bindata/translate.go

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// This work is subject to the CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
// license. Its contents can be found at:
// http://creativecommons.org/publicdomain/zero/1.0/
package main
import (
"compress/gzip"
"fmt"
"io"
)
// Translate the input file with optional GZIP compression.
// input [-> gzip] -> gowriter -> output.
func translate(input io.Reader, output io.Writer, pkgname, funcname string, uncompressed bool) {
fmt.Fprintf(output, `package %s
import (`, pkgname)
if uncompressed {
fmt.Fprint(output, `
"reflect"
"unsafe"`)
} else {
fmt.Fprint(output, `
"bytes"
"compress/gzip"
"io"
"reflect"
"unsafe"`)
}
fmt.Fprintf(output, `
)
var _%s = "`, funcname)
if uncompressed {
io.Copy(&GoWriter{Writer: output}, input)
} else {
gz := gzip.NewWriter(&GoWriter{Writer: output})
io.Copy(gz, input)
gz.Close()
}
fmt.Fprintf(output, `"
// %s returns the binary data for a given file.
func %s() []byte {`, funcname, funcname)
if uncompressed {
fmt.Fprintf(output, `
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// This bit of black magic ensures we do not get
// unneccesary memcpy's and can read directly from
// the .rodata section.
var empty [0]byte
sx := (*reflect.StringHeader)(unsafe.Pointer(&_%s))
b := empty[:]
bx := (*reflect.SliceHeader)(unsafe.Pointer(&b))
bx.Data = sx.Data
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bx.Len = len(_%s)
bx.Cap = bx.Len
return b`, funcname, funcname)
} else {
fmt.Fprintf(output, `
// This bit of black magic ensures we do not get
// unneccesary memcpy's and can read directly from
// the .rodata section.
var empty [0]byte
sx := (*reflect.StringHeader)(unsafe.Pointer(&_%s))
b := empty[:]
bx := (*reflect.SliceHeader)(unsafe.Pointer(&b))
bx.Data = sx.Data
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bx.Len = len(_%s)
bx.Cap = bx.Len
gz, err := gzip.NewReader(bytes.NewBuffer(b))
if err != nil {
panic("Decompression failed: " + err.Error())
}
var buf bytes.Buffer
io.Copy(&buf, gz)
gz.Close()
return buf.Bytes()`, funcname, funcname)
}
fmt.Fprintf(output, "\n}")
}