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return remainder;
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}
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/* Return floor(b/2^k) and set b to be the remainder. The returned quotient must be less than 2^32. */
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static uint32_t quorem2(Bigint *b, int32_t k)
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{
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ULong mask;
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ULong result;
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ULong *bx, *bxe;
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int32_t w;
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int32_t n = k >> 5;
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k &= 0x1F;
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mask = (1<<k) - 1;
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w = b->wds - n;
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if (w <= 0)
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return 0;
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JS_ASSERT(w <= 2);
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bx = b->x;
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bxe = bx + n;
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result = *bxe >> k;
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*bxe &= mask;
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if (w == 2) {
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JS_ASSERT(!(bxe[1] & ~mask));
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if (k)
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result |= bxe[1] << (32 - k);
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}
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n++;
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while (!*bxe && bxe != bx) {
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n--;
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bxe--;
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}
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b->wds = n;
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return result;
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}
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/* "-0.0000...(1073 zeros after decimal point)...0001\0" is the longest string that we could produce,
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* which occurs when printing -5e-324 in binary. We could compute a better estimate of the size of
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* the output string and malloc fewer bytes depending on d and base, but why bother? */
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#define DTOBASESTR_BUFFER_SIZE 1078
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#define BASEDIGIT(digit) ((char)(((digit) >= 10) ? 'a' - 10 + (digit) : '0' + (digit)))
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char *
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js_dtobasestr(DtoaState *state, int base, double dinput)
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{
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U d;
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char *buffer; /* The output string */
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char *p; /* Pointer to current position in the buffer */
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char *pInt; /* Pointer to the beginning of the integer part of the string */
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char *q;
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uint32_t digit;
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U di; /* d truncated to an integer */
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U df; /* The fractional part of d */
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JS_ASSERT(base >= 2 && base <= 36);
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dval(d) = dinput;
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buffer = (char*) js_malloc(DTOBASESTR_BUFFER_SIZE);
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if (!buffer)
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return nullptr;
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p = buffer;
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if (dval(d) < 0.0
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#if defined(XP_WIN)
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&& !((word0(d) & Exp_mask) == Exp_mask && ((word0(d) & Frac_mask) || word1(d))) /* Visual C++ doesn't know how to compare against NaN */
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#endif
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) {
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*p++ = '-';
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dval(d) = -dval(d);
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}
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/* Check for Infinity and NaN */
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if ((word0(d) & Exp_mask) == Exp_mask) {
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strcpy(p, !word1(d) && !(word0(d) & Frac_mask) ? "Infinity" : "NaN");
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return buffer;
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}
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/* Output the integer part of d with the digits in reverse order. */
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pInt = p;
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dval(di) = floor(dval(d));
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if (dval(di) <= 4294967295.0) {
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uint32_t n = (uint32_t)dval(di);
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if (n)
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do {
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uint32_t m = n / base;
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digit = n - m*base;
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n = m;
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JS_ASSERT(digit < (uint32_t)base);
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*p++ = BASEDIGIT(digit);
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} while (n);
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else *p++ = '0';
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} else {
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int e;
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int bits; /* Number of significant bits in di; not used. */
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Bigint *b = d2b(PASS_STATE di, &e, &bits);
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if (!b)
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goto nomem1;
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b = lshift(PASS_STATE b, e);
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if (!b) {
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nomem1:
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Bfree(PASS_STATE b);
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js_free(buffer);
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return nullptr;
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}
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do {
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digit = divrem(b, base);
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JS_ASSERT(digit < (uint32_t)base);
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*p++ = BASEDIGIT(digit);
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} while (b->wds);
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Bfree(PASS_STATE b);
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}
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/* Reverse the digits of the integer part of d. */
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q = p-1;
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while (q > pInt) {
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char ch = *pInt;
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*pInt++ = *q;
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*q-- = ch;
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}
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dval(df) = dval(d) - dval(di);
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if (dval(df) != 0.0) {
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/* We have a fraction. */
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int e, bbits;
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int32_t s2, done;
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Bigint *b, *s, *mlo, *mhi;
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b = s = mlo = mhi = nullptr;
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*p++ = '.';
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b = d2b(PASS_STATE df, &e, &bbits);
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if (!b) {
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nomem2:
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Bfree(PASS_STATE b);
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Bfree(PASS_STATE s);
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if (mlo != mhi)
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Bfree(PASS_STATE mlo);
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Bfree(PASS_STATE mhi);
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js_free(buffer);
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return nullptr;
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}
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JS_ASSERT(e < 0);
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/* At this point df = b * 2^e. e must be less than zero because 0 < df < 1. */
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s2 = -(int32_t)(word0(d) >> Exp_shift1 & Exp_mask>>Exp_shift1);
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#ifndef Sudden_Underflow
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if (!s2)
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s2 = -1;
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#endif
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s2 += Bias + P;
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/* 1/2^s2 = (nextDouble(d) - d)/2 */
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JS_ASSERT(-s2 < e);
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mlo = i2b(PASS_STATE 1);
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if (!mlo)
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goto nomem2;
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mhi = mlo;
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if (!word1(d) && !(word0(d) & Bndry_mask)
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#ifndef Sudden_Underflow
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&& word0(d) & (Exp_mask & Exp_mask << 1)
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#endif
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) {
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/* The special case. Here we want to be within a quarter of the last input
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significant digit instead of one half of it when the output string's value is less than d. */
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s2 += Log2P;
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mhi = i2b(PASS_STATE 1<<Log2P);
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if (!mhi)
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goto nomem2;
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}
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b = lshift(PASS_STATE b, e + s2);
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if (!b)
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goto nomem2;
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s = i2b(PASS_STATE 1);
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if (!s)
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goto nomem2;
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s = lshift(PASS_STATE s, s2);
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if (!s)
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goto nomem2;
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/* At this point we have the following:
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* s = 2^s2;
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* 1 > df = b/2^s2 > 0;
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* (d - prevDouble(d))/2 = mlo/2^s2;
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* (nextDouble(d) - d)/2 = mhi/2^s2. */
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done = false;
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do {
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int32_t j, j1;
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Bigint *delta;
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b = multadd(PASS_STATE b, base, 0);
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if (!b)
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goto nomem2;
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digit = quorem2(b, s2);
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if (mlo == mhi) {
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mlo = mhi = multadd(PASS_STATE mlo, base, 0);
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if (!mhi)
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goto nomem2;
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}
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else {
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mlo = multadd(PASS_STATE mlo, base, 0);
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if (!mlo)
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goto nomem2;
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mhi = multadd(PASS_STATE mhi, base, 0);
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if (!mhi)
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goto nomem2;
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}
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/* Do we yet have the shortest string that will round to d? */
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j = cmp(b, mlo);
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/* j is b/2^s2 compared with mlo/2^s2. */
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delta = diff(PASS_STATE s, mhi);
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if (!delta)
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goto nomem2;
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j1 = delta->sign ? 1 : cmp(b, delta);
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Bfree(PASS_STATE delta);
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/* j1 is b/2^s2 compared with 1 - mhi/2^s2. */
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#ifndef ROUND_BIASED
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if (j1 == 0 && !(word1(d) & 1)) {
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if (j > 0)
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digit++;
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done = true;
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} else
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#endif
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if (j < 0 || (j == 0
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#ifndef ROUND_BIASED
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&& !(word1(d) & 1)
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#endif
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)) {
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if (j1 > 0) {
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/* Either dig or dig+1 would work here as the least significant digit.
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Use whichever would produce an output value closer to d. */
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b = lshift(PASS_STATE b, 1);
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if (!b)
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goto nomem2;
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j1 = cmp(b, s);
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if (j1 > 0) /* The even test (|| (j1 == 0 && (digit & 1))) is not here because it messes up odd base output
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* such as 3.5 in base 3. */
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digit++;
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}
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done = true;
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} else if (j1 > 0) {
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digit++;
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done = true;
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}
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JS_ASSERT(digit < (uint32_t)base);
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*p++ = BASEDIGIT(digit);
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} while (!done);
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Bfree(PASS_STATE b);
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Bfree(PASS_STATE s);
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if (mlo != mhi)
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Bfree(PASS_STATE mlo);
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Bfree(PASS_STATE mhi);
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}
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JS_ASSERT(p < buffer + DTOBASESTR_BUFFER_SIZE);
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*p = '\0';
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return buffer;
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}
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DtoaState *
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js_NewDtoaState()
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{
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return newdtoa();
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}
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void
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js_DestroyDtoaState(DtoaState *state)
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{
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destroydtoa(state);
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}
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