Refactor random data generation

Add new RandomDataProvider object and implement existing random number
generation in terms of that.  This enables end users to supply their
own random data providers.

3 files changed, 82 insertions, 0 deletions

diff --git a/libtests/build.mk b/libtests/build.mk
index 7a535953..22d9299e 100644
--- a/libtests/build.mk
+++ b/libtests/build.mk
@@ -12,6 +12,7 @@ BINS_libtests = \
 	png_filter \
 	pointer_holder \
 	qutil \
+	random \
 	rc4 \
 	sha2
 
diff --git a/libtests/qtest/random.test b/libtests/qtest/random.test
new file mode 100644
index 00000000..c3b4b9d7
--- /dev/null
+++ b/libtests/qtest/random.test
@@ -0,0 +1,16 @@
+#!/usr/bin/env perl
+require 5.008;
+BEGIN { $^W = 1; }
+use strict;
+
+require TestDriver;
+
+my $td = new TestDriver('random');
+
+$td->runtest("Random Data Providers",
+	     {$td->COMMAND => "random"},
+	     {$td->STRING => "random: end of tests\n",
+	      $td->EXIT_STATUS => 0},
+	     $td->NORMALIZE_NEWLINES);
+
+$td->report(1);
diff --git a/libtests/random.cc b/libtests/random.cc
new file mode 100644
index 00000000..644fdd91
--- /dev/null
+++ b/libtests/random.cc
@@ -0,0 +1,65 @@
+#include <qpdf/QUtil.hh>
+#include <qpdf/InsecureRandomDataProvider.hh>
+#include <qpdf/SecureRandomDataProvider.hh>
+#include <iostream>
+
+class BogusRandomDataProvider: public RandomDataProvider
+{
+  public:
+    virtual ~BogusRandomDataProvider()
+    {
+    }
+    BogusRandomDataProvider()
+    {
+    }
+    virtual void provideRandomData(unsigned char* data, size_t len)
+    {
+        for (size_t i = 0; i < len; ++i)
+        {
+            data[i] = static_cast<unsigned char>(i & 0xff);
+        }
+    }
+};
+
+int main()
+{
+    long r1 = QUtil::random();
+    long r2 = QUtil::random();
+    if (r1 == r2)
+    {
+        std::cout << "fail: two randoms were the same\n";
+    }
+    InsecureRandomDataProvider irdp;
+    irdp.provideRandomData(reinterpret_cast<unsigned char*>(&r1), 4);
+    irdp.provideRandomData(reinterpret_cast<unsigned char*>(&r2), 4);
+    if (r1 == r2)
+    {
+        std::cout << "fail: two insecure randoms were the same\n";
+    }
+    SecureRandomDataProvider srdp;
+    srdp.provideRandomData(reinterpret_cast<unsigned char*>(&r1), 4);
+    srdp.provideRandomData(reinterpret_cast<unsigned char*>(&r2), 4);
+    if (r1 == r2)
+    {
+        std::cout << "fail: two secure randoms were the same\n";
+    }
+    BogusRandomDataProvider brdp;
+    QUtil::setRandomDataProvider(&brdp);
+    r1 = QUtil::random();
+    r2 = QUtil::random();
+    if (r1 != r2)
+    {
+        std::cout << "fail: two bogus randoms were different\n";
+    }
+    unsigned char buf[4];
+    QUtil::initializeWithRandomBytes(buf, 4);
+    if (! ((buf[0] == 0) &&
+           (buf[1] == 1) &&
+           (buf[2] == 2) &&
+           (buf[3] == 3)))
+    {
+        std::cout << "fail: bogus random didn't provide correct bytes\n";
+    }
+    std::cout << "random: end of tests\n";
+    return 0;
+}