/* This comparison routine is what we use for comparison operations
** between numeric values in an SQL expression. "Numeric" is a little
** bit misleading here. What we mean is that the strings have a
** type of "numeric" from the point of view of SQL. The strings
** do not necessarily contain numbers. They could contain text.
**
** If the input strings both look like actual numbers then they
** compare in numerical order. Numerical strings are always less
** than non-numeric strings so if one input string looks like a
** number and the other does not, then the one that looks like
** a number is the smaller. Non-numeric strings compare in
** lexigraphical order (the same order as strcmp()).
*/
int sqliteCompare(const char *atext, const char *btext){
int result;
int isNumA, isNumB;
if( atext==0 ){
return -1;
}else if( btext==0 ){
return 1;
}
isNumA = sqliteIsNumber(atext);
isNumB = sqliteIsNumber(btext);
if( isNumA ){
if( !isNumB ){
result = -1;
}else{
double rA, rB;
rA = sqliteAtoF(atext, 0);
rB = sqliteAtoF(btext, 0);
if( rA<rB ){
result = -1;
}else if( rA>rB ){
result = +1;
}else{
result = 0;
}
}
}else if( isNumB ){
result = +1;
}else {
result = strcmp(atext, btext);
}
return result;
}
/*
** This routine is used for sorting. Each key is a list of one or more
** null-terminated elements. The list is terminated by two nulls in
** a row. For example, the following text is a key with three elements
**
** Aone\000Dtwo\000Athree\000\000
**
** All elements begin with one of the characters "+-AD" and end with "\000"
** with zero or more text elements in between. Except, NULL elements
** consist of the special two-character sequence "N\000".
**
** Both arguments will have the same number of elements. This routine
** returns negative, zero, or positive if the first argument is less
** than, equal to, or greater than the first. (Result is a-b).
**
** Each element begins with one of the characters "+", "-", "A", "D".
** This character determines the sort order and collating sequence:
**
** + Sort numerically in ascending order
** - Sort numerically in descending order
** A Sort as strings in ascending order
** D Sort as strings in descending order.
**
** For the "+" and "-" sorting, pure numeric strings (strings for which the
** isNum() function above returns TRUE) always compare less than strings
** that are not pure numerics. Non-numeric strings compare in memcmp()
** order. This is the same sort order as the sqliteCompare() function
** above generates.
**
** The last point is a change from version 2.6.3 to version 2.7.0. In
** version 2.6.3 and earlier, substrings of digits compare in numerical
** and case was used only to break a tie.
**
** Elements that begin with 'A' or 'D' compare in memcmp() order regardless
** of whether or not they look like a number.
**
** Note that the sort order imposed by the rules above is the same
** from the ordering defined by the "<", "<=", ">", and ">=" operators
** of expressions and for indices. This was not the case for version
** 2.6.3 and earlier.
*/
int sqliteSortCompare(const char *a, const char *b){
int res = 0;
int isNumA, isNumB;
int dir = 0;
while( res==0 && *a && *b ){
if( a[0]=='N' || b[0]=='N' ){
if( a[0]==b[0] ){
a += 2;
b += 2;
continue;
}
if( a[0]=='N' ){
dir = b[0];
res = -1;
}else{
dir = a[0];
res = +1;
}
break;
}
assert( a[0]==b[0] );
if( (dir=a[0])=='A' || a[0]=='D' ){
res = strcmp(&a[1],&b[1]);
if( res ) break;
}else{
isNumA = sqliteIsNumber(&a[1]);
isNumB = sqliteIsNumber(&b[1]);
if( isNumA ){
double rA, rB;
if( !isNumB ){
res = -1;
break;
}
rA = sqliteAtoF(&a[1], 0);
rB = sqliteAtoF(&b[1], 0);
if( rA<rB ){
res = -1;
break;
}
if( rA>rB ){
res = +1;
break;
}
}else if( isNumB ){
res = +1;
break;
}else{
res = strcmp(&a[1],&b[1]);
if( res ) break;
}
}
a += strlen(&a[1]) + 2;
b += strlen(&b[1]) + 2;
}
if( dir=='-' || dir=='D' ) res = -res;
return res;
}
/*
** Routines used to compute the sum or average.
*/
static void sumStep(sqlite_func *context, int argc, const char **argv){
SumCtx *p;
if( argc<1 ) return;
p = sqlite_aggregate_context(context, sizeof(*p));
if( p && argv[0] ){
p->sum += sqliteAtoF(argv[0], 0);
p->cnt++;
}
}
/*
** Routines used to compute the standard deviation as an aggregate.
*/
static void stdDevStep(sqlite_func *context, int argc, const char **argv){
StdDevCtx *p;
double x;
if( argc<1 ) return;
p = sqlite_aggregate_context(context, sizeof(*p));
if( p && argv[0] ){
x = sqliteAtoF(argv[0], 0);
p->sum += x;
p->sum2 += x*x;
p->cnt++;
}
}
/*
** Implementation of the round() function
*/
static void roundFunc(sqlite_func *context, int argc, const char **argv){
int n;
double r;
char zBuf[100];
assert( argc==1 || argc==2 );
if( argv[0]==0 || (argc==2 && argv[1]==0) ) return;
n = argc==2 ? atoi(argv[1]) : 0;
if( n>30 ) n = 30;
if( n<0 ) n = 0;
r = sqliteAtoF(argv[0], 0);
sprintf(zBuf,"%.*f",n,r);
sqlite_set_result_string(context, zBuf, -1);
}
/*
** The following routine is a user-defined SQL function whose purpose
** is to test the sqlite_set_result() API.
*/
static void testFunc(sqlite_func *context, int argc, const char **argv){
while( argc>=2 ){
if( argv[0]==0 ){
sqlite_set_result_error(context, "first argument to test function "
"may not be NULL", -1);
}else if( sqliteStrICmp(argv[0],"string")==0 ){
sqlite_set_result_string(context, argv[1], -1);
}else if( argv[1]==0 ){
sqlite_set_result_error(context, "2nd argument may not be NULL if the "
"first argument is not \"string\"", -1);
}else if( sqliteStrICmp(argv[0],"int")==0 ){
sqlite_set_result_int(context, atoi(argv[1]));
}else if( sqliteStrICmp(argv[0],"double")==0 ){
sqlite_set_result_double(context, sqliteAtoF(argv[1], 0));
}else{
sqlite_set_result_error(context,"first argument should be one of: "
"string int double", -1);
}
argc -= 2;
argv += 2;
}
}
/*
** Attempt to parse the given string into a Julian Day Number. Return
** the number of errors.
**
** The following are acceptable forms for the input string:
**
** YYYY-MM-DD HH:MM:SS.FFF +/-HH:MM
** DDDD.DD
** now
**
** In the first form, the +/-HH:MM is always optional. The fractional
** seconds extension (the ".FFF") is optional. The seconds portion
** (":SS.FFF") is option. The year and date can be omitted as long
** as there is a time string. The time string can be omitted as long
** as there is a year and date.
*/
static int parseDateOrTime(const char *zDate, DateTime *p){
int i;
memset(p, 0, sizeof(*p));
for(i=0; isdigit(zDate[i]); i++){}
if( i==4 && zDate[i]=='-' ){
return parseYyyyMmDd(zDate, p);
}else if( i==2 && zDate[i]==':' ){
return parseHhMmSs(zDate, p);
return 0;
}else if( i==0 && sqliteStrICmp(zDate,"now")==0 ){
double r;
if( sqliteOsCurrentTime(&r)==0 ){
p->rJD = r;
p->validJD = 1;
return 0;
}
return 1;
}else if( sqliteIsNumber(zDate) ){
p->rJD = sqliteAtoF(zDate);
p->validJD = 1;
return 0;
}
return 1;
}
