/* File: index.c Author: Neil Cafferkey Copyright (C) 2000 Neil Cafferkey This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "viewer.h" #include #include #include #include #include "index_protos.h" #include "index_record_protos.h" #include "general_protos.h" #include const TEXT FIRST_REC_STRING[]="%FIRST-REC%"; #define FIRST_REC_SIZE 11 static UBYTE *DataSearch(ULONG length_1,ULONG length_2,UBYTE *buf_1, UBYTE *buf_2); static BOOL DataEqual(ULONG length,UBYTE *buf_1,UBYTE *buf_2); /* Function: CreateIndex * ===================== * Creates an Index. */ Index CreateIndex(TEXT *master_file_name,TEXT *index_file_name) { Index index; struct FileInfoBlock *temp_fib; BPTR master_file; if((index=(Index)AllocMem(sizeof(Index_imp),MEMF_CLEAR))!=NULL) { /* Open the main index file */ if(!(index->index_file=Open(index_file_name,MODE_OLDFILE))) ReportError(NULL,ERROR_REPORT_FILE,index_file_name,0); /* Open the master index file */ master_file=Open(master_file_name,MODE_OLDFILE); /* Copy master index file into memory */ if(master_file) { if((temp_fib=(struct FileInfoBlock *)AllocDosObjectTags( DOS_FIB,TAG_END))!=NULL) { /* Get master file size */ ExamineFH(master_file,temp_fib); index->block_count=temp_fib->fib_Size/MASTER_REF_SIZE; FreeDosObject(DOS_FIB,temp_fib); /* Allocate memory for master file data */ index->master_index=(UBYTE *)AllocMem(index->block_count *MASTER_REF_SIZE,MEMF_ANY); /* Read link data into memory */ if(index->master_index!=NULL) Read(master_file,index->master_index,index->block_count *MASTER_REF_SIZE); else { ReportError(NULL,ERROR_REPORT_MEM,NULL,0); } } else { ReportError(NULL,ERROR_REPORT_MEM,NULL,0); } Close(master_file); } else { ReportError(NULL,ERROR_REPORT_FILE,master_file_name,0); } /* Check if there were any errors */ if((index->index_file==NULL)||(index->master_index==NULL)) { KillIndex(index); index=NULL; } } else { ReportError(NULL,ERROR_REPORT_MEM,NULL,0); } return index; } /* Function: FindIndexRecords * ========================== * Searches for records within an index. */ struct List *FindIndexRecords(Index index,TEXT *search_string) { IndexRecord index_rec; UWORD first_block,last_block,mid; WORD low,high; UBYTE *p,*q,*index_buffer; struct List *rec_list; BOOL success=TRUE; /* Create a new list to contain the results */ rec_list=AllocMem(sizeof(struct List),MEMF_PUBLIC); if(rec_list!=NULL) { NewList(rec_list); /* Convert search string to uppercase */ for(p=search_string;*p!='\0';p++) *p=toupper(*p); /* Do a binary search to find the first block needed */ p=index->master_index; low=-1; high=index->block_count-1; while(high-low!=1) { mid=low+(high-low)/2; for(q=p+mid*MASTER_REF_SIZE;*q!=0;q-=MASTER_REF_SIZE); if(strncmp(search_string,q+1,MASTER_REF_SIZE-1)<=0) high=mid; else low=mid; } first_block=high; /* Do a binary search to find the last block needed */ low=-1; high=index->block_count-1; while(high-low!=1) { mid=low+(high-low)/2; for(q=p+mid*MASTER_REF_SIZE;*q!=0;q-=MASTER_REF_SIZE); if(strncmp(search_string,q+1,MASTER_REF_SIZE-1)<0) high=mid; else low=mid; } last_block=high; /* Allocate the index buffer */ index_buffer=AllocMem((last_block-first_block+1)*INDEX_BLOCK_SIZE, MEMF_ANY); if(index_buffer) { /* Read relevant index blocks into memory */ Seek(index->index_file,first_block*INDEX_BLOCK_SIZE, OFFSET_BEGINNING); Read(index->index_file,index_buffer,(last_block-first_block+1) *INDEX_BLOCK_SIZE); /* Find first-record marker */ p=DataSearch(FIRST_REC_SIZE,2*INDEX_BLOCK_SIZE, FIRST_REC_STRING,index_buffer); /* Find first matching record */ p+=FIRST_REC_SIZE; while(strcmp(p+10,search_string)<0) p+=GetLittleEndianUWord(p); /* Put all matching records into the list */ while(strcmp(p+10,search_string)==0) { index_rec=CreateIndexRecord(p); if(index_rec!=NULL) AddTail(rec_list,&index_rec->node); p+=GetLittleEndianUWord(p); } FreeMem(index_buffer,(last_block-first_block+1)*INDEX_BLOCK_SIZE); } else { ReportError(NULL,ERROR_REPORT_MEM,NULL,0); success=FALSE; } } else { ReportError(NULL,ERROR_REPORT_MEM,NULL,0); success=FALSE; } return rec_list; } /* Function: KillIndexResults * ========================== */ VOID KillIndexResults(struct List *list) { IndexRecord rec; while(rec=(IndexRecord)RemHead(list)) KillIndexRecord(rec); FreeMem(list,sizeof(struct List)); return; } /* Function: DataSearch * ==================== * Searches for one sequence within another sequence. */ static UBYTE *DataSearch(ULONG length_1,ULONG length_2,UBYTE *buf_1, UBYTE *buf_2) { ULONG i,last=length_2-length_1; REGISTER UBYTE first=*buf_1; BOOL equal=FALSE; for(i=0;(i<=last)&&!equal;i++) { if(first==*buf_2) equal=DataEqual(length_1,buf_1,buf_2); buf_2++; } if(i<=last) return --buf_2; return NULL; } /* Function: DataEqual * =================== * Returns TRUE if two data sequences are equal. */ static BOOL DataEqual(ULONG length,UBYTE *buf_1,UBYTE *buf_2) { ULONG i; for(i=0;(iindex_file!=NULL) Close(index->index_file); if(index->master_index!=NULL) FreeMem(index->master_index,index->block_count*MASTER_REF_SIZE); FreeMem(index,sizeof(Index_imp)); }