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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package lowmemjson_test
import (
"bytes"
"fmt"
"io"
"testing"
"github.com/stretchr/testify/assert"
"git.lukeshu.com/go/lowmemjson"
)
type ShortSum string
func (s ShortSum) EncodeJSON(w io.Writer) error {
// Test that it's OK to call lowmemjson.Encoder.Encode for the top-level value in a method.
return lowmemjson.NewEncoder(w).Encode(string(s))
}
type SumRun struct {
ChecksumSize int `json:",omitempty"`
Addr int64 `json:",omitempty"`
Sums ShortSum
}
type SumRunWithGaps struct {
Addr int64
Size int64
Runs []SumRun
}
func (sg SumRunWithGaps) EncodeJSON(w io.Writer) error {
if _, err := fmt.Fprintf(w, `{"Addr":%d,"Size":%d,"Runs":[`, sg.Addr, sg.Size); err != nil {
return err
}
cur := sg.Addr
for i, run := range sg.Runs {
if i > 0 {
if _, err := w.Write([]byte{','}); err != nil {
return err
}
}
if run.Addr > cur {
if _, err := fmt.Fprintf(w, `{"Gap":%d},`, run.Addr-cur); err != nil {
return err
}
}
if err := lowmemjson.NewEncoder(w).Encode(run); err != nil {
return err
}
}
end := sg.Addr + sg.Size
switch {
case end < cur:
return fmt.Errorf("invalid %T: addr went backwards: %v < %v", sg, end, cur)
case end > cur:
if _, err := fmt.Fprintf(w, `,{"Gap":%d}`, end-cur); err != nil {
return err
}
}
if _, err := w.Write([]byte("]}")); err != nil {
return err
}
return nil
}
func (sg *SumRunWithGaps) DecodeJSON(r io.RuneScanner) error {
*sg = SumRunWithGaps{}
var name string
return lowmemjson.DecodeObject(r,
func(r io.RuneScanner) error {
return lowmemjson.NewDecoder(r).Decode(&name)
},
func(r io.RuneScanner) error {
switch name {
case "Addr":
return lowmemjson.NewDecoder(r).Decode(&sg.Addr)
case "Size":
return lowmemjson.NewDecoder(r).Decode(&sg.Size)
case "Runs":
return lowmemjson.DecodeArray(r, func(r io.RuneScanner) error {
var run SumRun
if err := lowmemjson.NewDecoder(r).Decode(&run); err != nil {
return err
}
if run.ChecksumSize > 0 {
sg.Runs = append(sg.Runs, run)
}
return nil
})
default:
return fmt.Errorf("unknown key %q", name)
}
})
}
func TestMethods(t *testing.T) {
t.Parallel()
in := SumRunWithGaps{
Addr: 13631488,
Size: 416033783808,
Runs: []SumRun{
{
ChecksumSize: 4,
Addr: 1095761920,
Sums: "c160817cb5c72bbbe",
},
},
}
var buf bytes.Buffer
assert.NoError(t, lowmemjson.NewEncoder(&buf).Encode(in))
assert.Equal(t,
`{"Addr":13631488,"Size":416033783808,"Runs":[{"Gap":1082130432},{"ChecksumSize":4,"Addr":1095761920,"Sums":"c160817cb5c72bbbe"},{"Gap":416033783808}]}`,
buf.String())
var out SumRunWithGaps
assert.NoError(t, lowmemjson.NewDecoder(&buf).Decode(&out))
assert.Equal(t, in, out)
}
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