func()

in flexflate/huffman_bit_writer.go [207:285]

• 67 lines of code
• 11 McCabe index (conditional complexity)

func (w *huffmanBitWriter) generateCodegen(numLiterals int, numOffsets int) {
	for i := range w.codegenFreq {
		w.codegenFreq[i] = 0
	}
	// Note that we are using codegen both as a temporary variable for holding
	// a copy of the frequencies, and as the place where we put the result.
	// This is fine because the output is always shorter than the input used
	// so far.
	codegen := w.codegen // cache
	// Copy the concatenated code sizes to codegen.  Put a marker at the end.
	copy(codegen[0:numLiterals], w.literalEncoding.codeBits)
	copy(codegen[numLiterals:numLiterals+numOffsets], w.offsetEncoding.codeBits)
	codegen[numLiterals+numOffsets] = badCode

	size := codegen[0]
	count := 1
	outIndex := 0
	for inIndex := 1; size != badCode; inIndex++ {
		// INVARIANT: We have seen "count" copies of size that have not yet
		// had output generated for them.
		nextSize := codegen[inIndex]
		if nextSize == size {
			count++
			continue
		}
		// We need to generate codegen indicating "count" of size.
		if size != 0 {
			codegen[outIndex] = size
			outIndex++
			w.codegenFreq[size]++
			count--
			for count >= 3 {
				n := 6
				if n > count {
					n = count
				}
				codegen[outIndex] = 16
				outIndex++
				codegen[outIndex] = uint8(n - 3)
				outIndex++
				w.codegenFreq[16]++
				count -= n
			}
		} else {
			for count >= 11 {
				n := 138
				if n > count {
					n = count
				}
				codegen[outIndex] = 18
				outIndex++
				codegen[outIndex] = uint8(n - 11)
				outIndex++
				w.codegenFreq[18]++
				count -= n
			}
			if count >= 3 {
				// count >= 3 && count <= 10
				codegen[outIndex] = 17
				outIndex++
				codegen[outIndex] = uint8(count - 3)
				outIndex++
				w.codegenFreq[17]++
				count = 0
			}
		}
		count--
		for ; count >= 0; count-- {
			codegen[outIndex] = size
			outIndex++
			w.codegenFreq[size]++
		}
		// Set up invariant for next time through the loop.
		size = nextSize
		count = 1
	}
	// Marker indicating the end of the codegen.
	codegen[outIndex] = badCode
}