dictcore.c

基于东南大学开发的SEP3203的ARM7中的所有驱动

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

#include "pcdisk.h"
#include "dictcore.h"

static DICT	dic;	
static char IndexByteOrder;
static long CompareEntry(unsigned long, char *);
static long BinarySearch(unsigned long, unsigned long, long *, char *);

static unsigned int ArchSwap32(unsigned int D) 
{
    return ((D<<24)|((D<<8)&0x00FF0000)|((D>>8)&0x0000FF00)|(D>>24));
}


static unsigned short ArchSwap16(unsigned short D) 
{
    return ((D<<8)|(D>>8));
}


long InitDictCore(void)
{
    if(fpidx != DICT_CLOSED)              //字典已经打开
        return TRUE;	
    
    //第一次打开字典
    fpdic = NU_Open(DICT_FILE, PO_RDONLY, PS_IWRITE | PS_IREAD);    //打开字典库文件
    if(fpdic < DICT_CLOSED)
        return  FALSE;
            
    fpidx = NU_Open(INDEX_FILE, PO_RDONLY, PS_IWRITE | PS_IREAD);   //打开字典索引文件
    if(fpidx < DICT_CLOSED)
        return  FALSE; 
               
    if(NU_Read(fpidx, &dic.header, sizeof(DICT_HEADER)) == 0)    //读取索引文件头信息
        return  FALSE;                     
    
    
    //判断字典索引文件的字节序是否与系统匹配
    if(dic.header.symbol == BYTE_ORDER_SYM)
        IndexByteOrder = SAME_ENDIAN_ORDER;
    else if(dic.header.symbol == ArchSwap32(BYTE_ORDER_SYM))
        IndexByteOrder = DIFF_ENDIAN_ORDER;
    else  
        return FALSE;
     
    
    //不检查字典文件的字节序, 默认与字典索引文件的字节序一致
    NU_Seek(fpdic, sizeof(DICT_HEADER), SEEK_SET);
    
    
    //填充字典数据结构
    if(IndexByteOrder == DIFF_ENDIAN_ORDER)
        dic.header.num = ArchSwap32(dic.header.num);
    else
    {
        dic.open_num  = 1;
        dic.alpha_tbl = sizeof(DICT_HEADER);
        dic.entry_tbl = dic.alpha_tbl + TOP_INDEX_NUM * sizeof(ALPHABET_IDX);
    }   
    
    return TRUE;	
      	
}


long ExitDictCore(void)
{
    if(fpidx < DICT_CLOSED)              //字典文件已关闭
        return TRUE;
    
    //关闭字典文件
    NU_Close(fpidx);
    NU_Close(fpdic);

    fpidx = DICT_CLOSED;
    fpdic = DICT_CLOSED;
    
    return TRUE; 	
	
} 


//参数说明:   char*  key     待查找字符串;
//支持模糊查找;
//返回值说明: 正常情况下返回匹配的词条索引;
//            若未找到匹配词条或输入参数错误, 返回值为-1;
//功能说明:   根据输入字符串查找匹配词条;

long SearchEntry(char * buffer)
{
    long  blk_id, offset;
    long  result, index;
    char  ch; 
    ALPHABET_IDX  blk_info; 	
    
    if(fpidx < DICT_CLOSED||fpdic < DICT_CLOSED)   //字典未打开
        return -1;
        
    if(buffer == NULL)
        return -1;
        
    //分块查找二级索引, 获取分区号
    ch = tolower(buffer[0]);      //小写
    if(ch < 'a')
        blk_id = 0; 
    else if(ch > 'z')
        blk_id = TOP_INDEX_NUM - 1;        
    else     
        blk_id = ch - 'a' + 1; 
    
    //根据分区号获取分区信息
    offset = sizeof(DICT_HEADER) + blk_id * sizeof(ALPHABET_IDX);
    
    NU_Seek(fpidx, offset, SEEK_SET);
    
    NU_Read(fpidx, &blk_info, sizeof(ALPHABET_IDX)); 
    
    if(IndexByteOrder == DIFF_ENDIAN_ORDER)
    {
        blk_info.begin = ArchSwap32(blk_info.begin);
        blk_info.end   = ArchSwap32(blk_info.end);	
    }
    
    //二分法查找词条
    if(blk_info.begin != 0)     //当前分区有词条
    {
        result = BinarySearch(blk_info.begin, blk_info.end, &index, buffer);
    	
    	index = (index - dic.entry_tbl)/sizeof(ENTRY_IDX);
    	if((unsigned long)index >= dic.header.num)
    	    index = dic.header.num - 1;
    }
    else                        //当前分区无词条
    {
        NU_Seek(fpidx, offset, SEEK_SET);
        do                      //寻找以后的分区中第一个词条
        {
            NU_Read(fpidx, &blk_info, sizeof(ALPHABET_IDX));
            if(IndexByteOrder == DIFF_ENDIAN_ORDER)
                blk_info.begin = ArchSwap32(blk_info.begin);
            blk_id++;
        }while(blk_info.begin == 0 && blk_id < TOP_INDEX_NUM);
        
        if(blk_info.begin == 0)   //无词条
            index = -1;
        else
            index = (blk_info.begin - dic.entry_tbl)/sizeof(ENTRY_IDX);    	
    }
   
    return index;
     	
}


// 函数原型：
// long BinarySearch( unsigned long begin, unsigned long end, long *index, char *key )
//
// 参数说明：
// unsigned long	begin	区块在索引文件中的起始地址
// unsigned long	end	区块在索引文件中的结束地址
// unsigned long *	index	找到的匹配词条索引
// char *		key	待查找的字符串
//
// 返回值说明：
// long		字符串比较结果。
//
// 功能说明：
// 对二级索引表分区进行二分查找
static long BinarySearch(unsigned long begin, unsigned long end, long *index, char *buffer)
{
    volatile unsigned long a, b, mid;
    long result;
    
    a = begin;
    b = end;
    
    while(a < b)
    {
    	mid = (a + b) / 2;
    	mid -= (mid - dic.entry_tbl) % sizeof(ENTRY_IDX);
    	
    	result = CompareEntry(mid, buffer);
    	
    	if(result == 0)
    	{
    	    *index = (long)mid;
    	    return result;
    		
    	}
    	else if(result > 0)
    	{
    	    if(mid == end)
    	    {
    	        *index = mid + sizeof(ENTRY_IDX);
    	        return result;
    	    }	
            else
                a = mid + sizeof(ENTRY_IDX);		
        }
        else
        {
            if(mid == begin)
            {
                *index = mid;
                return result;	
            }
            else
                b = mid - sizeof(ENTRY_IDX);	
        }	
    }
	
    mid = (a + b)/2;
    mid -= (mid - dic.entry_tbl)%sizeof(ENTRY_IDX);
    result = CompareEntry(mid, buffer);
    
    if(result > 0)                                     //获取二级索引
        *index = (long)a + sizeof(ENTRY_IDX);
    else
        *index = (long)a;
        
    return result;

}


// 函数原型：
// long CompareEntry( unsigned long offset, char *key )
//
// 参数说明：
// unsigned long	offset	词条二级索引在索引文件中的偏移地址
// char *			key		待比较的字符串
//
// 返回值说明：
// long		字符串比较结果。
//
// 功能说明：
// 比较词条名称和指定字符串。
static long CompareEntry(unsigned long offset, char *buffer)
{
    char *buf;
    long result;
    unsigned short len[ENTRY_COMPOS_NUM];
    ENTRY_IDX index;	
	
    //获取二级索引
    NU_Seek(fpidx, offset, SEEK_SET);
    NU_Read(fpidx, &index, sizeof(ENTRY_IDX));
    if(IndexByteOrder == DIFF_ENDIAN_ORDER)
        index.begin = ArchSwap32(index.begin);
        
    //获取词条名称
    NU_Seek(fpdic, index.begin, SEEK_SET);
    NU_Read(fpdic, len, sizeof(unsigned short)*ENTRY_COMPOS_NUM);
    if(IndexByteOrder == DIFF_ENDIAN_ORDER)    
        len[0] = ArchSwap16(len[0]);
        
    buf = malloc(len[0]);
    if(buf == NULL)
		return -1;
	
    NU_Read(fpdic, buf, len[0]);
    buf[len[0] - 1] = '\0';
        
    result = CompareVocab(buffer, buf);
    free(buf);
    return result;
}


static int CompareVocab(char *str1, char *str2)
{
    int r1 = 0, r2 = 0;
    
    while((*str1 != '\0') && (*str2 != '\0'))
    {
        if(r1 == 0)
            r1 = tolower(*str1) - tolower(*str2);
        if(r2 == 0)
            r2 = *str1 - *str2;
        if(r1 != 0 && r2 != 0)
            break;
        str1++;
        str2++;	
    }
 
    if(r1 == 0)
        r1 = tolower(*str1) - tolower(*str2);
    if(r2 == 0)
        r2 = *str1 - *str2;
        
    return (r1 == 0 ? r2 : r1);
	
}


// 参数说明：
// ENTRY *		list	用于存放词条列表的空间（由用户
//				建立），不能为NULL
// long			index	列表首词条的二级索引
// unsigned long	len	词条列表的最大长度
//
// 返回值说明：
// long		        正常情况下返回获取的词条列表的实际长度。
//			若输入参数错误或获取失败，返回值为-1。
//
// 功能说明：
// 获取从首词条开始不超过限定长度的词条列表。词条列表存放的
// 是词条名称和二级索引。
long GetEntryList(ENTRY *list, long index, unsigned long length)
{
    unsigned long total_len;
    unsigned long i, j;
    unsigned long offset;
    unsigned short len_info[ENTRY_COMPOS_NUM];
    char *buf;
    ENTRY_IDX entry;
    
    if(fpidx < DICT_CLOSED||fpdic < DICT_CLOSED)
        return -1;
        
    if(list == NULL)
        return -1;
        
    if(index < 0 || (unsigned long)index >= dic.header.num)
        return -1;
        
    for(i = 0; i < length && (unsigned long)index < dic.header.num; i++, index++)
    {
         offset = dic.entry_tbl + index * sizeof(ENTRY_IDX);
         NU_Seek(fpidx, offset, SEEK_SET);
         if(NU_Read(fpidx, &entry, sizeof(ENTRY_IDX)) == 0)
             return FALSE;
         if(IndexByteOrder == DIFF_ENDIAN_ORDER)
             entry.begin = ArchSwap32(entry.begin);
         NU_Seek(fpdic, entry.begin, SEEK_SET);
         
         //获取词条内容的长度信息
         if(NU_Read(fpdic, len_info, sizeof(unsigned short)*ENTRY_COMPOS_NUM) != ENTRY_COMPOS_NUM*sizeof(unsigned short))
             return FALSE;
         /*follow is modified to decrease memory require*/
         /*
         total_len = 0;
         for(j = 0; j < ENTRY_COMPOS_NUM; j++)
         {
             if(IndexByteOrder == DIFF_ENDIAN_ORDER)
                 len_info[j] = ArchSwap16(len_info[j]);
             total_len += len_info[j];	
         }	
         
         buf = malloc(total_len);
	 	 if(buf == NULL)
		 	return -1;
	                
         if(NU_Read(fpdic, buf, total_len) == 0)
              return FALSE;
         
         //获取词条名称
         list[i].phrase = (char*)malloc(len_info[0]);
         if(list[i].phrase == NULL)
             return FALSE;
             
         memcpy(list[i].phrase, buf, len_info[0]);
         list[i].phrase[len_info[0] - 1] = '\0';
         list[i].index = index;
    	 free(buf);
    	 buf = NULL;
    	 */
    	 
    	 
    	 //获取词条名称
         total_len = 0;
         for(j = 0; j < ENTRY_COMPOS_NUM; j++)
         {
             if(IndexByteOrder == DIFF_ENDIAN_ORDER)
                 len_info[j] = ArchSwap16(len_info[j]);
             total_len += len_info[j];	
         }
         
         list[i].phrase = (char*)malloc(len_info[0]);
         if(list[i].phrase == NULL)
             return FALSE;
             
         if(NU_Read(fpdic, list[i].phrase, len_info[0]) == 0)
              return FALSE;
         list[i].phrase[len_info[0] - 1] = '\0';
         list[i].index = index;
         
         NU_Seek(fpdic, total_len - len_info[0], SEEK_CUR);
    	
    }
    
    
    
    return i;
    	
}


// 函数原型：
// char *GetEntryInfo( long index, unsigned long mode )
//
// 参数说明：
// unsigned long	index	待查找词条的二级索引
// unsigned long	mode	查找的模式，合法值为：
// 			        WORD_PHRASE	词条名称
// 			    	PRONUNCE	单词发音
// 			    	PARAPHRASE	词义
// 			    	ENTRY_ALL	全部内容
// 			    	以及上述模式的组合，如：WORD_PHRASE | PARAPHRASE
//
// 返回值说明：
// char *	词条内容，按照词条名称、音标和词义的顺序排列。
//			三部分用换行符（0x0A）分隔。
// 			若未找到词条内容或输入参数错误，返回值为NULL。
//
// 功能说明：
// 根据词条索引获取词条内容。
char *GetEntryInfo(long index, unsigned long mode)
{
    char *buf;
    unsigned short len[ENTRY_COMPOS_NUM], cur_len;
    unsigned char  need[ENTRY_COMPOS_NUM];
    unsigned long  offset;
    short total_len = 0, total_need = 0;
    int i, k;
    ENTRY_IDX entry;
    
    if(fpidx < DICT_CLOSED || fpdic < DICT_CLOSED)
        return NULL;
        
    if(index < 0 || (unsigned long)index >= dic.header.num)
        return NULL;
    
    //获取词条在字典中的位置    
    offset = dic.entry_tbl + index * sizeof(ENTRY_IDX);
    NU_Seek(fpidx, offset, SEEK_SET);
    
    if(NU_Read(fpidx, &entry, sizeof(ENTRY_IDX)) == 0)
        return NULL;
        
    if(IndexByteOrder == DIFF_ENDIAN_ORDER)
        entry.begin = ArchSwap32(entry.begin);
        
    NU_Seek(fpdic, entry.begin, SEEK_SET);
    NU_Read(fpdic, len, sizeof(unsigned short)*ENTRY_COMPOS_NUM);
    
    for(i = 0; i < ENTRY_COMPOS_NUM; i++)
    {
        if(IndexByteOrder == DIFF_ENDIAN_ORDER)
            len[i] = ArchSwap16(len[i]);
        if((mode >> i) & 1)
        {
            need[i] = 1;
            total_len += len[i];
            total_need++;	
        } 
       	else
       	    need[i] = 0;
    }    	
    
    buf = (char *)malloc(total_len);
    if(buf == NULL)
        return NULL;
       
    for(i = 0, k = 0; i < ENTRY_COMPOS_NUM; i++)
    {
        cur_len = len[i];
        if(need[i] && cur_len != 0)  //根据模式和词条内容的长度信息读取词条内容
        {
            NU_Read(fpdic, &buf[k], cur_len);
            k += cur_len;
            total_need--; 
    	    if(total_need == 0)
    	    {
    	        buf[k - 1] = '\0';
    	        break;	
    	    }
        }
        else
    	    NU_Seek(fpdic, cur_len, SEEK_CUR);
        
    }
    
    buf[k - 1] = '\0';
        
    return buf;		
	
	
}