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Enhancements to the DECIMAL extension:
(1) If the argument to decimal(X) is a floating point value (or an 8-byte blob), the floating point value is expanded into its exact decimal representation. (2) Function decimal_sci(X) works the same except it returns the result in scientific notation. (3) New function decimal_pow2(N) returns the full decimal expansion of the N-th integer power of 2. FossilOrigin-Name: 8baf8c10aecb261751f2b154356ab224b79d07230929ec9f123791278e601bba
This commit is contained in:
drh
@ -291,22 +291,6 @@ static void decimal_result_sci(sqlite3_context *pCtx, Decimal *p){
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sqlite3_result_text(pCtx, z, -1, sqlite3_free);
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}
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/*
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** SQL Function: decimal(X)
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**
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** Convert input X into decimal and then back into text
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*/
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static void decimalFunc(
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sqlite3_context *context,
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int argc,
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sqlite3_value **argv
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){
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Decimal *p = decimal_new(context, argv[0], 0, 0);
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UNUSED_PARAMETER(argc);
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decimal_result(context, p);
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decimal_free(p);
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}
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/*
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** Compare to Decimal objects. Return negative, 0, or positive if the
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** first object is less than, equal to, or greater than the second.
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@ -399,7 +383,7 @@ static void decimal_expand(Decimal *p, int nDigit, int nFrac){
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}
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/*
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** Add the value pB into pA.
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** Add the value pB into pA. A := A + B.
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**
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** Both pA and pB might become denormalized by this routine.
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*/
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@ -468,6 +452,200 @@ static void decimal_add(Decimal *pA, Decimal *pB){
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}
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}
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/*
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** Multiply A by B. A := A * B
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**
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** All significant digits after the decimal point are retained.
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** Trailing zeros after the decimal point are omitted as long as
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** the number of digits after the decimal point is no less than
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** either the number of digits in either input.
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*/
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static void decimalMul(Decimal *pA, Decimal *pB){
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signed char *acc = 0;
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int i, j, k;
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int minFrac;
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if( pA==0 || pA->oom || pA->isNull
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|| pB==0 || pB->oom || pB->isNull
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){
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goto mul_end;
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}
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acc = sqlite3_malloc64( pA->nDigit + pB->nDigit + 2 );
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if( acc==0 ){
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pA->oom = 1;
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goto mul_end;
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}
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memset(acc, 0, pA->nDigit + pB->nDigit + 2);
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minFrac = pA->nFrac;
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if( pB->nFrac<minFrac ) minFrac = pB->nFrac;
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for(i=pA->nDigit-1; i>=0; i--){
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signed char f = pA->a[i];
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int carry = 0, x;
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for(j=pB->nDigit-1, k=i+j+3; j>=0; j--, k--){
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x = acc[k] + f*pB->a[j] + carry;
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acc[k] = x%10;
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carry = x/10;
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}
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x = acc[k] + carry;
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acc[k] = x%10;
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acc[k-1] += x/10;
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}
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sqlite3_free(pA->a);
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pA->a = acc;
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acc = 0;
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pA->nDigit += pB->nDigit + 2;
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pA->nFrac += pB->nFrac;
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pA->sign ^= pB->sign;
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while( pA->nFrac>minFrac && pA->a[pA->nDigit-1]==0 ){
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pA->nFrac--;
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pA->nDigit--;
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}
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mul_end:
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sqlite3_free(acc);
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}
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/*
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** Create a new Decimal object that contains an integer power of 2.
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*/
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static Decimal *decimalPow2(int N){
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Decimal *pA = 0; /* The result to be returned */
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Decimal *pX = 0; /* Multiplier */
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if( N<-20000 || N>20000 ) goto pow2_fault;
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pA = decimal_new(0, 0, 3, (unsigned char*)"1.0");
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if( pA==0 || pA->oom ) goto pow2_fault;
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if( N==0 ) return pA;
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if( N>0 ){
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pX = decimal_new(0, 0, 3, (unsigned char*)"2.0");
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}else{
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N = -N;
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pX = decimal_new(0, 0, 3, (unsigned char*)"0.5");
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}
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if( pX==0 || pX->oom ) goto pow2_fault;
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while( 1 /* Exit by break */ ){
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if( N & 1 ){
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decimalMul(pA, pX);
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if( pA->oom ) goto pow2_fault;
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}
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N >>= 1;
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if( N==0 ) break;
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decimalMul(pX, pX);
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}
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decimal_free(pX);
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return pA;
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pow2_fault:
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decimal_free(pA);
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decimal_free(pX);
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return 0;
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}
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/*
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** Use an IEEE754 binary64 ("double") to generate a new Decimal object.
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*/
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static Decimal *decimalFromDouble(double r){
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sqlite3_int64 m, a;
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int e;
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int isNeg;
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Decimal *pA;
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Decimal *pX;
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char zNum[100];
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if( r<0.0 ){
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isNeg = 1;
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r = -r;
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}else{
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isNeg = 0;
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}
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memcpy(&a,&r,sizeof(a));
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if( a==0 ){
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e = 0;
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m = 0;
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}else{
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e = a>>52;
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m = a & ((((sqlite3_int64)1)<<52)-1);
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if( e==0 ){
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m <<= 1;
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}else{
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m |= ((sqlite3_int64)1)<<52;
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}
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while( e<1075 && m>0 && (m&1)==0 ){
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m >>= 1;
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e++;
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}
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if( isNeg ) m = -m;
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e = e - 1075;
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if( e>971 ){
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return 0; /* A NaN or an Infinity */
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}
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}
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/* At this point m is the integer significand and e is the exponent */
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sqlite3_snprintf(sizeof(zNum), zNum, "%lld", m);
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pA = decimal_new(0, 0, (int)strlen(zNum), (unsigned char*)zNum);
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pX = decimalPow2(e);
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decimalMul(pA, pX);
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decimal_free(pX);
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return pA;
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}
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/*
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** SQL Function: decimal(X)
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**
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** Convert input X into decimal and then back into text.
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**
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** If X is originally a float, then a full decoding of that floating
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** point value is done. Or if X is an 8-byte blob, it is interpreted
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** as a float and similarly expanded.
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*/
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static void decimalFunc(
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sqlite3_context *context,
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int argc,
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sqlite3_value **argv
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){
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Decimal *p = 0;
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UNUSED_PARAMETER(argc);
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switch( sqlite3_value_type(argv[0]) ){
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case SQLITE_TEXT:
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case SQLITE_INTEGER: {
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p = decimal_new(context, argv[0], 0, 0);
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break;
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}
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case SQLITE_FLOAT: {
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p = decimalFromDouble(sqlite3_value_double(argv[0]));
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break;
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}
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case SQLITE_BLOB: {
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const unsigned char *x;
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unsigned int i;
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sqlite3_uint64 v = 0;
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double r;
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if( sqlite3_value_bytes(argv[0])!=sizeof(r) ) break;
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x = sqlite3_value_blob(argv[0]);
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for(i=0; i<sizeof(r); i++){
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v = (v<<8) | x[i];
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}
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memcpy(&r, &v, sizeof(r));
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p = decimalFromDouble(r);
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break;
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}
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case SQLITE_NULL: {
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break;
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}
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}
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if( p ){
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if( sqlite3_user_data(context)!=0 ){
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decimal_result_sci(context, p);
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}else{
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decimal_result(context, p);
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}
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decimal_free(p);
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}
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}
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/*
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** Compare text in decimal order.
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*/
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@ -592,11 +770,6 @@ static void decimalSumFinalize(sqlite3_context *context){
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** SQL Function: decimal_mul(X, Y)
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**
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** Return the product of X and Y.
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**
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** All significant digits after the decimal point are retained.
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** Trailing zeros after the decimal point are omitted as long as
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** the number of digits after the decimal point is no less than
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** either the number of digits in either input.
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*/
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static void decimalMulFunc(
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sqlite3_context *context,
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@ -605,67 +778,39 @@ static void decimalMulFunc(
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){
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Decimal *pA = decimal_new(context, argv[0], 0, 0);
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Decimal *pB = decimal_new(context, argv[1], 0, 0);
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signed char *acc = 0;
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int i, j, k;
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int minFrac;
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UNUSED_PARAMETER(argc);
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if( pA==0 || pA->oom || pA->isNull
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|| pB==0 || pB->oom || pB->isNull
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){
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goto mul_end;
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}
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acc = sqlite3_malloc64( pA->nDigit + pB->nDigit + 2 );
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if( acc==0 ){
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sqlite3_result_error_nomem(context);
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decimalMul(pA, pB);
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if( pA->oom ){
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goto mul_end;
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}
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memset(acc, 0, pA->nDigit + pB->nDigit + 2);
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minFrac = pA->nFrac;
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if( pB->nFrac<minFrac ) minFrac = pB->nFrac;
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for(i=pA->nDigit-1; i>=0; i--){
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signed char f = pA->a[i];
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int carry = 0, x;
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for(j=pB->nDigit-1, k=i+j+3; j>=0; j--, k--){
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x = acc[k] + f*pB->a[j] + carry;
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acc[k] = x%10;
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carry = x/10;
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}
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x = acc[k] + carry;
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acc[k] = x%10;
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acc[k-1] += x/10;
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}
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sqlite3_free(pA->a);
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pA->a = acc;
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acc = 0;
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pA->nDigit += pB->nDigit + 2;
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pA->nFrac += pB->nFrac;
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pA->sign ^= pB->sign;
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while( pA->nFrac>minFrac && pA->a[pA->nDigit-1]==0 ){
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pA->nFrac--;
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pA->nDigit--;
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}
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decimal_result(context, pA);
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mul_end:
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sqlite3_free(acc);
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decimal_free(pA);
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decimal_free(pB);
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}
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/*
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** SQL Function: decimal_sci(X)
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** SQL Function: decimal_pow2(N)
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**
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** Convert decimal number X into scientific notation ("+N.NNNe+NN").
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** Return the N-th power of 2. N must be an integer.
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*/
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static void decimalSciFunc(
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static void decimalPow2Func(
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sqlite3_context *context,
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int argc,
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sqlite3_value **argv
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){
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Decimal *pA = decimal_new(context, argv[0], 0, 0);
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UNUSED_PARAMETER(argc);
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decimal_result_sci(context, pA);
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decimal_free(pA);
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if( sqlite3_value_type(argv[0])==SQLITE_INTEGER ){
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Decimal *pA = decimalPow2(sqlite3_value_int(argv[0]));
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decimal_result_sci(context, pA);
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decimal_free(pA);
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}
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}
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#ifdef _WIN32
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@ -680,14 +825,16 @@ int sqlite3_decimal_init(
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static const struct {
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const char *zFuncName;
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int nArg;
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int iArg;
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void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
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} aFunc[] = {
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{ "decimal", 1, decimalFunc },
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{ "decimal_cmp", 2, decimalCmpFunc },
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{ "decimal_add", 2, decimalAddFunc },
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{ "decimal_sub", 2, decimalSubFunc },
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{ "decimal_mul", 2, decimalMulFunc },
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{ "decimal_sci", 1, decimalSciFunc },
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{ "decimal", 1, 0, decimalFunc },
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{ "decimal_cmp", 2, 0, decimalCmpFunc },
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{ "decimal_add", 2, 0, decimalAddFunc },
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{ "decimal_sub", 2, 0, decimalSubFunc },
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{ "decimal_mul", 2, 0, decimalMulFunc },
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{ "decimal_sci", 1, 1, decimalFunc },
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{ "decimal_pow2", 1, 0, decimalPow2Func },
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};
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unsigned int i;
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(void)pzErrMsg; /* Unused parameter */
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@ -697,7 +844,7 @@ int sqlite3_decimal_init(
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for(i=0; i<(int)(sizeof(aFunc)/sizeof(aFunc[0])) && rc==SQLITE_OK; i++){
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rc = sqlite3_create_function(db, aFunc[i].zFuncName, aFunc[i].nArg,
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SQLITE_UTF8|SQLITE_INNOCUOUS|SQLITE_DETERMINISTIC,
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0, aFunc[i].xFunc, 0, 0);
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aFunc[i].iArg ? db : 0, aFunc[i].xFunc, 0, 0);
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}
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if( rc==SQLITE_OK ){
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rc = sqlite3_create_window_function(db, "decimal_sum", 1,
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