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> Whether you call the value 1 "bit 7", "bit 8", "bit 1" or "bit 0" is just, pardon the pun, word semantics.

It's extremely important to your mental model to understand how the bits are arranged, or left shift (<<) is going to produce different results in your head. If you think the value 1 is bit 7/8, you get:

1 0 0 0 0 0 0 0

Which would left shift to:

0 0 0 0 0 0 0 0

Which would not be equal to 2.

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> It's extremely important to your mental model to understand how the bits are arranged

And the shortcut for that is simply regard bytes as big-endian. On all platforms. Whether you're on a PPC or x86, the byte 0x80 is going to go out on the wire as 1 first, followed by 7 zeros.

So if you're writing a data compressor and the spec says that the variable-length bit strings (huffman or whatever) are stuffed into bytes in network order, that means you fill bytes from the left down. That is done with code that works the same way on BE or LE platforms.

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