}

// The following hash code is the heart of the algorithm:
// It builds a sliding hash sum of the previous 3-and-a-bit
// characters which will be used to index the guess table.
// A better hash function would result in additional compression,
// at the expense of time.
func (ctx *context) update(val byte) {
	ctx.hash = (ctx.hash << 4) ^ uint16(val)
}

type compressor func([]byte) error

func (w compressor) Write(data []byte) (int, error) {
	return len(data), w(data)
}

					// Guess was right - don't output
					buf[0] |= 1 << uint(i)
				} else {
					// Guess was wrong, output char
					ctx.table[ctx.hash] = current
					buf = append(buf, current)
				}
				ctx.update(current)
			}

			if _, err := writer.Write(buf); err != nil {
				return err
			}

			// Reset the flags and buffer for the next iteration

		// Check whether we have leftover data in the buffer
		if len(ctx.input) > 0 {
			rc = copy(output, ctx.input)

			// Check whether we still have leftover data in the buffer :)
			if rc < len(ctx.input) {
				// Shift the remaining bytes at the start of the buffer
				//  and resize the buffer accordingly
				ctx.input = ctx.input[:copy(ctx.input, ctx.input[rc:])]
			}
			return rc, nil
		}

		// Read the next prediction header
	readHeader:

		// Walk the buffer, filling in the predicted blanks,
		// relocating read bytes and and updating the guess table
		for i, a := 0, predicted; i < rc; i++ {
			if (flags & (1 << uint(i))) > 0 {
				// Guess succeeded, fill in from the table
				ctx.input[i] = ctx.table[ctx.hash]
			} else {
				// Relocate a read byte and advance the read byte index
				ctx.input[i], a = ctx.input[a], a+1
				// Guess failed, update the table
				ctx.table[ctx.hash] = ctx.input[i]
			}
			// Update the hash
			ctx.update(ctx.input[i])
		}

		// Copy the decompressed data to the output and accumulate the count

		copied = copy(output, ctx.input[:rc])

		total += copied

		// Check for remaining bytes that dont fit in the output buffer
		if copied < rc {
			// Shift the remaining bytes at the start of the buffer
			//  and resize the buffer accordingly
			ctx.input = ctx.input[:copy(ctx.input, ctx.input[copied:rc])]
		} else {
			// Clear the buffer
			ctx.input = ctx.input[:0]

			// Loop for another pass if there is available space in the output
			output = output[copied:]
			if len(output) > 0 && err == nil {
				goto readHeader
			}
		}

		return total, err
	})
}