Function duplicateKey

json_fuzz_test.go:701–759

duplicateKey injects a duplicate object key, turning {"k":1} into {"k":1,"k":1}. This exercises duplicate-key handling: the parser should return the first value for Get without structural corruption.

(r *rand.Rand, data []byte)

// {"k":1,"k":1}. This exercises duplicate-key handling: the parser should
// return the first value for Get without structural corruption.
func duplicateKey(r *rand.Rand, data []byte) []byte {
	for i := 0; i+2 < len(data); i++ {
		if data[i] != '"' {
			continue
		}
		// Find the closing quote of this key.
		keyEnd := -1
		for k := i + 1; k < len(data); k++ {
			if data[k] == '"' && data[k-1] != '\\' {
				keyEnd = k
				break
			}
		}
		if keyEnd == -1 || keyEnd+1 >= len(data) || data[keyEnd+1] != ':' {
			continue
		}
		// Find the end of the value (next ',' or '}' or ']' at depth 0).
		valEnd := keyEnd + 2
		depth := 0
		inStr := false
	done:
		for valEnd < len(data) {
			b := data[valEnd]
			if inStr {
				if b == '"' && data[valEnd-1] != '\\' {
					inStr = false
				}
			} else {
				switch b {
				case '"':
					inStr = true
				case '{', '[':
					depth++
				case '}', ']':
					if depth == 0 {
						break done
					}
					depth--
				case ',':
					if depth == 0 {
						break done
					}
				}
			}
			valEnd++
		}
		if valEnd <= keyEnd+2 || valEnd > len(data) {
			continue
		}
		pair := data[i:valEnd]
		out := make([]byte, 0, len(data)+len(pair)+1)
		out = append(out, data[:valEnd]...)
		out = append(out, ',')
		out = append(out, pair...)
		out = append(out, data[valEnd:]...)
		return out
	}
	return data