** 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: func.c,v 1.161 2007/06/22 15:21:16 danielk1977 Exp $
*/
#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;
}
................................................................................
/* 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:
**
................................................................................
*/
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;
}

/*
................................................................................
    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
    

** 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: func.c,v 1.162 2007/07/23 19:12:42 drh Exp $
*/
#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;
}
................................................................................
/* 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 };










/*
** 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:
**
................................................................................
*/
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 */
){
  int c, c2;
  int invert;
  int seen;

  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 = sqlite3Utf8Read(zPattern,0,&zPattern))!=0 ){
    if( !prevEscape && c==matchAll ){
      while( (c=sqlite3Utf8Read(zPattern,0,&zPattern)) == matchAll
               || c == matchOne ){
        if( c==matchOne && sqlite3Utf8Read(zString, 0, &zString)==0 ){
          return 0;

        }

      }
      if( c==0 ){
        return 1;
      }else if( c==esc ){
        c = sqlite3Utf8Read(zPattern, 0, &zPattern);
        if( c==0 ){
          return 0;
        }

      }else if( c==matchSet ){
        assert( esc==0 );         /* This is GLOB, not LIKE */
        assert( matchSet<0x80 );  /* '[' is a single-byte character */
        while( *zString && patternCompare(&zPattern[-1],zString,pInfo,esc)==0 ){
          SQLITE_SKIP_UTF8(zString);
        }
        return *zString!=0;


      }
      while( (c2 = sqlite3Utf8Read(zString,0,&zString))!=0 ){
        if( noCase ){
          c2 = c2<0x80 ? sqlite3UpperToLower[c2] : c2;
          c = c<0x80 ? sqlite3UpperToLower[c] : c;
          while( c2 != 0 && c2 != c ){
            c2 = sqlite3Utf8Read(zString, 0, &zString);
            if( c2<0x80 ) c2 = sqlite3UpperToLower[c2];
          }
        }else{
          while( c2 != 0 && c2 != c ){
            c2 = sqlite3Utf8Read(zString, 0, &zString);
          }
        }
        if( c2==0 ) return 0;
        if( patternCompare(zPattern,zString,pInfo,esc) ) return 1;

      }
      return 0;

    }else if( !prevEscape && c==matchOne ){
      if( sqlite3Utf8Read(zString, 0, &zString)==0 ){
        return 0;


      }
    }else if( c==matchSet ){
      int prior_c = 0;
      assert( esc==0 );    /* This only occurs for GLOB, not LIKE */
      seen = 0;
      invert = 0;
      c = sqlite3Utf8Read(zString, 0, &zString);
      if( c==0 ) return 0;
      c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
      if( c2=='^' ){
        invert = 1;
        c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
      }
      if( c2==']' ){
        if( c==']' ) seen = 1;

        c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
      }

      while( c2 && c2!=']' ){
        if( c2=='-' && zPattern[0]!=']' && zPattern[0]!=0 && prior_c>0 ){


          c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
          if( c>=prior_c && c<=c2 ) seen = 1;
          prior_c = 0;
        }else{
          if( c==c2 ){
            seen = 1;
          }
          prior_c = c2;


        }

        c2 = sqlite3Utf8Read(zPattern, 0, &zPattern);
      }
      if( c2==0 || (seen ^ invert)==0 ){


        return 0;
      }
    }else if( esc==c && !prevEscape ){
      prevEscape = 1;

    }else{
      c2 = sqlite3Utf8Read(zString, 0, &zString);
      if( noCase ){
        c = c<0x80 ? sqlite3UpperToLower[c] : c;

        c2 = c2<0x80 ? sqlite3UpperToLower[c2] : c2;
      }
      if( c!=c2 ){
        return 0;
      }


      prevEscape = 0;
    }
  }
  return *zString==0;
}

/*
................................................................................
    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 = sqlite3Utf8Read(zEsc, 0, &zEsc);
  }
  if( zA && zB ){
    struct compareInfo *pInfo = sqlite3_user_data(context);
#ifdef SQLITE_TEST
    sqlite3_like_count++;
#endif
    

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.578 2007/06/26 10:38:55 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_
#include "sqliteLimit.h"


#if defined(SQLITE_TCL) || defined(TCLSH)
................................................................................
 * This global flag is set for performance testing of triggers. When it is set
 * SQLite will perform the overhead of building new and old trigger references 
 * even when no triggers exist
 */
extern int sqlite3_always_code_trigger_setup;

/*
** A lookup table used by the SQLITE_READ_UTF8 macro.  The definition
** is in utf.c.
*/
extern const unsigned char sqlite3UtfTrans1[];

/*
** Macros for reading UTF8 characters.
**
** SQLITE_READ_UTF8(x,c) reads a single UTF8 value out of x and writes
** that value into c.  The type of x must be unsigned char*.  The type
** of c must be unsigned int.
**
** SQLITE_SKIP_UTF8(x) advances x forward by one character.  The type of
** x must be unsigned char*.
**
** Notes On Invalid UTF-8:
**
**  *  These macros never allow a 7-bit character (0x00 through 0x7f) to
**     be encoded as a multi-byte character.  Any multi-byte character that
**     attempts to encode a value between 0x00 and 0x7f is rendered as 0xfffd.
**
**  *  These macros never allow a UTF16 surrogate value to be encoded.
**     If a multi-byte character attempts to encode a value between
**     0xd800 and 0xe000 then it is rendered as 0xfffd.
**
**  *  Bytes in the range of 0x80 through 0xbf which occur as the first
**     byte of a character are interpreted as single-byte characters
**     and rendered as themselves even though they are technically
**     invalid characters.
**
**  *  These routines accept an infinite number of different UTF8 encodings
**     for unicode values 0x80 and greater.  They do not change over-length
**     encodings to 0xfffd as some systems recommend.
** 
*/
#define SQLITE_READ_UTF8(zIn, c) {                     \
  c = *(zIn++);                                        \
  if( c>=0xc0 ){                                       \
    c = sqlite3UtfTrans1[c-0xc0];                      \
    while( (*zIn & 0xc0)==0x80 ){                      \
      c = (c<<6) + (0x3f & *(zIn++));                  \
    }                                                  \
    if( c<0x80                                         \
        || (c&0xFFFFF800)==0xD800                      \
        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }    \
  }                                                    \
}
#define SQLITE_SKIP_UTF8(zIn) {                        \
  if( (*(zIn++))>=0xc0 ){                              \
    while( (*zIn & 0xc0)==0x80 ){ zIn++; }             \
  }                                                    \
}




/*
** The SQLITE_CORRUPT_BKPT macro can be either a constant (for production
** builds) or a function call (for debugging).  If it is a function call,
** it allows the operator to set a breakpoint at the spot where database
** corruption is first detected.
*/
................................................................................
int sqlite3FixTriggerStep(DbFixer*, TriggerStep*);
int sqlite3AtoF(const char *z, double*);
char *sqlite3_snprintf(int,char*,const char*,...);
int sqlite3GetInt32(const char *, int*);
int sqlite3FitsIn64Bits(const char *);
int sqlite3Utf16ByteLen(const void *pData, int nChar);
int sqlite3Utf8CharLen(const char *pData, int nByte);
u32 sqlite3ReadUtf8(const unsigned char *);
int sqlite3PutVarint(unsigned char *, u64);
int sqlite3GetVarint(const unsigned char *, u64 *);
int sqlite3GetVarint32(const unsigned char *, u32 *);
int sqlite3VarintLen(u64 v);
void sqlite3IndexAffinityStr(Vdbe *, Index *);
void sqlite3TableAffinityStr(Vdbe *, Table *);
char sqlite3CompareAffinity(Expr *pExpr, char aff2);

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.579 2007/07/23 19:12:42 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_
#include "sqliteLimit.h"


#if defined(SQLITE_TCL) || defined(TCLSH)
................................................................................
 * This global flag is set for performance testing of triggers. When it is set
 * SQLite will perform the overhead of building new and old trigger references 
 * even when no triggers exist
 */
extern int sqlite3_always_code_trigger_setup;

/*
** Assuming zIn points to the first byte of a UTF-8 character,
** advance zIn to point to the first byte of the next UTF-8 character.
*/












































#define SQLITE_SKIP_UTF8(zIn) {                        \
  if( (*(zIn++))>=0xc0 ){                              \
    while( (*zIn & 0xc0)==0x80 ){ zIn++; }             \
  }                                                    \
}




/*
** The SQLITE_CORRUPT_BKPT macro can be either a constant (for production
** builds) or a function call (for debugging).  If it is a function call,
** it allows the operator to set a breakpoint at the spot where database
** corruption is first detected.
*/
................................................................................
int sqlite3FixTriggerStep(DbFixer*, TriggerStep*);
int sqlite3AtoF(const char *z, double*);
char *sqlite3_snprintf(int,char*,const char*,...);
int sqlite3GetInt32(const char *, int*);
int sqlite3FitsIn64Bits(const char *);
int sqlite3Utf16ByteLen(const void *pData, int nChar);
int sqlite3Utf8CharLen(const char *pData, int nByte);
int sqlite3Utf8Read(const u8*, const u8*, const u8**);
int sqlite3PutVarint(unsigned char *, u64);
int sqlite3GetVarint(const unsigned char *, u64 *);
int sqlite3GetVarint32(const unsigned char *, u32 *);
int sqlite3VarintLen(u64 v);
void sqlite3IndexAffinityStr(Vdbe *, Index *);
void sqlite3TableAffinityStr(Vdbe *, Table *);
char sqlite3CompareAffinity(Expr *pExpr, char aff2);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used to translate between UTF-8, 
** UTF-16, UTF-16BE, and UTF-16LE.
**
** $Id: utf.c,v 1.51 2007/05/23 16:23:09 danielk1977 Exp $
**
** Notes on UTF-8:
**
**   Byte-0    Byte-1    Byte-2    Byte-3    Value
**  0xxxxxxx                                 00000000 00000000 0xxxxxxx
**  110yyyyy  10xxxxxx                       00000000 00000yyy yyxxxxxx
**  1110zzzz  10yyyyyy  10xxxxxx             00000000 zzzzyyyy yyxxxxxx
................................................................................
  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
};


#define WRITE_UTF8(zOut, c) {                          \
  if( c<0x00080 ){                                     \
    *zOut++ = (c&0xFF);                                \
  }                                                    \
  else if( c<0x00800 ){                                \
    *zOut++ = 0xC0 + ((c>>6)&0x1F);                    \
................................................................................
  if( c>=0xD800 && c<0xE000 ){                                       \
    int c2 = ((*zIn++)<<8);                                           \
    c2 += (*zIn++);                                                   \
    c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);   \
    if( (c & 0xFFFF0000)==0 ) c = 0xFFFD;                             \
  }                                                                   \
}

















































/*
** If the TRANSLATE_TRACE macro is defined, the value of each Mem is
** printed on stderr on the way into and out of sqlite3VdbeMemTranslate().
*/ 
/* #define TRANSLATE_TRACE 1 */

................................................................................
    if( !zOut ) return SQLITE_NOMEM;
  }else{
    zOut = zShort;
  }
  z = zOut;

  if( pMem->enc==SQLITE_UTF8 ){
    unsigned int iExtra = 0xD800;

    if( 0==(pMem->flags&MEM_Term) && zTerm>zIn && (zTerm[-1]&0x80) ){
      /* This UTF8 string is not nul-terminated, and the last byte is
      ** not a character in the ascii range (codpoints 0..127). This
      ** means the SQLITE_READ_UTF8() macro might read past the end
      ** of the allocated buffer.
      **
      ** There are four possibilities:
      **
      **   1. The last byte is the first byte of a non-ASCII character,
      **
      **   2. The final N bytes of the input string are continuation bytes
      **      and immediately preceding them is the first byte of a 
      **      non-ASCII character.
      **
      **   3. The final N bytes of the input string are continuation bytes
      **      and immediately preceding them is a byte that encodes a 
      **      character in the ASCII range.
      **
      **   4. The entire string consists of continuation characters.
      **
      ** Cases (3) and (4) require no special handling. The SQLITE_READ_UTF8()
      ** macro will not overread the buffer in these cases.
      */
      unsigned char *zExtra = &zTerm[-1];
      while( zExtra>zIn && (zExtra[0]&0xC0)==0x80 ){
        zExtra--;
      }

      if( (zExtra[0]&0xC0)==0xC0 ){
        /* Make a copy of the last character encoding in the input string.
        ** Then make sure it is nul-terminated and use SQLITE_READ_UTF8()
        ** to decode the codepoint. Store the codepoint in variable iExtra,
        ** it will be appended to the output string later.
        */
        unsigned char *zFree = 0;
        unsigned char zBuf[16];
        int nExtra = (pMem->n+zIn-zExtra);
        zTerm = zExtra;
        if( nExtra>15 ){
          zExtra = sqliteMallocRaw(nExtra+1);
          if( !zExtra ){
            return SQLITE_NOMEM;
          }
          zFree = zExtra;
        }else{
          zExtra = zBuf;
        }
        memcpy(zExtra, zTerm, nExtra);
        zExtra[nExtra] = '\0';
        SQLITE_READ_UTF8(zExtra, iExtra);
        sqliteFree(zFree);
      }
    }

    if( desiredEnc==SQLITE_UTF16LE ){
      /* UTF-8 -> UTF-16 Little-endian */
      while( zIn<zTerm ){
        SQLITE_READ_UTF8(zIn, c); 

        WRITE_UTF16LE(z, c);
      }
      if( iExtra!=0xD800 ){
        WRITE_UTF16LE(z, iExtra);
      }
    }else{
      assert( desiredEnc==SQLITE_UTF16BE );
      /* UTF-8 -> UTF-16 Big-endian */
      while( zIn<zTerm ){
        SQLITE_READ_UTF8(zIn, c); 
        WRITE_UTF16BE(z, c);
      }
      if( iExtra!=0xD800 ){
        WRITE_UTF16BE(z, iExtra);
      }
    }
    pMem->n = z - zOut;
    *z++ = 0;
  }else{
    assert( desiredEnc==SQLITE_UTF8 );
    if( pMem->enc==SQLITE_UTF16LE ){
      /* UTF-16 Little-endian -> UTF-8 */
................................................................................
**
** The translation is done in-place (since it is impossible for the
** correct UTF-8 encoding to be longer than a malformed encoding).
*/
int sqlite3Utf8To8(unsigned char *zIn){
  unsigned char *zOut = zIn;
  unsigned char *zStart = zIn;

  int c;

  while(1){
    SQLITE_READ_UTF8(zIn, c);
    if( c==0 ) break;
    if( c!=0xfffd ){
      WRITE_UTF8(zOut, c);
    }
  }
  *zOut = 0;
  return zOut - zStart;
}
................................................................................
** It checks that the primitives for serializing and deserializing
** characters in each encoding are inverses of each other.
*/
void sqlite3UtfSelfTest(){
  unsigned int i, t;
  unsigned char zBuf[20];
  unsigned char *z;

  int n;
  unsigned int c;

  for(i=0; i<0x00110000; i++){
    z = zBuf;
    WRITE_UTF8(z, i);
    n = z-zBuf;
    z[0] = 0;

    z = zBuf;
    SQLITE_READ_UTF8(z, c);

    t = i;
    if( i>=0xD800 && i<=0xDFFF ) t = 0xFFFD;
    if( (i&0xFFFFFFFE)==0xFFFE ) t = 0xFFFD;
    assert( c==t );
    assert( (z-zBuf)==n );
  }
  for(i=0; i<0x00110000; i++){

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used to translate between UTF-8, 
** UTF-16, UTF-16BE, and UTF-16LE.
**
** $Id: utf.c,v 1.52 2007/07/23 19:12:42 drh Exp $
**
** Notes on UTF-8:
**
**   Byte-0    Byte-1    Byte-2    Byte-3    Value
**  0xxxxxxx                                 00000000 00000000 0xxxxxxx
**  110yyyyy  10xxxxxx                       00000000 00000yyy yyxxxxxx
**  1110zzzz  10yyyyyy  10xxxxxx             00000000 zzzzyyyy yyxxxxxx
................................................................................
  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
};


#define WRITE_UTF8(zOut, c) {                          \
  if( c<0x00080 ){                                     \
    *zOut++ = (c&0xFF);                                \
  }                                                    \
  else if( c<0x00800 ){                                \
    *zOut++ = 0xC0 + ((c>>6)&0x1F);                    \
................................................................................
  if( c>=0xD800 && c<0xE000 ){                                       \
    int c2 = ((*zIn++)<<8);                                           \
    c2 += (*zIn++);                                                   \
    c = (c2&0x03FF) + ((c&0x003F)<<10) + (((c&0x03C0)+0x0040)<<10);   \
    if( (c & 0xFFFF0000)==0 ) c = 0xFFFD;                             \
  }                                                                   \
}

/*
** Translate a single UTF-8 character.  Return the unicode value.
**
** During translation, assume that the byte that zTerm points
** is a 0x00.
**
** Write a pointer to the next unread byte back into *pzNext.
**
** Notes On Invalid UTF-8:
**
**  *  This routine never allows a 7-bit character (0x00 through 0x7f) to
**     be encoded as a multi-byte character.  Any multi-byte character that
**     attempts to encode a value between 0x00 and 0x7f is rendered as 0xfffd.
**
**  *  This routine never allows a UTF16 surrogate value to be encoded.
**     If a multi-byte character attempts to encode a value between
**     0xd800 and 0xe000 then it is rendered as 0xfffd.
**
**  *  Bytes in the range of 0x80 through 0xbf which occur as the first
**     byte of a character are interpreted as single-byte characters
**     and rendered as themselves even though they are technically
**     invalid characters.
**
**  *  This routine accepts an infinite number of different UTF8 encodings
**     for unicode values 0x80 and greater.  It do not change over-length
**     encodings to 0xfffd as some systems recommend.
*/
int sqlite3Utf8Read(
  const unsigned char *z,         /* First byte of UTF-8 character */
  const unsigned char *zTerm,     /* Pretend this byte is 0x00 */
  const unsigned char **pzNext    /* Write first byte past UTF-8 char here */
){
  int c = *(z++);
  if( c>=0xc0 ){
    c = sqlite3UtfTrans1[c-0xc0];
    while( z!=zTerm && (*z & 0xc0)==0x80 ){
      c = (c<<6) + (0x3f & *(z++));
    }
    if( c<0x80
        || (c&0xFFFFF800)==0xD800
        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }
  }
  *pzNext = z;
  return c;
}



/*
** If the TRANSLATE_TRACE macro is defined, the value of each Mem is
** printed on stderr on the way into and out of sqlite3VdbeMemTranslate().
*/ 
/* #define TRANSLATE_TRACE 1 */

................................................................................
    if( !zOut ) return SQLITE_NOMEM;
  }else{
    zOut = zShort;
  }
  z = zOut;

  if( pMem->enc==SQLITE_UTF8 ){
























































    if( desiredEnc==SQLITE_UTF16LE ){
      /* UTF-8 -> UTF-16 Little-endian */
      while( zIn<zTerm ){

        c = sqlite3Utf8Read(zIn, zTerm, (const u8**)&zIn);
        WRITE_UTF16LE(z, c);
      }



    }else{
      assert( desiredEnc==SQLITE_UTF16BE );
      /* UTF-8 -> UTF-16 Big-endian */
      while( zIn<zTerm ){
        c = sqlite3Utf8Read(zIn, zTerm, (const u8**)&zIn);
        WRITE_UTF16BE(z, c);
      }



    }
    pMem->n = z - zOut;
    *z++ = 0;
  }else{
    assert( desiredEnc==SQLITE_UTF8 );
    if( pMem->enc==SQLITE_UTF16LE ){
      /* UTF-16 Little-endian -> UTF-8 */
................................................................................
**
** The translation is done in-place (since it is impossible for the
** correct UTF-8 encoding to be longer than a malformed encoding).
*/
int sqlite3Utf8To8(unsigned char *zIn){
  unsigned char *zOut = zIn;
  unsigned char *zStart = zIn;
  unsigned char *zTerm;
  u32 c;

  while( zIn[0] ){

    c = sqlite3Utf8Read(zIn, zTerm, (const u8**)&zIn);
    if( c!=0xfffd ){
      WRITE_UTF8(zOut, c);
    }
  }
  *zOut = 0;
  return zOut - zStart;
}
................................................................................
** It checks that the primitives for serializing and deserializing
** characters in each encoding are inverses of each other.
*/
void sqlite3UtfSelfTest(){
  unsigned int i, t;
  unsigned char zBuf[20];
  unsigned char *z;
  unsigned char *zTerm;
  int n;
  unsigned int c;

  for(i=0; i<0x00110000; i++){
    z = zBuf;
    WRITE_UTF8(z, i);
    n = z-zBuf;
    z[0] = 0;
    zTerm = z;
    z = zBuf;

    c = sqlite3Utf8Read(z, zTerm, (const u8**)&z);
    t = i;
    if( i>=0xD800 && i<=0xDFFF ) t = 0xFFFD;
    if( (i&0xFFFFFFFE)==0xFFFE ) t = 0xFFFD;
    assert( c==t );
    assert( (z-zBuf)==n );
  }
  for(i=0; i<0x00110000; i++){