Fix sign and conversion warnings (major)

This makes all integer type conversions that have potential data loss
explicit with calls that do range checks and raise an exception. After
this commit, qpdf builds with no warnings when -Wsign-conversion
-Wconversion is used with gcc or clang or when -W3 -Wd4800 is used
with MSVC. This significantly reduces the likelihood of potential
crashes from bogus integer values.

There are some parts of the code that take int when they should take
size_t or an offset. Such places would make qpdf not support files
with more than 2^31 of something that usually wouldn't be so large. In
the event that such a file shows up and is valid, at least qpdf would
raise an error in the right spot so the issue could be legitimately
addressed rather than failing in some weird way because of a silent
overflow condition.

1 files changed, 17 insertions, 15 deletions

diff --git a/libtests/bits.cc b/libtests/bits.cc
index 3b274f93..1dfd42ed 100644
--- a/libtests/bits.cc
+++ b/libtests/bits.cc
@@ -1,6 +1,8 @@
 #include <qpdf/BitStream.hh>
 #include <qpdf/BitWriter.hh>
 #include <qpdf/Pl_Buffer.hh>
+#include <qpdf/QUtil.hh>
+#include <qpdf/QIntC.hh>
 #include <iostream>
 #include <stdio.h>
 #include <stdlib.h>
@@ -12,8 +14,8 @@
 #include "../libqpdf/bits.icc"
 
 static void
-print_values(int byte_offset, unsigned int bit_offset,
-	     unsigned int bits_available)
+print_values(long long byte_offset, size_t bit_offset,
+	     size_t bits_available)
 {
     std::cout << "byte offset = " << byte_offset << ", "
 	      << "bit offset = " << bit_offset << ", "
@@ -22,11 +24,11 @@ print_values(int byte_offset, unsigned int bit_offset,
 
 static void
 test_read_bits(unsigned char const* buf,
-	       unsigned char const*& p, unsigned int& bit_offset,
-	       unsigned int& bits_available, int bits_wanted)
+	       unsigned char const*& p, size_t& bit_offset,
+	       size_t& bits_available, size_t bits_wanted)
 {
     unsigned long result =
-	read_bits(p, bit_offset, bits_available, bits_wanted);
+	QIntC::to_ulong(read_bits(p, bit_offset, bits_available, bits_wanted));
 
     std::cout << "bits read: " << bits_wanted << ", result = " << result
 	      << std::endl;
@@ -34,12 +36,12 @@ test_read_bits(unsigned char const* buf,
 }
 
 static void
-test_write_bits(unsigned char& ch, unsigned int& bit_offset, unsigned long val,
-		int bits, Pl_Buffer* bp)
+test_write_bits(unsigned char& ch, size_t& bit_offset, unsigned long val,
+		size_t bits, Pl_Buffer* bp)
 {
     write_bits(ch, bit_offset, val, bits, bp);
-    printf("ch = %02x, bit_offset = %d\n",
-           static_cast<unsigned int>(ch), bit_offset);
+    std::cout << "ch = " << QUtil::uint_to_string_base(ch, 16, 2)
+              << ", bit_offset = " << bit_offset << std::endl;
 }
 
 static void
@@ -51,10 +53,10 @@ print_buffer(Pl_Buffer* bp)
     size_t l = b->getSize();
     for (unsigned long i = 0; i < l; ++i)
     {
-	printf("%02x%s", static_cast<unsigned int>(p[i]),
-	       (i == l - 1) ? "\n" : " ");
+        std::cout << QUtil::uint_to_string_base(p[i], 16, 2)
+                  << ((i == l - 1) ? "\n" : " ");
     }
-    printf("\n");
+    std::cout << std::endl;
     delete b;
 }
 
@@ -71,8 +73,8 @@ test()
     };
 
     unsigned char const* p = buf;
-    unsigned int bit_offset = 7;
-    unsigned int bits_available = 64;
+    size_t bit_offset = 7;
+    size_t bits_available = 64;
 
     // 11110:101 0:001010:1 01100101: 01111001
     // 0:00:1:0010 10001001 01110101 01001:011
@@ -163,7 +165,7 @@ test()
     bw.writeBits(30UL, 5);
     bw.flush();
     bw.flush();
-    bw.writeBits(0xABUL, 8);
+    bw.writeBitsInt(0xAB, 8);
     bw.flush();
     print_buffer(bp);
     bw.writeBitsSigned(-1, 3);  // 111