### assumes that all chars are single-byte
write.dbf.SSN <- function(dataframe, file, factor2char = TRUE, max_nchar = 254)
{
suppressWarnings(warning("write.dbf.SSN"))
### need to check precision
allowed_classes <- c("logical", "integer", "numeric", "character",
"factor", "Date")
if (!is.data.frame(dataframe)) dataframe <- as.data.frame(dataframe)
if (any(sapply(dataframe, function(x) !is.null(dim(x)))))
stop("cannot handle matrix/array columns")
cl <- sapply(dataframe, function(x) class(x[1L]))
asis <- cl == "AsIs"
cl[asis & sapply(dataframe, mode) == "character"] <- "character"
if(length(cl0 <- setdiff(cl, allowed_classes)))
stop(sprintf(ngettext(length(cl0),
"data frame contains columns of unsupported class %s",
"data frame contains columns of unsupported classes %s"),
paste(dQuote(cl0), collapse = ",")), domain = NA)
m <- ncol(dataframe)
DataTypes <- c(logical="L", integer="N", numeric="F", character="C",
factor=if(factor2char) "C" else "N", Date="D")[cl]
for(i in seq_len(m)) {
x <- dataframe[[i]]
if(is.factor(x))
dataframe[[i]] <-
if(factor2char) as.character(x) else as.integer(x)
else if (inherits(x, "Date"))
dataframe[[i]] <- format(x, "%Y%m%d")
}
precision <- integer(m)
scale <- integer(m)
dfnames <- names(dataframe)
for (i in seq_len(m)) {
nlen <- nchar(dfnames[i], "b")
x <- dataframe[, i]
if (is.logical(x)) {
precision[i] <- 1L
scale[i] <- 0L
} else if (is.integer(x)) {
rx <- range(x, na.rm = TRUE)
rx[!is.finite(rx)] <- 0 # added RSB 2005-04-17
if (any(rx == 0)) rx <- rx + 1 # added RSB 2005-03-10
mrx <- as.integer(max(ceiling(log10(abs(rx))))+3L)
precision[i] <- min(max(nlen, mrx), 19L)
scale[i] <- 0L
} else if (is.double(x)) {
precision[i] <- 19L
rx <- range(x, na.rm = TRUE)
rx[!is.finite(rx)] <- 0 # added RSB 2005-04-17
mrx <- max(ceiling(log10(abs(rx))))
scale[i] <- min(precision[i] - ifelse(mrx > 0L, mrx+3L, 3L), 15L)
# modified RSB 2005-03-10 and 2005-04-17
} else if (is.character(x)) {
if(length(x) == sum(is.na(x))){
mf = max_nchar
} else {
mf <- max(nchar(x[!is.na(x)], "b"))
}
p <- max(nlen, mf)
if(p > max_nchar)
warning(gettext("character column %d will be truncated to %d bytes", i, max_nchar), domain = NA)
precision[i] <- min(p, max_nchar)
scale[i] <- 0L
} else stop("unknown column type in data frame")
}
if (any(is.na(precision))) stop("NA in precision") # added RSB 2005-04-17
if (any(is.na(scale))) stop("NA in scale") # added RSB 2005-04-17
#################################################################################
invisible( .Call("DoWritedbfSSN", as.character(file),
dataframe, as.integer(precision), as.integer(scale),
as.character(DataTypes)))
################################################################################
}
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