{"id":3582,"date":"2020-09-01T14:16:10","date_gmt":"2020-09-01T06:16:10","guid":{"rendered":"http:\/\/www.sniper97.cn\/?p=3582"},"modified":"2020-09-01T14:16:10","modified_gmt":"2020-09-01T06:16:10","slug":"sqlite%e6%9f%a5%e8%af%a2%e6%80%a7%e8%83%bd%e4%bc%98%e5%8c%96%ef%bc%88%e5%ae%9e%e6%b5%8b%e9%a1%b9%e7%9b%ae%e4%b8%ad%e8%8a%82%e7%9c%81%e4%b8%80%e5%8d%8a%e6%97%b6%e9%97%b4%ef%bc%89","status":"publish","type":"post","link":"http:\/\/www.sniper97.cn\/index.php\/qq%e7%ba%a2%e5%8c%85%e7%9a%84%e5%91%93%e8%af%ad\/3582\/","title":{"rendered":"sqlite\u67e5\u8be2\u6027\u80fd\u4f18\u5316\uff08\u5b9e\u6d4b\u9879\u76ee\u4e2d\u8282\u7701\u4e00\u534a\u65f6\u95f4\uff09"},"content":{"rendered":"\n

\u901a\u8fc7\u4f18\u5316\u8bfb\u53d6\u63d0\u5347\u67e5\u8be2\u6548\u7387<\/p>\n\n\n

\u53ea\u9700\u8981\u5728sqlite.c<\/strong>\u52a0\u5165\u5982\u4e0b\u4ee3\u7801\uff1a<\/p>\n\n\n

#define MAP_BUFFER_LEN 1024 * 1024 * 10\n#include <Windows.h>\ntypedef struct _FILE_MAPING\n{\n    HANDLE fileH;\n    HANDLE mapFileH;\n    char* map_buffer;\n    SIZE_T mapsize;\n    DWORD64 buffer_offset;\n    SIZE_T filesize;\n    int flag;\n}*PFILE_MAPING, FILE_MAPING;\nSIZE_T mGetFileSize(PFILE_MAPING p);\n    void reles(PFILE_MAPING p)\n    {\n        if (p->map_buffer)\n            UnmapViewOfFile(p->map_buffer);\n        if (p->mapFileH)\n            CloseHandle(p->mapFileH);\n        if (p->fileH)\n            CloseHandle(p->fileH);\n        memset(p, 0, sizeof(FILE_MAPING));\n        free(p);\n    }\n    int Init_Maping(PFILE_MAPING* p,wchar_t* path, DWORD access, DWORD sharemode, DWORD CreationDisposition, DWORD Flags)\n    {\n        (*p) = (PFILE_MAPING)malloc(sizeof(FILE_MAPING));\n         memset((*p),0, sizeof(FILE_MAPING));\n        (*p)->fileH = CreateFileW(path,\n            access\/*GENERIC_READ | GENERIC_WRITE*\/,\n            sharemode \/*FILE_SHARE_READ| GENERIC_WRITE*\/,\n            NULL,\n            CreationDisposition\/*OPEN_EXISTING*\/,\n            Flags\/*FILE_ATTRIBUTE_NORMAL*\/,\n            NULL);\n        if ((*p)->fileH == INVALID_HANDLE_VALUE)\n        {\n            int erro = GetLastError();\n            return 0;\n        }\n        (*p)->mapFileH = CreateFileMapping((*p)->fileH, NULL, PAGE_READONLY\/*PAGE_READWRITE*\/, 0, 0, 0);\n        if ((*p)->mapFileH == NULL)\n        {\n            int erro = GetLastError();\n            return 0;\n        }\n        return 1;\n    }\n    int ReadFile_Maping(PFILE_MAPING p,DWORD64 _offset, DWORD64 len, char** buffer, DWORD* readed, OVERLAPPED* poverlapped)\n    {\n        if (p == NULL || p->mapFileH == NULL || !len)\n        {\n            return ReadFile(p->fileH,*buffer, len, readed, poverlapped);\n        }\n        \/\/if (len > MAP_BUFFER_LEN)\n        \/\/    return 0;\n        SIZE_T llen = mGetFileSize(p);\n        if (p->map_buffer && _offset >= p->buffer_offset && (_offset + len) < (p->mapsize + p->buffer_offset))\n        {\n            \/\/*buffer = map_buffer + offset - buffer_offset;\n            memcpy(*buffer, p->map_buffer + _offset - p->buffer_offset, len);\n        }\n        else\n        {\n            if (p->map_buffer)\n            {\n                UnmapViewOfFile(p->map_buffer);\n                p->map_buffer = NULL;\n                p->buffer_offset = NULL;\n                p->mapsize = NULL;\n            }\n            static DWORD dwAllocationGranularity = 0;\n            if (!p->flag)\n            {\n                p->flag = 1;\n                SYSTEM_INFO sinf = { 0 };\n                GetSystemInfo(&sinf);\n                dwAllocationGranularity = sinf.dwAllocationGranularity;\n            }\n            DWORD64 needmapoffset = 0;\n            if(_offset)\n                needmapoffset = _offset - _offset % dwAllocationGranularity;\n            SIZE_T mapsize = MAP_BUFFER_LEN;\n            if (len > MAP_BUFFER_LEN)\n\t\t\t\tmapsize = (SIZE_T)len;\n\t\t\tif (needmapoffset + mapsize > llen)\n\t\t\t\tmapsize = llen - needmapoffset;\n            p->map_buffer = (char*)MapViewOfFile(p->mapFileH, FILE_MAP_READ, *(DWORD*)((char*)&needmapoffset + 4), (DWORD)(needmapoffset & 0xFFFFFFFF), mapsize);\n\t\t\tif (!p->map_buffer)\n\t\t\t{\n\t\t\t\t\/\/return 0;\n\t\t\t\treturn ReadFile(p->fileH, *buffer, len, readed, poverlapped);\n\t\t\t}\n\t\t\tif (_offset > llen)\n\t\t\t{\n\t\t\t\treturn ReadFile(p->fileH, *buffer, len, readed, poverlapped);\n\t\t\t}\n            p->buffer_offset = needmapoffset;\n            p->mapsize = mapsize;\n            \/\/*buffer = map_buffer + offset - buffer_offset;\n\t\t\tmemcpy(*buffer, p->map_buffer + _offset - needmapoffset, len);\n        }\n        *readed = len;\n        return 1;\n    }\n    SIZE_T mGetFileSize(PFILE_MAPING p)\n    {\n        if (p->filesize)\n            return  p->filesize;\n        if (p->fileH)\n        {\n            *(DWORD*)&p->filesize = GetFileSize(p->fileH, (DWORD*)((char*)&p->filesize + 4));\n            return  p->filesize;\n        }\n        return 0;\n    }\n<\/code><\/pre>\n\n\n
\"\"<\/figure>\n\n\n
\"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"
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