How do I determine FPGA image size within a POF

Pof file format:
    bytes 0 to 3:  "POF\0"
    bytes 4 to 7:  unknown
    bytes 8 to 11: number of 'packets'.
Each 'packet' starts with a header:
    bytes 0 and 1:   packet type
    bytes 2 to 5:    packet length
    bytes 6 onwards: data

Packet type 0x11 has a 12 byte header and then the raw data for the entire EPCQ.

Packet type 0x1a contains the string "mPage_0 00000000 0226A5F8;" the last number seems to be the data size in bits.

Don't know what packet 0x23 contains.

The last packet is a always type 8 and contains a crc of the file upto, but excluding, the crc data.

The crc is CRC-CCITT - and can be calculated by:

static uint32_t
pof_calc_crc(const uint8_t *dp, const uint8_t *end)
{
    uint32_t crc;
    uint32_t t;
    crc = 0xffff;
    while (dp < end) {
        crc ^= *dp++;
        t = (crc ^ crc << 4) & 0xff;
        crc = crc >> 8 ^ t << 8 ^ t << 3 ^ t >> 4;
    }
    return crc ^ 0xffff;
}

Remember to bit-reverse the data as you write it to the epcq.