1## This takes the definition of UTF-8 as RFC3629 (2003), 2## but not all software does. 3## See also https://en.wikipedia.org/wiki/UTF-8 4 5x <- 1L:0x10FFFF 6y <- intToUtf8(x, multiple = TRUE) 7names(y) <- sprintf("U+%4x", x) 8## values in the surrogate range: not handled in R < 3.4.3 9sr <- 0xD800:0xDFFF 10stopifnot(is.na(y[sr])) 11stopifnot(!is.na(y[-sr])) 12## too large values: originally handled by UTF-8, but not in RFC3629 13## R >= 3.4.3 conforms to RFC3629 14stopifnot(is.na(intToUtf8(c(0x200000, 0x10FFFF + 1:10)))) 15 16## next command is quite slow. 17xx <- sapply(y, function(x) tryCatch(utf8ToInt(x), 18 error = function(e) NA_character_)) 19invalid <- sr # previously included 0xFFFE and 0xFFFF 20 # but not other 'noncharacters'. 21stopifnot(is.na(xx[invalid]), !is.na(xx[!invalid])) 22stopifnot(xx[!invalid] == x[!invalid]) 23 24## The pre-2003 UTF-8 standard converted larger code-points to 4-6 bytes, 25## and was followed by intToUtf8 in earlier versions of R. 26## Earlier conversion of 0x111111, 0x200001, 0x10000001) 27x <- c("\xf4\x91\x84\x91", "\xf8\x80\x80\x80\x81", "\xfc\x90\x80\x80\x80\x81") 28xx <- sapply(x, function(x) tryCatch(utf8ToInt(x), 29 error = function(e) NA_character_)) 30stopifnot(is.na(xx)) # first was not in R < 3.4.3 31 32### test surrogate pairs 33surrogate_pair <- function(x) 34{ 35 if(any(x < 0x10000 | x > 0x10FFFF)) 36 stop("Surrogate pairs apply only to supplementary planes") 37 x <- x - 0x10000 38 as.vector(rbind(0xD800 + x %/% 1024, 0xDC00 + x %% 1024)) 39} 40## check the example: 41xx <- surrogate_pair(0x10437) 42sprintf("%X", xx) 43stopifnot(xx == c(0xD801, 0xDC37)) 44 45## there are 2^20 surrogate pairs, but fast enough to check them all 46x <- 0x10000:0x10FFFF 47x1 <- intToUtf8(x) 48x2 <- utf8ToInt(x1) 49stopifnot(x2 == x) 50 51z <- surrogate_pair(x) 52x1 <- intToUtf8(z, allow_surrogate_pairs = TRUE) 53x2 <- utf8ToInt(x1) 54stopifnot(x2 == x) 55