Printable View
i'm making a program that will export some data like a byte array...
the program array is coded in VB6 and stored in database, but i need to read this data through java program.
In vb6 we have the byte array filled by values that start at number 0 to number 255, but in the java the range is -127 at 128.
Using vb6, how can i let the vb6 byte array on the java standard?
The VB6 Byte type is an unsigned 8-bit integer.
Nothing prevents you from stuffing any bit pattern in there that you want. One possibility is to use VB6's Integer type (signed 16-bit integer) and move the lower 8 bits of that into a Byte.
Such moves could be done a number of ways (GetMem1/PutMem1, CopyMemory, UDTS and LSet, etc.). The only tricky part may be moving back from a negative "signed byte" value into an Integer. Then you need to check the high bit of the Byte value and if set be sure to move &HFF into the high byte of the Integer variable as well as copying the Byte into the low byte.
It sounds like the byte array is already in the database, put in from VB6.
You stated the range incorrectly, it would be -128 to 127 on the Java side.
If the meaning of the value has to have its VB6 meaning, i.e. 0 to 255 when read on the Java side, then I would read the data into a Java byte array, then loop through and set elements of an Integer array to the value in the byte array + 128.
If you had to write back to the database, then you would loop through the integer array and set the byte array value to integer value - 128.
Rereading the post, I guess it you want the VB6 side to treat the numbers as -128 to 127, then as dilettante has already said, use integers on the VB6 side to maintain the -128 to 127 values.
But you can still set just set the bytes in a byte array to the integer value + 128, before sending the byte array to the database, and do the reverse when reading them on the VB6 side.