Add random number functions to QUtil

3 files changed, 52 insertions, 18 deletions

diff --git a/include/qpdf/QUtil.hh b/include/qpdf/QUtil.hh
index cdeefd71..8baedab6 100644
--- a/include/qpdf/QUtil.hh
+++ b/include/qpdf/QUtil.hh
@@ -83,6 +83,18 @@ namespace QUtil
     // encoding for the unicode value passed in.
     QPDF_DLL
     std::string toUTF8(unsigned long uval);
+
+    // Wrapper around random from stdlib.  Calls srandom automatically
+    // the first time it is called.
+    QPDF_DLL
+    long random();
+
+    // Wrapper around srandom from stdlib.
+    QPDF_DLL
+    void srandom(unsigned int seed);
+
+    QPDF_DLL
+    void initializeWithRandomBytes(unsigned char* data, size_t len);
 };
 
 #endif // __QUTIL_HH__
diff --git a/libqpdf/Pl_AES_PDF.cc b/libqpdf/Pl_AES_PDF.cc
index 09c975d6..52876101 100644
--- a/libqpdf/Pl_AES_PDF.cc
+++ b/libqpdf/Pl_AES_PDF.cc
@@ -6,11 +6,6 @@
 #include <qpdf/rijndael.h>
 #include <string>
 #include <stdlib.h>
-#include <qpdf/qpdf-config.h>
-#ifndef HAVE_RANDOM
-# define random rand
-# define srandom srand
-#endif
 
 bool Pl_AES_PDF::use_static_iv = false;
 
@@ -155,15 +150,6 @@ Pl_AES_PDF::finish()
 void
 Pl_AES_PDF::initializeVector()
 {
-    static bool seeded_random = false;
-    if (! seeded_random)
-    {
-	// Seed the random number generator with something simple, but
-	// just to be interesting, don't use the unmodified current
-	// time....
-	srandom((int)QUtil::get_current_time() ^ 0xcccc);
-	seeded_random = true;
-    }
     if (use_zero_iv)
     {
 	for (unsigned int i = 0; i < this->buf_size; ++i)
@@ -184,10 +170,7 @@ Pl_AES_PDF::initializeVector()
     }
     else
     {
-	for (unsigned int i = 0; i < this->buf_size; ++i)
-	{
-	    this->cbc_block[i] = (unsigned char)((random() & 0xff0) >> 4);
-	}
+        QUtil::initializeWithRandomBytes(this->cbc_block, this->buf_size);
     }
 }
 
diff --git a/libqpdf/QUtil.cc b/libqpdf/QUtil.cc
index 20143087..3cdfdc49 100644
--- a/libqpdf/QUtil.cc
+++ b/libqpdf/QUtil.cc
@@ -333,3 +333,42 @@ QUtil::toUTF8(unsigned long uval)
 
     return result;
 }
+
+long
+QUtil::random()
+{
+    static bool seeded_random = false;
+    if (! seeded_random)
+    {
+	// Seed the random number generator with something simple, but
+	// just to be interesting, don't use the unmodified current
+	// time....
+        QUtil::srandom((int)QUtil::get_current_time() ^ 0xcccc);
+	seeded_random = true;
+    }
+
+#ifdef HAVE_RANDOM
+    return ::random();
+#else
+    return rand();
+#endif
+}
+
+void
+QUtil::srandom(unsigned int seed)
+{
+#ifdef HAVE_RANDOM
+    ::srandom(seed);
+#else
+    srand(seed);
+#endif
+}
+
+void
+QUtil::initializeWithRandomBytes(unsigned char* data, size_t len)
+{
+    for (size_t i = 0; i < len; ++i)
+    {
+        data[i] = (unsigned char)((QUtil::random() & 0xff0) >> 4);
+    }
+}