adc23d5f96
git-subtree-dir: x git-subtree-mainline: 7d05a6ee8f44b314fa697a427439e5fa4d78c3d7 git-subtree-split: a10a11b9d371f36b7c3510da32a1d70b74e27bd1
71 lines
1.6 KiB
Go
71 lines
1.6 KiB
Go
package gguf
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import "io"
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// A reader implements a sliding window over an io.Reader.
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type reader struct {
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data []byte
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offset int
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r io.Reader
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err error
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}
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// release discards n bytes from the front of the window.
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func (b *reader) release(n int) {
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b.offset += n
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}
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// window returns the current window.
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// The window is invalidated by calls to release or extend.
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func (b *reader) window() []byte {
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return b.data[b.offset:]
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}
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// tuning constants for byteReader.extend.
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const (
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newBufferSize = 8 << 10
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minReadSize = newBufferSize >> 2
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)
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// extend extends the window with data from the underlying reader.
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func (b *reader) extend() int {
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if b.err != nil {
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return 0
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}
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remaining := len(b.data) - b.offset
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if remaining == 0 {
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b.data = b.data[:0]
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b.offset = 0
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}
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if cap(b.data)-len(b.data) >= minReadSize {
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// nothing to do, enough space exists between len and cap.
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} else if cap(b.data)-remaining >= minReadSize {
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// buffer has enough space if we move the data to the front.
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b.compact()
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} else {
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// otherwise, we must allocate/extend a new buffer
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b.grow()
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}
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remaining += b.offset
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n, err := b.r.Read(b.data[remaining:cap(b.data)])
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// reduce length to the existing plus the data we read.
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b.data = b.data[:remaining+n]
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b.err = err
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return n
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}
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// grow grows the buffer, moving the active data to the front.
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func (b *reader) grow() {
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buf := make([]byte, max(cap(b.data)*2, newBufferSize))
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copy(buf, b.data[b.offset:])
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b.data = buf
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b.offset = 0
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}
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// compact moves the active data to the front of the buffer.
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func (b *reader) compact() {
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copy(b.data, b.data[b.offset:])
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b.offset = 0
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}
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