/*

** 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.

**

*************************************************************************

** An tokenizer for SQL

**

** This file contains C code that implements the sqlite3_complete() API.

** This code used to be part of the tokenizer.c source file.  But by

** separating it out, the code will be automatically omitted from

** static links that do not use it.

**

** $Id$

*/

#include "sqliteInt.h"

#ifndef SQLITE_OMIT_COMPLETE

/*

** This is defined in tokenize.c.  We just have to import the definition.

*/

#ifndef SQLITE_AMALGAMATION

#ifdef SQLITE_ASCII

extern const char sqlite3IsAsciiIdChar[];

#define IdChar(C)  (((c=C)&0x80)!=0 || (c>0x1f && sqlite3IsAsciiIdChar[c-0x20]))

#endif

#ifdef SQLITE_EBCDIC

extern const char sqlite3IsEbcdicIdChar[];

#define IdChar(C)  (((c=C)>=0x42 && sqlite3IsEbcdicIdChar[c-0x40]))

#endif

#endif /* SQLITE_AMALGAMATION */

/*

** Token types used by the sqlite3_complete() routine.  See the header

** comments on that procedure for additional information.

*/

#define tkSEMI    0

#define tkWS      1

#define tkOTHER   2

#define tkEXPLAIN 3

#define tkCREATE  4

#define tkTEMP    5

#define tkTRIGGER 6

#define tkEND     7

/*

** Return TRUE if the given SQL string ends in a semicolon.

**

** Special handling is require for CREATE TRIGGER statements.

** Whenever the CREATE TRIGGER keywords are seen, the statement

** must end with ";END;".

**

** This implementation uses a state machine with 7 states:

**

**   (0) START     At the beginning or end of an SQL statement.  This routine

**                 returns 1 if it ends in the START state and 0 if it ends

**                 in any other state.

**

**   (1) NORMAL    We are in the middle of statement which ends with a single

**                 semicolon.

**

**   (2) EXPLAIN   The keyword EXPLAIN has been seen at the beginning of 

**                 a statement.

**

**   (3) CREATE    The keyword CREATE has been seen at the beginning of a

**                 statement, possibly preceeded by EXPLAIN and/or followed by

**                 TEMP or TEMPORARY

**

**   (4) TRIGGER   We are in the middle of a trigger definition that must be

**                 ended by a semicolon, the keyword END, and another semicolon.

**

**   (5) SEMI      We've seen the first semicolon in the ";END;" that occurs at

**                 the end of a trigger definition.

**

**   (6) END       We've seen the ";END" of the ";END;" that occurs at the end

**                 of a trigger difinition.

**

** Transitions between states above are determined by tokens extracted

** from the input.  The following tokens are significant:

**

**   (0) tkSEMI      A semicolon.

**   (1) tkWS        Whitespace

**   (2) tkOTHER     Any other SQL token.

**   (3) tkEXPLAIN   The "explain" keyword.

**   (4) tkCREATE    The "create" keyword.

**   (5) tkTEMP      The "temp" or "temporary" keyword.

**   (6) tkTRIGGER   The "trigger" keyword.

**   (7) tkEND       The "end" keyword.

**

** Whitespace never causes a state transition and is always ignored.

**

** If we compile with SQLITE_OMIT_TRIGGER, all of the computation needed

** to recognize the end of a trigger can be omitted.  All we have to do

** is look for a semicolon that is not part of an string or comment.

*/

int sqlite3_complete(const char *zSql){

  u8 state = 0;   /* Current state, using numbers defined in header comment */

  u8 token;       /* Value of the next token */

#ifndef SQLITE_OMIT_TRIGGER

  /* A complex statement machine used to detect the end of a CREATE TRIGGER

  ** statement.  This is the normal case.

  */

  static const u8 trans[7][8] = {

                     /* Token:                                                */

     /* State:       **  SEMI  WS  OTHER EXPLAIN  CREATE  TEMP  TRIGGER  END  */

     /* 0   START: */ {    0,  0,     1,      2,      3,    1,       1,   1,  },

     /* 1  NORMAL: */ {    0,  1,     1,      1,      1,    1,       1,   1,  },

     /* 2 EXPLAIN: */ {    0,  2,     1,      1,      3,    1,       1,   1,  },

     /* 3  CREATE: */ {    0,  3,     1,      1,      1,    3,       4,   1,  },

     /* 4 TRIGGER: */ {    5,  4,     4,      4,      4,    4,       4,   4,  },

     /* 5    SEMI: */ {    5,  5,     4,      4,      4,    4,       4,   6,  },

     /* 6     END: */ {    0,  6,     4,      4,      4,    4,       4,   4,  },

  };

#else

  /* If triggers are not suppored by this compile then the statement machine

  ** used to detect the end of a statement is much simplier

  */

  static const u8 trans[2][3] = {

                     /* Token:           */

     /* State:       **  SEMI  WS  OTHER */

     /* 0   START: */ {    0,  0,     1, },

     /* 1  NORMAL: */ {    0,  1,     1, },

  };

#endif /* SQLITE_OMIT_TRIGGER */

  while( *zSql ){

    switch( *zSql ){

      case ';': {  /* A semicolon */

        token = tkSEMI;

        break;

      }

      case ' ':

      case '\r':

      case '\t':

      case '\n':

      case '\f': {  /* White space is ignored */

        token = tkWS;

        break;

      }

      case '/': {   /* C-style comments */

        if( zSql[1]!='*' ){

          token = tkOTHER;

          break;

        }

        zSql += 2;

        while( zSql[0] && (zSql[0]!='*' || zSql[1]!='/') ){ zSql++; }

        if( zSql[0]==0 ) return 0;

        zSql++;

        token = tkWS;

        break;

      }

      case '-': {   /* SQL-style comments from "--" to end of line */

        if( zSql[1]!='-' ){

          token = tkOTHER;

          break;

        }

        while( *zSql && *zSql!='\n' ){ zSql++; }

        if( *zSql==0 ) return state==0;

        token = tkWS;

        break;

      }

      case '[': {   /* Microsoft-style identifiers in [...] */

        zSql++;

        while( *zSql && *zSql!=']' ){ zSql++; }

        if( *zSql==0 ) return 0;

        token = tkOTHER;

        break;

      }

      case '`':     /* Grave-accent quoted symbols used by MySQL */

      case '"':     /* single- and double-quoted strings */

      case '\'': {

        int c = *zSql;

        zSql++;

        while( *zSql && *zSql!=c ){ zSql++; }

        if( *zSql==0 ) return 0;

        token = tkOTHER;

        break;

      }

      default: {

        int c;

        if( IdChar((u8)*zSql) ){

          /* Keywords and unquoted identifiers */

          int nId;

          for(nId=1; IdChar(zSql[nId]); nId++){}

#ifdef SQLITE_OMIT_TRIGGER

          token = tkOTHER;

#else

          switch( *zSql ){

            case 'c': case 'C': {

              if( nId==6 && sqlite3StrNICmp(zSql, "create", 6)==0 ){

                token = tkCREATE;

              }else{

                token = tkOTHER;

              }

              break;

            }

            case 't': case 'T': {

              if( nId==7 && sqlite3StrNICmp(zSql, "trigger", 7)==0 ){

                token = tkTRIGGER;

              }else if( nId==4 && sqlite3StrNICmp(zSql, "temp", 4)==0 ){

                token = tkTEMP;

              }else if( nId==9 && sqlite3StrNICmp(zSql, "temporary", 9)==0 ){

                token = tkTEMP;

              }else{

                token = tkOTHER;

              }

              break;

            }

            case 'e':  case 'E': {

              if( nId==3 && sqlite3StrNICmp(zSql, "end", 3)==0 ){

                token = tkEND;

              }else

#ifndef SQLITE_OMIT_EXPLAIN

              if( nId==7 && sqlite3StrNICmp(zSql, "explain", 7)==0 ){

                token = tkEXPLAIN;

              }else

#endif

              {

                token = tkOTHER;

              }

              break;

            }

            default: {

              token = tkOTHER;

              break;

            }

          }

#endif /* SQLITE_OMIT_TRIGGER */

          zSql += nId-1;

        }else{

          /* Operators and special symbols */

          token = tkOTHER;

        }

        break;

      }

    }

    state = trans[state][token];

    zSql++;

  }

  return state==0;

}

#ifndef SQLITE_OMIT_UTF16

/*

** This routine is the same as the sqlite3_complete() routine described

** above, except that the parameter is required to be UTF-16 encoded, not

** UTF-8.

*/

int sqlite3_complete16(const void *zSql){

  sqlite3_value *pVal;

  char const *zSql8;

  int rc = SQLITE_NOMEM;

  pVal = sqlite3ValueNew(0);

  sqlite3ValueSetStr(pVal, -1, zSql, SQLITE_UTF16NATIVE, SQLITE_STATIC);

  zSql8 = sqlite3ValueText(pVal, SQLITE_UTF8);

  if( zSql8 ){

    rc = sqlite3_complete(zSql8);

  }

  sqlite3ValueFree(pVal);

  return sqlite3ApiExit(0, rc);

}

#endif /* SQLITE_OMIT_UTF16 */

#endif /* SQLITE_OMIT_COMPLETE */