add text argument to gzcon(); makes connection text-oriented (not tex…

…t mode)

git-svn-id: https://svn.r-project.org/R/trunk@70399 00db46b3-68df-0310-9c12-caf00c1e9a41

doc/NEWS.Rd

@@ -342,6 +342,10 @@
       directly aim for less than \code{min(n,p)} PC's.  The
       \code{summary()} and its \code{print()} method have been amended,
       notably for this case.
+
+      \item \code{gzcon} gains a new option \code{text}, which marks the
+      connection as text-oriented (so e.g. \code{pushBack} works). It is
+      still always opened in binary mode.
     }
   }
 

src/library/base/R/connections.R

@@ -267,8 +267,8 @@ writeChar <- function(object, con, nchars = nchar(object, type="chars"),
     .Internal(writeChar(object, con, as.integer(nchars), eos, useBytes))
 }
 
-gzcon <- function(con, level = 6, allowNonCompressed = TRUE)
-    .Internal(gzcon(con, level, allowNonCompressed))
+gzcon <- function(con, level = 6, allowNonCompressed = TRUE, text = FALSE)
+    .Internal(gzcon(con, level, allowNonCompressed, text))
 
 socketSelect <- function(socklist, write = FALSE, timeout = NULL) {
     if (is.null(timeout))

src/library/base/man/gzcon.Rd

@@ -14,13 +14,17 @@
   connection.  Standard \code{gzip} headers are assumed.
 }
 \usage{
-gzcon(con, level = 6, allowNonCompressed = TRUE)
+gzcon(con, level = 6, allowNonCompressed = TRUE, text = FALSE)
 }
 \arguments{
   \item{con}{a connection.}
   \item{level}{integer between 0 and 9, the compression level when writing.}
   \item{allowNonCompressed}{logical.  When reading, should
     non-compressed input be allowed?}
+  \item{text}{logical. Should the connection be text-oriented? This is
+    distinct from the mode of the connection (must always be binary).
+    If \code{TRUE}, \code{\link{pushBack}} works on the connection,
+    otherwise \code{\link{readBin}} and friends apply.}
 }
 \details{
   If \code{con} is open then the modified connection is opened.  Closing

src/main/connections.c

@@ -5482,6 +5482,7 @@ SEXP attribute_hidden do_gzcon(SEXP call, SEXP op, SEXP args, SEXP rho)
     int icon, level, allow;
     Rconnection incon = NULL, new = NULL;
     char *m, *mode = NULL /* -Wall */,  description[1000];
+    Rboolean text;
 
     checkArity(op, args);
     if(!inherits(CAR(args), "connection"))
@@ -5493,7 +5494,10 @@ SEXP attribute_hidden do_gzcon(SEXP call, SEXP op, SEXP args, SEXP rho)
     allow = asLogical(CADDR(args));
     if(allow == NA_INTEGER)
 	error(_("'allowNonCompression' must be TRUE or FALSE"));
-
+    text = asLogical(CADDDR(args));
+    if(text == NA_INTEGER)
+        error(_("'text' must be TRUE or FALSE"));
+
     if(incon->isGzcon) {
 	warning(_("this is already a 'gzcon' connection"));
 	return CAR(args);
@@ -5524,7 +5528,7 @@ SEXP attribute_hidden do_gzcon(SEXP call, SEXP op, SEXP args, SEXP rho)
 	error(_("allocation of 'gzcon' connection failed"));
     }
     init_con(new, description, CE_NATIVE, mode);
-    new->text = FALSE;
+    new->text = text;
     new->isGzcon = TRUE;
     new->open = &gzcon_open;
     new->close = &gzcon_close;

src/main/names.c

@@ -869,7 +869,7 @@ FUNTAB R_FunTab[] =
 {"getConnection",do_getconnection,0,	11,	1,      {PP_FUNCALL, PREC_FN,	0}},
 {"getAllConnections",do_getallconnections,0,11, 0,      {PP_FUNCALL, PREC_FN,	0}},
 {"summary.connection",do_sumconnection,0,11,    1,      {PP_FUNCALL, PREC_FN,	0}},
-{"gzcon",	do_gzcon,	0,      11,     3,      {PP_FUNCALL, PREC_FN,	0}},
+{"gzcon",	do_gzcon,	0,      11,     4,      {PP_FUNCALL, PREC_FN,	0}},
 {"memCompress",do_memCompress,	0,	11,     2,      {PP_FUNCALL, PREC_FN,	0}},
 {"memDecompress",do_memDecompress,0,	11,     2,      {PP_FUNCALL, PREC_FN,	0}},