blob: 7adce4ef03742530bed5c9719f85483e91b81847 [file] [log] [blame]
/*
** 2001 September 15
**
** 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.
**
*************************************************************************
** Utility functions used throughout sqlite.
**
** This file contains functions for allocating memory, comparing
** strings, and stuff like that.
**
*/
#include "sqliteInt.h"
#include <stdarg.h>
#include <math.h>
/*
** Routine needed to support the testcase() macro.
*/
#ifdef SQLITE_COVERAGE_TEST
void sqlite3Coverage(int x){
static unsigned dummy = 0;
dummy += (unsigned)x;
}
#endif
/*
** Calls to sqlite3FaultSim() are used to simulate a failure during testing,
** or to bypass normal error detection during testing in order to let
** execute proceed futher downstream.
**
** In deployment, sqlite3FaultSim() *always* return SQLITE_OK (0). The
** sqlite3FaultSim() function only returns non-zero during testing.
**
** During testing, if the test harness has set a fault-sim callback using
** a call to sqlite3_test_control(SQLITE_TESTCTRL_FAULT_INSTALL), then
** each call to sqlite3FaultSim() is relayed to that application-supplied
** callback and the integer return value form the application-supplied
** callback is returned by sqlite3FaultSim().
**
** The integer argument to sqlite3FaultSim() is a code to identify which
** sqlite3FaultSim() instance is being invoked. Each call to sqlite3FaultSim()
** should have a unique code. To prevent legacy testing applications from
** breaking, the codes should not be changed or reused.
*/
#ifndef SQLITE_UNTESTABLE
int sqlite3FaultSim(int iTest){
int (*xCallback)(int) = sqlite3GlobalConfig.xTestCallback;
return xCallback ? xCallback(iTest) : SQLITE_OK;
}
#endif
#ifndef SQLITE_OMIT_FLOATING_POINT
/*
** Return true if the floating point value is Not a Number (NaN).
*/
int sqlite3IsNaN(double x){
u64 y;
memcpy(&y,&x,sizeof(y));
return IsNaN(y);
}
#endif /* SQLITE_OMIT_FLOATING_POINT */
/*
** Compute a string length that is limited to what can be stored in
** lower 30 bits of a 32-bit signed integer.
**
** The value returned will never be negative. Nor will it ever be greater
** than the actual length of the string. For very long strings (greater
** than 1GiB) the value returned might be less than the true string length.
*/
int sqlite3Strlen30(const char *z){
if( z==0 ) return 0;
return 0x3fffffff & (int)strlen(z);
}
/*
** Return the declared type of a column. Or return zDflt if the column
** has no declared type.
**
** The column type is an extra string stored after the zero-terminator on
** the column name if and only if the COLFLAG_HASTYPE flag is set.
*/
char *sqlite3ColumnType(Column *pCol, char *zDflt){
if( (pCol->colFlags & COLFLAG_HASTYPE)==0 ) return zDflt;
return pCol->zName + strlen(pCol->zName) + 1;
}
/*
** Helper function for sqlite3Error() - called rarely. Broken out into
** a separate routine to avoid unnecessary register saves on entry to
** sqlite3Error().
*/
static SQLITE_NOINLINE void sqlite3ErrorFinish(sqlite3 *db, int err_code){
if( db->pErr ) sqlite3ValueSetNull(db->pErr);
sqlite3SystemError(db, err_code);
}
/*
** Set the current error code to err_code and clear any prior error message.
** Also set iSysErrno (by calling sqlite3System) if the err_code indicates
** that would be appropriate.
*/
void sqlite3Error(sqlite3 *db, int err_code){
assert( db!=0 );
db->errCode = err_code;
if( err_code || db->pErr ) sqlite3ErrorFinish(db, err_code);
}
/*
** Load the sqlite3.iSysErrno field if that is an appropriate thing
** to do based on the SQLite error code in rc.
*/
void sqlite3SystemError(sqlite3 *db, int rc){
if( rc==SQLITE_IOERR_NOMEM ) return;
rc &= 0xff;
if( rc==SQLITE_CANTOPEN || rc==SQLITE_IOERR ){
db->iSysErrno = sqlite3OsGetLastError(db->pVfs);
}
}
/*
** Set the most recent error code and error string for the sqlite
** handle "db". The error code is set to "err_code".
**
** If it is not NULL, string zFormat specifies the format of the
** error string in the style of the printf functions: The following
** format characters are allowed:
**
** %s Insert a string
** %z A string that should be freed after use
** %d Insert an integer
** %T Insert a token
** %S Insert the first element of a SrcList
**
** zFormat and any string tokens that follow it are assumed to be
** encoded in UTF-8.
**
** To clear the most recent error for sqlite handle "db", sqlite3Error
** should be called with err_code set to SQLITE_OK and zFormat set
** to NULL.
*/
void sqlite3ErrorWithMsg(sqlite3 *db, int err_code, const char *zFormat, ...){
assert( db!=0 );
db->errCode = err_code;
sqlite3SystemError(db, err_code);
if( zFormat==0 ){
sqlite3Error(db, err_code);
}else if( db->pErr || (db->pErr = sqlite3ValueNew(db))!=0 ){
char *z;
va_list ap;
va_start(ap, zFormat);
z = sqlite3VMPrintf(db, zFormat, ap);
va_end(ap);
sqlite3ValueSetStr(db->pErr, -1, z, SQLITE_UTF8, SQLITE_DYNAMIC);
}
}
/*
** Add an error message to pParse->zErrMsg and increment pParse->nErr.
** The following formatting characters are allowed:
**
** %s Insert a string
** %z A string that should be freed after use
** %d Insert an integer
** %T Insert a token
** %S Insert the first element of a SrcList
**
** This function should be used to report any error that occurs while
** compiling an SQL statement (i.e. within sqlite3_prepare()). The
** last thing the sqlite3_prepare() function does is copy the error
** stored by this function into the database handle using sqlite3Error().
** Functions sqlite3Error() or sqlite3ErrorWithMsg() should be used
** during statement execution (sqlite3_step() etc.).
*/
void sqlite3ErrorMsg(Parse *pParse, const char *zFormat, ...){
char *zMsg;
va_list ap;
sqlite3 *db = pParse->db;
va_start(ap, zFormat);
zMsg = sqlite3VMPrintf(db, zFormat, ap);
va_end(ap);
if( db->suppressErr ){
sqlite3DbFree(db, zMsg);
}else{
pParse->nErr++;
sqlite3DbFree(db, pParse->zErrMsg);
pParse->zErrMsg = zMsg;
pParse->rc = SQLITE_ERROR;
}
}
/*
** If database connection db is currently parsing SQL, then transfer
** error code errCode to that parser if the parser has not already
** encountered some other kind of error.
*/
int sqlite3ErrorToParser(sqlite3 *db, int errCode){
Parse *pParse;
if( db==0 || (pParse = db->pParse)==0 ) return errCode;
pParse->rc = errCode;
pParse->nErr++;
return errCode;
}
/*
** Convert an SQL-style quoted string into a normal string by removing
** the quote characters. The conversion is done in-place. If the
** input does not begin with a quote character, then this routine
** is a no-op.
**
** The input string must be zero-terminated. A new zero-terminator
** is added to the dequoted string.
**
** The return value is -1 if no dequoting occurs or the length of the
** dequoted string, exclusive of the zero terminator, if dequoting does
** occur.
**
** 2002-02-14: This routine is extended to remove MS-Access style
** brackets from around identifiers. For example: "[a-b-c]" becomes
** "a-b-c".
*/
void sqlite3Dequote(char *z){
char quote;
int i, j;
if( z==0 ) return;
quote = z[0];
if( !sqlite3Isquote(quote) ) return;
if( quote=='[' ) quote = ']';
for(i=1, j=0;; i++){
assert( z[i] );
if( z[i]==quote ){
if( z[i+1]==quote ){
z[j++] = quote;
i++;
}else{
break;
}
}else{
z[j++] = z[i];
}
}
z[j] = 0;
}
void sqlite3DequoteExpr(Expr *p){
assert( sqlite3Isquote(p->u.zToken[0]) );
p->flags |= p->u.zToken[0]=='"' ? EP_Quoted|EP_DblQuoted : EP_Quoted;
sqlite3Dequote(p->u.zToken);
}
/*
** Generate a Token object from a string
*/
void sqlite3TokenInit(Token *p, char *z){
p->z = z;
p->n = sqlite3Strlen30(z);
}
/* Convenient short-hand */
#define UpperToLower sqlite3UpperToLower
/*
** Some systems have stricmp(). Others have strcasecmp(). Because
** there is no consistency, we will define our own.
**
** IMPLEMENTATION-OF: R-30243-02494 The sqlite3_stricmp() and
** sqlite3_strnicmp() APIs allow applications and extensions to compare
** the contents of two buffers containing UTF-8 strings in a
** case-independent fashion, using the same definition of "case
** independence" that SQLite uses internally when comparing identifiers.
*/
int sqlite3_stricmp(const char *zLeft, const char *zRight){
if( zLeft==0 ){
return zRight ? -1 : 0;
}else if( zRight==0 ){
return 1;
}
return sqlite3StrICmp(zLeft, zRight);
}
int sqlite3StrICmp(const char *zLeft, const char *zRight){
unsigned char *a, *b;
int c, x;
a = (unsigned char *)zLeft;
b = (unsigned char *)zRight;
for(;;){
c = *a;
x = *b;
if( c==x ){
if( c==0 ) break;
}else{
c = (int)UpperToLower[c] - (int)UpperToLower[x];
if( c ) break;
}
a++;
b++;
}
return c;
}
int sqlite3_strnicmp(const char *zLeft, const char *zRight, int N){
register unsigned char *a, *b;
if( zLeft==0 ){
return zRight ? -1 : 0;
}else if( zRight==0 ){
return 1;
}
a = (unsigned char *)zLeft;
b = (unsigned char *)zRight;
while( N-- > 0 && *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
return N<0 ? 0 : UpperToLower[*a] - UpperToLower[*b];
}
/*
** Compute 10 to the E-th power. Examples: E==1 results in 10.
** E==2 results in 100. E==50 results in 1.0e50.
**
** This routine only works for values of E between 1 and 341.
*/
static LONGDOUBLE_TYPE sqlite3Pow10(int E){
#if defined(_MSC_VER)
static const LONGDOUBLE_TYPE x[] = {
1.0e+001L,
1.0e+002L,
1.0e+004L,
1.0e+008L,
1.0e+016L,
1.0e+032L,
1.0e+064L,
1.0e+128L,
1.0e+256L
};
LONGDOUBLE_TYPE r = 1.0;
int i;
assert( E>=0 && E<=307 );
for(i=0; E!=0; i++, E >>=1){
if( E & 1 ) r *= x[i];
}
return r;
#else
LONGDOUBLE_TYPE x = 10.0;
LONGDOUBLE_TYPE r = 1.0;
while(1){
if( E & 1 ) r *= x;
E >>= 1;
if( E==0 ) break;
x *= x;
}
return r;
#endif
}
/*
** The string z[] is an text representation of a real number.
** Convert this string to a double and write it into *pResult.
**
** The string z[] is length bytes in length (bytes, not characters) and
** uses the encoding enc. The string is not necessarily zero-terminated.
**
** Return TRUE if the result is a valid real number (or integer) and FALSE
** if the string is empty or contains extraneous text. More specifically
** return
** 1 => The input string is a pure integer
** 2 or more => The input has a decimal point or eNNN clause
** 0 or less => The input string is not a valid number
** -1 => Not a valid number, but has a valid prefix which
** includes a decimal point and/or an eNNN clause
**
** Valid numbers are in one of these formats:
**
** [+-]digits[E[+-]digits]
** [+-]digits.[digits][E[+-]digits]
** [+-].digits[E[+-]digits]
**
** Leading and trailing whitespace is ignored for the purpose of determining
** validity.
**
** If some prefix of the input string is a valid number, this routine
** returns FALSE but it still converts the prefix and writes the result
** into *pResult.
*/
int sqlite3AtoF(const char *z, double *pResult, int length, u8 enc){
#ifndef SQLITE_OMIT_FLOATING_POINT
int incr;
const char *zEnd = z + length;
/* sign * significand * (10 ^ (esign * exponent)) */
int sign = 1; /* sign of significand */
i64 s = 0; /* significand */
int d = 0; /* adjust exponent for shifting decimal point */
int esign = 1; /* sign of exponent */
int e = 0; /* exponent */
int eValid = 1; /* True exponent is either not used or is well-formed */
double result;
int nDigit = 0; /* Number of digits processed */
int eType = 1; /* 1: pure integer, 2+: fractional -1 or less: bad UTF16 */
assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
*pResult = 0.0; /* Default return value, in case of an error */
if( enc==SQLITE_UTF8 ){
incr = 1;
}else{
int i;
incr = 2;
assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
testcase( enc==SQLITE_UTF16LE );
testcase( enc==SQLITE_UTF16BE );
for(i=3-enc; i<length && z[i]==0; i+=2){}
if( i<length ) eType = -100;
zEnd = &z[i^1];
z += (enc&1);
}
/* skip leading spaces */
while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
if( z>=zEnd ) return 0;
/* get sign of significand */
if( *z=='-' ){
sign = -1;
z+=incr;
}else if( *z=='+' ){
z+=incr;
}
/* copy max significant digits to significand */
while( z<zEnd && sqlite3Isdigit(*z) ){
s = s*10 + (*z - '0');
z+=incr; nDigit++;
if( s>=((LARGEST_INT64-9)/10) ){
/* skip non-significant significand digits
** (increase exponent by d to shift decimal left) */
while( z<zEnd && sqlite3Isdigit(*z) ){ z+=incr; d++; }
}
}
if( z>=zEnd ) goto do_atof_calc;
/* if decimal point is present */
if( *z=='.' ){
z+=incr;
eType++;
/* copy digits from after decimal to significand
** (decrease exponent by d to shift decimal right) */
while( z<zEnd && sqlite3Isdigit(*z) ){
if( s<((LARGEST_INT64-9)/10) ){
s = s*10 + (*z - '0');
d--;
nDigit++;
}
z+=incr;
}
}
if( z>=zEnd ) goto do_atof_calc;
/* if exponent is present */
if( *z=='e' || *z=='E' ){
z+=incr;
eValid = 0;
eType++;
/* This branch is needed to avoid a (harmless) buffer overread. The
** special comment alerts the mutation tester that the correct answer
** is obtained even if the branch is omitted */
if( z>=zEnd ) goto do_atof_calc; /*PREVENTS-HARMLESS-OVERREAD*/
/* get sign of exponent */
if( *z=='-' ){
esign = -1;
z+=incr;
}else if( *z=='+' ){
z+=incr;
}
/* copy digits to exponent */
while( z<zEnd && sqlite3Isdigit(*z) ){
e = e<10000 ? (e*10 + (*z - '0')) : 10000;
z+=incr;
eValid = 1;
}
}
/* skip trailing spaces */
while( z<zEnd && sqlite3Isspace(*z) ) z+=incr;
do_atof_calc:
/* adjust exponent by d, and update sign */
e = (e*esign) + d;
if( e<0 ) {
esign = -1;
e *= -1;
} else {
esign = 1;
}
if( s==0 ) {
/* In the IEEE 754 standard, zero is signed. */
result = sign<0 ? -(double)0 : (double)0;
} else {
/* Attempt to reduce exponent.
**
** Branches that are not required for the correct answer but which only
** help to obtain the correct answer faster are marked with special
** comments, as a hint to the mutation tester.
*/
while( e>0 ){ /*OPTIMIZATION-IF-TRUE*/
if( esign>0 ){
if( s>=(LARGEST_INT64/10) ) break; /*OPTIMIZATION-IF-FALSE*/
s *= 10;
}else{
if( s%10!=0 ) break; /*OPTIMIZATION-IF-FALSE*/
s /= 10;
}
e--;
}
/* adjust the sign of significand */
s = sign<0 ? -s : s;
if( e==0 ){ /*OPTIMIZATION-IF-TRUE*/
result = (double)s;
}else{
/* attempt to handle extremely small/large numbers better */
if( e>307 ){ /*OPTIMIZATION-IF-TRUE*/
if( e<342 ){ /*OPTIMIZATION-IF-TRUE*/
LONGDOUBLE_TYPE scale = sqlite3Pow10(e-308);
if( esign<0 ){
result = s / scale;
result /= 1.0e+308;
}else{
result = s * scale;
result *= 1.0e+308;
}
}else{ assert( e>=342 );
if( esign<0 ){
result = 0.0*s;
}else{
#ifdef INFINITY
result = INFINITY*s;
#else
result = 1e308*1e308*s; /* Infinity */
#endif
}
}
}else{
LONGDOUBLE_TYPE scale = sqlite3Pow10(e);
if( esign<0 ){
result = s / scale;
}else{
result = s * scale;
}
}
}
}
/* store the result */
*pResult = result;
/* return true if number and no extra non-whitespace chracters after */
if( z==zEnd && nDigit>0 && eValid && eType>0 ){
return eType;
}else if( eType>=2 && (eType==3 || eValid) && nDigit>0 ){
return -1;
}else{
return 0;
}
#else
return !sqlite3Atoi64(z, pResult, length, enc);
#endif /* SQLITE_OMIT_FLOATING_POINT */
}
/*
** Compare the 19-character string zNum against the text representation
** value 2^63: 9223372036854775808. Return negative, zero, or positive
** if zNum is less than, equal to, or greater than the string.
** Note that zNum must contain exactly 19 characters.
**
** Unlike memcmp() this routine is guaranteed to return the difference
** in the values of the last digit if the only difference is in the
** last digit. So, for example,
**
** compare2pow63("9223372036854775800", 1)
**
** will return -8.
*/
static int compare2pow63(const char *zNum, int incr){
int c = 0;
int i;
/* 012345678901234567 */
const char *pow63 = "922337203685477580";
for(i=0; c==0 && i<18; i++){
c = (zNum[i*incr]-pow63[i])*10;
}
if( c==0 ){
c = zNum[18*incr] - '8';
testcase( c==(-1) );
testcase( c==0 );
testcase( c==(+1) );
}
return c;
}
/*
** Convert zNum to a 64-bit signed integer. zNum must be decimal. This
** routine does *not* accept hexadecimal notation.
**
** Returns:
**
** -1 Not even a prefix of the input text looks like an integer
** 0 Successful transformation. Fits in a 64-bit signed integer.
** 1 Excess non-space text after the integer value
** 2 Integer too large for a 64-bit signed integer or is malformed
** 3 Special case of 9223372036854775808
**
** length is the number of bytes in the string (bytes, not characters).
** The string is not necessarily zero-terminated. The encoding is
** given by enc.
*/
int sqlite3Atoi64(const char *zNum, i64 *pNum, int length, u8 enc){
int incr;
u64 u = 0;
int neg = 0; /* assume positive */
int i;
int c = 0;
int nonNum = 0; /* True if input contains UTF16 with high byte non-zero */
int rc; /* Baseline return code */
const char *zStart;
const char *zEnd = zNum + length;
assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
if( enc==SQLITE_UTF8 ){
incr = 1;
}else{
incr = 2;
assert( SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
for(i=3-enc; i<length && zNum[i]==0; i+=2){}
nonNum = i<length;
zEnd = &zNum[i^1];
zNum += (enc&1);
}
while( zNum<zEnd && sqlite3Isspace(*zNum) ) zNum+=incr;
if( zNum<zEnd ){
if( *zNum=='-' ){
neg = 1;
zNum+=incr;
}else if( *zNum=='+' ){
zNum+=incr;
}
}
zStart = zNum;
while( zNum<zEnd && zNum[0]=='0' ){ zNum+=incr; } /* Skip leading zeros. */
for(i=0; &zNum[i]<zEnd && (c=zNum[i])>='0' && c<='9'; i+=incr){
u = u*10 + c - '0';
}
testcase( i==18*incr );
testcase( i==19*incr );
testcase( i==20*incr );
if( u>LARGEST_INT64 ){
/* This test and assignment is needed only to suppress UB warnings
** from clang and -fsanitize=undefined. This test and assignment make
** the code a little larger and slower, and no harm comes from omitting
** them, but we must appaise the undefined-behavior pharisees. */
*pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
}else if( neg ){
*pNum = -(i64)u;
}else{
*pNum = (i64)u;
}
rc = 0;
if( i==0 && zStart==zNum ){ /* No digits */
rc = -1;
}else if( nonNum ){ /* UTF16 with high-order bytes non-zero */
rc = 1;
}else if( &zNum[i]<zEnd ){ /* Extra bytes at the end */
int jj = i;
do{
if( !sqlite3Isspace(zNum[jj]) ){
rc = 1; /* Extra non-space text after the integer */
break;
}
jj += incr;
}while( &zNum[jj]<zEnd );
}
if( i<19*incr ){
/* Less than 19 digits, so we know that it fits in 64 bits */
assert( u<=LARGEST_INT64 );
return rc;
}else{
/* zNum is a 19-digit numbers. Compare it against 9223372036854775808. */
c = i>19*incr ? 1 : compare2pow63(zNum, incr);
if( c<0 ){
/* zNum is less than 9223372036854775808 so it fits */
assert( u<=LARGEST_INT64 );
return rc;
}else{
*pNum = neg ? SMALLEST_INT64 : LARGEST_INT64;
if( c>0 ){
/* zNum is greater than 9223372036854775808 so it overflows */
return 2;
}else{
/* zNum is exactly 9223372036854775808. Fits if negative. The
** special case 2 overflow if positive */
assert( u-1==LARGEST_INT64 );
return neg ? rc : 3;
}
}
}
}
/*
** Transform a UTF-8 integer literal, in either decimal or hexadecimal,
** into a 64-bit signed integer. This routine accepts hexadecimal literals,
** whereas sqlite3Atoi64() does not.
**
** Returns:
**
** 0 Successful transformation. Fits in a 64-bit signed integer.
** 1 Excess text after the integer value
** 2 Integer too large for a 64-bit signed integer or is malformed
** 3 Special case of 9223372036854775808
*/
int sqlite3DecOrHexToI64(const char *z, i64 *pOut){
#ifndef SQLITE_OMIT_HEX_INTEGER
if( z[0]=='0'
&& (z[1]=='x' || z[1]=='X')
){
u64 u = 0;
int i, k;
for(i=2; z[i]=='0'; i++){}
for(k=i; sqlite3Isxdigit(z[k]); k++){
u = u*16 + sqlite3HexToInt(z[k]);
}
memcpy(pOut, &u, 8);
return (z[k]==0 && k-i<=16) ? 0 : 2;
}else
#endif /* SQLITE_OMIT_HEX_INTEGER */
{
return sqlite3Atoi64(z, pOut, sqlite3Strlen30(z), SQLITE_UTF8);
}
}
/*
** If zNum represents an integer that will fit in 32-bits, then set
** *pValue to that integer and return true. Otherwise return false.
**
** This routine accepts both decimal and hexadecimal notation for integers.
**
** Any non-numeric characters that following zNum are ignored.
** This is different from sqlite3Atoi64() which requires the
** input number to be zero-terminated.
*/
int sqlite3GetInt32(const char *zNum, int *pValue){
sqlite_int64 v = 0;
int i, c;
int neg = 0;
if( zNum[0]=='-' ){
neg = 1;
zNum++;
}else if( zNum[0]=='+' ){
zNum++;
}
#ifndef SQLITE_OMIT_HEX_INTEGER
else if( zNum[0]=='0'
&& (zNum[1]=='x' || zNum[1]=='X')
&& sqlite3Isxdigit(zNum[2])
){
u32 u = 0;
zNum += 2;
while( zNum[0]=='0' ) zNum++;
for(i=0; sqlite3Isxdigit(zNum[i]) && i<8; i++){
u = u*16 + sqlite3HexToInt(zNum[i]);
}
if( (u&0x80000000)==0 && sqlite3Isxdigit(zNum[i])==0 ){
memcpy(pValue, &u, 4);
return 1;
}else{
return 0;
}
}
#endif
if( !sqlite3Isdigit(zNum[0]) ) return 0;
while( zNum[0]=='0' ) zNum++;
for(i=0; i<11 && (c = zNum[i] - '0')>=0 && c<=9; i++){
v = v*10 + c;
}
/* The longest decimal representation of a 32 bit integer is 10 digits:
**
** 1234567890
** 2^31 -> 2147483648
*/
testcase( i==10 );
if( i>10 ){
return 0;
}
testcase( v-neg==2147483647 );
if( v-neg>2147483647 ){
return 0;
}
if( neg ){
v = -v;
}
*pValue = (int)v;
return 1;
}
/*
** Return a 32-bit integer value extracted from a string. If the
** string is not an integer, just return 0.
*/
int sqlite3Atoi(const char *z){
int x = 0;
if( z ) sqlite3GetInt32(z, &x);
return x;
}
/*
** The variable-length integer encoding is as follows:
**
** KEY:
** A = 0xxxxxxx 7 bits of data and one flag bit
** B = 1xxxxxxx 7 bits of data and one flag bit
** C = xxxxxxxx 8 bits of data
**
** 7 bits - A
** 14 bits - BA
** 21 bits - BBA
** 28 bits - BBBA
** 35 bits - BBBBA
** 42 bits - BBBBBA
** 49 bits - BBBBBBA
** 56 bits - BBBBBBBA
** 64 bits - BBBBBBBBC
*/
/*
** Write a 64-bit variable-length integer to memory starting at p[0].
** The length of data write will be between 1 and 9 bytes. The number
** of bytes written is returned.
**
** A variable-length integer consists of the lower 7 bits of each byte
** for all bytes that have the 8th bit set and one byte with the 8th
** bit clear. Except, if we get to the 9th byte, it stores the full
** 8 bits and is the last byte.
*/
static int SQLITE_NOINLINE putVarint64(unsigned char *p, u64 v){
int i, j, n;
u8 buf[10];
if( v & (((u64)0xff000000)<<32) ){
p[8] = (u8)v;
v >>= 8;
for(i=7; i>=0; i--){
p[i] = (u8)((v & 0x7f) | 0x80);
v >>= 7;
}
return 9;
}
n = 0;
do{
buf[n++] = (u8)((v & 0x7f) | 0x80);
v >>= 7;
}while( v!=0 );
buf[0] &= 0x7f;
assert( n<=9 );
for(i=0, j=n-1; j>=0; j--, i++){
p[i] = buf[j];
}
return n;
}
int sqlite3PutVarint(unsigned char *p, u64 v){
if( v<=0x7f ){
p[0] = v&0x7f;
return 1;
}
if( v<=0x3fff ){
p[0] = ((v>>7)&0x7f)|0x80;
p[1] = v&0x7f;
return 2;
}
return putVarint64(p,v);
}
/*
** Bitmasks used by sqlite3GetVarint(). These precomputed constants
** are defined here rather than simply putting the constant expressions
** inline in order to work around bugs in the RVT compiler.
**
** SLOT_2_0 A mask for (0x7f<<14) | 0x7f
**
** SLOT_4_2_0 A mask for (0x7f<<28) | SLOT_2_0
*/
#define SLOT_2_0 0x001fc07f
#define SLOT_4_2_0 0xf01fc07f
/*
** Read a 64-bit variable-length integer from memory starting at p[0].
** Return the number of bytes read. The value is stored in *v.
*/
u8 sqlite3GetVarint(const unsigned char *p, u64 *v){
u32 a,b,s;
if( ((signed char*)p)[0]>=0 ){
*v = *p;
return 1;
}
if( ((signed char*)p)[1]>=0 ){
*v = ((u32)(p[0]&0x7f)<<7) | p[1];
return 2;
}
/* Verify that constants are precomputed correctly */
assert( SLOT_2_0 == ((0x7f<<14) | (0x7f)) );
assert( SLOT_4_2_0 == ((0xfU<<28) | (0x7f<<14) | (0x7f)) );
a = ((u32)p[0])<<14;
b = p[1];
p += 2;
a |= *p;
/* a: p0<<14 | p2 (unmasked) */
if (!(a&0x80))
{
a &= SLOT_2_0;
b &= 0x7f;
b = b<<7;
a |= b;
*v = a;
return 3;
}
/* CSE1 from below */
a &= SLOT_2_0;
p++;
b = b<<14;
b |= *p;
/* b: p1<<14 | p3 (unmasked) */
if (!(b&0x80))
{
b &= SLOT_2_0;
/* moved CSE1 up */
/* a &= (0x7f<<14)|(0x7f); */
a = a<<7;
a |= b;
*v = a;
return 4;
}
/* a: p0<<14 | p2 (masked) */
/* b: p1<<14 | p3 (unmasked) */
/* 1:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
/* moved CSE1 up */
/* a &= (0x7f<<14)|(0x7f); */
b &= SLOT_2_0;
s = a;
/* s: p0<<14 | p2 (masked) */
p++;
a = a<<14;
a |= *p;
/* a: p0<<28 | p2<<14 | p4 (unmasked) */
if (!(a&0x80))
{
/* we can skip these cause they were (effectively) done above
** while calculating s */
/* a &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
/* b &= (0x7f<<14)|(0x7f); */
b = b<<7;
a |= b;
s = s>>18;
*v = ((u64)s)<<32 | a;
return 5;
}
/* 2:save off p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
s = s<<7;
s |= b;
/* s: p0<<21 | p1<<14 | p2<<7 | p3 (masked) */
p++;
b = b<<14;
b |= *p;
/* b: p1<<28 | p3<<14 | p5 (unmasked) */
if (!(b&0x80))
{
/* we can skip this cause it was (effectively) done above in calc'ing s */
/* b &= (0x7f<<28)|(0x7f<<14)|(0x7f); */
a &= SLOT_2_0;
a = a<<7;
a |= b;
s = s>>18;
*v = ((u64)s)<<32 | a;
return 6;
}
p++;
a = a<<14;
a |= *p;
/* a: p2<<28 | p4<<14 | p6 (unmasked) */
if (!(a&0x80))
{
a &= SLOT_4_2_0;
b &= SLOT_2_0;
b = b<<7;
a |= b;
s = s>>11;
*v = ((u64)s)<<32 | a;
return 7;
}
/* CSE2 from below */
a &= SLOT_2_0;
p++;
b = b<<14;
b |= *p;
/* b: p3<<28 | p5<<14 | p7 (unmasked) */
if (!(b&0x80))
{
b &= SLOT_4_2_0;
/* moved CSE2 up */
/* a &= (0x7f<<14)|(0x7f); */
a = a<<7;
a |= b;
s = s>>4;
*v = ((u64)s)<<32 | a;
return 8;
}
p++;
a = a<<15;
a |= *p;
/* a: p4<<29 | p6<<15 | p8 (unmasked) */
/* moved CSE2 up */
/* a &= (0x7f<<29)|(0x7f<<15)|(0xff); */
b &= SLOT_2_0;
b = b<<8;
a |= b;
s = s<<4;
b = p[-4];
b &= 0x7f;
b = b>>3;
s |= b;
*v = ((u64)s)<<32 | a;
return 9;
}
/*
** Read a 32-bit variable-length integer from memory starting at p[0].
** Return the number of bytes read. The value is stored in *v.
**
** If the varint stored in p[0] is larger than can fit in a 32-bit unsigned
** integer, then set *v to 0xffffffff.
**
** A MACRO version, getVarint32, is provided which inlines the
** single-byte case. All code should use the MACRO version as
** this function assumes the single-byte case has already been handled.
*/
u8 sqlite3GetVarint32(const unsigned char *p, u32 *v){
u32 a,b;
/* The 1-byte case. Overwhelmingly the most common. Handled inline
** by the getVarin32() macro */
a = *p;
/* a: p0 (unmasked) */
#ifndef getVarint32
if (!(a&0x80))
{
/* Values between 0 and 127 */
*v = a;
return 1;
}
#endif
/* The 2-byte case */
p++;
b = *p;
/* b: p1 (unmasked) */
if (!(b&0x80))
{
/* Values between 128 and 16383 */
a &= 0x7f;
a = a<<7;
*v = a | b;
return 2;
}
/* The 3-byte case */
p++;
a = a<<14;
a |= *p;
/* a: p0<<14 | p2 (unmasked) */
if (!(a&0x80))
{
/* Values between 16384 and 2097151 */
a &= (0x7f<<14)|(0x7f);
b &= 0x7f;
b = b<<7;
*v = a | b;
return 3;
}
/* A 32-bit varint is used to store size information in btrees.
** Objects are rarely larger than 2MiB limit of a 3-byte varint.
** A 3-byte varint is sufficient, for example, to record the size
** of a 1048569-byte BLOB or string.
**
** We only unroll the first 1-, 2-, and 3- byte cases. The very
** rare larger cases can be handled by the slower 64-bit varint
** routine.
*/
#if 1
{
u64 v64;
u8 n;
p -= 2;
n = sqlite3GetVarint(p, &v64);
assert( n>3 && n<=9 );
if( (v64 & SQLITE_MAX_U32)!=v64 ){
*v = 0xffffffff;
}else{
*v = (u32)v64;
}
return n;
}
#else
/* For following code (kept for historical record only) shows an
** unrolling for the 3- and 4-byte varint cases. This code is
** slightly faster, but it is also larger and much harder to test.
*/
p++;
b = b<<14;
b |= *p;
/* b: p1<<14 | p3 (unmasked) */
if (!(b&0x80))
{
/* Values between 2097152 and 268435455 */
b &= (0x7f<<14)|(0x7f);
a &= (0x7f<<14)|(0x7f);
a = a<<7;
*v = a | b;
return 4;
}
p++;
a = a<<14;
a |= *p;
/* a: p0<<28 | p2<<14 | p4 (unmasked) */
if (!(a&0x80))
{
/* Values between 268435456 and 34359738367 */
a &= SLOT_4_2_0;
b &= SLOT_4_2_0;
b = b<<7;
*v = a | b;
return 5;
}
/* We can only reach this point when reading a corrupt database
** file. In that case we are not in any hurry. Use the (relatively
** slow) general-purpose sqlite3GetVarint() routine to extract the
** value. */
{
u64 v64;
u8 n;
p -= 4;
n = sqlite3GetVarint(p, &v64);
assert( n>5 && n<=9 );
*v = (u32)v64;
return n;
}
#endif
}
/*
** Return the number of bytes that will be needed to store the given
** 64-bit integer.
*/
int sqlite3VarintLen(u64 v){
int i;
for(i=1; (v >>= 7)!=0; i++){ assert( i<10 ); }
return i;
}
/*
** Read or write a four-byte big-endian integer value.
*/
u32 sqlite3Get4byte(const u8 *p){
#if SQLITE_BYTEORDER==4321
u32 x;
memcpy(&x,p,4);
return x;
#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
u32 x;
memcpy(&x,p,4);
return __builtin_bswap32(x);
#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
u32 x;
memcpy(&x,p,4);
return _byteswap_ulong(x);
#else
testcase( p[0]&0x80 );
return ((unsigned)p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
#endif
}
void sqlite3Put4byte(unsigned char *p, u32 v){
#if SQLITE_BYTEORDER==4321
memcpy(p,&v,4);
#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
u32 x = __builtin_bswap32(v);
memcpy(p,&x,4);
#elif SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
u32 x = _byteswap_ulong(v);
memcpy(p,&x,4);
#else
p[0] = (u8)(v>>24);
p[1] = (u8)(v>>16);
p[2] = (u8)(v>>8);
p[3] = (u8)v;
#endif
}
/*
** Translate a single byte of Hex into an integer.
** This routine only works if h really is a valid hexadecimal
** character: 0..9a..fA..F
*/
u8 sqlite3HexToInt(int h){
assert( (h>='0' && h<='9') || (h>='a' && h<='f') || (h>='A' && h<='F') );
#ifdef SQLITE_ASCII
h += 9*(1&(h>>6));
#endif
#ifdef SQLITE_EBCDIC
h += 9*(1&~(h>>4));
#endif
return (u8)(h & 0xf);
}
#if !defined(SQLITE_OMIT_BLOB_LITERAL) || defined(SQLITE_HAS_CODEC)
/*
** Convert a BLOB literal of the form "x'hhhhhh'" into its binary
** value. Return a pointer to its binary value. Space to hold the
** binary value has been obtained from malloc and must be freed by
** the calling routine.
*/
void *sqlite3HexToBlob(sqlite3 *db, const char *z, int n){
char *zBlob;
int i;
zBlob = (char *)sqlite3DbMallocRawNN(db, n/2 + 1);
n--;
if( zBlob ){
for(i=0; i<n; i+=2){
zBlob[i/2] = (sqlite3HexToInt(z[i])<<4) | sqlite3HexToInt(z[i+1]);
}
zBlob[i/2] = 0;
}
return zBlob;
}
#endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC */
/*
** Log an error that is an API call on a connection pointer that should
** not have been used. The "type" of connection pointer is given as the
** argument. The zType is a word like "NULL" or "closed" or "invalid".
*/
static void logBadConnection(const char *zType){
sqlite3_log(SQLITE_MISUSE,
"API call with %s database connection pointer",
zType
);
}
/*
** Check to make sure we have a valid db pointer. This test is not
** foolproof but it does provide some measure of protection against
** misuse of the interface such as passing in db pointers that are
** NULL or which have been previously closed. If this routine returns
** 1 it means that the db pointer is valid and 0 if it should not be
** dereferenced for any reason. The calling function should invoke
** SQLITE_MISUSE immediately.
**
** sqlite3SafetyCheckOk() requires that the db pointer be valid for
** use. sqlite3SafetyCheckSickOrOk() allows a db pointer that failed to
** open properly and is not fit for general use but which can be
** used as an argument to sqlite3_errmsg() or sqlite3_close().
*/
int sqlite3SafetyCheckOk(sqlite3 *db){
u32 magic;
if( db==0 ){
logBadConnection("NULL");
return 0;
}
magic = db->magic;
if( magic!=SQLITE_MAGIC_OPEN ){
if( sqlite3SafetyCheckSickOrOk(db) ){
testcase( sqlite3GlobalConfig.xLog!=0 );
logBadConnection("unopened");
}
return 0;
}else{
return 1;
}
}
int sqlite3SafetyCheckSickOrOk(sqlite3 *db){
u32 magic;
magic = db->magic;
if( magic!=SQLITE_MAGIC_SICK &&
magic!=SQLITE_MAGIC_OPEN &&
magic!=SQLITE_MAGIC_BUSY ){
testcase( sqlite3GlobalConfig.xLog!=0 );
logBadConnection("invalid");
return 0;
}else{
return 1;
}
}
/*
** Attempt to add, substract, or multiply the 64-bit signed value iB against
** the other 64-bit signed integer at *pA and store the result in *pA.
** Return 0 on success. Or if the operation would have resulted in an
** overflow, leave *pA unchanged and return 1.
*/
int sqlite3AddInt64(i64 *pA, i64 iB){
#if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
return __builtin_add_overflow(*pA, iB, pA);
#else
i64 iA = *pA;
testcase( iA==0 ); testcase( iA==1 );
testcase( iB==-1 ); testcase( iB==0 );
if( iB>=0 ){
testcase( iA>0 && LARGEST_INT64 - iA == iB );
testcase( iA>0 && LARGEST_INT64 - iA == iB - 1 );
if( iA>0 && LARGEST_INT64 - iA < iB ) return 1;
}else{
testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 1 );
testcase( iA<0 && -(iA + LARGEST_INT64) == iB + 2 );
if( iA<0 && -(iA + LARGEST_INT64) > iB + 1 ) return 1;
}
*pA += iB;
return 0;
#endif
}
int sqlite3SubInt64(i64 *pA, i64 iB){
#if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
return __builtin_sub_overflow(*pA, iB, pA);
#else
testcase( iB==SMALLEST_INT64+1 );
if( iB==SMALLEST_INT64 ){
testcase( (*pA)==(-1) ); testcase( (*pA)==0 );
if( (*pA)>=0 ) return 1;
*pA -= iB;
return 0;
}else{
return sqlite3AddInt64(pA, -iB);
}
#endif
}
int sqlite3MulInt64(i64 *pA, i64 iB){
#if GCC_VERSION>=5004000 && !defined(__INTEL_COMPILER)
return __builtin_mul_overflow(*pA, iB, pA);
#else
i64 iA = *pA;
if( iB>0 ){
if( iA>LARGEST_INT64/iB ) return 1;
if( iA<SMALLEST_INT64/iB ) return 1;
}else if( iB<0 ){
if( iA>0 ){
if( iB<SMALLEST_INT64/iA ) return 1;
}else if( iA<0 ){
if( iB==SMALLEST_INT64 ) return 1;
if( iA==SMALLEST_INT64 ) return 1;
if( -iA>LARGEST_INT64/-iB ) return 1;
}
}
*pA = iA*iB;
return 0;
#endif
}
/*
** Compute the absolute value of a 32-bit signed integer, of possible. Or
** if the integer has a value of -2147483648, return +2147483647
*/
int sqlite3AbsInt32(int x){
if( x>=0 ) return x;
if( x==(int)0x80000000 ) return 0x7fffffff;
return -x;
}
#ifdef SQLITE_ENABLE_8_3_NAMES
/*
** If SQLITE_ENABLE_8_3_NAMES is set at compile-time and if the database
** filename in zBaseFilename is a URI with the "8_3_names=1" parameter and
** if filename in z[] has a suffix (a.k.a. "extension") that is longer than
** three characters, then shorten the suffix on z[] to be the last three
** characters of the original suffix.
**
** If SQLITE_ENABLE_8_3_NAMES is set to 2 at compile-time, then always
** do the suffix shortening regardless of URI parameter.
**
** Examples:
**
** test.db-journal => test.nal
** test.db-wal => test.wal
** test.db-shm => test.shm
** test.db-mj7f3319fa => test.9fa
*/
void sqlite3FileSuffix3(const char *zBaseFilename, char *z){
#if SQLITE_ENABLE_8_3_NAMES<2
if( sqlite3_uri_boolean(zBaseFilename, "8_3_names", 0) )
#endif
{
int i, sz;
sz = sqlite3Strlen30(z);
for(i=sz-1; i>0 && z[i]!='/' && z[i]!='.'; i--){}
if( z[i]=='.' && ALWAYS(sz>i+4) ) memmove(&z[i+1], &z[sz-3], 4);
}
}
#endif
/*
** Find (an approximate) sum of two LogEst values. This computation is
** not a simple "+" operator because LogEst is stored as a logarithmic
** value.
**
*/
LogEst sqlite3LogEstAdd(LogEst a, LogEst b){
static const unsigned char x[] = {
10, 10, /* 0,1 */
9, 9, /* 2,3 */
8, 8, /* 4,5 */
7, 7, 7, /* 6,7,8 */
6, 6, 6, /* 9,10,11 */
5, 5, 5, /* 12-14 */
4, 4, 4, 4, /* 15-18 */
3, 3, 3, 3, 3, 3, /* 19-24 */
2, 2, 2, 2, 2, 2, 2, /* 25-31 */
};
if( a>=b ){
if( a>b+49 ) return a;
if( a>b+31 ) return a+1;
return a+x[a-b];
}else{
if( b>a+49 ) return b;
if( b>a+31 ) return b+1;
return b+x[b-a];
}
}
/*
** Convert an integer into a LogEst. In other words, compute an
** approximation for 10*log2(x).
*/
LogEst sqlite3LogEst(u64 x){
static LogEst a[] = { 0, 2, 3, 5, 6, 7, 8, 9 };
LogEst y = 40;
if( x<8 ){
if( x<2 ) return 0;
while( x<8 ){ y -= 10; x <<= 1; }
}else{
#if GCC_VERSION>=5004000
int i = 60 - __builtin_clzll(x);
y += i*10;
x >>= i;
#else
while( x>255 ){ y += 40; x >>= 4; } /*OPTIMIZATION-IF-TRUE*/
while( x>15 ){ y += 10; x >>= 1; }
#endif
}
return a[x&7] + y - 10;
}
#ifndef SQLITE_OMIT_VIRTUALTABLE
/*
** Convert a double into a LogEst
** In other words, compute an approximation for 10*log2(x).
*/
LogEst sqlite3LogEstFromDouble(double x){
u64 a;
LogEst e;
assert( sizeof(x)==8 && sizeof(a)==8 );
if( x<=1 ) return 0;
if( x<=2000000000 ) return sqlite3LogEst((u64)x);
memcpy(&a, &x, 8);
e = (a>>52) - 1022;
return e*10;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */
#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || \
defined(SQLITE_ENABLE_STAT4) || \
defined(SQLITE_EXPLAIN_ESTIMATED_ROWS)
/*
** Convert a LogEst into an integer.
**
** Note that this routine is only used when one or more of various
** non-standard compile-time options is enabled.
*/
u64 sqlite3LogEstToInt(LogEst x){
u64 n;
n = x%10;
x /= 10;
if( n>=5 ) n -= 2;
else if( n>=1 ) n -= 1;
#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || \
defined(SQLITE_EXPLAIN_ESTIMATED_ROWS)
if( x>60 ) return (u64)LARGEST_INT64;
#else
/* If only SQLITE_ENABLE_STAT4 is on, then the largest input
** possible to this routine is 310, resulting in a maximum x of 31 */
assert( x<=60 );
#endif
return x>=3 ? (n+8)<<(x-3) : (n+8)>>(3-x);
}
#endif /* defined SCANSTAT or STAT4 or ESTIMATED_ROWS */
/*
** Add a new name/number pair to a VList. This might require that the
** VList object be reallocated, so return the new VList. If an OOM
** error occurs, the original VList returned and the
** db->mallocFailed flag is set.
**
** A VList is really just an array of integers. To destroy a VList,
** simply pass it to sqlite3DbFree().
**
** The first integer is the number of integers allocated for the whole
** VList. The second integer is the number of integers actually used.
** Each name/number pair is encoded by subsequent groups of 3 or more
** integers.
**
** Each name/number pair starts with two integers which are the numeric
** value for the pair and the size of the name/number pair, respectively.
** The text name overlays one or more following integers. The text name
** is always zero-terminated.
**
** Conceptually:
**
** struct VList {
** int nAlloc; // Number of allocated slots
** int nUsed; // Number of used slots
** struct VListEntry {
** int iValue; // Value for this entry
** int nSlot; // Slots used by this entry
** // ... variable name goes here
** } a[0];
** }
**
** During code generation, pointers to the variable names within the
** VList are taken. When that happens, nAlloc is set to zero as an
** indication that the VList may never again be enlarged, since the
** accompanying realloc() would invalidate the pointers.
*/
VList *sqlite3VListAdd(
sqlite3 *db, /* The database connection used for malloc() */
VList *pIn, /* The input VList. Might be NULL */
const char *zName, /* Name of symbol to add */
int nName, /* Bytes of text in zName */
int iVal /* Value to associate with zName */
){
int nInt; /* number of sizeof(int) objects needed for zName */
char *z; /* Pointer to where zName will be stored */
int i; /* Index in pIn[] where zName is stored */
nInt = nName/4 + 3;
assert( pIn==0 || pIn[0]>=3 ); /* Verify ok to add new elements */
if( pIn==0 || pIn[1]+nInt > pIn[0] ){
/* Enlarge the allocation */
sqlite3_int64 nAlloc = (pIn ? 2*(sqlite3_int64)pIn[0] : 10) + nInt;
VList *pOut = sqlite3DbRealloc(db, pIn, nAlloc*sizeof(int));
if( pOut==0 ) return pIn;
if( pIn==0 ) pOut[1] = 2;
pIn = pOut;
pIn[0] = nAlloc;
}
i = pIn[1];
pIn[i] = iVal;
pIn[i+1] = nInt;
z = (char*)&pIn[i+2];
pIn[1] = i+nInt;
assert( pIn[1]<=pIn[0] );
memcpy(z, zName, nName);
z[nName] = 0;
return pIn;
}
/*
** Return a pointer to the name of a variable in the given VList that
** has the value iVal. Or return a NULL if there is no such variable in
** the list
*/
const char *sqlite3VListNumToName(VList *pIn, int iVal){
int i, mx;
if( pIn==0 ) return 0;
mx = pIn[1];
i = 2;
do{
if( pIn[i]==iVal ) return (char*)&pIn[i+2];
i += pIn[i+1];
}while( i<mx );
return 0;
}
/*
** Return the number of the variable named zName, if it is in VList.
** or return 0 if there is no such variable.
*/
int sqlite3VListNameToNum(VList *pIn, const char *zName, int nName){
int i, mx;
if( pIn==0 ) return 0;
mx = pIn[1];
i = 2;
do{
const char *z = (const char*)&pIn[i+2];
if( strncmp(z,zName,nName)==0 && z[nName]==0 ) return pIn[i];
i += pIn[i+1];
}while( i<mx );
return 0;
}