25 lines
772 B
Go
25 lines
772 B
Go
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package meta
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import "io"
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// readString reads and returns exactly n bytes from the provided io.Reader.
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//
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// The error is io.EOF only if no bytes were read. If an io.EOF happens after
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// reading some but not all the bytes, ReadFull returns io.ErrUnexpectedEOF. On
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// return, n == len(buf) if and only if err == nil.
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func readString(r io.Reader, n int) (string, error) {
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// readBuf is the local buffer used by readBytes.
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var backingArray [4096]byte // hopefully allocated on stack.
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readBuf := backingArray[:]
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if n > len(readBuf) {
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// The local buffer is initially 4096 bytes and will grow automatically if
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// so required.
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readBuf = make([]byte, n)
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}
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_, err := io.ReadFull(r, readBuf[:n])
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if err != nil {
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return "", err
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}
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return string(readBuf[:n]), nil
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}
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