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dta.byte <- 251
dta.short <- 252
dta.long <- 253
dta.float <- 254
dta.double <- 255
dta.byte.missrange <- c(0x64,0x7f)
dta.short.missrange <- c(0x7fe5,0x7fff)
dta.long.missrange <- c(0x7fffffe5L,0x7fffffffL)
dta.float.missrange <- c(2.0^0x7f,Inf)
dta.double.missrange <- c(2.0^0x3ff,Inf)
missnames <- paste(".",c("",letters),sep="")
dta.byte.misslab <- structure(0x64 + 1:27,names=missnames)
dta.short.misslab <- structure(0x7fe4 + 1:27,names=missnames)
dta.long.misslab <- structure(0x7fffffe4L + 1:27,names=missnames)
dta.float.misslab <- structure((1+(0:26)/16^3)*2.0^0x7f,names=missnames)
dta.double.misslab <- structure((1+(0:26)/16^3)*2.0^0x3ff,names=missnames)
new.dta <- function(file) .Call("dta_file_open",file,"rb")
dta.read.version <- function(bf) .Call("dta_read_version",bf)
dta.read.header <- function(bf,lablen).Call("dta_read_header",bf,lablen)
dta.read.descriptors <- function(bf,nvar,len.varn,len.fmt,len.lbl)
.Call("dta_read_descriptors",bf,nvar,len.varn,len.fmt,len.lbl)
dta.read.varlabs <- function(bf,nvar,len.varlab)
.Call("dta_read_varlabs",bf,nvar,len.varlab)
dta.read.expansion.fields <- function(bf,shortext)
.Call("dta_read_expansion_fields",bf,shortext)
# dta.read.data <- function(bf,nobs,types)
# .Call("dta_read_data",bf,nobs,types)
dta.read.labels <- function(bf,lbllen,padding)
.Call("dta_read_labels",bf,lbllen,padding)
# dta.read.chunk <- function(bf,vars,obs,types)
# .Call("dta_read_chunk",bf,vars,obs,types)
dta.trans.types <- function(types)
.Call("dta_trans_types",types)
dta.calc.obssize <- function(bf,types)
.Call("dta_calc_obssize",bf,types)
dta.tell <- function(bf) .Call("dta_ftell",bf)
dta.seek <- function(bf,pos,whence) .Call("dta_fseek",bf,pos,whence)
dta.feof <- function(bf) .Call("dta_feof",bf)
dta.skip.records <- function(bf,n) .Call("dta_skip_records",bf,n)
dta.seek.data <- function(bf) .Call("dta_seek_data",bf)
get.dictionary.dta <- function(bf){
version <- dta.read.version(bf)
if(version==105){ ## Stata 5
version.string <- "Stata 5"
len.varn <- 8
len.fmt <- 11
len.lbl <- 8
len.varlab <- 31
ext.short <- TRUE
conv.types <- FALSE
}
else if(version==108){ ## Stata 6
version.string <- "Stata 6"
len.varn <- 8
len.fmt <- 11
len.lbl <- 8
len.varlab <- 80
ext.short <- TRUE
conv.types <- FALSE
}
else if(version==110){ ## Stata 7
version.string <- "Stata 7"
len.varn <- 32
len.fmt <- 11
len.lbl <- 32
len.varlab <- 80
ext.short <- FALSE
conv.types <- TRUE
}
else if(version==111){ ## Stata 7 SE
version.string <- "Stata 7 SE"
len.varn <- 32
len.fmt <- 11
len.lbl <- 32
len.varlab <- 80
ext.short <- FALSE
conv.types <- FALSE
}
else if(version==113){ ## Stata 8
version.string <- "Stata 8"
len.varn <- 32
len.fmt <- 11
len.lbl <- 32
len.varlab <- 80
ext.short <- FALSE
conv.types <- FALSE
}
else if(version %in% c(114,115)){ ## Newer
version.string <- if(version==114) "Stata 9" else "Stata 10"
len.varn <- 32
len.fmt <- 48
len.lbl <- 32
len.varlab <- 80
ext.short <- FALSE
conv.types <- FALSE
} else {
stop("version ",version," not yet supported")
}
hdr <- dta.read.header(bf,len.varlab)
nobs <- hdr$nobs
nvar <- hdr$nvar
descriptors <- dta.read.descriptors(bf,
nvar=nvar,
len.varn=len.varn,
len.fmt=len.fmt,
len.lbl=len.lbl)
varnames <- descriptors$varlist
types <- if(conv.types) dta.trans.types(descriptors$typelist)
else descriptors$typelist
names(types) <- varnames
obs_size <- dta.calc.obssize(bf,types)
varlab <- dta.read.varlabs(bf,
nvar=nvar,
len.varlab=len.varlab)
names(varlab) <- varnames
dta.read.expansion.fields(bf,ext.short)
vallabs <- descriptors$lbllist
names(vallabs) <- varnames
vallabs <- vallabs[nzchar(vallabs)]
if(version>105){
dta.skip.records(bf,nobs)
vallab.patterns <- list()
while(!dta.feof(bf))
vallab.patterns <- c(vallab.patterns,dta.read.labels(bf,len.lbl,3))
if(!any(sapply(vallab.patterns,length)>0))
vallab.patterns <- NULL
}
else
vallab.patterns <- NULL
if(length(vallab.patterns)){
vallabs[] <- vallab.patterns[vallabs]
}
if(version >= 113){
missing.values <- dta_missing.values(types)
missval_labels <- dta_missval_labels(types)
}
else {
missing.values <- NULL
missval_labels <- NULL
}
list(names=varnames,
types=types,
nobs=nobs,
nvar=nvar,
varlabs=varlab,
value.labels=vallabs,
missing.values=missing.values,
missval_labels=missval_labels,
version.string=version.string
)
}
dta_missing.values <- function(types){
nvar <- length(length)
missing.values <- vector(nvar,mode="list")
missing.values[types==dta.byte] <- list(list(range=dta.byte.missrange))
missing.values[types==dta.short] <- list(list(range=dta.short.missrange))
missing.values[types==dta.long] <- list(list(range=dta.long.missrange))
missing.values[types==dta.float] <- list(list(range=dta.float.missrange))
missing.values[types==dta.double] <- list(list(range=dta.double.missrange))
names(missing.values) <- names(types)
missing.values
}
dta_missval_labels <- function(types){
nvar <- length(length)
missval_labels <- vector(nvar,mode="list")
missval_labels[types==dta.byte] <- list(dta.byte.misslab)
missval_labels[types==dta.short] <- list(dta.short.misslab)
missval_labels[types==dta.long] <- list(dta.long.misslab)
missval_labels[types==dta.float] <- list(dta.float.misslab)
missval_labels[types==dta.double] <- list(dta.double.misslab)
names(missval_labels) <- names(types)
missval_labels
}
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