FlashDB.cpp

00001 /*****************************************************************************
00002 *
00003 *  FlashDB.c
00004 *  Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
00005 *
00006 *  Redistribution and use in source and binary forms, with or without
00007 *  modification, are permitted provided that the following conditions
00008 *  are met:
00009 *
00010 *    Redistributions of source code must retain the above copyright
00011 *    notice, this list of conditions and the following disclaimer.
00012 *
00013 *    Redistributions in binary form must reproduce the above copyright
00014 *    notice, this list of conditions and the following disclaimer in the
00015 *    documentation and/or other materials provided with the   
00016 *    distribution.
00017 *
00018 *    Neither the name of Texas Instruments Incorporated nor the names of
00019 *    its contributors may be used to endorse or promote products derived
00020 *    from this software without specific prior written permission.
00021 *
00022 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
00023 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
00024 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
00025 *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
00026 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
00027 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
00028 *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
00029 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
00030 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
00031 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
00032 *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00033 *
00034 *****************************************************************************/
00035 #include "mbed.h"
00036 #include "Common.h"
00037 #include "FlashDB.h"
00038 #include "HttpString.h"
00039 #include "string.h"
00040 
00041 
00042 /// This database flag indicates that all resource strings are to be matched with a case-sensitive string comparison function
00043 #define FLASH_DB_FLAG_CASE_SENSITIVE (1 << 0)
00044 
00045 /**
00046  * The header structure of the flash database
00047  */
00048 //#ifdef __CCS__
00049 struct __attribute__ ((__packed__)) FlashDBHeader
00050 //#elif __IAR_SYSTEMS_ICC__
00051 //#pragma pack(1)
00052 //struct FlashDBHeader
00053 //#endif
00054 {
00055     /// Amount of content type entries
00056     uint16 uContentTypeAmount;
00057     /// Offset of content-type entry list
00058     uint16 uContentTypeOffset;
00059     /// Amount of content entries
00060     uint16 uContentAmount;
00061     /// Offset of content entry list
00062     uint16 uContentOffset;
00063     /// Database flags. See FLASH_DB_FLAG_*
00064     uint16 uFlags;
00065 };
00066 
00067 /**
00068  * The header structure for a content entity in the database
00069  */
00070 //#ifdef __CCS__
00071 struct __attribute__ ((__packed__)) FlashDBContentTypeEntry
00072 //#elif __IAR_SYSTEMS_ICC__
00073 //#pragma pack(1)
00074 //struct FlashDBContentTypeEntry
00075 //#endif
00076 {
00077     /// Length of the value string. Should be 255 characters at most.
00078     uint16 uValueLength;
00079     /// Offset of the value string
00080     uint16 uValueOffset;
00081 };
00082 
00083 extern const char FlashDBContentData[];
00084 
00085 /**
00086  * The header structure for a content entity in the database
00087  */
00088 //#ifdef __CCS__
00089 struct __attribute__ ((__packed__)) FlashDBContentEntry
00090 //#elif __IAR_SYSTEMS_ICC__
00091 //#pragma pack(1)
00092 //struct FlashDBContentEntry
00093 //#endif
00094 {
00095     /// Length of the resource string. Should be 255 characters at most.
00096     uint16 uResourceLength;
00097     /// Offset of the resource string
00098     //uint32 uResourceOffset;
00099     unsigned long uResourceOffset;
00100     /// Flags. See FLASHDB_FLAG_*
00101     uint16 uFlags;
00102     /// Index of content type entry for this resource, in the content type list
00103     uint16 uContentType;
00104     /// Length (in bytes) of the content blob
00105     uint16 uContentLength;
00106     /// Offset of the content blob in the database
00107     //uint32 uContentOffset;
00108     unsigned long uContentOffset;
00109 };
00110 
00111 extern const char FlashDBContentData[];
00112 
00113 /**
00114  * The layout of the database file is as follows:
00115  *    Database Header
00116  *    Content type entry 1
00117  *    Content type entry 2
00118  *      and so on...
00119  *    Content entry 1
00120  *    Content entry 2
00121  *      and so on...
00122  *    Content type string 1
00123  *    Content type string 2
00124  *      and so on...
00125  *    Content blob 1
00126  *    Content blob 2
00127  *      and so on...
00128  *
00129  * Note: All offsets in the structures are absolute offsets, meaning they are relative to the database base pointer, as passed to FlashDB_Init()
00130  */
00131 
00132 /* this global shows a sample how static pages/files are stored in the memory */
00133    
00134 #if 0
00135 struct StaticExamplePages
00136 {
00137     struct FlashDBHeader                header;
00138     struct FlashDBContentTypeEntry      contentTypeList[];
00139     struct FlashDBContentEntry          ContentList[];
00140     char                        contentType[][];
00141     char                        resource[][];
00142     char                            content[][];
00143 };
00144 #endif
00145 
00146 struct FlashDBHeader    *gFlashDB;
00147 
00148 /**
00149  * Initialize the flash database module
00150  * @param pDatabase Pointer to the beginning of the database in flash memory
00151  */
00152 void FlashDB_Init()
00153 {
00154         gFlashDB = (struct FlashDBHeader *)FlashDBContentData;
00155 }
00156 
00157 /**
00158  * Find a content-type in the database
00159  * @param index The index of the content type in the database
00160  * @param[out] pResult Returns the string and its length
00161  * @return nonzero if successful. zero if index out of range.
00162  */
00163 int FlashDB_FindContentType(uint16 index, struct HttpBlob* pResult)
00164 {
00165     struct FlashDBContentTypeEntry  *pContentTypeEntryList;
00166 
00167     if (index > gFlashDB->uContentTypeAmount)
00168         return 0;
00169     
00170     pContentTypeEntryList = (struct FlashDBContentTypeEntry *)((unsigned char*)gFlashDB + gFlashDB->uContentTypeOffset);
00171     pContentTypeEntryList = (struct FlashDBContentTypeEntry *)(pContentTypeEntryList + index);
00172     pResult->uLength = pContentTypeEntryList->uValueLength;
00173     pResult->pData =  (unsigned char*)((unsigned char*)gFlashDB + pContentTypeEntryList->uValueOffset);
00174 
00175     return 1;
00176 }
00177 
00178 /**
00179  * Lookup content in the database, given a resource identifier
00180  * @param pResource The resource as given in the HTTP request
00181  * @param[out] pResult Returns the content and its metadata
00182  * @return nonzero if successful. zero if such a resource was not found.
00183  */
00184 int FlashDB_FindContent(struct HttpBlob pResource, struct FlashDBContent* pResult)
00185 {
00186     /* it is assumed that the resource list is sorted */
00187     struct FlashDBContentEntry *pContentFieldStart;
00188     struct FlashDBContentEntry *pContentFieldMoving;
00189     struct HttpBlob MainPage;
00190     uint16  uLowSearchIndex = 0;
00191     uint16  uMidSearchIndex;
00192     uint16  uHighSearchIndex;
00193     int     uComparison;
00194     int16   found = -1; /* not found */
00195     struct HttpBlob ResourceBlob;
00196     
00197     uHighSearchIndex = gFlashDB->uContentAmount - 1;
00198     pContentFieldStart = (struct FlashDBContentEntry *)((unsigned char*)gFlashDB + gFlashDB->uContentOffset);
00199 
00200     while (uLowSearchIndex <= uHighSearchIndex)
00201     {
00202         uMidSearchIndex = (uLowSearchIndex + uHighSearchIndex)/2;
00203         pContentFieldMoving = pContentFieldStart + uMidSearchIndex;
00204         ResourceBlob.pData = (unsigned char*)((unsigned char*)gFlashDB + pContentFieldMoving->uResourceOffset);
00205         ResourceBlob.uLength = pContentFieldMoving->uResourceLength;
00206         
00207                 if(pResource.uLength ==1 && *(pResource.pData)=='/')
00208                 {
00209                   MainPage.uLength = 11;
00210                   MainPage.pData = (unsigned char*)"/index.html";
00211                   uComparison = HttpString_strcmp(MainPage, ResourceBlob);
00212                 }
00213                 else
00214                   uComparison = HttpString_strcmp(pResource, ResourceBlob);
00215         // found the exact blob 
00216         if (uComparison == 0)
00217         {
00218             found = 1;
00219             printf("Content found \r\n");
00220             break;
00221         }
00222         
00223         // the requested blob is "larger" than the current blob 
00224         else if (uComparison > 0)
00225         {
00226             uLowSearchIndex = uMidSearchIndex + 1;
00227             
00228         }
00229         // the requested blob is "smaller" than the current blob 
00230         else
00231         {
00232             uHighSearchIndex = uMidSearchIndex - 1;
00233             
00234         }
00235     }
00236     
00237     if (found == -1)
00238        {
00239         printf("Content not found \r\n");
00240         return 0;
00241         }
00242     else
00243     {
00244         pResult->uContentType = pContentFieldMoving->uContentType;
00245         pResult->uFlags = pContentFieldMoving->uFlags;
00246         pResult->contentBlob.uLength = pContentFieldMoving->uContentLength;
00247         pResult->contentBlob.pData = (unsigned char*)((unsigned char*)gFlashDB + pContentFieldMoving->uContentOffset);
00248         return 1;
00249     }
00250 }
00251