mirror of https://github.com/certusone/wasmd.git
46 lines
1.1 KiB
Go
46 lines
1.1 KiB
Go
package ioutils
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import (
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"bytes"
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"compress/gzip"
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)
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// Note: []byte can never be const as they are inherently mutable
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var (
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// magic bytes to identify gzip.
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// See https://www.ietf.org/rfc/rfc1952.txt
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// and https://github.com/golang/go/blob/master/src/net/http/sniff.go#L186
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gzipIdent = []byte("\x1F\x8B\x08")
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// magic number for Wasm is "\0asm"
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// See https://webassembly.github.io/spec/core/binary/modules.html#binary-module
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wasmIdent = []byte("\x00\x61\x73\x6D")
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)
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// IsGzip returns checks if the file contents are gzip compressed
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func IsGzip(input []byte) bool {
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return len(input) >= 3 && bytes.Equal(gzipIdent, input[0:3])
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}
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// IsWasm checks if the file contents are of wasm binary
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func IsWasm(input []byte) bool {
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return bytes.Equal(input[:4], wasmIdent)
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}
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// GzipIt compresses the input ([]byte)
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func GzipIt(input []byte) ([]byte, error) {
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// Create gzip writer.
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var b bytes.Buffer
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w := gzip.NewWriter(&b)
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_, err := w.Write(input)
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if err != nil {
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return nil, err
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}
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err = w.Close() // You must close this first to flush the bytes to the buffer.
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if err != nil {
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return nil, err
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}
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return b.Bytes(), nil
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}
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