fs/yaffs2/yaffs_format_data_translate.c

   1 //#include "yaffs_packedtags2.h"\r
   2 #include "fdl_yaffs2.h"\r
   3 #include "yaffs_format_data_translate.h"\r
   4 \r
   5 #define YAFFS_LOWEST_SEQUENCE_NUMBER    0x00001000\r
   6 #define YAFFS_HIGHEST_SEQUENCE_NUMBER   0xEFFFFF00\r
   7 #define NULL ((void*)0)\r
   8 //global variables\r
   9 static unsigned long totalchunk = 0;\r
  10 static unsigned long chunknumber = 0;\r
  11 /*******************************************************************************\r
  12 * this function used to translate yaffs format binary data stream.\r
  13 * p_dst_page->p_pagedata        hold the actually one dst 'page' data that needed.\r
  14 * the return values:\r
  15 * -1    there is an error occured\r
  16 * >0    how many src 'pages' has been translated in the src binary data stream.\r
  17 ********************************************************************************/\r
  18 int yaffs_page_translate(yaffs_page *p_src_page,yaffs_page *p_dst_page){\r
  19 \r
  20         int ret = -1;\r
  21         yaffs_ObjectHeader * pheader = NULL;\r
  22         //src chunk\r
  23         char *p_src_data = p_src_page->p_pagedata;\r
  24         yaffs_PackedTags2 *p_src_spare = (yaffs_PackedTags2*)&p_src_page->p_pagedata[p_src_page->pagesize];\r
  25         //dst chunk\r
  26         char *p_dst_data = p_dst_page->p_pagedata;\r
  27         yaffs_PackedTags2 *p_dst_spare = (yaffs_PackedTags2*)&p_dst_page->p_pagedata[p_dst_page->pagesize];\r
  28         //how many src_page become one dst page\r
  29         int  count = p_dst_page->pagesize/p_src_page->pagesize;\r
  30         //object id,this used to identify which fileobject this chunk belongs to\r
  31         unsigned int  object_id = p_src_spare->t.objectId;\r
  32 \r
  33         if(p_dst_page->pagesize%p_src_page->pagesize != 0){\r
  34                 //the translation may become too complex,here we do not cover it.\r
  35                 return ret;\r
  36         }\r
  37 \r
  38         //first of all,reset the buffer.\r
  39         memset(p_dst_page->p_pagedata,0xff,p_dst_page->pagesize+p_dst_page->oobsize);\r
  40         if(p_src_spare->t.chunkId == 0){\r
  41                 //header chunk\r
  42                 //data\r
  43                 memcpy(p_dst_data,p_src_data,p_src_page->pagesize);\r
  44                 //spare\r
  45                 p_dst_spare->t.chunkId = 0;//p_src_spare->t.chunkId;\r
  46                 p_dst_spare->t.sequenceNumber = YAFFS_LOWEST_SEQUENCE_NUMBER;\r
  47                 p_dst_spare->t.byteCount = p_src_spare->t.byteCount;\r
  48                 p_dst_spare->t.objectId = object_id;\r
  49                 yaffs_ECCCalculateOther((unsigned char *)&p_dst_spare->t, sizeof(yaffs_PackedTags2TagsPart), &p_dst_spare->ecc);\r
  50                 //store the number of trunks hold by this file\r
  51                 pheader = (yaffs_ObjectHeader *)p_src_data;\r
  52                 if (pheader->type == YAFFS_OBJECT_TYPE_FILE) {\r
  53                         totalchunk = (pheader->fileSize + p_src_page->pagesize - 1) / p_src_page->pagesize;\r
  54                         chunknumber = 0;\r
  55                 }\r
  56                 ret = 1;\r
  57         }else if(p_src_spare->t.chunkId > 0){\r
  58                 //common data chunk\r
  59                 unsigned int offset = 0;\r
  60                 unsigned int i = count;\r
  61                 //data\r
  62                 ret = 0;\r
  63                 while(i){\r
  64                         //every time canculate one 'src' page\r
  65                         chunknumber++;\r
  66                         if(chunknumber > totalchunk){\r
  67                                 //now we run out of the end of the file.\r
  68                                 i--;\r
  69                                 continue;\r
  70                         }\r
  71                         if(object_id != p_src_spare->t.objectId){\r
  72                                 //the two trunk do not belongs to the same fileobject.error!!\r
  73                                 return -1;\r
  74                         }\r
  75 \r
  76                         memcpy(&p_dst_data[offset],p_src_data,p_src_spare->t.byteCount);\r
  77                         offset += p_src_spare->t.byteCount;\r
  78 \r
  79                         //update iterators\r
  80                         ret++;\r
  81                         i--;\r
  82                         p_src_data += p_src_page->pagesize + p_src_page->oobsize;\r
  83                         p_src_spare = (yaffs_PackedTags2*)&p_src_data[p_src_page->pagesize];\r
  84                 }\r
  85                 //spare\r
  86                 p_dst_spare->t.chunkId = chunknumber/count;\r
  87                 p_dst_spare->t.sequenceNumber = YAFFS_LOWEST_SEQUENCE_NUMBER;\r
  88                 p_dst_spare->t.byteCount = offset;\r
  89                 p_dst_spare->t.objectId = object_id;\r
  90                 yaffs_ECCCalculateOther((unsigned char *)&p_dst_spare->t, sizeof(yaffs_PackedTags2TagsPart), &p_dst_spare->ecc);\r
  91         }else{\r
  92                 //unused chunk,current it means encounter an fatal error.\r
  93                 return ret;\r
  94         }\r
  95 \r
  96         //reset global contex\r
  97         if(chunknumber >= totalchunk){\r
  98                 chunknumber = 0;\r
  99                 totalchunk = 0;\r
 100         }\r
 101 \r
 102         return ret;\r
 103 }\r