swq.c

在linux环境下

/******************************************************************************
 *
 * Component: OGDI Driver Support Library
 * Purpose: Generic SQL WHERE Expression Implementation.
 * Author: Frank Warmerdam <[e-mail]>
 * 
 ******************************************************************************
 * Copyright (C) 2001 Information Interoperability Institute (3i)
 *
 * Permission to use, copy, modify and distribute this software and
 * its documentation for any purpose and without fee is hereby granted,
 * provided that the above copyright notice appear in all copies, that
 * both the copyright notice and this permission notice appear in
 * supporting documentation, and that the name of 3i not be used 
 * in advertising or publicity pertaining to distribution of the software 
 * without specific, written prior permission.  3i makes no
 * representations about the suitability of this software for any purpose.
 * It is provided "as is" without express or implied warranty.
 ******************************************************************************
 *
 * $Log: swq.c,v $
 * Revision 1.22  2003/05/21 04:49:17  warmerda
 * avoid warnings
 *
 * Revision 1.21  2003/03/26 16:08:20  warmerda
 * fixed table_def parsing when table name is quoted (literal)
 *
 * Revision 1.20  2003/03/21 03:39:10  warmerda
 * allow more than one LEFT JOIN per SELECT
 *
 * Revision 1.19  2003/03/19 20:26:33  warmerda
 * fixed memory leak for join info
 *
 * Revision 1.18  2003/03/19 05:12:08  warmerda
 * support table.* wildcard expansion
 *
 * Revision 1.17  2003/03/05 05:08:29  warmerda
 * added preliminary support for joins
 *
 * Revision 1.16  2003/01/10 15:35:24  warmerda
 * fixed and tested support for single quoted strings
 *
 * Revision 1.15  2002/08/08 13:41:36  warmerda
 * added support for single quoted string constants
 *
 * Revision 1.14  2002/04/30 18:19:01  warmerda
 * eat newlines as whitespace
 *
 * Revision 1.13  2002/04/29 19:32:34  warmerda
 * added swq_select_parse, fix problem with where parsing and sorting code
 *
 * Revision 1.12  2002/04/25 20:57:35  warmerda
 * expand tabs
 *
 * Revision 1.11  2002/04/25 20:45:57  warmerda
 * fixed some bugs with WHERE processing
 *
 * Revision 1.10  2002/04/25 19:33:23  warmerda
 * avoid warning
 *
 * Revision 1.9  2002/04/25 19:32:06  warmerda
 * added swq_select_reform_command
 *
 * Revision 1.8  2002/04/25 16:06:57  warmerda
 * added more general distinct support
 *
 * Revision 1.7  2002/04/25 02:23:43  warmerda
 * fixed support for ORDER BY <field> ASC
 *
 * Revision 1.6  2002/04/23 20:05:23  warmerda
 * added SELECT statement parsing
 *
 * Revision 1.5  2002/04/19 20:46:06  warmerda
 * added [NOT] IN, [NOT] LIKE and IS [NOT] NULL support
 *
 * Revision 1.4  2002/03/01 04:13:40  warmerda
 * Made swq_error static.
 *
 * Revision 1.3  2001/11/07 12:45:42  danmo
 * Use #ifdef _WIN32 instead of WIN32 for strcasecmp check
 *
 * Revision 1.2  2001/06/26 00:59:39  warmerda
 * fixed strcasecmp on WIN32
 *
 * Revision 1.1  2001/06/19 15:46:30  warmerda
 * New
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "swq.h"

#ifndef SWQ_MALLOC
#define SWQ_MALLOC(x) malloc(x)
#define SWQ_FREE(x) free(x)
#endif

#ifndef TRUE
#  define TRUE 1
#endif

#ifndef FALSE
#  define FALSE 0
#endif

#ifdef _WIN32
#  define strcasecmp stricmp
#endif

static char     swq_error[1024];

#define SWQ_OP_IS_LOGICAL(op) ((op) == SWQ_OR || (op) == SWQ_AND || (op) == SWQ_NOT)
#define SWQ_OP_IS_POSTUNARY(op) ((op) == SWQ_ISNULL || (op) == SWQ_ISNOTNULL)

/************************************************************************/
/*                              swq_free()                              */
/************************************************************************/

void swq_free( void *pMemory )

{
    SWQ_FREE( pMemory );
}

/************************************************************************/
/*                             swq_malloc()                             */
/************************************************************************/

void *swq_malloc( int nSize )

{
    return SWQ_MALLOC(nSize);
}

/************************************************************************/
/*                            swq_realloc()                             */
/************************************************************************/

void *swq_realloc( void *old_mem, int old_size, int new_size )

{
    void *new_mem;

    new_mem = swq_malloc( new_size );

    if( old_mem != NULL )
    {
        memcpy( new_mem, old_mem, old_size );
        SWQ_FREE( old_mem );
    }

    memset( ((char *) new_mem) + old_size, 0, new_size - old_size );

    return new_mem;
}


/************************************************************************/
/*                           swq_isalphanum()                           */
/*                                                                      */
/*      Is the passed character in the set of things that could         */
/*      occur in an alphanumeric token, or a number?                    */
/************************************************************************/

static int swq_isalphanum( char c )

{

    if( (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')
        || (c >= '0' && c <= '9') || c == '.' || c == '+' || c == '-'
        || c == '_' || c == '*' )
        return TRUE;
    else
        return FALSE;
}

/************************************************************************/
/*                             swq_token()                              */
/************************************************************************/

static char *swq_token( const char *expression, char **next, int *is_literal )

{
    char        *token;
    int         i_token;

    if( is_literal != NULL )
        *is_literal = 0;

    while( *expression == ' ' || *expression == '\t'
           || *expression == 10 || *expression == 13 )
        expression++;

    if( *expression == '\0' )
    {
        *next = (char *) expression;
        return NULL; 
    }

/* -------------------------------------------------------------------- */
/*      Handle string constants.                                        */
/* -------------------------------------------------------------------- */
    if( *expression == '"' || *expression == '\'' )
    {
        expression++;

        token = (char *) SWQ_MALLOC(strlen(expression)+1);
        i_token = 0;

        while( *expression != '\0' )
        {
            if( *expression == '\\' && expression[1] == '"' )
                expression++;
            else if( *expression == '\\' && expression[1] == '\'' )
                expression++;
            else if( *expression == '"' )
            {
                expression++;
                break;
            }
            else if( *expression == '\'' )
            {
                expression++;
                break;
            }
            
            token[i_token++] = *(expression++);
        }
        token[i_token] = '\0';

        if( is_literal != NULL )
            *is_literal = 1;
    }

/* -------------------------------------------------------------------- */
/*      Handle alpha-numerics.                                          */
/* -------------------------------------------------------------------- */
    else if( swq_isalphanum( *expression ) )
    {
        token = (char *) SWQ_MALLOC(strlen(expression)+1);
        i_token = 0;

        while( swq_isalphanum( *expression ) )
        {
            token[i_token++] = *(expression++);
        }

        token[i_token] = '\0';
    }

/* -------------------------------------------------------------------- */
/*      Handle special tokens.                                          */
/* -------------------------------------------------------------------- */
    else
    {
        token = (char *) SWQ_MALLOC(3);
        token[0] = *expression;
        token[1] = '\0';
        expression++;

        /* special logic to group stuff like '>=' into one token. */

        if( (*token == '<' || *token == '>' || *token == '=' || *token == '!')
           && (*expression == '<' || *expression == '>' || *expression == '='))
        {
            token[1] = *expression;
            token[2] = '\0';
            expression++;
        }
    }

    *next = (char *) expression;

    return token;
}

/************************************************************************/
/*                             swq_strdup()                             */
/************************************************************************/

static char *swq_strdup( const char *input )

{
    char *result;

    result = (char *) SWQ_MALLOC(strlen(input)+1);
    strcpy( result, input );

    return result;
}

/************************************************************************/
/* ==================================================================== */
/*              WHERE clause parsing                                    */
/* ==================================================================== */
/************************************************************************/

/************************************************************************/
/*                           swq_test_like()                            */
/*                                                                      */
/*      Does input match pattern?                                       */
/************************************************************************/

int swq_test_like( const char *input, const char *pattern )

{
    if( input == NULL || pattern == NULL )
        return 0;

    while( *input != '\0' )
    {
        if( *pattern == '\0' )
            return 0;

        else if( *pattern == '_' )
        {
            input++;
            pattern++;
        }
        else if( *pattern == '%' )
        {
            int   eat;

            if( pattern[1] == '\0' )
                return 1;

            /* try eating varying amounts of the input till we get a positive*/
            for( eat = 0; input[eat] != '\0'; eat++ )
            {
                if( swq_test_like(input+eat,pattern+1) )
                    return 1;
            }

            return 0;
        }
        else
        {
            if( tolower(*pattern) != tolower(*input) )
                return 0;
            else
            {
                input++;
                pattern++;
            }
        }
    }

    if( *pattern != '\0' && strcmp(pattern,"%") != 0 )
        return 0;
    else
        return 1;
}

/************************************************************************/
/*                          swq_identify_op()                           */
/************************************************************************/

static swq_op swq_identify_op( char **tokens, int *tokens_consumed )

{
    const char *token = tokens[*tokens_consumed];

    if( strcasecmp(token,"OR") == 0 )
        return SWQ_OR;
    
    if( strcasecmp(token,"AND") == 0 )
        return SWQ_AND;
    
    if( strcasecmp(token,"NOT") == 0 )
    {
        if( tokens[*tokens_consumed+1] != NULL
            && strcasecmp(tokens[*tokens_consumed+1],"LIKE") == 0 )
        {
            *tokens_consumed += 1;
            return SWQ_NOTLIKE;
        }
        else if( tokens[*tokens_consumed+1] != NULL
            && strcasecmp(tokens[*tokens_consumed+1],"IN") == 0 )
        {
            *tokens_consumed += 1;
            return SWQ_NOTIN;
        }
        else
            return SWQ_NOT;
    }
    
    if( strcasecmp(token,"<=") == 0 )
        return SWQ_LE;

    if( strcasecmp(token,">=") == 0 )
        return SWQ_GE;
    
    if( strcasecmp(token,"=") == 0 )
        return SWQ_EQ;