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Cleanup and commenting of the new DECIMAL extension code. No functional

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changes.

FossilOrigin-Name: 5124481663eb8e74a9f861be98adb7075ea911fcff0216d98c658e955acadf14
This commit is contained in:
drh
2023-06-29 23:03:30 +00:00
parent ec3e57fa92
commit 2ddfa6a360
3 changed files with 110 additions and 86 deletions
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182
ext/misc/decimal.c
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@ -58,41 +58,24 @@ static void decimal_free(Decimal *p){
}
/*
** Allocate a new Decimal object. Initialize it to the number given
** by the input string.
** Allocate a new Decimal object initialized to the text in zIn[].
** Return NULL if any kind of error occurs.
*/
static Decimal *decimal_new(
sqlite3_context *pCtx,
sqlite3_value *pIn,
int nAlt,
const unsigned char *zAlt
){
Decimal *p;
int n, i;
const unsigned char *zIn;
static Decimal *decimalNewFromText(const char *zIn, int n){
Decimal *p = 0;
int i;
int iExp = 0;
p = sqlite3_malloc( sizeof(*p) );
if( p==0 ) goto new_no_mem;
if( p==0 ) goto new_from_text_failed;
p->sign = 0;
p->oom = 0;
p->isInit = 1;
p->isNull = 0;
p->nDigit = 0;
p->nFrac = 0;
if( zAlt ){
n = nAlt,
zIn = zAlt;
}else{
if( sqlite3_value_type(pIn)==SQLITE_NULL ){
p->a = 0;
p->isNull = 1;
return p;
}
n = sqlite3_value_bytes(pIn);
zIn = sqlite3_value_text(pIn);
}
p->a = sqlite3_malloc64( n+1 );
if( p->a==0 ) goto new_no_mem;
if( p->a==0 ) goto new_from_text_failed;
for(i=0; isspace(zIn[i]); i++){}
if( zIn[i]=='-' ){
p->sign = 1;
@ -143,7 +126,7 @@ static Decimal *decimal_new(
}
if( iExp>0 ){
p->a = sqlite3_realloc64(p->a, p->nDigit + iExp + 1 );
if( p->a==0 ) goto new_no_mem;
if( p->a==0 ) goto new_from_text_failed;
memset(p->a+p->nDigit, 0, iExp);
p->nDigit += iExp;
}
@ -162,7 +145,7 @@ static Decimal *decimal_new(
}
if( iExp>0 ){
p->a = sqlite3_realloc64(p->a, p->nDigit + iExp + 1 );
if( p->a==0 ) goto new_no_mem;
if( p->a==0 ) goto new_from_text_failed;
memmove(p->a+iExp, p->a, p->nDigit);
memset(p->a, 0, iExp);
p->nDigit += iExp;
@ -171,7 +154,76 @@ static Decimal *decimal_new(
}
return p;
new_no_mem:
new_from_text_failed:
if( p ){
if( p->a ) sqlite3_free(p->a);
sqlite3_free(p);
}
return 0;
}
/* Forward reference */
static Decimal *decimalFromDouble(double);
/*
** Allocate a new Decimal object from an sqlite3_value. Return a pointer
** to the new object, or NULL if there is an error. If the pCtx argument
** is not NULL, then errors are reported on it as well.
**
** If the pIn argument is SQLITE_TEXT or SQLITE_INTEGER, it is converted
** directly into a Decimal. For SQLITE_FLOAT or for SQLITE_BLOB of length
** 8 bytes, the resulting double value is expanded into its decimal equivalent.
** If pIn is NULL or if it is a BLOB that is not exactly 8 bytes in length,
** then NULL is returned.
*/
static Decimal *decimal_new(
sqlite3_context *pCtx, /* Report error here, if not null */
sqlite3_value *pIn, /* Construct the decimal object from this */
int bTextOnly /* Always interpret pIn as text if true */
){
Decimal *p = 0;
int eType = sqlite3_value_type(pIn);
if( bTextOnly && (eType==SQLITE_FLOAT || eType==SQLITE_BLOB) ){
eType = SQLITE_TEXT;
}
switch( eType ){
case SQLITE_TEXT:
case SQLITE_INTEGER: {
const char *zIn = (const char*)sqlite3_value_text(pIn);
int n = sqlite3_value_bytes(pIn);
p = decimalNewFromText(zIn, n);
if( p==0 ) goto new_failed;
break;
}
case SQLITE_FLOAT: {
p = decimalFromDouble(sqlite3_value_double(pIn));
break;
}
case SQLITE_BLOB: {
const unsigned char *x;
unsigned int i;
sqlite3_uint64 v = 0;
double r;
if( sqlite3_value_bytes(pIn)!=sizeof(r) ) break;
x = sqlite3_value_blob(pIn);
for(i=0; i<sizeof(r); i++){
v = (v<<8) | x[i];
}
memcpy(&r, &v, sizeof(r));
p = decimalFromDouble(r);
break;
}
case SQLITE_NULL: {
break;
}
}
return p;
new_failed:
if( pCtx ) sqlite3_result_error_nomem(pCtx);
sqlite3_free(p);
return 0;
@ -341,9 +393,9 @@ static void decimalCmpFunc(
int rc;
UNUSED_PARAMETER(argc);
pA = decimal_new(context, argv[0], 0, 0);
pA = decimal_new(context, argv[0], 1);
if( pA==0 || pA->isNull ) goto cmp_done;
pB = decimal_new(context, argv[1], 0, 0);
pB = decimal_new(context, argv[1], 1);
if( pB==0 || pB->isNull ) goto cmp_done;
rc = decimal_cmp(pA, pB);
if( rc<0 ) rc = -1;
@ -512,14 +564,14 @@ static Decimal *decimalPow2(int N){
Decimal *pA = 0; /* The result to be returned */
Decimal *pX = 0; /* Multiplier */
if( N<-20000 || N>20000 ) goto pow2_fault;
pA = decimal_new(0, 0, 3, (unsigned char*)"1.0");
pA = decimalNewFromText("1.0", 3);
if( pA==0 || pA->oom ) goto pow2_fault;
if( N==0 ) return pA;
if( N>0 ){
pX = decimal_new(0, 0, 3, (unsigned char*)"2.0");
pX = decimalNewFromText("2.0", 3);
}else{
N = -N;
pX = decimal_new(0, 0, 3, (unsigned char*)"0.5");
pX = decimalNewFromText("0.5", 3);
}
if( pX==0 || pX->oom ) goto pow2_fault;
while( 1 /* Exit by break */ ){
@ -581,7 +633,7 @@ static Decimal *decimalFromDouble(double r){
/* At this point m is the integer significand and e is the exponent */
sqlite3_snprintf(sizeof(zNum), zNum, "%lld", m);
pA = decimal_new(0, 0, (int)strlen(zNum), (unsigned char*)zNum);
pA = decimalNewFromText(zNum, (int)strlen(zNum));
pX = decimalPow2(e);
decimalMul(pA, pX);
decimal_free(pX);
@ -590,52 +642,24 @@ static Decimal *decimalFromDouble(double r){
/*
** SQL Function: decimal(X)
** OR: decimal_sci(X)
**
** Convert input X into decimal and then back into text.
**
** If X is originally a float, then a full decoding of that floating
** If X is originally a float, then a full decimal expansion of that floating
** point value is done. Or if X is an 8-byte blob, it is interpreted
** as a float and similarly expanded.
**
** The decimal_sci(X) function returns the result in scientific notation.
** decimal(X) returns a complete decimal, without the e+NNN at the end.
*/
static void decimalFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
Decimal *p = 0;
Decimal *p = decimal_new(context, argv[0], 0);
UNUSED_PARAMETER(argc);
switch( sqlite3_value_type(argv[0]) ){
case SQLITE_TEXT:
case SQLITE_INTEGER: {
p = decimal_new(context, argv[0], 0, 0);
break;
}
case SQLITE_FLOAT: {
p = decimalFromDouble(sqlite3_value_double(argv[0]));
break;
}
case SQLITE_BLOB: {
const unsigned char *x;
unsigned int i;
sqlite3_uint64 v = 0;
double r;
if( sqlite3_value_bytes(argv[0])!=sizeof(r) ) break;
x = sqlite3_value_blob(argv[0]);
for(i=0; i<sizeof(r); i++){
v = (v<<8) | x[i];
}
memcpy(&r, &v, sizeof(r));
p = decimalFromDouble(r);
break;
}
case SQLITE_NULL: {
break;
}
}
if( p ){
if( sqlite3_user_data(context)!=0 ){
decimal_result_sci(context, p);
@ -656,8 +680,8 @@ static int decimalCollFunc(
){
const unsigned char *zA = (const unsigned char*)pKey1;
const unsigned char *zB = (const unsigned char*)pKey2;
Decimal *pA = decimal_new(0, 0, nKey1, zA);
Decimal *pB = decimal_new(0, 0, nKey2, zB);
Decimal *pA = decimalNewFromText((const char*)zA, nKey1);
Decimal *pB = decimalNewFromText((const char*)zB, nKey2);
int rc;
UNUSED_PARAMETER(notUsed);
if( pA==0 || pB==0 ){
@ -682,8 +706,8 @@ static void decimalAddFunc(
int argc,
sqlite3_value **argv
){
Decimal *pA = decimal_new(context, argv[0], 0, 0);
Decimal *pB = decimal_new(context, argv[1], 0, 0);
Decimal *pA = decimal_new(context, argv[0], 1);
Decimal *pB = decimal_new(context, argv[1], 1);
UNUSED_PARAMETER(argc);
decimal_add(pA, pB);
decimal_result(context, pA);
@ -695,8 +719,8 @@ static void decimalSubFunc(
int argc,
sqlite3_value **argv
){
Decimal *pA = decimal_new(context, argv[0], 0, 0);
Decimal *pB = decimal_new(context, argv[1], 0, 0);
Decimal *pA = decimal_new(context, argv[0], 1);
Decimal *pB = decimal_new(context, argv[1], 1);
UNUSED_PARAMETER(argc);
if( pB ){
pB->sign = !pB->sign;
@ -734,7 +758,7 @@ static void decimalSumStep(
p->nFrac = 0;
}
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
pArg = decimal_new(context, argv[0], 0, 0);
pArg = decimal_new(context, argv[0], 1);
decimal_add(p, pArg);
decimal_free(pArg);
}
@ -749,7 +773,7 @@ static void decimalSumInverse(
p = sqlite3_aggregate_context(context, sizeof(*p));
if( p==0 ) return;
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
pArg = decimal_new(context, argv[0], 0, 0);
pArg = decimal_new(context, argv[0], 1);
if( pArg ) pArg->sign = !pArg->sign;
decimal_add(p, pArg);
decimal_free(pArg);
@ -776,8 +800,8 @@ static void decimalMulFunc(
int argc,
sqlite3_value **argv
){
Decimal *pA = decimal_new(context, argv[0], 0, 0);
Decimal *pB = decimal_new(context, argv[1], 0, 0);
Decimal *pA = decimal_new(context, argv[0], 1);
Decimal *pB = decimal_new(context, argv[1], 1);
UNUSED_PARAMETER(argc);
if( pA==0 || pA->oom || pA->isNull
|| pB==0 || pB->oom || pB->isNull
@ -829,11 +853,11 @@ int sqlite3_decimal_init(
void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
} aFunc[] = {
{ "decimal", 1, 0, decimalFunc },
{ "decimal_sci", 1, 1, decimalFunc },
{ "decimal_cmp", 2, 0, decimalCmpFunc },
{ "decimal_add", 2, 0, decimalAddFunc },
{ "decimal_sub", 2, 0, decimalSubFunc },
{ "decimal_mul", 2, 0, decimalMulFunc },
{ "decimal_sci", 1, 1, decimalFunc },
{ "decimal_pow2", 1, 0, decimalPow2Func },
};
unsigned int i;