786    png_uint_32        IDAT_len; /* Used when re-chunking IDAT chunks */  member
1492          png_uint_32 IDAT_len = ps->IDAT_len;  in store_read_chunk()  local
1499          if (IDAT_pos == IDAT_len)  in store_read_chunk()
1508             if (IDAT_len == 0U) /* First IDAT */  in store_read_chunk()
1512                   case 0U: IDAT_len = 12U; break; /* 0 bytes */  in store_read_chunk()
1513                   case 1U: IDAT_len = 13U; break; /* 1 byte */  in store_read_chunk()
1514                   default: IDAT_len = random_u32();  in store_read_chunk()
1515                            IDAT_len %= IDAT_size;  in store_read_chunk()
1516                            IDAT_len += 13U; /* 1..IDAT_size bytes */  in store_read_chunk()
1533                   IDAT_len = 12U; /* Output another 0 length IDAT */  in store_read_chunk()
1545                   ps->IDAT_len = IDAT_len;  in store_read_chunk()
1556                IDAT_len = random_u32();  in store_read_chunk()
1557                IDAT_len &= (1U << (1U + random % ps->IDAT_bits)) - 1U;  in store_read_chunk()
1558                if (IDAT_len > IDAT_size)  in store_read_chunk()
1559                   IDAT_len = IDAT_size;  in store_read_chunk()
1560                IDAT_len += 12U; /* zero bytes may occur */  in store_read_chunk()
1573                b = IDAT_len - 12U;  in store_read_chunk()
1588          else if (IDAT_pos < IDAT_len - 4U) /* I.e not the CRC */  in store_read_chunk()
1594                if (avail > (IDAT_len-4U) - IDAT_pos)  in store_read_chunk()
1595                   avail = (uInt)/*SAFE*/((IDAT_len-4U) - IDAT_pos);  in store_read_chunk()
1624             unsigned int shift = (IDAT_len - IDAT_pos); /* 4..1 */  in store_read_chunk()
1632          while (--st > 0 && IDAT_pos < IDAT_len);  in store_read_chunk()
1635          ps->IDAT_len = IDAT_len;  in store_read_chunk()
1644          if (ps->IDAT_len > 0 && ps->IDAT_size > 0)  in store_read_chunk()
1647          if (chunktype == CHUNK_IEND && ps->IDAT_len == 0U)  in store_read_chunk()
2128          ps->IDAT_len = 0;  in store_read_set()