FlashFile.hxx

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#ifndef _FREERTOS_DRIVERS_COMMON_FLASHFILE_HXX_
#define _FREERTOS_DRIVERS_COMMON_FLASHFILE_HXX_
 
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
 
#include "freertos_drivers/common/DeviceFile.hxx"
 
template <class FLASH> class FlashFile : public DeviceFile
{
public:
    FlashFile(const char *name, FLASH *flash, size_t address, size_t size)
        : DeviceFile(name)
        , flash_(flash)
        , flashStart_(address)
        , size_(size)
    {
        auto start_sec = flash_->next_sector_address(flashStart_);
        // Beginning of the file must be on a sector boundary.
        HASSERT(start_sec == flashStart_);
    }
 
    int open(File *file, const char *path, int flags, int mode) override
    {
        if ((flags & O_TRUNC) && ((flags & O_ACCMODE) != O_RDONLY))
        {
            // erase entire file.
            flash_->erase(flashStart_, size_);
            flags &= ~O_TRUNC;
        }
        return DeviceFile::open(file, path, flags, mode);
    }
 
    int fstat(File *file, struct stat *stat) override
    {
        DeviceFile::fstat(file, stat);
        stat->st_size = size_;
        return 0;
    }
 
    ssize_t write(unsigned int index, const void *buf, size_t len) override
    {
        if (index >= size_)
        {
            return 0; // EOF
        }
        if (len > size_ - index)
        {
            len = size_ - index;
        }
        size_t addr = flashStart_ + index;
        size_t sec_addr = flash_->next_sector_address(addr);
        if (addr == sec_addr)
        {
            size_t next_sec = flash_->next_sector_address(sec_addr + 1);
            flash_->erase(sec_addr, next_sec - sec_addr);
            sec_addr = next_sec;
        }
        if ((sec_addr - addr) < len)
        {
            len = sec_addr - addr;
        }
        flash_->write(addr, buf, len);
        return len;
    }
 
    ssize_t read(unsigned int index, void *buf, size_t len) override
    {
        if (index >= size_)
        {
            return 0; // EOF
        }
        if (len > size_ - index)
        {
            len = size_ - index;
        }
        size_t addr = flashStart_ + index;
        flash_->read(addr, buf, len);
        return len;
    }
 
private:
    FLASH *flash_;
    size_t flashStart_;
    size_t size_;
};
 
#endif