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sourcemod/extensions/sqlite/sqlite-source/func.c
David Anderson 9f6a67ba17 initial import of sqlite extension 
--HG--
extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%401209
2007-07-29 01:15:31 +00:00

1494 lines
43 KiB
C
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/*
** 2002 February 23
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the C functions that implement various SQL
** functions of SQLite.
**
** There is only one exported symbol in this file - the function
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id$
*/
#include "sqliteInt.h"
#include <ctype.h>
/* #include <math.h> */
#include <stdlib.h>
#include <assert.h>
#include "vdbeInt.h"
#include "os.h"
/*
** Return the collating function associated with a function.
*/
static CollSeq *sqlite3GetFuncCollSeq(sqlite3_context *context){
return context->pColl;
}
/*
** Implementation of the non-aggregate min() and max() functions
*/
static void minmaxFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
int i;
int mask; /* 0 for min() or 0xffffffff for max() */
int iBest;
CollSeq *pColl;
if( argc==0 ) return;
mask = sqlite3_user_data(context)==0 ? 0 : -1;
pColl = sqlite3GetFuncCollSeq(context);
assert( pColl );
assert( mask==-1 || mask==0 );
iBest = 0;
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
for(i=1; i<argc; i++){
if( sqlite3_value_type(argv[i])==SQLITE_NULL ) return;
if( (sqlite3MemCompare(argv[iBest], argv[i], pColl)^mask)>=0 ){
iBest = i;
}
}
sqlite3_result_value(context, argv[iBest]);
}
/*
** Return the type of the argument.
*/
static void typeofFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const char *z = 0;
switch( sqlite3_value_type(argv[0]) ){
case SQLITE_NULL: z = "null"; break;
case SQLITE_INTEGER: z = "integer"; break;
case SQLITE_TEXT: z = "text"; break;
case SQLITE_FLOAT: z = "real"; break;
case SQLITE_BLOB: z = "blob"; break;
}
sqlite3_result_text(context, z, -1, SQLITE_STATIC);
}
/*
** Implementation of the length() function
*/
static void lengthFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
int len;
assert( argc==1 );
switch( sqlite3_value_type(argv[0]) ){
case SQLITE_BLOB:
case SQLITE_INTEGER:
case SQLITE_FLOAT: {
sqlite3_result_int(context, sqlite3_value_bytes(argv[0]));
break;
}
case SQLITE_TEXT: {
const unsigned char *z = sqlite3_value_text(argv[0]);
if( z==0 ) return;
len = 0;
while( *z ){
len++;
SQLITE_SKIP_UTF8(z);
}
sqlite3_result_int(context, len);
break;
}
default: {
sqlite3_result_null(context);
break;
}
}
}
/*
** Implementation of the abs() function
*/
static void absFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
assert( argc==1 );
switch( sqlite3_value_type(argv[0]) ){
case SQLITE_INTEGER: {
i64 iVal = sqlite3_value_int64(argv[0]);
if( iVal<0 ){
if( (iVal<<1)==0 ){
sqlite3_result_error(context, "integer overflow", -1);
return;
}
iVal = -iVal;
}
sqlite3_result_int64(context, iVal);
break;
}
case SQLITE_NULL: {
sqlite3_result_null(context);
break;
}
default: {
double rVal = sqlite3_value_double(argv[0]);
if( rVal<0 ) rVal = -rVal;
sqlite3_result_double(context, rVal);
break;
}
}
}
/*
** Implementation of the substr() function.
**
** substr(x,p1,p2) returns p2 characters of x[] beginning with p1.
** p1 is 1-indexed. So substr(x,1,1) returns the first character
** of x. If x is text, then we actually count UTF-8 characters.
** If x is a blob, then we count bytes.
**
** If p1 is negative, then we begin abs(p1) from the end of x[].
*/
static void substrFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const unsigned char *z;
const unsigned char *z2;
int len;
int p0type;
i64 p1, p2;
assert( argc==3 );
p0type = sqlite3_value_type(argv[0]);
if( p0type==SQLITE_BLOB ){
len = sqlite3_value_bytes(argv[0]);
z = sqlite3_value_blob(argv[0]);
if( z==0 ) return;
assert( len==sqlite3_value_bytes(argv[0]) );
}else{
z = sqlite3_value_text(argv[0]);
if( z==0 ) return;
len = 0;
for(z2=z; *z2; len++){
SQLITE_SKIP_UTF8(z2);
}
}
p1 = sqlite3_value_int(argv[1]);
p2 = sqlite3_value_int(argv[2]);
if( p1<0 ){
p1 += len;
if( p1<0 ){
p2 += p1;
p1 = 0;
}
}else if( p1>0 ){
p1--;
}
if( p1+p2>len ){
p2 = len-p1;
}
if( p0type!=SQLITE_BLOB ){
while( *z && p1 ){
SQLITE_SKIP_UTF8(z);
p1--;
}
for(z2=z; *z2 && p2; p2--){
SQLITE_SKIP_UTF8(z2);
}
sqlite3_result_text(context, (char*)z, z2-z, SQLITE_TRANSIENT);
}else{
if( p2<0 ) p2 = 0;
sqlite3_result_blob(context, (char*)&z[p1], p2, SQLITE_TRANSIENT);
}
}
/*
** Implementation of the round() function
*/
static void roundFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
int n = 0;
double r;
char zBuf[500]; /* larger than the %f representation of the largest double */
assert( argc==1 || argc==2 );
if( argc==2 ){
if( SQLITE_NULL==sqlite3_value_type(argv[1]) ) return;
n = sqlite3_value_int(argv[1]);
if( n>30 ) n = 30;
if( n<0 ) n = 0;
}
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
r = sqlite3_value_double(argv[0]);
sqlite3_snprintf(sizeof(zBuf),zBuf,"%.*f",n,r);
sqlite3AtoF(zBuf, &r);
sqlite3_result_double(context, r);
}
/*
** Implementation of the upper() and lower() SQL functions.
*/
static void upperFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
char *z1;
const char *z2;
int i, n;
if( argc<1 || SQLITE_NULL==sqlite3_value_type(argv[0]) ) return;
z2 = (char*)sqlite3_value_text(argv[0]);
n = sqlite3_value_bytes(argv[0]);
/* Verify that the call to _bytes() does not invalidate the _text() pointer */
assert( z2==(char*)sqlite3_value_text(argv[0]) );
if( z2 ){
z1 = sqlite3_malloc(n+1);
if( z1 ){
memcpy(z1, z2, n+1);
for(i=0; z1[i]; i++){
z1[i] = toupper(z1[i]);
}
sqlite3_result_text(context, z1, -1, sqlite3_free);
}
}
}
static void lowerFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
char *z1;
const char *z2;
int i, n;
if( argc<1 || SQLITE_NULL==sqlite3_value_type(argv[0]) ) return;
z2 = (char*)sqlite3_value_text(argv[0]);
n = sqlite3_value_bytes(argv[0]);
/* Verify that the call to _bytes() does not invalidate the _text() pointer */
assert( z2==(char*)sqlite3_value_text(argv[0]) );
if( z2 ){
z1 = sqlite3_malloc(n+1);
if( z1 ){
memcpy(z1, z2, n+1);
for(i=0; z1[i]; i++){
z1[i] = tolower(z1[i]);
}
sqlite3_result_text(context, z1, -1, sqlite3_free);
}
}
}
/*
** Implementation of the IFNULL(), NVL(), and COALESCE() functions.
** All three do the same thing. They return the first non-NULL
** argument.
*/
static void ifnullFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
int i;
for(i=0; i<argc; i++){
if( SQLITE_NULL!=sqlite3_value_type(argv[i]) ){
sqlite3_result_value(context, argv[i]);
break;
}
}
}
/*
** Implementation of random(). Return a random integer.
*/
static void randomFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
sqlite_int64 r;
sqlite3Randomness(sizeof(r), &r);
if( (r<<1)==0 ) r = 0; /* Prevent 0x8000.... as the result so that we */
/* can always do abs() of the result */
sqlite3_result_int64(context, r);
}
/*
** Implementation of randomblob(N). Return a random blob
** that is N bytes long.
*/
static void randomBlob(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
int n;
unsigned char *p;
assert( argc==1 );
n = sqlite3_value_int(argv[0]);
if( n<1 ){
n = 1;
}
if( n>SQLITE_MAX_LENGTH ){
sqlite3_result_error_toobig(context);
return;
}
p = sqliteMalloc(n);
if( p ){
sqlite3Randomness(n, p);
sqlite3_result_blob(context, (char*)p, n, sqlite3FreeX);
}
}
/*
** Implementation of the last_insert_rowid() SQL function. The return
** value is the same as the sqlite3_last_insert_rowid() API function.
*/
static void last_insert_rowid(
sqlite3_context *context,
int arg,
sqlite3_value **argv
){
sqlite3 *db = sqlite3_user_data(context);
sqlite3_result_int64(context, sqlite3_last_insert_rowid(db));
}
/*
** Implementation of the changes() SQL function. The return value is the
** same as the sqlite3_changes() API function.
*/
static void changes(
sqlite3_context *context,
int arg,
sqlite3_value **argv
){
sqlite3 *db = sqlite3_user_data(context);
sqlite3_result_int(context, sqlite3_changes(db));
}
/*
** Implementation of the total_changes() SQL function. The return value is
** the same as the sqlite3_total_changes() API function.
*/
static void total_changes(
sqlite3_context *context,
int arg,
sqlite3_value **argv
){
sqlite3 *db = sqlite3_user_data(context);
sqlite3_result_int(context, sqlite3_total_changes(db));
}
/*
** A structure defining how to do GLOB-style comparisons.
*/
struct compareInfo {
u8 matchAll;
u8 matchOne;
u8 matchSet;
u8 noCase;
};
static const struct compareInfo globInfo = { '*', '?', '[', 0 };
/* The correct SQL-92 behavior is for the LIKE operator to ignore
** case. Thus 'a' LIKE 'A' would be true. */
static const struct compareInfo likeInfoNorm = { '%', '_', 0, 1 };
/* If SQLITE_CASE_SENSITIVE_LIKE is defined, then the LIKE operator
** is case sensitive causing 'a' LIKE 'A' to be false */
static const struct compareInfo likeInfoAlt = { '%', '_', 0, 0 };
/*
** Read a single UTF-8 character and return its value.
*/
u32 sqlite3ReadUtf8(const unsigned char *z){
u32 c;
SQLITE_READ_UTF8(z, c);
return c;
}
/*
** Compare two UTF-8 strings for equality where the first string can
** potentially be a "glob" expression. Return true (1) if they
** are the same and false (0) if they are different.
**
** Globbing rules:
**
** '*' Matches any sequence of zero or more characters.
**
** '?' Matches exactly one character.
**
** [...] Matches one character from the enclosed list of
** characters.
**
** [^...] Matches one character not in the enclosed list.
**
** With the [...] and [^...] matching, a ']' character can be included
** in the list by making it the first character after '[' or '^'. A
** range of characters can be specified using '-'. Example:
** "[a-z]" matches any single lower-case letter. To match a '-', make
** it the last character in the list.
**
** This routine is usually quick, but can be N**2 in the worst case.
**
** Hints: to match '*' or '?', put them in "[]". Like this:
**
** abc[*]xyz Matches "abc*xyz" only
*/
static int patternCompare(
const u8 *zPattern, /* The glob pattern */
const u8 *zString, /* The string to compare against the glob */
const struct compareInfo *pInfo, /* Information about how to do the compare */
const int esc /* The escape character */
){
register int c;
int invert;
int seen;
int c2;
u8 matchOne = pInfo->matchOne;
u8 matchAll = pInfo->matchAll;
u8 matchSet = pInfo->matchSet;
u8 noCase = pInfo->noCase;
int prevEscape = 0; /* True if the previous character was 'escape' */
while( (c = *zPattern)!=0 ){
if( !prevEscape && c==matchAll ){
while( (c=zPattern[1]) == matchAll || c == matchOne ){
if( c==matchOne ){
if( *zString==0 ) return 0;
SQLITE_SKIP_UTF8(zString);
}
zPattern++;
}
if( c && esc && sqlite3ReadUtf8(&zPattern[1])==esc ){
u8 const *zTemp = &zPattern[1];
SQLITE_SKIP_UTF8(zTemp);
c = *zTemp;
}
if( c==0 ) return 1;
if( c==matchSet ){
assert( esc==0 ); /* This is GLOB, not LIKE */
while( *zString && patternCompare(&zPattern[1],zString,pInfo,esc)==0 ){
SQLITE_SKIP_UTF8(zString);
}
return *zString!=0;
}else{
while( (c2 = *zString)!=0 ){
if( noCase ){
c2 = sqlite3UpperToLower[c2];
c = sqlite3UpperToLower[c];
while( c2 != 0 && c2 != c ){ c2 = sqlite3UpperToLower[*++zString]; }
}else{
while( c2 != 0 && c2 != c ){ c2 = *++zString; }
}
if( c2==0 ) return 0;
if( patternCompare(&zPattern[1],zString,pInfo,esc) ) return 1;
SQLITE_SKIP_UTF8(zString);
}
return 0;
}
}else if( !prevEscape && c==matchOne ){
if( *zString==0 ) return 0;
SQLITE_SKIP_UTF8(zString);
zPattern++;
}else if( c==matchSet ){
int prior_c = 0;
assert( esc==0 ); /* This only occurs for GLOB, not LIKE */
seen = 0;
invert = 0;
c = sqlite3ReadUtf8(zString);
if( c==0 ) return 0;
c2 = *++zPattern;
if( c2=='^' ){ invert = 1; c2 = *++zPattern; }
if( c2==']' ){
if( c==']' ) seen = 1;
c2 = *++zPattern;
}
while( (c2 = sqlite3ReadUtf8(zPattern))!=0 && c2!=']' ){
if( c2=='-' && zPattern[1]!=']' && zPattern[1]!=0 && prior_c>0 ){
zPattern++;
c2 = sqlite3ReadUtf8(zPattern);
if( c>=prior_c && c<=c2 ) seen = 1;
prior_c = 0;
}else if( c==c2 ){
seen = 1;
prior_c = c2;
}else{
prior_c = c2;
}
SQLITE_SKIP_UTF8(zPattern);
}
if( c2==0 || (seen ^ invert)==0 ) return 0;
SQLITE_SKIP_UTF8(zString);
zPattern++;
}else if( esc && !prevEscape && sqlite3ReadUtf8(zPattern)==esc){
prevEscape = 1;
SQLITE_SKIP_UTF8(zPattern);
}else{
if( noCase ){
if( sqlite3UpperToLower[c] != sqlite3UpperToLower[*zString] ) return 0;
}else{
if( c != *zString ) return 0;
}
zPattern++;
zString++;
prevEscape = 0;
}
}
return *zString==0;
}
/*
** Count the number of times that the LIKE operator (or GLOB which is
** just a variation of LIKE) gets called. This is used for testing
** only.
*/
#ifdef SQLITE_TEST
int sqlite3_like_count = 0;
#endif
/*
** Implementation of the like() SQL function. This function implements
** the build-in LIKE operator. The first argument to the function is the
** pattern and the second argument is the string. So, the SQL statements:
**
** A LIKE B
**
** is implemented as like(B,A).
**
** This same function (with a different compareInfo structure) computes
** the GLOB operator.
*/
static void likeFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const unsigned char *zA, *zB;
int escape = 0;
zB = sqlite3_value_text(argv[0]);
zA = sqlite3_value_text(argv[1]);
/* Limit the length of the LIKE or GLOB pattern to avoid problems
** of deep recursion and N*N behavior in patternCompare().
*/
if( sqlite3_value_bytes(argv[0])>SQLITE_MAX_LIKE_PATTERN_LENGTH ){
sqlite3_result_error(context, "LIKE or GLOB pattern too complex", -1);
return;
}
assert( zB==sqlite3_value_text(argv[0]) ); /* Encoding did not change */
if( argc==3 ){
/* The escape character string must consist of a single UTF-8 character.
** Otherwise, return an error.
*/
const unsigned char *zEsc = sqlite3_value_text(argv[2]);
if( zEsc==0 ) return;
if( sqlite3Utf8CharLen((char*)zEsc, -1)!=1 ){
sqlite3_result_error(context,
"ESCAPE expression must be a single character", -1);
return;
}
escape = sqlite3ReadUtf8(zEsc);
}
if( zA && zB ){
struct compareInfo *pInfo = sqlite3_user_data(context);
#ifdef SQLITE_TEST
sqlite3_like_count++;
#endif
sqlite3_result_int(context, patternCompare(zB, zA, pInfo, escape));
}
}
/*
** Implementation of the NULLIF(x,y) function. The result is the first
** argument if the arguments are different. The result is NULL if the
** arguments are equal to each other.
*/
static void nullifFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
CollSeq *pColl = sqlite3GetFuncCollSeq(context);
if( sqlite3MemCompare(argv[0], argv[1], pColl)!=0 ){
sqlite3_result_value(context, argv[0]);
}
}
/*
** Implementation of the VERSION(*) function. The result is the version
** of the SQLite library that is running.
*/
static void versionFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
sqlite3_result_text(context, sqlite3_version, -1, SQLITE_STATIC);
}
/* Array for converting from half-bytes (nybbles) into ASCII hex
** digits. */
static const char hexdigits[] = {
'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
};
/*
** EXPERIMENTAL - This is not an official function. The interface may
** change. This function may disappear. Do not write code that depends
** on this function.
**
** Implementation of the QUOTE() function. This function takes a single
** argument. If the argument is numeric, the return value is the same as
** the argument. If the argument is NULL, the return value is the string
** "NULL". Otherwise, the argument is enclosed in single quotes with
** single-quote escapes.
*/
static void quoteFunc(sqlite3_context *context, int argc, sqlite3_value **argv){
if( argc<1 ) return;
switch( sqlite3_value_type(argv[0]) ){
case SQLITE_NULL: {
sqlite3_result_text(context, "NULL", 4, SQLITE_STATIC);
break;
}
case SQLITE_INTEGER:
case SQLITE_FLOAT: {
sqlite3_result_value(context, argv[0]);
break;
}
case SQLITE_BLOB: {
char *zText = 0;
char const *zBlob = sqlite3_value_blob(argv[0]);
int nBlob = sqlite3_value_bytes(argv[0]);
assert( zBlob==sqlite3_value_blob(argv[0]) ); /* No encoding change */
if( 2*nBlob+4>SQLITE_MAX_LENGTH ){
sqlite3_result_error_toobig(context);
return;
}
zText = (char *)sqliteMalloc((2*nBlob)+4);
if( !zText ){
sqlite3_result_error(context, "out of memory", -1);
}else{
int i;
for(i=0; i<nBlob; i++){
zText[(i*2)+2] = hexdigits[(zBlob[i]>>4)&0x0F];
zText[(i*2)+3] = hexdigits[(zBlob[i])&0x0F];
}
zText[(nBlob*2)+2] = '\'';
zText[(nBlob*2)+3] = '\0';
zText[0] = 'X';
zText[1] = '\'';
sqlite3_result_text(context, zText, -1, SQLITE_TRANSIENT);
sqliteFree(zText);
}
break;
}
case SQLITE_TEXT: {
int i,j;
u64 n;
const unsigned char *zArg = sqlite3_value_text(argv[0]);
char *z;
if( zArg==0 ) return;
for(i=0, n=0; zArg[i]; i++){ if( zArg[i]=='\'' ) n++; }
if( i+n+3>SQLITE_MAX_LENGTH ){
sqlite3_result_error_toobig(context);
return;
}
z = sqliteMalloc( i+n+3 );
if( z==0 ) return;
z[0] = '\'';
for(i=0, j=1; zArg[i]; i++){
z[j++] = zArg[i];
if( zArg[i]=='\'' ){
z[j++] = '\'';
}
}
z[j++] = '\'';
z[j] = 0;
sqlite3_result_text(context, z, j, SQLITE_TRANSIENT);
sqliteFree(z);
}
}
}
/*
** The hex() function. Interpret the argument as a blob. Return
** a hexadecimal rendering as text.
*/
static void hexFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
int i, n;
const unsigned char *pBlob;
char *zHex, *z;
assert( argc==1 );
pBlob = sqlite3_value_blob(argv[0]);
n = sqlite3_value_bytes(argv[0]);
if( n*2+1>SQLITE_MAX_LENGTH ){
sqlite3_result_error_toobig(context);
return;
}
assert( pBlob==sqlite3_value_blob(argv[0]) ); /* No encoding change */
z = zHex = sqlite3_malloc(n*2 + 1);
if( zHex==0 ) return;
for(i=0; i<n; i++, pBlob++){
unsigned char c = *pBlob;
*(z++) = hexdigits[(c>>4)&0xf];
*(z++) = hexdigits[c&0xf];
}
*z = 0;
sqlite3_result_text(context, zHex, n*2, sqlite3_free);
}
/*
** The zeroblob(N) function returns a zero-filled blob of size N bytes.
*/
static void zeroblobFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
i64 n;
assert( argc==1 );
n = sqlite3_value_int64(argv[0]);
if( n>SQLITE_MAX_LENGTH ){
sqlite3_result_error_toobig(context);
}else{
sqlite3_result_zeroblob(context, n);
}
}
/*
** The replace() function. Three arguments are all strings: call
** them A, B, and C. The result is also a string which is derived
** from A by replacing every occurance of B with C. The match
** must be exact. Collating sequences are not used.
*/
static void replaceFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const unsigned char *zStr; /* The input string A */
const unsigned char *zPattern; /* The pattern string B */
const unsigned char *zRep; /* The replacement string C */
unsigned char *zOut; /* The output */
int nStr; /* Size of zStr */
int nPattern; /* Size of zPattern */
int nRep; /* Size of zRep */
i64 nOut; /* Maximum size of zOut */
int loopLimit; /* Last zStr[] that might match zPattern[] */
int i, j; /* Loop counters */
assert( argc==3 );
zStr = sqlite3_value_text(argv[0]);
if( zStr==0 ) return;
nStr = sqlite3_value_bytes(argv[0]);
assert( zStr==sqlite3_value_text(argv[0]) ); /* No encoding change */
zPattern = sqlite3_value_text(argv[1]);
if( zPattern==0 || zPattern[0]==0 ) return;
nPattern = sqlite3_value_bytes(argv[1]);
assert( zPattern==sqlite3_value_text(argv[1]) ); /* No encoding change */
zRep = sqlite3_value_text(argv[2]);
if( zRep==0 ) return;
nRep = sqlite3_value_bytes(argv[2]);
assert( zRep==sqlite3_value_text(argv[2]) );
nOut = nStr + 1;
assert( nOut<SQLITE_MAX_LENGTH );
zOut = sqlite3_malloc((int)nOut);
if( zOut==0 ){
return;
}
loopLimit = nStr - nPattern;
for(i=j=0; i<=loopLimit; i++){
if( zStr[i]!=zPattern[0] || memcmp(&zStr[i], zPattern, nPattern) ){
zOut[j++] = zStr[i];
}else{
nOut += nRep - nPattern;
if( nOut>=SQLITE_MAX_LENGTH ){
sqlite3_result_error_toobig(context);
sqlite3_free(zOut);
return;
}
zOut = sqlite3_realloc(zOut, (int)nOut);
if( zOut==0 ){
return;
}
memcpy(&zOut[j], zRep, nRep);
j += nRep;
i += nPattern-1;
}
}
assert( j+nStr-i+1==nOut );
memcpy(&zOut[j], &zStr[i], nStr-i);
j += nStr - i;
assert( j<=nOut );
zOut[j] = 0;
sqlite3_result_text(context, (char*)zOut, j, sqlite3_free);
}
/*
** Implementation of the TRIM(), LTRIM(), and RTRIM() functions.
** The userdata is 0x1 for left trim, 0x2 for right trim, 0x3 for both.
*/
static void trimFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
const unsigned char *zIn; /* Input string */
const unsigned char *zCharSet; /* Set of characters to trim */
int nIn; /* Number of bytes in input */
int flags; /* 1: trimleft 2: trimright 3: trim */
int i; /* Loop counter */
unsigned char *aLen; /* Length of each character in zCharSet */
const unsigned char **azChar; /* Individual characters in zCharSet */
int nChar; /* Number of characters in zCharSet */
if( sqlite3_value_type(argv[0])==SQLITE_NULL ){
return;
}
zIn = sqlite3_value_text(argv[0]);
if( zIn==0 ) return;
nIn = sqlite3_value_bytes(argv[0]);
assert( zIn==sqlite3_value_text(argv[0]) );
if( argc==1 ){
static const unsigned char lenOne[] = { 1 };
static const unsigned char *azOne[] = { (u8*)" " };
nChar = 1;
aLen = (u8*)lenOne;
azChar = azOne;
zCharSet = 0;
}else if( (zCharSet = sqlite3_value_text(argv[1]))==0 ){
return;
}else{
const unsigned char *z;
for(z=zCharSet, nChar=0; *z; nChar++){
SQLITE_SKIP_UTF8(z);
}
if( nChar>0 ){
azChar = sqlite3_malloc( nChar*(sizeof(char*)+1) );
if( azChar==0 ){
return;
}
aLen = (unsigned char*)&azChar[nChar];
for(z=zCharSet, nChar=0; *z; nChar++){
azChar[nChar] = z;
SQLITE_SKIP_UTF8(z);
aLen[nChar] = z - azChar[nChar];
}
}
}
if( nChar>0 ){
flags = (int)sqlite3_user_data(context);
if( flags & 1 ){
while( nIn>0 ){
int len;
for(i=0; i<nChar; i++){
len = aLen[i];
if( memcmp(zIn, azChar[i], len)==0 ) break;
}
if( i>=nChar ) break;
zIn += len;
nIn -= len;
}
}
if( flags & 2 ){
while( nIn>0 ){
int len;
for(i=0; i<nChar; i++){
len = aLen[i];
if( len<=nIn && memcmp(&zIn[nIn-len],azChar[i],len)==0 ) break;
}
if( i>=nChar ) break;
nIn -= len;
}
}
if( zCharSet ){
sqlite3_free(azChar);
}
}
sqlite3_result_text(context, (char*)zIn, nIn, SQLITE_TRANSIENT);
}
#ifdef SQLITE_SOUNDEX
/*
** Compute the soundex encoding of a word.
*/
static void soundexFunc(
sqlite3_context *context,
int argc,
sqlite3_value **argv
){
char zResult[8];
const u8 *zIn;
int i, j;
static const unsigned char iCode[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
0, 0, 1, 2, 3, 0, 1, 2, 0, 0, 2, 2, 4, 5, 5, 0,
1, 2, 6, 2, 3, 0, 1, 0, 2, 0, 2, 0, 0, 0, 0, 0,
};
assert( argc==1 );
zIn = (u8*)sqlite3_value_text(argv[0]);
if( zIn==0 ) zIn = (u8*)"";
for(i=0; zIn[i] && !isalpha(zIn[i]); i++){}
if( zIn[i] ){
u8 prevcode = iCode[zIn[i]&0x7f];
zResult[0] = toupper(zIn[i]);
for(j=1; j<4 && zIn[i]; i++){
int code = iCode[zIn[i]&0x7f];
if( code>0 ){
if( code!=prevcode ){
prevcode = code;
zResult[j++] = code + '0';
}
}else{
prevcode = 0;
}
}
while( j<4 ){
zResult[j++] = '0';
}
zResult[j] = 0;
sqlite3_result_text(context, zResult, 4, SQLITE_TRANSIENT);
}else{
sqlite3_result_text(context, "?000", 4, SQLITE_STATIC);
}
}
#endif
#ifndef SQLITE_OMIT_LOAD_EXTENSION
/*
** A function that loads a shared-library extension then returns NULL.
*/
static void loadExt(sqlite3_context *context, int argc, sqlite3_value **argv){
const char *zFile = (const char *)sqlite3_value_text(argv[0]);
const char *zProc;
sqlite3 *db = sqlite3_user_data(context);
char *zErrMsg = 0;
if( argc==2 ){
zProc = (const char *)sqlite3_value_text(argv[1]);
}else{
zProc = 0;
}
if( zFile && sqlite3_load_extension(db, zFile, zProc, &zErrMsg) ){
sqlite3_result_error(context, zErrMsg, -1);
sqlite3_free(zErrMsg);
}
}
#endif
#ifdef SQLITE_TEST
/*
** This function generates a string of random characters. Used for
** generating test data.
*/
static void randStr(sqlite3_context *context, int argc, sqlite3_value **argv){
static const unsigned char zSrc[] =
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"0123456789"
".-!,:*^+=_|?/<> ";
int iMin, iMax, n, r, i;
unsigned char zBuf[1000];
if( argc>=1 ){
iMin = sqlite3_value_int(argv[0]);
if( iMin<0 ) iMin = 0;
if( iMin>=sizeof(zBuf) ) iMin = sizeof(zBuf)-1;
}else{
iMin = 1;
}
if( argc>=2 ){
iMax = sqlite3_value_int(argv[1]);
if( iMax<iMin ) iMax = iMin;
if( iMax>=sizeof(zBuf) ) iMax = sizeof(zBuf)-1;
}else{
iMax = 50;
}
n = iMin;
if( iMax>iMin ){
sqlite3Randomness(sizeof(r), &r);
r &= 0x7fffffff;
n += r%(iMax + 1 - iMin);
}
assert( n<sizeof(zBuf) );
sqlite3Randomness(n, zBuf);
for(i=0; i<n; i++){
zBuf[i] = zSrc[zBuf[i]%(sizeof(zSrc)-1)];
}
zBuf[n] = 0;
sqlite3_result_text(context, (char*)zBuf, n, SQLITE_TRANSIENT);
}
#endif /* SQLITE_TEST */
#ifdef SQLITE_TEST
/*
** The following two SQL functions are used to test returning a text
** result with a destructor. Function 'test_destructor' takes one argument
** and returns the same argument interpreted as TEXT. A destructor is
** passed with the sqlite3_result_text() call.
**
** SQL function 'test_destructor_count' returns the number of outstanding
** allocations made by 'test_destructor';
**
** WARNING: Not threadsafe.
*/
static int test_destructor_count_var = 0;
static void destructor(void *p){
char *zVal = (char *)p;
assert(zVal);
zVal--;
sqliteFree(zVal);
test_destructor_count_var--;
}
static void test_destructor(
sqlite3_context *pCtx,
int nArg,
sqlite3_value **argv
){
char *zVal;
int len;
sqlite3 *db = sqlite3_user_data(pCtx);
test_destructor_count_var++;
assert( nArg==1 );
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
len = sqlite3ValueBytes(argv[0], ENC(db));
zVal = sqliteMalloc(len+3);
zVal[len] = 0;
zVal[len-1] = 0;
assert( zVal );
zVal++;
memcpy(zVal, sqlite3ValueText(argv[0], ENC(db)), len);
if( ENC(db)==SQLITE_UTF8 ){
sqlite3_result_text(pCtx, zVal, -1, destructor);
#ifndef SQLITE_OMIT_UTF16
}else if( ENC(db)==SQLITE_UTF16LE ){
sqlite3_result_text16le(pCtx, zVal, -1, destructor);
}else{
sqlite3_result_text16be(pCtx, zVal, -1, destructor);
#endif /* SQLITE_OMIT_UTF16 */
}
}
static void test_destructor_count(
sqlite3_context *pCtx,
int nArg,
sqlite3_value **argv
){
sqlite3_result_int(pCtx, test_destructor_count_var);
}
#endif /* SQLITE_TEST */
#ifdef SQLITE_TEST
/*
** Routines for testing the sqlite3_get_auxdata() and sqlite3_set_auxdata()
** interface.
**
** The test_auxdata() SQL function attempts to register each of its arguments
** as auxiliary data. If there are no prior registrations of aux data for
** that argument (meaning the argument is not a constant or this is its first
** call) then the result for that argument is 0. If there is a prior
** registration, the result for that argument is 1. The overall result
** is the individual argument results separated by spaces.
*/
static void free_test_auxdata(void *p) {sqliteFree(p);}
static void test_auxdata(
sqlite3_context *pCtx,
int nArg,
sqlite3_value **argv
){
int i;
char *zRet = sqliteMalloc(nArg*2);
if( !zRet ) return;
for(i=0; i<nArg; i++){
char const *z = (char*)sqlite3_value_text(argv[i]);
if( z ){
char *zAux = sqlite3_get_auxdata(pCtx, i);
if( zAux ){
zRet[i*2] = '1';
if( strcmp(zAux, z) ){
sqlite3_result_error(pCtx, "Auxilary data corruption", -1);
return;
}
}else{
zRet[i*2] = '0';
zAux = sqliteStrDup(z);
sqlite3_set_auxdata(pCtx, i, zAux, free_test_auxdata);
}
zRet[i*2+1] = ' ';
}
}
sqlite3_result_text(pCtx, zRet, 2*nArg-1, free_test_auxdata);
}
#endif /* SQLITE_TEST */
#ifdef SQLITE_TEST
/*
** A function to test error reporting from user functions. This function
** returns a copy of it's first argument as an error.
*/
static void test_error(
sqlite3_context *pCtx,
int nArg,
sqlite3_value **argv
){
sqlite3_result_error(pCtx, (char*)sqlite3_value_text(argv[0]), 0);
}
#endif /* SQLITE_TEST */
/*
** An instance of the following structure holds the context of a
** sum() or avg() aggregate computation.
*/
typedef struct SumCtx SumCtx;
struct SumCtx {
double rSum; /* Floating point sum */
i64 iSum; /* Integer sum */
i64 cnt; /* Number of elements summed */
u8 overflow; /* True if integer overflow seen */
u8 approx; /* True if non-integer value was input to the sum */
};
/*
** Routines used to compute the sum, average, and total.
**
** The SUM() function follows the (broken) SQL standard which means
** that it returns NULL if it sums over no inputs. TOTAL returns
** 0.0 in that case. In addition, TOTAL always returns a float where
** SUM might return an integer if it never encounters a floating point
** value. TOTAL never fails, but SUM might through an exception if
** it overflows an integer.
*/
static void sumStep(sqlite3_context *context, int argc, sqlite3_value **argv){
SumCtx *p;
int type;
assert( argc==1 );
p = sqlite3_aggregate_context(context, sizeof(*p));
type = sqlite3_value_numeric_type(argv[0]);
if( p && type!=SQLITE_NULL ){
p->cnt++;
if( type==SQLITE_INTEGER ){
i64 v = sqlite3_value_int64(argv[0]);
p->rSum += v;
if( (p->approx|p->overflow)==0 ){
i64 iNewSum = p->iSum + v;
int s1 = p->iSum >> (sizeof(i64)*8-1);
int s2 = v >> (sizeof(i64)*8-1);
int s3 = iNewSum >> (sizeof(i64)*8-1);
p->overflow = (s1&s2&~s3) | (~s1&~s2&s3);
p->iSum = iNewSum;
}
}else{
p->rSum += sqlite3_value_double(argv[0]);
p->approx = 1;
}
}
}
static void sumFinalize(sqlite3_context *context){
SumCtx *p;
p = sqlite3_aggregate_context(context, 0);
if( p && p->cnt>0 ){
if( p->overflow ){
sqlite3_result_error(context,"integer overflow",-1);
}else if( p->approx ){
sqlite3_result_double(context, p->rSum);
}else{
sqlite3_result_int64(context, p->iSum);
}
}
}
static void avgFinalize(sqlite3_context *context){
SumCtx *p;
p = sqlite3_aggregate_context(context, 0);
if( p && p->cnt>0 ){
sqlite3_result_double(context, p->rSum/(double)p->cnt);
}
}
static void totalFinalize(sqlite3_context *context){
SumCtx *p;
p = sqlite3_aggregate_context(context, 0);
sqlite3_result_double(context, p ? p->rSum : 0.0);
}
/*
** The following structure keeps track of state information for the
** count() aggregate function.
*/
typedef struct CountCtx CountCtx;
struct CountCtx {
i64 n;
};
/*
** Routines to implement the count() aggregate function.
*/
static void countStep(sqlite3_context *context, int argc, sqlite3_value **argv){
CountCtx *p;
p = sqlite3_aggregate_context(context, sizeof(*p));
if( (argc==0 || SQLITE_NULL!=sqlite3_value_type(argv[0])) && p ){
p->n++;
}
}
static void countFinalize(sqlite3_context *context){
CountCtx *p;
p = sqlite3_aggregate_context(context, 0);
sqlite3_result_int64(context, p ? p->n : 0);
}
/*
** Routines to implement min() and max() aggregate functions.
*/
static void minmaxStep(sqlite3_context *context, int argc, sqlite3_value **argv){
Mem *pArg = (Mem *)argv[0];
Mem *pBest;
if( sqlite3_value_type(argv[0])==SQLITE_NULL ) return;
pBest = (Mem *)sqlite3_aggregate_context(context, sizeof(*pBest));
if( !pBest ) return;
if( pBest->flags ){
int max;
int cmp;
CollSeq *pColl = sqlite3GetFuncCollSeq(context);
/* This step function is used for both the min() and max() aggregates,
** the only difference between the two being that the sense of the
** comparison is inverted. For the max() aggregate, the
** sqlite3_user_data() function returns (void *)-1. For min() it
** returns (void *)db, where db is the sqlite3* database pointer.
** Therefore the next statement sets variable 'max' to 1 for the max()
** aggregate, or 0 for min().
*/
max = sqlite3_user_data(context)!=0;
cmp = sqlite3MemCompare(pBest, pArg, pColl);
if( (max && cmp<0) || (!max && cmp>0) ){
sqlite3VdbeMemCopy(pBest, pArg);
}
}else{
sqlite3VdbeMemCopy(pBest, pArg);
}
}
static void minMaxFinalize(sqlite3_context *context){
sqlite3_value *pRes;
pRes = (sqlite3_value *)sqlite3_aggregate_context(context, 0);
if( pRes ){
if( pRes->flags ){
sqlite3_result_value(context, pRes);
}
sqlite3VdbeMemRelease(pRes);
}
}
/*
** This function registered all of the above C functions as SQL
** functions. This should be the only routine in this file with
** external linkage.
*/
void sqlite3RegisterBuiltinFunctions(sqlite3 *db){
static const struct {
char *zName;
signed char nArg;
u8 argType; /* ff: db 1: 0, 2: 1, 3: 2,... N: N-1. */
u8 eTextRep; /* 1: UTF-16. 0: UTF-8 */
u8 needCollSeq;
void (*xFunc)(sqlite3_context*,int,sqlite3_value **);
} aFuncs[] = {
{ "min", -1, 0, SQLITE_UTF8, 1, minmaxFunc },
{ "min", 0, 0, SQLITE_UTF8, 1, 0 },
{ "max", -1, 1, SQLITE_UTF8, 1, minmaxFunc },
{ "max", 0, 1, SQLITE_UTF8, 1, 0 },
{ "typeof", 1, 0, SQLITE_UTF8, 0, typeofFunc },
{ "length", 1, 0, SQLITE_UTF8, 0, lengthFunc },
{ "substr", 3, 0, SQLITE_UTF8, 0, substrFunc },
{ "abs", 1, 0, SQLITE_UTF8, 0, absFunc },
{ "round", 1, 0, SQLITE_UTF8, 0, roundFunc },
{ "round", 2, 0, SQLITE_UTF8, 0, roundFunc },
{ "upper", 1, 0, SQLITE_UTF8, 0, upperFunc },
{ "lower", 1, 0, SQLITE_UTF8, 0, lowerFunc },
{ "coalesce", -1, 0, SQLITE_UTF8, 0, ifnullFunc },
{ "coalesce", 0, 0, SQLITE_UTF8, 0, 0 },
{ "coalesce", 1, 0, SQLITE_UTF8, 0, 0 },
{ "hex", 1, 0, SQLITE_UTF8, 0, hexFunc },
{ "ifnull", 2, 0, SQLITE_UTF8, 1, ifnullFunc },
{ "random", -1, 0, SQLITE_UTF8, 0, randomFunc },
{ "randomblob", 1, 0, SQLITE_UTF8, 0, randomBlob },
{ "nullif", 2, 0, SQLITE_UTF8, 1, nullifFunc },
{ "sqlite_version", 0, 0, SQLITE_UTF8, 0, versionFunc},
{ "quote", 1, 0, SQLITE_UTF8, 0, quoteFunc },
{ "last_insert_rowid", 0, 0xff, SQLITE_UTF8, 0, last_insert_rowid },
{ "changes", 0, 0xff, SQLITE_UTF8, 0, changes },
{ "total_changes", 0, 0xff, SQLITE_UTF8, 0, total_changes },
{ "replace", 3, 0, SQLITE_UTF8, 0, replaceFunc },
{ "ltrim", 1, 1, SQLITE_UTF8, 0, trimFunc },
{ "ltrim", 2, 1, SQLITE_UTF8, 0, trimFunc },
{ "rtrim", 1, 2, SQLITE_UTF8, 0, trimFunc },
{ "rtrim", 2, 2, SQLITE_UTF8, 0, trimFunc },
{ "trim", 1, 3, SQLITE_UTF8, 0, trimFunc },
{ "trim", 2, 3, SQLITE_UTF8, 0, trimFunc },
{ "zeroblob", 1, 0, SQLITE_UTF8, 0, zeroblobFunc },
#ifdef SQLITE_SOUNDEX
{ "soundex", 1, 0, SQLITE_UTF8, 0, soundexFunc},
#endif
#ifndef SQLITE_OMIT_LOAD_EXTENSION
{ "load_extension", 1, 0xff, SQLITE_UTF8, 0, loadExt },
{ "load_extension", 2, 0xff, SQLITE_UTF8, 0, loadExt },
#endif
#ifdef SQLITE_TEST
{ "randstr", 2, 0, SQLITE_UTF8, 0, randStr },
{ "test_destructor", 1, 0xff, SQLITE_UTF8, 0, test_destructor},
{ "test_destructor_count", 0, 0, SQLITE_UTF8, 0, test_destructor_count},
{ "test_auxdata", -1, 0, SQLITE_UTF8, 0, test_auxdata},
{ "test_error", 1, 0, SQLITE_UTF8, 0, test_error},
#endif
};
static const struct {
char *zName;
signed char nArg;
u8 argType;
u8 needCollSeq;
void (*xStep)(sqlite3_context*,int,sqlite3_value**);
void (*xFinalize)(sqlite3_context*);
} aAggs[] = {
{ "min", 1, 0, 1, minmaxStep, minMaxFinalize },
{ "max", 1, 1, 1, minmaxStep, minMaxFinalize },
{ "sum", 1, 0, 0, sumStep, sumFinalize },
{ "total", 1, 0, 0, sumStep, totalFinalize },
{ "avg", 1, 0, 0, sumStep, avgFinalize },
{ "count", 0, 0, 0, countStep, countFinalize },
{ "count", 1, 0, 0, countStep, countFinalize },
};
int i;
for(i=0; i<sizeof(aFuncs)/sizeof(aFuncs[0]); i++){
void *pArg;
u8 argType = aFuncs[i].argType;
if( argType==0xff ){
pArg = db;
}else{
pArg = (void*)(int)argType;
}
sqlite3CreateFunc(db, aFuncs[i].zName, aFuncs[i].nArg,
aFuncs[i].eTextRep, pArg, aFuncs[i].xFunc, 0, 0);
if( aFuncs[i].needCollSeq ){
FuncDef *pFunc = sqlite3FindFunction(db, aFuncs[i].zName,
strlen(aFuncs[i].zName), aFuncs[i].nArg, aFuncs[i].eTextRep, 0);
if( pFunc && aFuncs[i].needCollSeq ){
pFunc->needCollSeq = 1;
}
}
}
#ifndef SQLITE_OMIT_ALTERTABLE
sqlite3AlterFunctions(db);
#endif
#ifndef SQLITE_OMIT_PARSER
sqlite3AttachFunctions(db);
#endif
for(i=0; i<sizeof(aAggs)/sizeof(aAggs[0]); i++){
void *pArg = (void*)(int)aAggs[i].argType;
sqlite3CreateFunc(db, aAggs[i].zName, aAggs[i].nArg, SQLITE_UTF8,
pArg, 0, aAggs[i].xStep, aAggs[i].xFinalize);
if( aAggs[i].needCollSeq ){
FuncDef *pFunc = sqlite3FindFunction( db, aAggs[i].zName,
strlen(aAggs[i].zName), aAggs[i].nArg, SQLITE_UTF8, 0);
if( pFunc && aAggs[i].needCollSeq ){
pFunc->needCollSeq = 1;
}
}
}
sqlite3RegisterDateTimeFunctions(db);
if( !sqlite3MallocFailed() ){
int rc = sqlite3_overload_function(db, "MATCH", 2);
assert( rc==SQLITE_NOMEM || rc==SQLITE_OK );
if( rc==SQLITE_NOMEM ){
sqlite3FailedMalloc();
}
}
#ifdef SQLITE_SSE
(void)sqlite3SseFunctions(db);
#endif
#ifdef SQLITE_CASE_SENSITIVE_LIKE
sqlite3RegisterLikeFunctions(db, 1);
#else
sqlite3RegisterLikeFunctions(db, 0);
#endif
}
/*
** Set the LIKEOPT flag on the 2-argument function with the given name.
*/
static void setLikeOptFlag(sqlite3 *db, const char *zName, int flagVal){
FuncDef *pDef;
pDef = sqlite3FindFunction(db, zName, strlen(zName), 2, SQLITE_UTF8, 0);
if( pDef ){
pDef->flags = flagVal;
}
}
/*
** Register the built-in LIKE and GLOB functions. The caseSensitive
** parameter determines whether or not the LIKE operator is case
** sensitive. GLOB is always case sensitive.
*/
void sqlite3RegisterLikeFunctions(sqlite3 *db, int caseSensitive){
struct compareInfo *pInfo;
if( caseSensitive ){
pInfo = (struct compareInfo*)&likeInfoAlt;
}else{
pInfo = (struct compareInfo*)&likeInfoNorm;
}
sqlite3CreateFunc(db, "like", 2, SQLITE_UTF8, pInfo, likeFunc, 0, 0);
sqlite3CreateFunc(db, "like", 3, SQLITE_UTF8, pInfo, likeFunc, 0, 0);
sqlite3CreateFunc(db, "glob", 2, SQLITE_UTF8,
(struct compareInfo*)&globInfo, likeFunc, 0,0);
setLikeOptFlag(db, "glob", SQLITE_FUNC_LIKE | SQLITE_FUNC_CASE);
setLikeOptFlag(db, "like",
caseSensitive ? (SQLITE_FUNC_LIKE | SQLITE_FUNC_CASE) : SQLITE_FUNC_LIKE);
}
/*
** pExpr points to an expression which implements a function. If
** it is appropriate to apply the LIKE optimization to that function
** then set aWc[0] through aWc[2] to the wildcard characters and
** return TRUE. If the function is not a LIKE-style function then
** return FALSE.
*/
int sqlite3IsLikeFunction(sqlite3 *db, Expr *pExpr, int *pIsNocase, char *aWc){
FuncDef *pDef;
if( pExpr->op!=TK_FUNCTION || !pExpr->pList ){
return 0;
}
if( pExpr->pList->nExpr!=2 ){
return 0;
}
pDef = sqlite3FindFunction(db, (char*)pExpr->token.z, pExpr->token.n, 2,
SQLITE_UTF8, 0);
if( pDef==0 || (pDef->flags & SQLITE_FUNC_LIKE)==0 ){
return 0;
}
/* The memcpy() statement assumes that the wildcard characters are
** the first three statements in the compareInfo structure. The
** asserts() that follow verify that assumption
*/
memcpy(aWc, pDef->pUserData, 3);
assert( (char*)&likeInfoAlt == (char*)&likeInfoAlt.matchAll );
assert( &((char*)&likeInfoAlt)[1] == (char*)&likeInfoAlt.matchOne );
assert( &((char*)&likeInfoAlt)[2] == (char*)&likeInfoAlt.matchSet );
*pIsNocase = (pDef->flags & SQLITE_FUNC_CASE)==0;
return 1;
}
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