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rockbox/apps/plugins/searchengine/parser.c
Michiel Van Der Kolk f5eae08361 Starts with and ends with support (for strings), as requested. 
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@6454 a1c6a512-1295-4272-9138-f99709370657
2005-05-10 23:44:22 +00:00

293 lines
8.8 KiB
C
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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2005 by Michiel van der Kolk
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "searchengine.h"
#include "token.h"
#include "dbinterface.h"
#include "parser.h"
struct token *currentToken, curtoken;
unsigned char *filter[20],*nofilter=0;
int currentlevel=0;
int syntaxerror;
int parse_fd;
char errormsg[250];
unsigned char *parse(int fd) {
unsigned char *ret=0;
int i;
syntaxerror=0;
parse_fd=fd;
currentlevel=0;
if(nofilter==0) {
nofilter=my_malloc(sizeof(unsigned char)*rb->tagdbheader->filecount);
rb->memset(nofilter,1,rb->tagdbheader->filecount);
}
for(i=0;i<20;i++)
filter[i]=nofilter;
database_init();
parser_acceptIt();
currentToken=&curtoken;
PUTS("parse");
ret=parseMExpr();
if(syntaxerror) {
PUTS("Syntaxerror");
rb->splash(HZ*3,true,errormsg);
}
parser_accept(TOKEN_EOF);
return ret;
}
void parser_acceptIt(void) {
if(syntaxerror) return;
rb->read(parse_fd,&curtoken,sizeof(struct token));
}
int parser_accept(unsigned char kind) {
if(currentToken->kind!=kind) {
syntaxerror=1;
rb->snprintf(errormsg,250,"'%d' found where '%d' expected\n",currentToken->kind,kind);
return 0;
}
else {
parser_acceptIt();
return 1;
}
}
unsigned char *parseCompareNum() {
struct token number1,number2;
unsigned char *ret;
int i,n1=-1,n2=-1;
int op;
if(syntaxerror) return 0;
PUTS("parseCompareNum");
if(currentToken->kind==TOKEN_NUM ||
currentToken->kind==TOKEN_NUMIDENTIFIER) {
rb->memcpy(&number1,currentToken,sizeof(struct token));
parser_acceptIt();
}
else {
syntaxerror=1;
rb->snprintf(errormsg,250,"'%d' found where NUM/NUMID expected\n",currentToken->kind);
return 0;
}
if(currentToken->kind>=TOKEN_GT && currentToken->kind <= TOKEN_NE) {
op=currentToken->kind;
parser_acceptIt();
}
else {
syntaxerror=1;
rb->snprintf(errormsg,250,"'%d' found where NUMOP expected\n",currentToken->kind);
return 0;
}
if(currentToken->kind==TOKEN_NUM ||
currentToken->kind==TOKEN_NUMIDENTIFIER) {
rb->memcpy(&number2,currentToken,sizeof(struct token));
parser_acceptIt();
}
else {
syntaxerror=1;
rb->snprintf(errormsg,250,"'%d' found where NUM/NUMID expected\n",currentToken->kind);
return 0;
}
ret=my_malloc(sizeof(unsigned char)*rb->tagdbheader->filecount);
if(number1.kind==TOKEN_NUM)
n1=getvalue(&number1);
if(number2.kind==TOKEN_NUM)
n2=getvalue(&number2);
for(i=0;i<rb->tagdbheader->filecount;i++)
if(filter[currentlevel][i]) {
loadentry(i);
if(number1.kind==TOKEN_NUMIDENTIFIER)
n1=getvalue(&number1);
if(number2.kind==TOKEN_NUMIDENTIFIER)
n2=getvalue(&number2);
switch(op) {
case TOKEN_GT:
ret[i]=n1 > n2;
break;
case TOKEN_GTE:
ret[i]=n1 >= n2;
break;
case TOKEN_LT:
ret[i]=n1 < n2;
break;
case TOKEN_LTE:
ret[i]=n1 <= n2;
break;
case TOKEN_EQ:
ret[i]=n1 == n2;
break;
case TOKEN_NE:
ret[i]=n1 != n2;
break;
}
}
return ret;
}
unsigned char *parseCompareString() {
struct token string1,string2;
unsigned char *ret;
char *s1=NULL,*s2=NULL;
int i,i2;
int op;
if(syntaxerror) return 0;
PUTS("parseCompareString");
if(currentToken->kind==TOKEN_STRING ||
currentToken->kind==TOKEN_STRINGIDENTIFIER) {
rb->memcpy(&string1,currentToken,sizeof(struct token));
parser_acceptIt();
}
else {
syntaxerror=1;
rb->snprintf(errormsg,250,"'%d' found where STRING/STRINGID expected\n",currentToken->kind);
return 0;
}
op=currentToken->kind;
if(op>=TOKEN_CONTAINS&&op<=TOKEN_ENDSWITH) {
parser_acceptIt();
} else {
syntaxerror=1;
rb->snprintf(errormsg,250,"'%d' found where STROP expected\n",op);
return 0;
}
if(currentToken->kind==TOKEN_STRING ||
currentToken->kind==TOKEN_STRINGIDENTIFIER) {
rb->memcpy(&string2,currentToken,sizeof(struct token));
parser_acceptIt();
}
else {
syntaxerror=1;
rb->snprintf(errormsg,250,"'%d' found where STRING/STRINGID expected\n",currentToken->kind);
return 0;
}
ret=my_malloc(sizeof(unsigned char)*rb->tagdbheader->filecount);
if(string1.kind==TOKEN_STRING)
s1=getstring(&string1);
if(string2.kind==TOKEN_STRING)
s2=getstring(&string2);
for(i=0;i<rb->tagdbheader->filecount;i++)
if(filter[currentlevel][i]) {
loadentry(i);
if(string1.kind==TOKEN_STRINGIDENTIFIER)
s1=getstring(&string1);
if(string2.kind==TOKEN_STRINGIDENTIFIER)
s2=getstring(&string2);
switch(op) {
case TOKEN_CONTAINS:
ret[i]=rb->strcasestr(s1,s2)!=0;
break;
case TOKEN_EQUALS:
ret[i]=rb->strcasecmp(s1,s2)==0;
break;
case TOKEN_STARTSWITH:
ret[i]=rb->strncasecmp(s1,s2,rb->strlen(s2))==0;
break;
case TOKEN_ENDSWITH:
i2=rb->strlen(s2);
ret[i]=rb->strncasecmp(s1+rb->strlen(s1)-i2,s2,i2)==0;
break;
}
}
return ret;
}
unsigned char *parseExpr() {
unsigned char *ret;
int i;
if(syntaxerror) return 0;
PUTS("parseExpr");
switch(currentToken->kind) {
case TOKEN_NOT:
parser_accept(TOKEN_NOT);
PUTS("parseNot");
ret = parseExpr();
if(ret==NULL) return 0;
for(i=0;i<rb->tagdbheader->filecount;i++)
if(filter[currentlevel][i])
ret[i]=!ret[i];
break;
case TOKEN_LPAREN:
parser_accept(TOKEN_LPAREN);
currentlevel++;
ret = parseMExpr();
currentlevel--;
if(ret==NULL) return 0;
parser_accept(TOKEN_RPAREN);
break;
case TOKEN_NUM:
case TOKEN_NUMIDENTIFIER:
ret = parseCompareNum();
if(ret==NULL) return 0;
break;
case TOKEN_STRING:
case TOKEN_STRINGIDENTIFIER:
ret = parseCompareString();
if(ret==NULL) return 0;
break;
default:
// error, unexpected symbol
syntaxerror=1;
rb->snprintf(errormsg,250,"unexpected '%d' found at parseExpr\n",currentToken->kind);
ret=0;
break;
}
return ret;
}
unsigned char *parseMExpr() {
unsigned char *ret,*ret2;
int i;
if(syntaxerror) return 0;
PUTS("parseMExpr");
ret=parseLExpr();
while(currentToken->kind==TOKEN_OR) {
parser_accept(TOKEN_OR);
PUTS("parseOr");
ret2 = parseLExpr();
if(ret2==NULL) return 0;
for(i=0;i<rb->tagdbheader->filecount;i++)
if(filter[currentlevel][i]) // this should always be true
ret[i]=ret[i] || ret2[i];
else
rb->splash(HZ*2,true,"An or is having a filter, bad.");
}
return ret;
}
unsigned char *parseLExpr() {
unsigned char *ret,*ret2;
int i;
if(syntaxerror) return 0;
PUTS("parseLExpr");
filter[currentlevel]=nofilter;
ret=parseExpr();
filter[currentlevel]=ret;
while(currentToken->kind==TOKEN_AND) {
parser_accept(TOKEN_AND);
PUTS("parseAnd");
ret2 = parseExpr();
if(ret2==NULL) return 0;
for(i=0;i<rb->tagdbheader->filecount;i++)
ret[i]=ret[i] && ret2[i];
}
filter[currentlevel]=nofilter;
return ret;
}
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