66 lines
1.2 KiB
Go
66 lines
1.2 KiB
Go
package internal
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// Minimal protobuf wire helpers (bytes/string fields only).
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const (
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errCodeOverflow = -2
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errCodeTruncated = -1
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)
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func consumeVarint(b []byte) (uint64, int) {
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var x uint64
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var s uint
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for i, c := range b {
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if c < 0x80 {
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if i > 9 || i == 9 && c > 1 {
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return 0, errCodeOverflow
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}
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return x | uint64(c)<<s, i + 1
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}
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x |= uint64(c&0x7f) << s
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s += 7
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}
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return 0, errCodeTruncated
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}
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// ConsumeBytes parses a length-delimited bytes field.
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func ConsumeBytes(b []byte) ([]byte, int) {
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v, n := consumeVarint(b)
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if n < 0 {
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return nil, n
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}
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if v > uint64(len(b)-n) {
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return nil, errCodeOverflow
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}
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return b[n : n+int(v)], n + int(v)
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}
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// ConsumeString parses a length-delimited string field.
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func ConsumeString(b []byte) (string, int) {
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v, n := ConsumeBytes(b)
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if n < 0 {
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return "", n
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}
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return string(v), n
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}
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func parseError(code int) error {
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switch code {
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case errCodeOverflow:
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return errOverflow
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case errCodeTruncated:
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return errTruncated
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default:
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return errTruncated
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}
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}
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var (
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errOverflow = &parseErr{"overflow"}
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errTruncated = &parseErr{"truncated"}
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)
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type parseErr struct{ msg string }
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func (e *parseErr) Error() string { return "protowire: " + e.msg }
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