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https://github.com/wader/fq.git
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7c5215347d
Remove bitio.Buffer layer. bitio.Buffer was a kitchen sink layer with helpers now it's just a buffer and most functions have been moved to decode instead. bitio package now only have primitive types and functions simialar to standard library io and bytes packages. Make nearly eveything internally use bitio.Bit* interfaces so that slicing work correctly this will also make it possible to start experimenting with more complicated silcing helpers, ex things like: breplace(.header.bitrate; 123) to get a new buffer with bitrate changed.
105 lines
2.4 KiB
Go
105 lines
2.4 KiB
Go
package hexpairwriter
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// TODO: generalize and rename? make buffer more flexible
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import (
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"io"
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)
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type Writer struct {
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w io.Writer
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width int
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startLineOffset int
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fn func(v byte) string
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offset int
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buf []byte
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bufOffset int
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}
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// for i in $(seq 0 255) ; do printf "%02x" $i ; done | while read -n 32 s ; do echo "\"$s\""+; done
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const hexstring = "" +
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"000102030405060708090a0b0c0d0e0f" +
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"101112131415161718191a1b1c1d1e1f" +
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"202122232425262728292a2b2c2d2e2f" +
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"303132333435363738393a3b3c3d3e3f" +
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"404142434445464748494a4b4c4d4e4f" +
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"505152535455565758595a5b5c5d5e5f" +
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"606162636465666768696a6b6c6d6e6f" +
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"707172737475767778797a7b7c7d7e7f" +
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"808182838485868788898a8b8c8d8e8f" +
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"909192939495969798999a9b9c9d9e9f" +
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"a0a1a2a3a4a5a6a7a8a9aaabacadaeaf" +
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"b0b1b2b3b4b5b6b7b8b9babbbcbdbebf" +
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"c0c1c2c3c4c5c6c7c8c9cacbcccdcecf" +
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"d0d1d2d3d4d5d6d7d8d9dadbdcdddedf" +
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"e0e1e2e3e4e5e6e7e8e9eaebecedeeef" +
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"f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff"
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func Pair(c byte) string {
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return hexstring[int(c)*2 : int(c)*2+2]
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}
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func New(w io.Writer, width int, startLineOffset int, fn func(b byte) string) *Writer {
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return &Writer{
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w: w,
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width: width,
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startLineOffset: startLineOffset,
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fn: fn,
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offset: 0,
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// TODO: ansi length? nicer reusable buffer?
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buf: make([]byte, width*200+1), // worst case " " or "\n" + width*(XX "+ansi) + "\n"
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}
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}
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func (h *Writer) Write(p []byte) (n int, err error) {
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for h.offset < h.startLineOffset {
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b := []byte(" ")
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if h.offset%h.width == h.width-1 {
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b = []byte(" \n")
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}
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if _, err := h.w.Write(b); err != nil {
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return 0, err
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}
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h.offset++
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}
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if h.offset > h.startLineOffset {
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if h.offset%h.width == 0 {
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h.buf[0] = '\n'
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} else {
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h.buf[0] = ' '
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}
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h.bufOffset = 1
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}
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for i := 0; i < len(p); i++ {
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lineOffset := h.offset % h.width
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s := []byte(h.fn(p[i]))
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copy(h.buf[h.bufOffset:], s)
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h.bufOffset += len(s)
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h.buf[h.bufOffset] = ' '
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h.bufOffset++
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var b []byte
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switch {
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case i < len(p)-1 && lineOffset == h.width-1:
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h.buf[h.bufOffset-1] = '\n'
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b = h.buf[:h.bufOffset]
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case i == len(p)-1:
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b = h.buf[:h.bufOffset-1]
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}
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// log.Printf("i=%d h.bufOffset=%d lineOffset=%d h.width-1=%d b=%q\n", i, h.bufOffset, lineOffset, h.width-1, b)
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if b != nil {
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if _, err := h.w.Write(b); err != nil {
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return 0, err
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}
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h.bufOffset = 0
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}
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h.offset++
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}
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return len(p), nil
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}
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