[Rprotobuf-commits] r768 - pkg/vignettes

[noreply at r-forge.r-project.org]

Author: murray
Date: 2014-01-13 22:26:03 +0100 (Mon, 13 Jan 2014)
New Revision: 768

Modified:
   pkg/vignettes/RProtoBuf-intro.Rnw
Log:
Wrap int64 usage behind an if statement for .Machine$sizeof.longlong
and correct a typo.



Modified: pkg/vignettes/RProtoBuf-intro.Rnw
===================================================================
--- pkg/vignettes/RProtoBuf-intro.Rnw	2014-01-13 19:59:07 UTC (rev 767)
+++ pkg/vignettes/RProtoBuf-intro.Rnw	2014-01-13 21:26:03 UTC (rev 768)
@@ -2038,7 +2038,8 @@
 Protocol Buffers are frequently used to pass data between different
 systems, however, and most other systems these days have support for
 64-bit integers.  To work around this, RProtoBuf allows users to get
-and set 64-bit integer types by treating them as characters.
+and set 64-bit integer types by treating them as characters when
+running on a platform with a 64-bit long long type available.
 
 <<echo=FALSE,print=FALSE>>=
 if (!exists("protobuf_unittest.TestAllTypes",
@@ -2054,9 +2055,11 @@
 precision:
 
 <<>>=
-test <- new(protobuf_unittest.TestAllTypes)
-test$repeated_int64 <- c(2^53, 2^53+1)
-length(unique(test$repeated_int64))
+if (.Machine$sizeof.longlong >= 8) {
+  test <- new(protobuf_unittest.TestAllTypes)
+  test$repeated_int64 <- c(2^53, 2^53+1)
+  length(unique(test$repeated_int64))
+}
 @
 
 However, we can specify the values as character strings so that the
@@ -2064,7 +2067,9 @@
 integer representation of the data.
 
 <<>>=
-test$repeated_int64 <- c("9007199254740992", "9007199254740993")
+if (.Machine$sizeof.longlong >= 8) {
+  test$repeated_int64 <- c("9007199254740992", "9007199254740993")
+}
 @
 
 When reading the value back into R, numeric types are returned by
@@ -2072,13 +2077,19 @@
 will be returned if the \texttt{RProtoBuf.int64AsString} option is set
 to \texttt{TRUE}.
 
-<<>>=
-options("RProtoBuf.int64AsString" = FALSE)
-test$repeated_int64
-length(unique(test$repeated_int64))
-options("RProtoBuf.int64AsString" = TRUE)
-test$repeated_int64
-length(unique(test$repeated_int64))
+% TODO: the if statement prevents us from seeing line by line
+% output inside the block (E.g. the output of test$repeated_int64).
+% This reduces the usefulness of this example when we are on a 64-bit
+% platform.  E.g. only the final ``2'' is returned.
+<<echo=TRUE,print=TRUE>>=
+if (.Machine$sizeof.longlong >= 8) {
+  options("RProtoBuf.int64AsString" = FALSE)
+  test$repeated_int64
+  length(unique(test$repeated_int64))
+  options("RProtoBuf.int64AsString" = TRUE)
+  test$repeated_int64
+  length(unique(test$repeated_int64))
+}
 @
 
 <<echo=FALSE,print=FALSE>>=
@@ -2128,7 +2139,7 @@
 structures using external pointers, etc ...). We'd like to thank
 Simon for his indirect involvment on \texttt{RProtoBuf}.
 
-The user defined table mechasnism, implemented by Duncan Temple Lang
+The user defined table mechanism, implemented by Duncan Temple Lang
 for the purpose of the \texttt{RObjectTables} package allowed the
 dynamic symbol lookup (see section~\ref{sec-lookup}). Many thanks
 to Duncan for this amazing feature.