Preparsing JSON

Preparse.go

// Example of how to preparse a JSON String.
// Useful if the json is massive and what you are looking for is on the top.
// 
// Use: 
// preParseString(JSONKey, JSONBody) => Value of JSONKey, or "" if not found.
// 
func preParseString(key string, body []byte) string {
	var buffer []byte
	level := 0
	qO := false   // quoteOpen
	eonf := false // end on next flush
	escaped := false
	for ii := 0; ii < len(body); ii++ {
		switch body[ii] {
		case '"':
			if !escaped {
				qO = !qO // Toggle.
				// Flush.
				if !qO {
					if len(buffer) > 0 {
						if eonf {
							return string(buffer)
						}
						if string(buffer) == key {
							eonf = true
						}
						buffer = make([]byte, 0) // Clear.
					}
				}
			} else {
				escaped = false
				buffer = append(buffer, body[ii])
			}
		case '{':
			if !qO {
				level++
			}else {
				buffer = append(buffer, body[ii])
			}
		case '}':
			if !qO {
				level--
			}else {
				buffer = append(buffer, body[ii])
			}
		case '[', ':': // Level handling.
			if qO {
				buffer = append(buffer, body[ii])
			}
			// Ignore.
		case ',', ']':
			if eonf && !qO {
				return ""
			}
			if qO {
				buffer = append(buffer, body[ii])
			}
		case '\\':
			if escaped {
				buffer = append(buffer, body[ii])
			}
			escaped = !escaped // TODO make sure the next character is the one we are escaping.
		default:
			if escaped {
				// Ignore?
				escaped = false
			} else if qO {
				if level == 1 {
					buffer = append(buffer, body[ii])
				}
			}
		}
	}
	return "" // If it isn't found, reutrn nil.
}

https://play.golang.org/p/8QhwnH5DNp