MCL/sf/os/persistentdata: comparison persistentstorage/sqlite3api/SQLite/util.c

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--1:000000000000
+:08ec8eefde2f
+/*
+** 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.
+**
+** $Id: util.c,v 1.241 2008/07/28 19:34:54 drh Exp $
+*/
+#include "sqliteInt.h"
+#include <stdarg.h>
+#include <ctype.h>
+/*
+** Return true if the floating point value is Not a Number (NaN).
+*/
+int sqlite3IsNaN(double x){
+/* This NaN test sometimes fails if compiled on GCC with -ffast-math.
+** On the other hand, the use of -ffast-math comes with the following
+** warning:
+**
+**      This option [-ffast-math] should never be turned on by any
+**      -O option since it can result in incorrect output for programs
+**      which depend on an exact implementation of IEEE or ISO
+**      rules/specifications for math functions.
+**
+** Under MSVC, this NaN test may fail if compiled with a floating-
+** point precision mode other than /fp:precise.  From the MSDN
+** documentation:
+**
+**      The compiler [with /fp:precise] will properly handle comparisons
+**      involving NaN. For example, x != x evaluates to true if x is NaN
+**      ...
+*/
+#ifdef __FAST_MATH__
+# error SQLite will not work correctly with the -ffast-math option of GCC.
+#endif
+volatile double y = x;
+volatile double z = y;
+return y!=z;
+}
+/*
+** Return the length of a string, except do not allow the string length
+** to exceed the SQLITE_LIMIT_LENGTH setting.
+*/
+int sqlite3Strlen(sqlite3 *db, const char *z){
+const char *z2 = z;
+int len;
+size_t x;
+while( *z2 ){ z2++; }
+x = z2 - z;
+len = 0x7fffffff & x;
+if( len!=x || len > db->aLimit[SQLITE_LIMIT_LENGTH] ){
+return db->aLimit[SQLITE_LIMIT_LENGTH];
+}else{
+return len;
+}
+}
+/*
+** 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 sqlite3Error(sqlite3 *db, int err_code, const char *zFormat, ...){
+if( db && (db->pErr || (db->pErr = sqlite3ValueNew(db))!=0) ){
+db->errCode = err_code;
+if( zFormat ){
+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);
+}else{
+sqlite3ValueSetStr(db->pErr, 0, 0, SQLITE_UTF8, SQLITE_STATIC);
+}
+}
+}
+/*
+** 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 whilst
+** 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().
+** Function sqlite3Error() should be used during statement execution
+** (sqlite3_step() etc.).
+*/
+void sqlite3ErrorMsg(Parse *pParse, const char *zFormat, ...){
+va_list ap;
+sqlite3 *db = pParse->db;
+pParse->nErr++;
+sqlite3DbFree(db, pParse->zErrMsg);
+va_start(ap, zFormat);
+pParse->zErrMsg = sqlite3VMPrintf(db, zFormat, ap);
+va_end(ap);
+if( pParse->rc==SQLITE_OK ){
+pParse->rc = SQLITE_ERROR;
+}
+}
+/*
+** Clear the error message in pParse, if any
+*/
+void sqlite3ErrorClear(Parse *pParse){
+sqlite3DbFree(pParse->db, pParse->zErrMsg);
+pParse->zErrMsg = 0;
+pParse->nErr = 0;
+}
+/*
+** 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.
+**
+** 2002-Feb-14: This routine is extended to remove MS-Access style
+** brackets from around identifers.  For example:  "[a-b-c]" becomes
+** "a-b-c".
+*/
+void sqlite3Dequote(char *z){
+int quote;
+int i, j;
+if( z==0 ) return;
+quote = z[0];
+switch( quote ){
+case '\'':  break;
+case '"':   break;
+case '`':   break;                /* For MySQL compatibility */
+case '[':   quote = ']';  break;  /* For MS SqlServer compatibility */
+default:    return;
+}
+for(i=1, j=0; z[i]; i++){
+if( z[i]==quote ){
+if( z[i+1]==quote ){
+z[j++] = quote;
+i++;
+}else{
+z[j++] = 0;
+break;
+}
+}else{
+z[j++] = z[i];
+}
+}
+}
+/* Convenient short-hand */
+#define UpperToLower sqlite3UpperToLower
+/*
+** Some systems have stricmp().  Others have strcasecmp().  Because
+** there is no consistency, we will define our own.
+*/
+int sqlite3StrICmp(const char *zLeft, const char *zRight){
+register unsigned char *a, *b;
+a = (unsigned char *)zLeft;
+b = (unsigned char *)zRight;
+while( *a!=0 && UpperToLower[*a]==UpperToLower[*b]){ a++; b++; }
+return UpperToLower[*a] - UpperToLower[*b];
+}
+int sqlite3StrNICmp(const char *zLeft, const char *zRight, int N){
+register unsigned char *a, *b;
+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];
+}
+/*
+** Return TRUE if z is a pure numeric string.  Return FALSE if the
+** string contains any character which is not part of a number. If
+** the string is numeric and contains the '.' character, set *realnum
+** to TRUE (otherwise FALSE).
+**
+** An empty string is considered non-numeric.
+*/
+int sqlite3IsNumber(const char *z, int *realnum, u8 enc){
+int incr = (enc==SQLITE_UTF8?1:2);
+if( enc==SQLITE_UTF16BE ) z++;
+if( *z=='-' || *z=='+' ) z += incr;
+if( !isdigit(*(u8*)z) ){
+return 0;
+}
+z += incr;
+if( realnum ) *realnum = 0;
+while( isdigit(*(u8*)z) ){ z += incr; }
+if( *z=='.' ){
+z += incr;
+if( !isdigit(*(u8*)z) ) return 0;
+while( isdigit(*(u8*)z) ){ z += incr; }
+if( realnum ) *realnum = 1;
+}
+if( *z=='e' || *z=='E' ){
+z += incr;
+if( *z=='+' || *z=='-' ) z += incr;
+if( !isdigit(*(u8*)z) ) return 0;
+while( isdigit(*(u8*)z) ){ z += incr; }
+if( realnum ) *realnum = 1;
+}
+return *z==0;
+}
+/*
+** The string z[] is an ascii representation of a real number.
+** Convert this string to a double.
+**
+** This routine assumes that z[] really is a valid number.  If it
+** is not, the result is undefined.
+**
+** This routine is used instead of the library atof() function because
+** the library atof() might want to use "," as the decimal point instead
+** of "." depending on how locale is set.  But that would cause problems
+** for SQL.  So this routine always uses "." regardless of locale.
+*/
+int sqlite3AtoF(const char *z, double *pResult){
+#ifndef SQLITE_OMIT_FLOATING_POINT
+int sign = 1;
+const char *zBegin = z;
+LONGDOUBLE_TYPE v1 = 0.0;
+int nSignificant = 0;
+while( isspace(*(u8*)z) ) z++;
+if( *z=='-' ){
+sign = -1;
+z++;
+}else if( *z=='+' ){
+z++;
+}
+while( z[0]=='0' ){
+z++;
+}
+while( isdigit(*(u8*)z) ){
+v1 = v1*10.0 + (*z - '0');
+z++;
+nSignificant++;
+}
+if( *z=='.' ){
+LONGDOUBLE_TYPE divisor = 1.0;
+z++;
+if( nSignificant==0 ){
+while( z[0]=='0' ){
+divisor *= 10.0;
+z++;
+}
+}
+while( isdigit(*(u8*)z) ){
+if( nSignificant<18 ){
+v1 = v1*10.0 + (*z - '0');
+divisor *= 10.0;
+nSignificant++;
+}
+z++;
+}
+v1 /= divisor;
+}
+if( *z=='e' || *z=='E' ){
+int esign = 1;
+int eval = 0;
+LONGDOUBLE_TYPE scale = 1.0;
+z++;
+if( *z=='-' ){
+esign = -1;
+z++;
+}else if( *z=='+' ){
+z++;
+}
+while( isdigit(*(u8*)z) ){
+eval = eval*10 + *z - '0';
+z++;
+}
+while( eval>=64 ){ scale *= 1.0e+64; eval -= 64; }
+while( eval>=16 ){ scale *= 1.0e+16; eval -= 16; }
+while( eval>=4 ){ scale *= 1.0e+4; eval -= 4; }
+while( eval>=1 ){ scale *= 1.0e+1; eval -= 1; }
+if( esign<0 ){
+v1 /= scale;
+}else{
+v1 *= scale;
+}
+}
+*pResult = sign<0 ? -v1 : v1;
+return z - zBegin;
+#else
+return sqlite3Atoi64(z, pResult);
+#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.
+**
+** 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")
+**
+** will return -8.
+*/
+static int compare2pow63(const char *zNum){
+int c;
+c = memcmp(zNum,"922337203685477580",18);
+if( c==0 ){
+c = zNum[18] - '8';
+}
+return c;
+}
+/*
+** Return TRUE if zNum is a 64-bit signed integer and write
+** the value of the integer into *pNum.  If zNum is not an integer
+** or is an integer that is too large to be expressed with 64 bits,
+** then return false.
+**
+** When this routine was originally written it dealt with only
+** 32-bit numbers.  At that time, it was much faster than the
+** atoi() library routine in RedHat 7.2.
+*/
+int sqlite3Atoi64(const char *zNum, i64 *pNum){
+i64 v = 0;
+int neg;
+int i, c;
+const char *zStart;
+while( isspace(*(u8*)zNum) ) zNum++;
+if( *zNum=='-' ){
+neg = 1;
+zNum++;
+}else if( *zNum=='+' ){
+neg = 0;
+zNum++;
+}else{
+neg = 0;
+}
+zStart = zNum;
+while( zNum[0]=='0' ){ zNum++; } /* Skip over leading zeros. Ticket #2454 */
+for(i=0; (c=zNum[i])>='0' && c<='9'; i++){
+v = v*10 + c - '0';
+}
+*pNum = neg ? -v : v;
+if( c!=0 || (i==0 && zStart==zNum) || i>19 ){
+/* zNum is empty or contains non-numeric text or is longer
+** than 19 digits (thus guaranting that it is too large) */
+return 0;
+}else if( i<19 ){
+/* Less than 19 digits, so we know that it fits in 64 bits */
+return 1;
+}else{
+/* 19-digit numbers must be no larger than 9223372036854775807 if positive
+** or 9223372036854775808 if negative.  Note that 9223372036854665808
+** is 2^63. */
+return compare2pow63(zNum)<neg;
+}
+}
+/*
+** The string zNum represents an integer.  There might be some other
+** information following the integer too, but that part is ignored.
+** If the integer that the prefix of zNum represents will fit in a
+** 64-bit signed integer, return TRUE.  Otherwise return FALSE.
+**
+** This routine returns FALSE for the string -9223372036854775808 even that
+** that number will, in theory fit in a 64-bit integer.  Positive
+** 9223373036854775808 will not fit in 64 bits.  So it seems safer to return
+** false.
+*/
+int sqlite3FitsIn64Bits(const char *zNum, int negFlag){
+int i, c;
+int neg = 0;
+if( *zNum=='-' ){
+neg = 1;
+zNum++;
+}else if( *zNum=='+' ){
+zNum++;
+}
+if( negFlag ) neg = 1-neg;
+while( *zNum=='0' ){
+zNum++;   /* Skip leading zeros.  Ticket #2454 */
+}
+for(i=0; (c=zNum[i])>='0' && c<='9'; i++){}
+if( i<19 ){
+/* Guaranteed to fit if less than 19 digits */
+return 1;
+}else if( i>19 ){
+/* Guaranteed to be too big if greater than 19 digits */
+return 0;
+}else{
+/* Compare against 2^63. */
+return compare2pow63(zNum)<neg;
+}
+}
+/*
+** If zNum represents an integer that will fit in 32-bits, then set
+** *pValue to that integer and return true.  Otherwise return false.
+**
+** 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++;
+}
+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
+*/
+if( i>10 ){
+return 0;
+}
+if( v-neg>2147483647 ){
+return 0;
+}
+if( neg ){
+v = -v;
+}
+*pValue = (int)v;
+return 1;
+}
+/*
+** 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.
+*/
+int sqlite3PutVarint(unsigned char *p, u64 v){
+int i, j, n;
+u8 buf[10];
+if( v & (((u64)0xff000000)<<32) ){
+p[8] = v;
+v >>= 8;
+for(i=7; i>=0; i--){
+p[i] = (v & 0x7f) | 0x80;
+v >>= 7;
+}
+return 9;
+}
+n = 0;
+do{
+buf[n++] = (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;
+}
+/*
+** This routine is a faster version of sqlite3PutVarint() that only
+** works for 32-bit positive integers and which is optimized for
+** the common case of small integers.  A MACRO version, putVarint32,
+** 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.
+*/
+int sqlite3PutVarint32(unsigned char *p, u32 v){
+#ifndef putVarint32
+if( (v & ~0x7f)==0 ){
+p[0] = v;
+return 1;
+}
+#endif
+if( (v & ~0x3fff)==0 ){
+p[0] = (v>>7) | 0x80;
+p[1] = v & 0x7f;
+return 2;
+}
+return sqlite3PutVarint(p, v);
+}
+/*
+** 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.
+*/
+int sqlite3GetVarint(const unsigned char *p, u64 *v){
+u32 a,b,s;
+a = *p;
+/* a: p0 (unmasked) */
+if (!(a&0x80))
+{
+*v = a;
+return 1;
+}
+p++;
+b = *p;
+/* b: p1 (unmasked) */
+if (!(b&0x80))
+{
+a &= 0x7f;
+a = a<<7;
+a |= b;
+*v = a;
+return 2;
+}
+p++;
+a = a<<14;
+a |= *p;
+/* a: p0<<14 | p2 (unmasked) */
+if (!(a&0x80))
+{
+a &= (0x7f<<14)|(0x7f);
+b &= 0x7f;
+b = b<<7;
+a |= b;
+*v = a;
+return 3;
+}
+/* CSE1 from below */
+a &= (0x7f<<14)|(0x7f);
+p++;
+b = b<<14;
+b |= *p;
+/* b: p1<<14 | p3 (unmasked) */
+if (!(b&0x80))
+{
+b &= (0x7f<<14)|(0x7f);
+/* 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 &= (0x7f<<14)|(0x7f);
+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 in calc'ing 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 &= (0x7f<<14)|(0x7f);
+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 &= (0x7f<<28)|(0x7f<<14)|(0x7f);
+b &= (0x7f<<14)|(0x7f);
+b = b<<7;
+a |= b;
+s = s>>11;
+*v = ((u64)s)<<32 | a;
+return 7;
+}
+/* CSE2 from below */
+a &= (0x7f<<14)|(0x7f);
+p++;
+b = b<<14;
+b |= *p;
+/* b: p3<<28 | p5<<14 | p7 (unmasked) */
+if (!(b&0x80))
+{
+b &= (0x7f<<28)|(0x7f<<14)|(0x7f);
+/* 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 &= (0x7f<<14)|(0x7f);
+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.
+** 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.
+*/
+int sqlite3GetVarint32(const unsigned char *p, u32 *v){
+u32 a,b;
+a = *p;
+/* a: p0 (unmasked) */
+#ifndef getVarint32
+if (!(a&0x80))
+{
+*v = a;
+return 1;
+}
+#endif
+p++;
+b = *p;
+/* b: p1 (unmasked) */
+if (!(b&0x80))
+{
+a &= 0x7f;
+a = a<<7;
+*v = a | b;
+return 2;
+}
+p++;
+a = a<<14;
+a |= *p;
+/* a: p0<<14 | p2 (unmasked) */
+if (!(a&0x80))
+{
+a &= (0x7f<<14)|(0x7f);
+b &= 0x7f;
+b = b<<7;
+*v = a | b;
+return 3;
+}
+p++;
+b = b<<14;
+b |= *p;
+/* b: p1<<14 | p3 (unmasked) */
+if (!(b&0x80))
+{
+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))
+{
+a &= (0x7f<<28)|(0x7f<<14)|(0x7f);
+b &= (0x7f<<28)|(0x7f<<14)|(0x7f);
+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;
+int n;
+p -= 4;
+n = sqlite3GetVarint(p, &v64);
+assert( n>5 && n<=9 );
+*v = (u32)v64;
+return n;
+}
+}
+/*
+** Return the number of bytes that will be needed to store the given
+** 64-bit integer.
+*/
+int sqlite3VarintLen(u64 v){
+int i = 0;
+do{
+i++;
+v >>= 7;
+}while( v!=0 && i<9 );
+return i;
+}
+/*
+** Read or write a four-byte big-endian integer value.
+*/
+u32 sqlite3Get4byte(const u8 *p){
+return (p[0]<<24) | (p[1]<<16) | (p[2]<<8) | p[3];
+}
+void sqlite3Put4byte(unsigned char *p, u32 v){
+p[0] = v>>24;
+p[1] = v>>16;
+p[2] = v>>8;
+p[3] = v;
+}
+#if !defined(SQLITE_OMIT_BLOB_LITERAL) || defined(SQLITE_HAS_CODEC)
+/*
+** Translate a single byte of Hex into an integer.
+** This routinen only works if h really is a valid hexadecimal
+** character:  0..9a..fA..F
+*/
+static int hexToInt(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 h & 0xf;
+}
+#endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC */
+#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 *)sqlite3DbMallocRaw(db, n/2 + 1);
+n--;
+if( zBlob ){
+for(i=0; i<n; i+=2){
+zBlob[i/2] = (hexToInt(z[i])<<4) | hexToInt(z[i+1]);
+}
+zBlob[i/2] = 0;
+}
+return zBlob;
+}
+#endif /* !SQLITE_OMIT_BLOB_LITERAL || SQLITE_HAS_CODEC */
+/*
+** Change the sqlite.magic from SQLITE_MAGIC_OPEN to SQLITE_MAGIC_BUSY.
+** Return an error (non-zero) if the magic was not SQLITE_MAGIC_OPEN
+** when this routine is called.
+**
+** This routine is called when entering an SQLite API.  The SQLITE_MAGIC_OPEN
+** value indicates that the database connection passed into the API is
+** open and is not being used by another thread.  By changing the value
+** to SQLITE_MAGIC_BUSY we indicate that the connection is in use.
+** sqlite3SafetyOff() below will change the value back to SQLITE_MAGIC_OPEN
+** when the API exits.
+**
+** This routine is a attempt to detect if two threads use the
+** same sqlite* pointer at the same time.  There is a race
+** condition so it is possible that the error is not detected.
+** But usually the problem will be seen.  The result will be an
+** error which can be used to debug the application that is
+** using SQLite incorrectly.
+**
+** Ticket #202:  If db->magic is not a valid open value, take care not
+** to modify the db structure at all.  It could be that db is a stale
+** pointer.  In other words, it could be that there has been a prior
+** call to sqlite3_close(db) and db has been deallocated.  And we do
+** not want to write into deallocated memory.
+*/
+#ifdef SQLITE_DEBUG
+int sqlite3SafetyOn(sqlite3 *db){
+if( db->magic==SQLITE_MAGIC_OPEN ){
+db->magic = SQLITE_MAGIC_BUSY;
+assert( sqlite3_mutex_held(db->mutex) );
+return 0;
+}else if( db->magic==SQLITE_MAGIC_BUSY ){
+db->magic = SQLITE_MAGIC_ERROR;
+db->u1.isInterrupted = 1;
+}
+return 1;
+}
+#endif
+/*
+** Change the magic from SQLITE_MAGIC_BUSY to SQLITE_MAGIC_OPEN.
+** Return an error (non-zero) if the magic was not SQLITE_MAGIC_BUSY
+** when this routine is called.
+*/
+#ifdef SQLITE_DEBUG
+int sqlite3SafetyOff(sqlite3 *db){
+if( db->magic==SQLITE_MAGIC_BUSY ){
+db->magic = SQLITE_MAGIC_OPEN;
+assert( sqlite3_mutex_held(db->mutex) );
+return 0;
+}else{
+db->magic = SQLITE_MAGIC_ERROR;
+db->u1.isInterrupted = 1;
+return 1;
+}
+}
+#endif
+/*
+** 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){
+int magic;
+if( db==0 ) return 0;
+magic = db->magic;
+if( magic!=SQLITE_MAGIC_OPEN &&
+magic!=SQLITE_MAGIC_BUSY ) return 0;
+return 1;
+}
+int sqlite3SafetyCheckSickOrOk(sqlite3 *db){
+int magic;
+if( db==0 ) return 0;
+magic = db->magic;
+if( magic!=SQLITE_MAGIC_SICK &&
+magic!=SQLITE_MAGIC_OPEN &&
+magic!=SQLITE_MAGIC_BUSY ) return 0;
+return 1;
+}