ml
35 lines
869 B
Go
35 lines
869 B
Go
package compression
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// BitstreamWriter is a utility to write big-endian integer values of arbitrary bit size to a bitstream.
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type BitstreamWriter struct {
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buf []byte
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offset uint
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}
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// Buffer returns the currently stored buffer.
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func (w BitstreamWriter) Buffer() []byte {
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return w.buf
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}
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// Write stores the given amount of bits from the provided value.
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// Trying to write more than 32 bits will cause panic.
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func (w *BitstreamWriter) Write(bits uint, value uint32) {
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if bits > 32 {
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panic("maximum of 32 bits are possible to be written")
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}
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for bits > 0 {
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temp := (uint64(value) & ^(^uint64(0) << bits)) << (40 - bits - w.offset)
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if w.offset == 0 {
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w.buf = append(w.buf, 0x00)
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}
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w.buf[len(w.buf)-1] |= byte(temp >> 32)
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written := 8 - w.offset
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if written > bits {
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written = bits
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}
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bits -= written
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w.offset = (w.offset + written) % 8
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}
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}
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