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native.go
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native.go
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package native
/*
#include "zlib/zlib.h"
*/
import "C"
import "fmt"
const minWritable = 8192
const assumedCompressionFactor = 7
// StreamCloser can indicate whether their underlying stream is closed.
// If so, the StreamCloser must not be used anymore
type StreamCloser interface {
// IsClosed returns whether the StreamCloser has closed the underlying stream
IsClosed() bool
}
func grow(b []byte, n int) []byte {
if cap(b)-len(b) >= n {
return b
}
new := make([]byte, len(b), len(b)+n)
// supposedly faster than copy(new, b)
for i := 0; i < len(b); i++ {
new[i] = b[i]
}
return new
}
func determineError(parent error, errCode C.int) error {
var err error
switch errCode {
case C.Z_OK:
fallthrough
case C.Z_STREAM_END:
fallthrough
case C.Z_NEED_DICT:
return nil
case C.Z_STREAM_ERROR:
err = errStream
case C.Z_DATA_ERROR:
err = errData
case C.Z_MEM_ERROR:
err = errMem
case C.Z_VERSION_ERROR:
err = errVersion
case C.Z_BUF_ERROR:
err = errBuf
default:
err = errUnknown
}
if parent == nil {
return err
}
return fmt.Errorf("%s: %s", parent.Error(), err.Error())
}
func startMemAddress(b []byte) *byte {
if len(b) > 0 {
return &b[0]
}
if cap(b) > 0 {
return &b[:1][0]
}
b = append(b, 0)
ptr := &b[0]
b = b[0:0]
return ptr
}