coverity: remove dead code

Found with: CID 1521533
Unsigned compared against 0 (NO_EFFECT)

Signed-off-by: Rosen Penev <rosenp@gmail.com>

src/image.cpp

@@ -383,8 +383,6 @@ void Image::printIFDStructure(BasicIo& io, std::ostream& out, Exiv2::PrintStruct
       if (allocate64 > io.size()) {
         throw Error(ErrorCode::kerInvalidMalloc);
       }
-      // Overflow check
-      Internal::enforce(allocate64 <= std::numeric_limits<size_t>::max(), ErrorCode::kerCorruptedMetadata);
       DataBuf buf(allocate64);                     // allocate a buffer
       std::copy_n(dir.c_data(8), 4, buf.begin());  // copy dir[8:11] into buffer (short strings)
 

src/pngchunk_int.cpp

@@ -520,9 +520,6 @@ DataBuf PngChunk::readRawProfile(const DataBuf& text, bool iTXt) {
   while ('0' <= *sp && *sp <= '9') {
     // Compute the new length using unsigned long, so that we can check for overflow.
     const size_t newlength = (10 * length) + (*sp - '0');
-    if (newlength > std::numeric_limits<size_t>::max()) {
-      return {};  // Integer overflow.
-    }
     length = newlength;
     sp++;
     if (sp == eot) {

src/preview.cpp

@@ -874,8 +874,6 @@ DataBuf decodeBase64(const std::string& src) {
   const unsigned long destSize = (validSrcSize * 3) / 4;
 
   // allocate dest buffer
-  if (destSize > LONG_MAX)
-    return {};  // avoid integer overflow
   DataBuf dest(destSize);
 
   // decode

src/rafimage.cpp

@@ -245,11 +245,6 @@ void RafImage::readMetadata() {
 
   Internal::enforce(Safe::add(jpg_img_off_u32, jpg_img_len_u32) <= io_->size(), ErrorCode::kerCorruptedMetadata);
 
-#if LONG_MAX < UINT_MAX
-  Internal::enforce(jpg_img_off_u32 <= std::numeric_limits<uint32_t>::max(), ErrorCode::kerCorruptedMetadata);
-  Internal::enforce(jpg_img_len_u32 <= std::numeric_limits<uint32_t>::max(), ErrorCode::kerCorruptedMetadata);
-#endif
-
   auto jpg_img_off = static_cast<long>(jpg_img_off_u32);
   auto jpg_img_len = static_cast<long>(jpg_img_len_u32);
 

src/tiffcomposite_int.cpp

@@ -1456,7 +1456,7 @@ static const TagInfo* findTagInfo(uint16_t tag, IfdId group) {
   const TagInfo* result = nullptr;
   const TagInfo* tags = [=] {
     if (group == IfdId::gpsId)
-      return group == IfdId::exifId ? Internal::exifTagList() : Internal::gpsTagList();
+      return Internal::gpsTagList();
     return group == IfdId::exifId ? Internal::exifTagList() : nullptr;
   }();
   if (tags) {

src/value.cpp

@@ -977,7 +977,7 @@ std::ostream& TimeValue::write(std::ostream& os) const {
 int64_t TimeValue::toInt64(size_t /*n*/) const {
   // Returns number of seconds in the day in UTC.
   auto result = static_cast<int64_t>(time_.hour - time_.tzHour) * 60 * 60;
-  result += (time_.minute - time_.tzMinute) * 60;
+  result += static_cast<int64_t>(time_.minute - time_.tzMinute) * 60;
   result += time_.second;
   if (result < 0) {
     result += 86400;