ToC path:

mco_flashsim_media_context
RT

Retrieve the internal media context of a flash simulator instance for integration with eXtremeDB database.

Prototype

    MCO_RET mco_flashsim_media_context(
        /*IN*/  mco_flashsim_h fs,
        /*OUT*/ void **context,
        /*OUT*/ mco_size_t *context_size
    );

Arguments

fs

Handle to an open flash simulator instance.

context

Pointer to a variable that will receive the address of the simulator’s internal media context.

context_size

Pointer to a variable that will receive the size (in bytes) of the media context structure.

Description

This function provides access to the internal media context of the flash simulator, which is required when binding the simulator to an eXtremeDB persistent device. The context contains the memory device descriptor used by the simulator and is assigned to the dev.file.media_context field of the persistent device during database configuration.

The returned context is a pointer to the simulator’s context. This allows the database runtime to interact with the simulator as if it were real flash media.

Return Codes

MCO_S_OK

Media context successfully retrieved.

MCO_E_INVALID_HANDLE

The provided simulator handle is invalid or not initialized.

MCO_E_ILLEGAL_PARAM

One or both output pointers (context, context_size) are NULL.

Example

    mco_device_t db_devs[3];  // memory & persistent devices for database
    mco_device_t sim_dev;    // memory device for flash simulator
    mco_db_params_t    db_params;
    mco_flashsim_params_t fsp = {0};
    mco_flashsim_h flash_handle;

    /***************** Create flash simulator *****************/
    fsp.page_size       = P_RAMFLASH_PAGE_SIZE;
    fsp.pages_per_block = P_RAMFLASH_PAGES_PER_BLOCK;
    fsp.n_blocks        = P_RAMFLASH_NUM_BLOCKS;

    sim_dev.assignment = MCO_MEMORY_ASSIGN_PERSISTENT;
    sim_dev.type       = MCO_MEMORY_CONV;
    sim_dev.size       = mco_flashsim_memory_size(&fsp); // get required memory size
    sim_dev.dev.conv.ptr = (char*)malloc(sim_dev.size);  // allocate memory
    sim_dev.dev.conv.flags = 0;

    CHECK(mco_flashsim_open(&sim_dev, &fsp, &flash_handle)); // create flash simulator, flash_handle refers

    /***************** Create database *****************/
    db_devs[0].assignment = MCO_MEMORY_ASSIGN_DATABASE;
    /*   ...fill db_devs[0]     */

    db_devs[1].assignment = MCO_MEMORY_ASSIGN_CACHE;
    /*   ...fill db_devs[1]     */

    db_devs[2].assignment = MCO_MEMORY_ASSIGN_PERSISTENT;
    db_devs[2].type       = MCO_MEMORY_FILE;
    db_devs[2].dev.file.flags = MCO_FILE_OPEN_WITH_MEDIA_CTX; // media context attached
    db_devs[2].dev.file.name[0] = '\0';    // not used
    // get context by flashsim handle
    CHECK(mco_flashsim_media_context(flash_handle, &db_devs[2].dev.file.media_context, &db_devs[2].dev.file.media_context_size));

    mco_db_params_init ( &db_params );
    /*  ...set db_params        */

    CHECK(mco_db_open_dev(db_name, perf_get_dictionary(), db_devs, 3, &db_params ));

    /***************** Use database *****************/

    /***************** Cleanup *****************/
    CHECK(mco_db_close(db_name));
    CHECK(mco_flashsim_close(flash_handle));
    /*  ...free malloc()-ed memory   */

Files

Header file:

mcoflashsim.h

Source file:

mcoflashsim.c

Library:

libmcolib.a

mco_flashsim_media_context RT