39 lines
1.1 KiB
Go
39 lines
1.1 KiB
Go
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package rtcp
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// getPadding Returns the padding required to make the length a multiple of 4
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func getPadding(len int) int {
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if len%4 == 0 {
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return 0
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}
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return 4 - (len % 4)
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}
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// setNBitsOfUint16 will truncate the value to size, left-shift to startIndex position and set
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func setNBitsOfUint16(src, size, startIndex, val uint16) (uint16, error) {
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if startIndex+size > 16 {
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return 0, errInvalidSizeOrStartIndex
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}
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// truncate val to size bits
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val &= (1 << size) - 1
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return src | (val << (16 - size - startIndex)), nil
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}
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// appendBit32 will left-shift and append n bits of val
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func appendNBitsToUint32(src, n, val uint32) uint32 {
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return (src << n) | (val & (0xFFFFFFFF >> (32 - n)))
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}
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// getNBit get n bits from 1 byte, begin with a position
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func getNBitsFromByte(b byte, begin, n uint16) uint16 {
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endShift := 8 - (begin + n)
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mask := (0xFF >> begin) & uint8(0xFF<<endShift)
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return uint16(b&mask) >> endShift
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}
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// get24BitFromBytes get 24bits from `[3]byte` slice
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func get24BitsFromBytes(b []byte) uint32 {
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return uint32(b[0])<<16 + uint32(b[1])<<8 + uint32(b[2])
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}
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