Check-in [3ea011cf07]
Overview
SHA1:3ea011cf07938f5ec605e43ea957f6135dd47e57
Date: 2015-01-14 20:46:02
User: spaskalev
Comment:Use for range in mtf's encoder for the position table.
Timelines: family | ancestors | descendants | both | trunk
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Tags And Properties
Context
2015-01-26
20:30
[61b0c5b57a] Added tbd from gophergala/tbd :) (user: spaskalev, tags: trunk)
2015-01-14
20:46
[3ea011cf07] Use for range in mtf's encoder for the position table. (user: spaskalev, tags: trunk)
2015-01-11
08:44
[90877fa64f] Switched encoding/fibonacci.Encoder back to using a 2-bytes array as a preallocated write buffer. It seems that it otherwise escapes everytime and calls a causes a lot of allocations and subsequent gc work. (user: spaskalev, tags: trunk)
Changes

Modified src/0dev.org/encoding/mtf/mtf.go from [76460f96cb] to [f784336e1a].

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type context struct {
	table [256]byte
}

// Encodes data in place
func (c *context) encode(data []byte) {
	for index, value := range data {
		// Loop over the MTF table
		for i := byte(0); i <= 255; i++ {
			if c.table[i] == value {
				// Output the value
				data[index] = i

				// Shift the table
				copy(c.table[1:], c.table[:i])

				// Restore the value in front and break
				c.table[0] = value
				break
			}
		}
	}
}

// Decode data in place







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type context struct {
	table [256]byte
}

// Encodes data in place
func (c *context) encode(data []byte) {
	for dataIndex, dataValue := range data {
		// Loop over the MTF table
		for tableIndex, tableValue := range c.table {
			if tableValue == dataValue {
				// Output the value
				data[dataIndex] = byte(tableIndex)

				// Shift the table
				copy(c.table[1:], c.table[:tableIndex])

				// Restore the value in front and break
				c.table[0] = dataValue
				break
			}
		}
	}
}

// Decode data in place

Modified src/0dev.org/encoding/mtf/mtf_test.go from [74a3c46eb8] to [7051812004].

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	io.Copy(&output, decoder)
	processed := output.Bytes()

	delta := diff.Diff(diff.D{Len1: len(data), Len2: len(processed),
		EqualFunc: func(i, j int) bool { return data[i] == processed[j] }})
	if len(delta.Added) > 0 || len(delta.Removed) > 0 {
		t.Error("Differences detected ", delta)
	}
}







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	io.Copy(&output, decoder)
	processed := output.Bytes()

	delta := diff.Diff(diff.D{Len1: len(data), Len2: len(processed),
		EqualFunc: func(i, j int) bool { return data[i] == processed[j] }})
	if len(delta.Added) > 0 || len(delta.Removed) > 0 {
		t.Error("Differences detected ", delta, processed)
	}
}