Difference between revisions of "Bcopy"

Revision as of 18:37, 13 October 2006

The bcopy command is used to copy a (part of a) binary file.

bcopy [-zc] <&copy> <N> <&source> <S> <M>

This copies M bytes from &source starting at position S to &copy starting at position N. If &copy doesn't exist yet, the binary file will be created and zero filled to the Nth byte. If &copy already exists but smaller then N bytes, it will be extended with zeros to the Nth byte. If &copy already exists and is N bytes or larger, the copied bytes will overwrite the old bytes in &copy. If &source is smaller then S + M - 1 bytes and &source is equal or larger then S bytes, then all bytes starting from S to the last byte will be copied. If &source is smaller then S bytes, you will get an error. You can use M = -1 to copy all bytes starting from byte S to the last byte.

The -z switch will zero fill all bytes in &source that were copied. The -c switch will chop &copy to N + M bytes.

Examples

bset &data 1 65 66 67 68 69
bcopy &test 1 &data 3 2
echo -a $bvar(&test,1,$bvar(&test,0))

This will copy the values 67 68 from &data to the first position of &test.

bset &data 1 65 66 67 68 69
bset &test 1 97
bcopy &test 5 &data 4 -1
echo -a $bvar(&test,1,$bvar(&test,0))

This will copy values 68 69 from &data to the fifth postion of &test. Positions 2-4 of &test will be zero filled. The echo will return: 97 0 0 0 68 69

bset &data 1 65 66 67 68 69
bset &test 1 97 98 99 100
bcopy -z &test 2 &data 4 2
echo -a $bvar(&data,1,$bvar(&data,0))
echo -a $bvar(&test,1,$bvar(&test,0))

This will copy values 68 69 from &data to the second position of &test. The -z switch will zero fill the copied values 68 69 of &data. Notice that values 98 99 will be overwritten. The first echo will return: 65 66 67 0 0. The second echo will return: 97 68 69 100

bset &data 1 65 66 67 68 69
bset &test 1 97 98 99 100
bcopy -c &test 2 &data 3 2
echo -a $bvar(&test,1,$bvar(&test,0))

This will copy values 67 68 from &data to the second position of &test. The -c switch will chop value 100. The echo will return: 97 67 68