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https://github.com/wader/fq.git
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9b81d4d3ab
Preparation to make decoder use less memory and API more type safe. Now each scalar type has it's own struct type so it can store different things and enables to have a scalar interface. Also own types will enable experimenting with decode DLS designs like using chained methods that are type aware.
51 lines
1.5 KiB
Go
51 lines
1.5 KiB
Go
package ar
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import (
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"github.com/wader/fq/format"
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"github.com/wader/fq/pkg/decode"
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"github.com/wader/fq/pkg/interp"
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"github.com/wader/fq/pkg/scalar"
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)
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var probeFormat decode.Group
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func init() {
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interp.RegisterFormat(decode.Format{
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Name: format.AR,
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Description: "Unix archive",
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Groups: []string{format.PROBE},
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DecodeFn: decodeAr,
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Dependencies: []decode.Dependency{
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{Names: []string{format.PROBE}, Group: &probeFormat},
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},
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})
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}
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func decodeAr(d *decode.D, _ any) any {
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d.FieldUTF8("signature", 8, d.StrAssert("!<arch>\n"))
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d.FieldArray("files", func(d *decode.D) {
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for !d.End() {
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d.FieldStruct("file", func(d *decode.D) {
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d.FieldUTF8("identifier", 16, scalar.ActualTrimSpace)
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d.FieldUTF8("modification_timestamp", 12, scalar.ActualTrimSpace, scalar.TryStrSymParseUint(10))
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d.FieldUTF8("owner_id", 6, scalar.ActualTrimSpace, scalar.TryStrSymParseUint(10))
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d.FieldUTF8("group_id", 6, scalar.ActualTrimSpace, scalar.TryStrSymParseUint(10))
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d.FieldUTF8("file_mode", 8, scalar.ActualTrimSpace, scalar.TryStrSymParseUint(8)) // Octal
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sizeStr := d.FieldScalarUTF8("file_size", 10, scalar.ActualTrimSpace, scalar.TryStrSymParseUint(10))
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if sizeStr.Sym == nil {
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d.Fatalf("could not decode file_size")
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}
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size := int64(sizeStr.SymUint()) * 8
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d.FieldUTF8("ending_characters", 2)
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d.FieldFormatOrRawLen("data", size, probeFormat, nil)
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padding := d.AlignBits(16)
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if padding > 0 {
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d.FieldRawLen("padding", int64(padding))
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}
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})
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}
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})
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return nil
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}
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