diff options
Diffstat (limited to 'vendor/github.com/rs/zerolog/internal/json/string.go')
-rw-r--r-- | vendor/github.com/rs/zerolog/internal/json/string.go | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/vendor/github.com/rs/zerolog/internal/json/string.go b/vendor/github.com/rs/zerolog/internal/json/string.go new file mode 100644 index 00000000..fd7770f2 --- /dev/null +++ b/vendor/github.com/rs/zerolog/internal/json/string.go @@ -0,0 +1,149 @@ +package json + +import ( + "fmt" + "unicode/utf8" +) + +const hex = "0123456789abcdef" + +var noEscapeTable = [256]bool{} + +func init() { + for i := 0; i <= 0x7e; i++ { + noEscapeTable[i] = i >= 0x20 && i != '\\' && i != '"' + } +} + +// AppendStrings encodes the input strings to json and +// appends the encoded string list to the input byte slice. +func (e Encoder) AppendStrings(dst []byte, vals []string) []byte { + if len(vals) == 0 { + return append(dst, '[', ']') + } + dst = append(dst, '[') + dst = e.AppendString(dst, vals[0]) + if len(vals) > 1 { + for _, val := range vals[1:] { + dst = e.AppendString(append(dst, ','), val) + } + } + dst = append(dst, ']') + return dst +} + +// AppendString encodes the input string to json and appends +// the encoded string to the input byte slice. +// +// The operation loops though each byte in the string looking +// for characters that need json or utf8 encoding. If the string +// does not need encoding, then the string is appended in its +// entirety to the byte slice. +// If we encounter a byte that does need encoding, switch up +// the operation and perform a byte-by-byte read-encode-append. +func (Encoder) AppendString(dst []byte, s string) []byte { + // Start with a double quote. + dst = append(dst, '"') + // Loop through each character in the string. + for i := 0; i < len(s); i++ { + // Check if the character needs encoding. Control characters, slashes, + // and the double quote need json encoding. Bytes above the ascii + // boundary needs utf8 encoding. + if !noEscapeTable[s[i]] { + // We encountered a character that needs to be encoded. Switch + // to complex version of the algorithm. + dst = appendStringComplex(dst, s, i) + return append(dst, '"') + } + } + // The string has no need for encoding and therefore is directly + // appended to the byte slice. + dst = append(dst, s...) + // End with a double quote + return append(dst, '"') +} + +// AppendStringers encodes the provided Stringer list to json and +// appends the encoded Stringer list to the input byte slice. +func (e Encoder) AppendStringers(dst []byte, vals []fmt.Stringer) []byte { + if len(vals) == 0 { + return append(dst, '[', ']') + } + dst = append(dst, '[') + dst = e.AppendStringer(dst, vals[0]) + if len(vals) > 1 { + for _, val := range vals[1:] { + dst = e.AppendStringer(append(dst, ','), val) + } + } + return append(dst, ']') +} + +// AppendStringer encodes the input Stringer to json and appends the +// encoded Stringer value to the input byte slice. +func (e Encoder) AppendStringer(dst []byte, val fmt.Stringer) []byte { + if val == nil { + return e.AppendInterface(dst, nil) + } + return e.AppendString(dst, val.String()) +} + +//// appendStringComplex is used by appendString to take over an in +// progress JSON string encoding that encountered a character that needs +// to be encoded. +func appendStringComplex(dst []byte, s string, i int) []byte { + start := 0 + for i < len(s) { + b := s[i] + if b >= utf8.RuneSelf { + r, size := utf8.DecodeRuneInString(s[i:]) + if r == utf8.RuneError && size == 1 { + // In case of error, first append previous simple characters to + // the byte slice if any and append a replacement character code + // in place of the invalid sequence. + if start < i { + dst = append(dst, s[start:i]...) + } + dst = append(dst, `\ufffd`...) + i += size + start = i + continue + } + i += size + continue + } + if noEscapeTable[b] { + i++ + continue + } + // We encountered a character that needs to be encoded. + // Let's append the previous simple characters to the byte slice + // and switch our operation to read and encode the remainder + // characters byte-by-byte. + if start < i { + dst = append(dst, s[start:i]...) + } + switch b { + case '"', '\\': + dst = append(dst, '\\', b) + case '\b': + dst = append(dst, '\\', 'b') + case '\f': + dst = append(dst, '\\', 'f') + case '\n': + dst = append(dst, '\\', 'n') + case '\r': + dst = append(dst, '\\', 'r') + case '\t': + dst = append(dst, '\\', 't') + default: + dst = append(dst, '\\', 'u', '0', '0', hex[b>>4], hex[b&0xF]) + } + i++ + start = i + } + if start < len(s) { + dst = append(dst, s[start:]...) + } + return dst +} |