Caleb Gardner
16ef5838c3
This is largely a move to simplify a lot of the readers Also further breaks out functions.
78 lines
1.4 KiB
Go
78 lines
1.4 KiB
Go
package data
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import (
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"bytes"
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"io"
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"github.com/CalebQ42/squashfs/internal/decompress"
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)
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type Reader struct {
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master io.Reader
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cur io.Reader
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fragRdr io.Reader
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d decompress.Decompressor
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blockSizes []uint32
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blockSize uint32
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}
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func NewReader(r io.Reader, d decompress.Decompressor, blockSizes []uint32, blockSize uint32) (*Reader, error) {
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var out Reader
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out.d = d
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out.master = r
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out.blockSizes = blockSizes
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out.blockSize = blockSize
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err := out.advance()
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return &out, err
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}
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func (r *Reader) AddFragment(rdr io.Reader) {
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r.fragRdr = rdr
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}
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func realSize(siz uint32) uint32 {
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return siz &^ (1 << 24)
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}
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func (r *Reader) advance() (err error) {
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if clr, ok := r.cur.(io.Closer); ok {
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clr.Close()
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}
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if len(r.blockSizes) == 0 {
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return io.EOF
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}
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if len(r.blockSizes) == 1 && r.fragRdr != nil {
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r.cur = r.fragRdr
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} else {
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size := realSize(r.blockSizes[0])
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if size == 0 {
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r.cur = bytes.NewReader(make([]byte, r.blockSize))
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} else {
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r.cur = io.LimitReader(r.master, int64(size))
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if size == r.blockSizes[0] {
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r.cur, err = r.d.Reader(r.cur)
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}
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}
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}
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r.blockSizes = r.blockSizes[1:]
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return
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}
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func (r *Reader) Read(p []byte) (n int, err error) {
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n, err = r.cur.Read(p)
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if err == io.EOF {
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err = r.advance()
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if err != nil {
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return
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}
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var tmpN int
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tmp := make([]byte, len(p)-n)
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tmpN, err = r.Read(tmp)
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for i := range tmp {
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p[n+i] = tmp[i]
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}
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n += tmpN
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}
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return
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}
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