libdecnumber: Introduce decNumberIntegralToInt64
Introduce a new conversion function to the libdecnumber library. This function converts a decNumber to a signed 64-bit integer. In order to support 64-bit integers (which may have up to 19 decimal digits), the existing "powers of 10" array is expanded from 10 to 19 entries. Signed-off-by: Tom Musta <tommusta@gmail.com> [agraf: fix 32bit host compile] Signed-off-by: Alexander Graf <agraf@suse.de>
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@ -122,6 +122,7 @@
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char * decNumberToEngString(const decNumber *, char *);
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uint32_t decNumberToUInt32(const decNumber *, decContext *);
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int32_t decNumberToInt32(const decNumber *, decContext *);
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int64_t decNumberIntegralToInt64(const decNumber *dn, decContext *set);
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uint8_t * decNumberGetBCD(const decNumber *, uint8_t *);
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decNumber * decNumberSetBCD(decNumber *, const uint8_t *, uint32_t);
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@ -98,7 +98,7 @@
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/* Shared lookup tables */
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extern const uByte DECSTICKYTAB[10]; /* re-round digits if sticky */
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extern const uInt DECPOWERS[10]; /* powers of ten table */
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extern const uLong DECPOWERS[19]; /* powers of ten table */
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/* The following are included from decDPD.h */
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extern const uShort DPD2BIN[1024]; /* DPD -> 0-999 */
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extern const uShort BIN2DPD[1000]; /* 0-999 -> DPD */
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@ -56,8 +56,10 @@ const uByte DECSTICKYTAB[10]={1,1,2,3,4,6,6,7,8,9}; /* used if sticky */
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/* ------------------------------------------------------------------ */
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/* Powers of ten (powers[n]==10**n, 0<=n<=9) */
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/* ------------------------------------------------------------------ */
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const uInt DECPOWERS[10]={1, 10, 100, 1000, 10000, 100000, 1000000,
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10000000, 100000000, 1000000000};
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const uLong DECPOWERS[19] = {1, 10, 100, 1000, 10000, 100000, 1000000,
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10000000, 100000000, 1000000000, 10000000000ULL, 100000000000ULL,
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1000000000000ULL, 10000000000000ULL, 100000000000000ULL, 1000000000000000ULL,
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10000000000000000ULL, 100000000000000000ULL, 1000000000000000000ULL, };
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/* ------------------------------------------------------------------ */
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/* decContextClearStatus -- clear bits in current status */
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@ -465,6 +465,50 @@ decNumber *decNumberFromUInt64(decNumber *dn, uint64_t uin)
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return dn;
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} /* decNumberFromUInt64 */
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/* ------------------------------------------------------------------ */
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/* to-int64 -- conversion to int64 */
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/* */
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/* dn is the decNumber to convert. dn is assumed to have been */
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/* rounded to a floating point integer value. */
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/* set is the context for reporting errors */
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/* returns the converted decNumber, or 0 if Invalid is set */
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/* */
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/* Invalid is set if the decNumber is a NaN, Infinite or is out of */
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/* range for a signed 64 bit integer. */
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/* ------------------------------------------------------------------ */
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int64_t decNumberIntegralToInt64(const decNumber *dn, decContext *set)
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{
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if (decNumberIsSpecial(dn) || (dn->exponent < 0) ||
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(dn->digits + dn->exponent > 19)) {
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goto Invalid;
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} else {
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int64_t d; /* work */
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const Unit *up; /* .. */
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uint64_t hi = 0;
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up = dn->lsu; /* -> lsu */
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for (d = 1; d <= dn->digits; up++, d += DECDPUN) {
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uint64_t prev = hi;
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hi += *up * powers[d-1];
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if ((hi < prev) || (hi > INT64_MAX)) {
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goto Invalid;
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}
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}
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uint64_t prev = hi;
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hi *= (uint64_t)powers[dn->exponent];
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if ((hi < prev) || (hi > INT64_MAX)) {
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goto Invalid;
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}
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return (decNumberIsNegative(dn)) ? -((int64_t)hi) : (int64_t)hi;
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}
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Invalid:
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decContextSetStatus(set, DEC_Invalid_operation);
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return 0;
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} /* decNumberIntegralToInt64 */
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/* ------------------------------------------------------------------ */
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/* to-scientific-string -- conversion to numeric string */
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@ -4259,7 +4303,7 @@ static decNumber * decDivideOp(decNumber *res,
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uByte bits; /* working sign */
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Unit *target; /* work */
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const Unit *source; /* .. */
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uInt const *pow; /* .. */
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uLong const *pow; /* .. */
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Int shift, cut; /* .. */
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#if DECSUBSET
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Int dropped; /* work */
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