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Do not allocate so much surplus memory in the implementation of the

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replace() function. (CVS 3951)

FossilOrigin-Name: 0cf518ceebda8e7421d054813f97cc447d292344
This commit is contained in:
drh
2007-05-08 15:46:18 +00:00
parent beb818d1fd
commit 2e6400ba9e
3 changed files with 21 additions and 17 deletions
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24
src/func.c
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@@ -16,7 +16,7 @@
** sqliteRegisterBuildinFunctions() found at the bottom of the file.
** All other code has file scope.
**
** $Id: func.c,v 1.150 2007/05/08 15:34:48 drh Exp $
** $Id: func.c,v 1.151 2007/05/08 15:46:18 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
@@ -748,7 +748,7 @@ static void replaceFunc(
int nStr; /* Size of zStr */
int nPattern; /* Size of zPattern */
int nRep; /* Size of zRep */
int nOut; /* Maximum size of zOut */
i64 nOut; /* Maximum size of zOut */
int loopLimit; /* Last zStr[] that might match zPattern[] */
int i, j; /* Loop counters */
@@ -762,29 +762,33 @@ static void replaceFunc(
nRep = sqlite3_value_bytes(argv[2]);
zRep = sqlite3_value_text(argv[2]);
if( zRep==0 ) return;
if( nPattern>=nRep ){
nOut = nStr;
}else{
i64 nOut64 = (i64)(nStr/nPattern + 1) * (i64)nRep;
nOut = ((nOut64>SQLITE_MAX_LENGTH) ? SQLITE_MAX_LENGTH : nOut64);
nOut = nStr + 1;
assert( nOut<SQLITE_MAX_LENGTH );
zOut = sqlite3_malloc((int)nOut);
if( zOut==0 ){
return;
}
zOut = sqlite3_malloc(nOut+1);
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{
if( (j+nRep+loopLimit-i)>SQLITE_MAX_LENGTH ){
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 );