wine/gecko
0
0
Fork 0
mirror of https://gitlab.winehq.org/wine/wine-gecko.git synced 2024-09-13 09:24:08 -07:00
Code Issues Packages Projects Releases Wiki Activity
a9ebdaf602
gecko/js/src/jsdtoa.cpp
Luke Wagner 99411cc93d Bug 549143 - fatvals
2010-07-14 23:19:36 -07:00

540 lines
17 KiB
C++
Raw Blame History

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* ***** BEGIN LICENSE BLOCK *****
* 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
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the terms of
* 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"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/*
* Portable double to alphanumeric string and back converters.
*/
#include "jstypes.h"
#include "jsstdint.h"
#include "jsdtoa.h"
#include "jsprf.h"
#include "jsapi.h"
#include "jsprvtd.h"
#include "jsnum.h"
#include "jsbit.h"
#include "jslibmath.h"
#include "jscntxt.h"
#include "jsobjinlines.h"
#ifdef IS_LITTLE_ENDIAN
#define IEEE_8087
#else
#define IEEE_MC68k
#endif
#ifndef Long
#define Long int32
#endif
#ifndef ULong
#define ULong uint32
#endif
/*
#ifndef Llong
#define Llong JSInt64
#endif
#ifndef ULlong
#define ULlong JSUint64
#endif
*/
#define NO_GLOBAL_STATE
#define MALLOC js_malloc
#define FREE js_free
#include "dtoa.c"
/* Mapping of JSDToStrMode -> js_dtoa mode */
static const uint8 dtoaModes[] = {
0, /* DTOSTR_STANDARD */
0, /* DTOSTR_STANDARD_EXPONENTIAL, */
3, /* DTOSTR_FIXED, */
2, /* DTOSTR_EXPONENTIAL, */
2}; /* DTOSTR_PRECISION */
double
js_strtod_harder(DtoaState *state, const char *s00, char **se, int *err)
{
double retval;
if (err)
*err = 0;
retval = _strtod(state, s00, se);
return retval;
}
char *
js_dtostr(DtoaState *state, char *buffer, size_t bufferSize, JSDToStrMode mode, int precision,
double dinput)
{
U d;
int decPt; /* Offset of decimal point from first digit */
int sign; /* Nonzero if the sign bit was set in d */
int nDigits; /* Number of significand digits returned by js_dtoa */
char *numBegin; /* Pointer to the digits returned by js_dtoa */
char *numEnd = 0; /* Pointer past the digits returned by js_dtoa */
JS_ASSERT(bufferSize >= (size_t)(mode <= DTOSTR_STANDARD_EXPONENTIAL
? DTOSTR_STANDARD_BUFFER_SIZE
: DTOSTR_VARIABLE_BUFFER_SIZE(precision)));
/*
* Change mode here rather than below because the buffer may not be large
* enough to hold a large integer.
*/
if (mode == DTOSTR_FIXED && (dinput >= 1e21 || dinput <= -1e21))
mode = DTOSTR_STANDARD;
dval(d) = dinput;
numBegin = dtoa(PASS_STATE d, dtoaModes[mode], precision, &decPt, &sign, &numEnd);
if (!numBegin) {
return NULL;
}
nDigits = numEnd - numBegin;
JS_ASSERT((size_t) nDigits <= bufferSize - 2);
if ((size_t) nDigits > bufferSize - 2) {
return NULL;
}
memcpy(buffer + 2, numBegin, nDigits);
freedtoa(PASS_STATE numBegin);
numBegin = buffer + 2; /* +2 leaves space for sign and/or decimal point */
numEnd = numBegin + nDigits;
*numEnd = '\0';
/* If Infinity, -Infinity, or NaN, return the string regardless of mode. */
if (decPt != 9999) {
JSBool exponentialNotation = JS_FALSE;
int minNDigits = 0; /* Min number of significant digits required */
char *p;
char *q;
switch (mode) {
case DTOSTR_STANDARD:
if (decPt < -5 || decPt > 21)
exponentialNotation = JS_TRUE;
else
minNDigits = decPt;
break;
case DTOSTR_FIXED:
if (precision >= 0)
minNDigits = decPt + precision;
else
minNDigits = decPt;
break;
case DTOSTR_EXPONENTIAL:
JS_ASSERT(precision > 0);
minNDigits = precision;
/* Fall through */
case DTOSTR_STANDARD_EXPONENTIAL:
exponentialNotation = JS_TRUE;
break;
case DTOSTR_PRECISION:
JS_ASSERT(precision > 0);
minNDigits = precision;
if (decPt < -5 || decPt > precision)
exponentialNotation = JS_TRUE;
break;
}
/* If the number has fewer than minNDigits, end-pad it with zeros. */
if (nDigits < minNDigits) {
p = numBegin + minNDigits;
nDigits = minNDigits;
do {
*numEnd++ = '0';
} while (numEnd != p);
*numEnd = '\0';
}
if (exponentialNotation) {
/* Insert a decimal point if more than one significand digit */
if (nDigits != 1) {
numBegin--;
numBegin[0] = numBegin[1];
numBegin[1] = '.';
}
JS_snprintf(numEnd, bufferSize - (numEnd - buffer), "e%+d", decPt-1);
} else if (decPt != nDigits) {
/* Some kind of a fraction in fixed notation */
JS_ASSERT(decPt <= nDigits);
if (decPt > 0) {
/* dd...dd . dd...dd */
p = --numBegin;
do {
*p = p[1];
p++;
} while (--decPt);
*p = '.';
} else {
/* 0 . 00...00dd...dd */
p = numEnd;
numEnd += 1 - decPt;
q = numEnd;
JS_ASSERT(numEnd < buffer + bufferSize);
*numEnd = '\0';
while (p != numBegin)
*--q = *--p;
for (p = numBegin + 1; p != q; p++)
*p = '0';
*numBegin = '.';
*--numBegin = '0';
}
}
}
/* If negative and neither -0.0 nor NaN, output a leading '-'. */
if (sign &&
!(word0(d) == Sign_bit && word1(d) == 0) &&
!((word0(d) & Exp_mask) == Exp_mask &&
(word1(d) || (word0(d) & Frac_mask)))) {
*--numBegin = '-';
}
return numBegin;
}
/* Let b = floor(b / divisor), and return the remainder. b must be nonnegative.
* divisor must be between 1 and 65536.
* This function cannot run out of memory. */
static uint32
divrem(Bigint *b, uint32 divisor)
{
int32 n = b->wds;
uint32 remainder = 0;
ULong *bx;
ULong *bp;
JS_ASSERT(divisor > 0 && divisor <= 65536);
if (!n)
return 0; /* b is zero */
bx = b->x;
bp = bx + n;
do {
ULong a = *--bp;
ULong dividend = remainder << 16 | a >> 16;
ULong quotientHi = dividend / divisor;
ULong quotientLo;
remainder = dividend - quotientHi*divisor;
JS_ASSERT(quotientHi <= 0xFFFF && remainder < divisor);
dividend = remainder << 16 | (a & 0xFFFF);
quotientLo = dividend / divisor;
remainder = dividend - quotientLo*divisor;
JS_ASSERT(quotientLo <= 0xFFFF && remainder < divisor);
*bp = quotientHi << 16 | quotientLo;
} while (bp != bx);
/* Decrease the size of the number if its most significant word is now zero. */
if (bx[n-1] == 0)
b->wds--;
return remainder;
}
/* Return floor(b/2^k) and set b to be the remainder. The returned quotient must be less than 2^32. */
static uint32 quorem2(Bigint *b, int32 k)
{
ULong mask;
ULong result;
ULong *bx, *bxe;
int32 w;
int32 n = k >> 5;
k &= 0x1F;
mask = (1<<k) - 1;
w = b->wds - n;
if (w <= 0)
return 0;
JS_ASSERT(w <= 2);
bx = b->x;
bxe = bx + n;
result = *bxe >> k;
*bxe &= mask;
if (w == 2) {
JS_ASSERT(!(bxe[1] & ~mask));
if (k)
result |= bxe[1] << (32 - k);
}
n++;
while (!*bxe && bxe != bx) {
n--;
bxe--;
}
b->wds = n;
return result;
}
/* "-0.0000...(1073 zeros after decimal point)...0001\0" is the longest string that we could produce,
* which occurs when printing -5e-324 in binary. We could compute a better estimate of the size of
* the output string and malloc fewer bytes depending on d and base, but why bother? */
#define DTOBASESTR_BUFFER_SIZE 1078
#define BASEDIGIT(digit) ((char)(((digit) >= 10) ? 'a' - 10 + (digit) : '0' + (digit)))
char *
js_dtobasestr(DtoaState *state, int base, double dinput)
{
U d;
char *buffer; /* The output string */
char *p; /* Pointer to current position in the buffer */
char *pInt; /* Pointer to the beginning of the integer part of the string */
char *q;
uint32 digit;
U di; /* d truncated to an integer */
U df; /* The fractional part of d */
JS_ASSERT(base >= 2 && base <= 36);
dval(d) = dinput;
buffer = (char*) js_malloc(DTOBASESTR_BUFFER_SIZE);
if (buffer) {
p = buffer;
if (dval(d) < 0.0
#if defined(XP_WIN) || defined(XP_OS2)
&& !((word0(d) & Exp_mask) == Exp_mask && ((word0(d) & Frac_mask) || word1(d))) /* Visual C++ doesn't know how to compare against NaN */
#endif
) {
*p++ = '-';
dval(d) = -dval(d);
}
/* Check for Infinity and NaN */
if ((word0(d) & Exp_mask) == Exp_mask) {
strcpy(p, !word1(d) && !(word0(d) & Frac_mask) ? "Infinity" : "NaN");
return buffer;
}
/* Output the integer part of d with the digits in reverse order. */
pInt = p;
dval(di) = floor(dval(d));
if (dval(di) <= 4294967295.0) {
uint32 n = (uint32)dval(di);
if (n)
do {
uint32 m = n / base;
digit = n - m*base;
n = m;
JS_ASSERT(digit < (uint32)base);
*p++ = BASEDIGIT(digit);
} while (n);
else *p++ = '0';
} else {
int e;
int bits; /* Number of significant bits in di; not used. */
Bigint *b = d2b(PASS_STATE di, &e, &bits);
if (!b)
goto nomem1;
b = lshift(PASS_STATE b, e);
if (!b) {
nomem1:
Bfree(PASS_STATE b);
js_free(buffer);
return NULL;
}
do {
digit = divrem(b, base);
JS_ASSERT(digit < (uint32)base);
*p++ = BASEDIGIT(digit);
} while (b->wds);
Bfree(PASS_STATE b);
}
/* Reverse the digits of the integer part of d. */
q = p-1;
while (q > pInt) {
char ch = *pInt;
*pInt++ = *q;
*q-- = ch;
}
dval(df) = dval(d) - dval(di);
if (dval(df) != 0.0) {
/* We have a fraction. */
int e, bbits;
int32 s2, done;
Bigint *b, *s, *mlo, *mhi;
b = s = mlo = mhi = NULL;
*p++ = '.';
b = d2b(PASS_STATE df, &e, &bbits);
if (!b) {
nomem2:
Bfree(PASS_STATE b);
Bfree(PASS_STATE s);
if (mlo != mhi)
Bfree(PASS_STATE mlo);
Bfree(PASS_STATE mhi);
js_free(buffer);
return NULL;
}
JS_ASSERT(e < 0);
/* At this point df = b * 2^e. e must be less than zero because 0 < df < 1. */
s2 = -(int32)(word0(d) >> Exp_shift1 & Exp_mask>>Exp_shift1);
#ifndef Sudden_Underflow
if (!s2)
s2 = -1;
#endif
s2 += Bias + P;
/* 1/2^s2 = (nextDouble(d) - d)/2 */
JS_ASSERT(-s2 < e);
mlo = i2b(PASS_STATE 1);
if (!mlo)
goto nomem2;
mhi = mlo;
if (!word1(d) && !(word0(d) & Bndry_mask)
#ifndef Sudden_Underflow
&& word0(d) & (Exp_mask & Exp_mask << 1)
#endif
) {
/* The special case. Here we want to be within a quarter of the last input
significant digit instead of one half of it when the output string's value is less than d. */
s2 += Log2P;
mhi = i2b(PASS_STATE 1<<Log2P);
if (!mhi)
goto nomem2;
}
b = lshift(PASS_STATE b, e + s2);
if (!b)
goto nomem2;
s = i2b(PASS_STATE 1);
if (!s)
goto nomem2;
s = lshift(PASS_STATE s, s2);
if (!s)
goto nomem2;
/* At this point we have the following:
* s = 2^s2;
* 1 > df = b/2^s2 > 0;
* (d - prevDouble(d))/2 = mlo/2^s2;
* (nextDouble(d) - d)/2 = mhi/2^s2. */
done = JS_FALSE;
do {
int32 j, j1;
Bigint *delta;
b = multadd(PASS_STATE b, base, 0);
if (!b)
goto nomem2;
digit = quorem2(b, s2);
if (mlo == mhi) {
mlo = mhi = multadd(PASS_STATE mlo, base, 0);
if (!mhi)
goto nomem2;
}
else {
mlo = multadd(PASS_STATE mlo, base, 0);
if (!mlo)
goto nomem2;
mhi = multadd(PASS_STATE mhi, base, 0);
if (!mhi)
goto nomem2;
}
/* Do we yet have the shortest string that will round to d? */
j = cmp(b, mlo);
/* j is b/2^s2 compared with mlo/2^s2. */
delta = diff(PASS_STATE s, mhi);
if (!delta)
goto nomem2;
j1 = delta->sign ? 1 : cmp(b, delta);
Bfree(PASS_STATE delta);
/* j1 is b/2^s2 compared with 1 - mhi/2^s2. */
#ifndef ROUND_BIASED
if (j1 == 0 && !(word1(d) & 1)) {
if (j > 0)
digit++;
done = JS_TRUE;
} else
#endif
if (j < 0 || (j == 0
#ifndef ROUND_BIASED
&& !(word1(d) & 1)
#endif
)) {
if (j1 > 0) {
/* Either dig or dig+1 would work here as the least significant digit.
Use whichever would produce an output value closer to d. */
b = lshift(PASS_STATE b, 1);
if (!b)
goto nomem2;
j1 = cmp(b, s);
if (j1 > 0) /* The even test (|| (j1 == 0 && (digit & 1))) is not here because it messes up odd base output
* such as 3.5 in base 3. */
digit++;
}
done = JS_TRUE;
} else if (j1 > 0) {
digit++;
done = JS_TRUE;
}
JS_ASSERT(digit < (uint32)base);
*p++ = BASEDIGIT(digit);
} while (!done);
Bfree(PASS_STATE b);
Bfree(PASS_STATE s);
if (mlo != mhi)
Bfree(PASS_STATE mlo);
Bfree(PASS_STATE mhi);
}
JS_ASSERT(p < buffer + DTOBASESTR_BUFFER_SIZE);
*p = '\0';
}
return buffer;
}
DtoaState *
js_NewDtoaState()
{
return newdtoa();
}
void
js_DestroyDtoaState(DtoaState *state)
{
destroydtoa(state);
}
Reference in New Issue View Git Blame Copy Permalink