diff --git a/src/bmffimage.cpp b/src/bmffimage.cpp
index e17fd6cb54..83ec152184 100644
--- a/src/bmffimage.cpp
+++ b/src/bmffimage.cpp
@@ -203,7 +203,7 @@ class BrotliDecoderWrapper {
 void BmffImage::brotliUncompress(const byte* compressedBuf, size_t compressedBufSize, DataBuf& arr) {
   BrotliDecoderWrapper decoder;
   size_t uncompressedLen = compressedBufSize * 2;  // just a starting point
-  BrotliDecoderResult result;
+  BrotliDecoderResult result = BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT;
   int dos = 0;
   size_t available_in = compressedBufSize;
   const byte* next_in = compressedBuf;
@@ -211,7 +211,7 @@ void BmffImage::brotliUncompress(const byte* compressedBuf, size_t compressedBuf
   byte* next_out;
   size_t total_out = 0;
 
-  do {
+  while (result != BROTLI_DECODER_RESULT_SUCCESS) {
     arr.alloc(uncompressedLen);
     available_out = uncompressedLen - total_out;
     next_out = arr.data() + total_out;
@@ -234,7 +234,7 @@ void BmffImage::brotliUncompress(const byte* compressedBuf, size_t compressedBuf
       // something bad happened
       throw Error(ErrorCode::kerErrorMessage, BrotliDecoderErrorString(BrotliDecoderGetErrorCode(decoder.get())));
     }
-  } while (result != BROTLI_DECODER_RESULT_SUCCESS);
+  };
 
   if (result != BROTLI_DECODER_RESULT_SUCCESS) {
     throw Error(ErrorCode::kerFailedToReadImageData);
diff --git a/src/minoltamn_int.cpp b/src/minoltamn_int.cpp
index c1fa6edd5d..3192a037b9 100644
--- a/src/minoltamn_int.cpp
+++ b/src/minoltamn_int.cpp
@@ -1674,7 +1674,7 @@ static std::vector<std::string> split(const std::string& str, const std::string&
   std::vector<std::string> tokens;
   size_t prev = 0;
   size_t pos = 0;
-  do {
+  while (pos < str.length() && prev < str.length()) {
     pos = str.find(delim, prev);
     if (pos == std::string::npos)
       pos = str.length();
@@ -1682,7 +1682,7 @@ static std::vector<std::string> split(const std::string& str, const std::string&
     if (!token.empty())
       tokens.push_back(std::move(token));
     prev = pos + delim.length();
-  } while (pos < str.length() && prev < str.length());
+  };
   return tokens;
 }
 
diff --git a/src/pngchunk_int.cpp b/src/pngchunk_int.cpp
index 82ae6d4161..9e62855777 100644
--- a/src/pngchunk_int.cpp
+++ b/src/pngchunk_int.cpp
@@ -334,10 +334,10 @@ std::string PngChunk::makeMetadataChunk(const std::string& metadata, MetadataId
 
 void PngChunk::zlibUncompress(const byte* compressedText, unsigned int compressedTextSize, DataBuf& arr) {
   uLongf uncompressedLen = compressedTextSize * 2;  // just a starting point
-  int zlibResult;
+  int zlibResult = Z_BUF_ERROR;
   int dos = 0;
 
-  do {
+  while (zlibResult == Z_BUF_ERROR) {
     arr.alloc(uncompressedLen);
     zlibResult = uncompress(arr.data(), &uncompressedLen, compressedText, compressedTextSize);
     if (zlibResult == Z_OK) {
@@ -355,7 +355,7 @@ void PngChunk::zlibUncompress(const byte* compressedText, unsigned int compresse
       // something bad happened
       throw Error(ErrorCode::kerFailedToReadImageData);
     }
-  } while (zlibResult == Z_BUF_ERROR);
+  };
 
   if (zlibResult != Z_OK) {
     throw Error(ErrorCode::kerFailedToReadImageData);
@@ -364,10 +364,10 @@ void PngChunk::zlibUncompress(const byte* compressedText, unsigned int compresse
 
 std::string PngChunk::zlibCompress(const std::string& text) {
   auto compressedLen = static_cast<uLongf>(text.size() * 2);  // just a starting point
-  int zlibResult;
+  int zlibResult = Z_BUF_ERROR;
 
   DataBuf arr;
-  do {
+  while (zlibResult == Z_BUF_ERROR) {
     arr.resize(compressedLen);
     zlibResult = compress2(arr.data(), &compressedLen, reinterpret_cast<const Bytef*>(text.data()),
                            static_cast<uLong>(text.size()), Z_BEST_COMPRESSION);
@@ -390,7 +390,7 @@ std::string PngChunk::zlibCompress(const std::string& text) {
         // Something bad happened
         throw Error(ErrorCode::kerFailedToReadImageData);
     }
-  } while (zlibResult == Z_BUF_ERROR);
+  };
 
   return {arr.c_str(), arr.size()};
 
diff --git a/src/pngimage.cpp b/src/pngimage.cpp
index cf936b0739..0a2386b72e 100644
--- a/src/pngimage.cpp
+++ b/src/pngimage.cpp
@@ -75,7 +75,7 @@ static bool zlibToDataBuf(const byte* bytes, uLongf length, DataBuf& result) {
   uLongf uncompressedLen = length;  // just a starting point
   int zlibResult = Z_BUF_ERROR;
 
-  do {
+  while (zlibResult == Z_BUF_ERROR) {
     result.alloc(uncompressedLen);
     zlibResult = uncompress(result.data(), &uncompressedLen, bytes, length);
     // if result buffer is large than necessary, redo to fit perfectly.
@@ -95,7 +95,7 @@ static bool zlibToDataBuf(const byte* bytes, uLongf length, DataBuf& result) {
       else
         uncompressedLen *= 2;
     }
-  } while (zlibResult == Z_BUF_ERROR);
+  };
 
   return zlibResult == Z_OK;
 }
@@ -104,7 +104,7 @@ static bool zlibToCompressed(const byte* bytes, uLongf length, DataBuf& result)
   uLongf compressedLen = length;  // just a starting point
   int zlibResult = Z_BUF_ERROR;
 
-  do {
+  while (zlibResult == Z_BUF_ERROR) {
     result.alloc(compressedLen);
     zlibResult = compress(result.data(), &compressedLen, bytes, length);
     if (zlibResult == Z_BUF_ERROR) {
@@ -116,7 +116,7 @@ static bool zlibToCompressed(const byte* bytes, uLongf length, DataBuf& result)
       result.alloc(compressedLen);
       zlibResult = compress(result.data(), &compressedLen, bytes, length);
     }
-  } while (zlibResult == Z_BUF_ERROR);
+  };
 
   return zlibResult == Z_OK;
 }
@@ -443,9 +443,10 @@ void PngImage::readMetadata() {
       } else if (chunkType == "iCCP") {
         // The ICC profile name can vary from 1-79 characters.
         uint32_t iccOffset = 0;
-        do {
+        while (chunkData.read_uint8(iccOffset) != 0x00) {
           enforce(iccOffset < 80 && iccOffset < chunkLength, Exiv2::ErrorCode::kerCorruptedMetadata);
-        } while (chunkData.read_uint8(iccOffset++) != 0x00);
+          ++iccOffset;
+        };
 
         profileName_ = std::string(chunkData.c_str(), iccOffset - 1);
         ++iccOffset;  // +1 = 'compressed' flag
diff --git a/src/types.cpp b/src/types.cpp
index 88381372ed..210a784f07 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -460,11 +460,12 @@ void hexdump(std::ostream& os, const byte* buf, size_t len, size_t offset) {
   while (i < len) {
     os << "  " << std::setw(4) << std::setfill('0') << std::hex << i + offset << "  ";
     std::ostringstream ss;
-    do {
+    while (i < len && i % 16 != 0) {
       byte c = buf[i];
       os << std::setw(2) << std::setfill('0') << std::right << std::hex << static_cast<int>(c) << " ";
       ss << (static_cast<int>(c) >= 31 && static_cast<int>(c) < 127 ? static_cast<char>(buf[i]) : '.');
-    } while (++i < len && i % 16 != 0);
+      ++i;
+    };
     std::string::size_type width = 9 + (((i - 1) % 16 + 1) * 3);
     os << (width > pos ? "" : align.substr(width)) << ss.str() << "\n";
   }