diff options
Diffstat (limited to 'vendor/github.com/buger/jsonparser/escape.go')
| -rw-r--r-- | vendor/github.com/buger/jsonparser/escape.go | 173 |
1 files changed, 0 insertions, 173 deletions
diff --git a/vendor/github.com/buger/jsonparser/escape.go b/vendor/github.com/buger/jsonparser/escape.go deleted file mode 100644 index 49669b942..000000000 --- a/vendor/github.com/buger/jsonparser/escape.go +++ /dev/null @@ -1,173 +0,0 @@ -package jsonparser - -import ( - "bytes" - "unicode/utf8" -) - -// JSON Unicode stuff: see https://tools.ietf.org/html/rfc7159#section-7 - -const supplementalPlanesOffset = 0x10000 -const highSurrogateOffset = 0xD800 -const lowSurrogateOffset = 0xDC00 - -const basicMultilingualPlaneReservedOffset = 0xDFFF -const basicMultilingualPlaneOffset = 0xFFFF - -func combineUTF16Surrogates(high, low rune) rune { - return supplementalPlanesOffset + (high-highSurrogateOffset)<<10 + (low - lowSurrogateOffset) -} - -const badHex = -1 - -func h2I(c byte) int { - switch { - case c >= '0' && c <= '9': - return int(c - '0') - case c >= 'A' && c <= 'F': - return int(c - 'A' + 10) - case c >= 'a' && c <= 'f': - return int(c - 'a' + 10) - } - return badHex -} - -// decodeSingleUnicodeEscape decodes a single \uXXXX escape sequence. The prefix \u is assumed to be present and -// is not checked. -// In JSON, these escapes can either come alone or as part of "UTF16 surrogate pairs" that must be handled together. -// This function only handles one; decodeUnicodeEscape handles this more complex case. -func decodeSingleUnicodeEscape(in []byte) (rune, bool) { - // We need at least 6 characters total - if len(in) < 6 { - return utf8.RuneError, false - } - - // Convert hex to decimal - h1, h2, h3, h4 := h2I(in[2]), h2I(in[3]), h2I(in[4]), h2I(in[5]) - if h1 == badHex || h2 == badHex || h3 == badHex || h4 == badHex { - return utf8.RuneError, false - } - - // Compose the hex digits - return rune(h1<<12 + h2<<8 + h3<<4 + h4), true -} - -// isUTF16EncodedRune checks if a rune is in the range for non-BMP characters, -// which is used to describe UTF16 chars. -// Source: https://en.wikipedia.org/wiki/Plane_(Unicode)#Basic_Multilingual_Plane -func isUTF16EncodedRune(r rune) bool { - return highSurrogateOffset <= r && r <= basicMultilingualPlaneReservedOffset -} - -func decodeUnicodeEscape(in []byte) (rune, int) { - if r, ok := decodeSingleUnicodeEscape(in); !ok { - // Invalid Unicode escape - return utf8.RuneError, -1 - } else if r <= basicMultilingualPlaneOffset && !isUTF16EncodedRune(r) { - // Valid Unicode escape in Basic Multilingual Plane - return r, 6 - } else if r2, ok := decodeSingleUnicodeEscape(in[6:]); !ok { // Note: previous decodeSingleUnicodeEscape success guarantees at least 6 bytes remain - // UTF16 "high surrogate" without manditory valid following Unicode escape for the "low surrogate" - return utf8.RuneError, -1 - } else if r2 < lowSurrogateOffset { - // Invalid UTF16 "low surrogate" - return utf8.RuneError, -1 - } else { - // Valid UTF16 surrogate pair - return combineUTF16Surrogates(r, r2), 12 - } -} - -// backslashCharEscapeTable: when '\X' is found for some byte X, it is to be replaced with backslashCharEscapeTable[X] -var backslashCharEscapeTable = [...]byte{ - '"': '"', - '\\': '\\', - '/': '/', - 'b': '\b', - 'f': '\f', - 'n': '\n', - 'r': '\r', - 't': '\t', -} - -// unescapeToUTF8 unescapes the single escape sequence starting at 'in' into 'out' and returns -// how many characters were consumed from 'in' and emitted into 'out'. -// If a valid escape sequence does not appear as a prefix of 'in', (-1, -1) to signal the error. -func unescapeToUTF8(in, out []byte) (inLen int, outLen int) { - if len(in) < 2 || in[0] != '\\' { - // Invalid escape due to insufficient characters for any escape or no initial backslash - return -1, -1 - } - - // https://tools.ietf.org/html/rfc7159#section-7 - switch e := in[1]; e { - case '"', '\\', '/', 'b', 'f', 'n', 'r', 't': - // Valid basic 2-character escapes (use lookup table) - out[0] = backslashCharEscapeTable[e] - return 2, 1 - case 'u': - // Unicode escape - if r, inLen := decodeUnicodeEscape(in); inLen == -1 { - // Invalid Unicode escape - return -1, -1 - } else { - // Valid Unicode escape; re-encode as UTF8 - outLen := utf8.EncodeRune(out, r) - return inLen, outLen - } - } - - return -1, -1 -} - -// unescape unescapes the string contained in 'in' and returns it as a slice. -// If 'in' contains no escaped characters: -// Returns 'in'. -// Else, if 'out' is of sufficient capacity (guaranteed if cap(out) >= len(in)): -// 'out' is used to build the unescaped string and is returned with no extra allocation -// Else: -// A new slice is allocated and returned. -func Unescape(in, out []byte) ([]byte, error) { - firstBackslash := bytes.IndexByte(in, '\\') - if firstBackslash == -1 { - return in, nil - } - - // Get a buffer of sufficient size (allocate if needed) - if cap(out) < len(in) { - out = make([]byte, len(in)) - } else { - out = out[0:len(in)] - } - - // Copy the first sequence of unescaped bytes to the output and obtain a buffer pointer (subslice) - copy(out, in[:firstBackslash]) - in = in[firstBackslash:] - buf := out[firstBackslash:] - - for len(in) > 0 { - // Unescape the next escaped character - inLen, bufLen := unescapeToUTF8(in, buf) - if inLen == -1 { - return nil, MalformedStringEscapeError - } - - in = in[inLen:] - buf = buf[bufLen:] - - // Copy everything up until the next backslash - nextBackslash := bytes.IndexByte(in, '\\') - if nextBackslash == -1 { - copy(buf, in) - buf = buf[len(in):] - break - } else { - copy(buf, in[:nextBackslash]) - buf = buf[nextBackslash:] - in = in[nextBackslash:] - } - } - - // Trim the out buffer to the amount that was actually emitted - return out[:len(out)-len(buf)], nil -} |