add support for md5sum(bytes=) hashing a raw vector

git-svn-id: https://svn.r-project.org/R/trunk@87162 00db46b3-68df-0310-9c12-caf00c1e9a41

doc/NEWS.Rd

@@ -87,6 +87,10 @@
 
  \item The set operations now avoid the \code{as.vector()}
  transformation for same-kind apparently vector-like operands.
+
+ \item \code{md5sum()} can be used to compute an MD5 hash of a raw
+ vector of bytes by using the \code{bytes=} argument instead
+ of \code{files=}. The two arguments are mutually exclusive.
  }
  }
 

src/library/tools/R/md5.R

@@ -16,9 +16,16 @@
 # A copy of the GNU General Public License is available at
 # https://www.R-project.org/Licenses/
 
-md5sum <- function(files) {
- files <- path.expand(files)
- structure(.Call(C_Rmd5, files), names=files)
+md5sum <- function(files, bytes) {
+ if (!missing(files) && !missing(bytes))
+ stop("files and bytes are mutually exclusive")
+ if (!missing(bytes)) {
+ if (!is.raw(bytes)) stop("bytes must be a raw vector")
+ .Call(C_Rmd5, bytes)
+ } else {
+ files <- path.expand(files)
+ structure(.Call(C_Rmd5, files), names=files)
+ }
 }
 
 .installMD5sums <- function(pkgDir, outDir = pkgDir)

src/library/tools/man/md5sum.Rd

@@ -7,13 +7,15 @@
 \alias{md5sum}
 \title{Compute MD5 Checksums}
 \description{
- Compute the 32-byte MD5 hashes of one or more files.
+ Compute the 32-byte MD5 hashes of one or more files, or a raw vector of bytes.
 }
 \usage{
-md5sum(files)
+md5sum(files, bytes)
 }
 \arguments{
  \item{files}{character. The paths of file(s) whose contents are to be hashed.}
+ \item{bytes}{raw. Bytes to be hashed.
+ NB: \code{bytes} and \code{files} are mutually exclusive.}
 }
 \details{
  A MD5 \sQuote{hash} or \sQuote{checksum} or \sQuote{message digest} is
@@ -34,6 +36,8 @@ md5sum(files)
  equal to \code{files} (possibly expanded). The elements will be
  \code{NA} for non-existent or unreadable files, otherwise a
  32-character string of hexadecimal digits.
+
+ For \code{bytes} the result is a single 32-character string.
 }
 \source{
  The underlying C code was written by \I{Ulrich Drepper} and extracted from
@@ -44,6 +48,8 @@ md5sum(files)
 }
 \examples{
 as.vector(md5sum(dir(R.home(), pattern = "^COPY", full.names = TRUE)))
+md5sum(bytes=raw())
+md5sum(bytes=charToRaw("abc"))
 }
 \keyword{utilities}
 

src/library/tools/src/Rmd5.c

@@ -44,6 +44,16 @@ SEXP Rmd5(SEXP files)
  FILE *fp;
  unsigned char resblock[16];
 
+ /* RAW mode: hash of one buffer instead of files */
+ if (TYPEOF(files) == RAWSXP) {
+ /* there is really no failure possible, but just in case... */
+ if (!md5_buffer(RAW(files), XLENGTH(files), resblock))
+ return ScalarString(NA_STRING);
+ for(j = 0; j < 16; j++)
+ snprintf (out+2*j, 33-2*j, "%02x", resblock[j]);
+ return mkString(out);
+ }
+ /* otherwise list of files */
  if(!isString(files)) error(_("argument 'files' must be character"));
  PROTECT(ans = allocVector(STRSXP, nfiles));
  for(i = 0; i < nfiles; i++) {

src/library/tools/src/md5.c

@@ -163,12 +163,11 @@ md5_stream (FILE *stream, void *resblock)
  return 0;
 }
 
-#ifdef UNUSED
 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
  result is always in little endian byte order, so that a byte-wise
  output yields to the wanted ASCII representation of the message
  digest. */
-static void *
+void *
 md5_buffer (const char *buffer, size_t len, void *resblock)
 {
  struct md5_ctx ctx;
@@ -182,7 +181,6 @@ md5_buffer (const char *buffer, size_t len, void *resblock)
  /* Put result in desired memory area. */
  return md5_finish_ctx (&ctx, resblock);
 }
-#endif
 
 static void
  md5_process_bytes (const void *buffer, size_t len, struct md5_ctx *ctx)

src/library/tools/src/md5.h

@@ -100,6 +100,8 @@ struct md5_ctx
  resulting message digest number will be written into the 16 bytes
  beginning at RESBLOCK. */
 extern int md5_stream __P ((FILE *stream, void *resblock));
+/* same as above for a buffer instead of file; returns resblock on success */
+extern void* md5_buffer __P ((const char *buffer, size_t len, void *resblock));
 
 #ifndef ROL_UNUSED
 /* The following is from gnupg-1.0.2's cipher/bithelp.h. */

tests/Examples/tools-Ex.Rout.save

@@ -796,6 +796,10 @@ character(0)
 > 
 > as.vector(md5sum(dir(R.home(), pattern = "^COPY", full.names = TRUE)))
 [1] "eb723b61539feef013de476e68b5c50a"
+> md5sum(bytes=raw())
+[1] "d41d8cd98f00b204e9800998ecf8427e"
+> md5sum(bytes=charToRaw("abc"))
+[1] "900150983cd24fb0d6963f7d28e17f72"
 > 
 > 
 >