diff --git a/miniz_tinfl.c b/miniz_tinfl.c
index f7c8815..a2a2a3b 100644
--- a/miniz_tinfl.c
+++ b/miniz_tinfl.c
@@ -203,6 +203,10 @@ tinfl_status tinfl_decompress(tinfl_decompressor *r, const mz_uint8 *pIn_buf_nex
     size_t out_buf_size_mask = (decomp_flags & TINFL_FLAG_USING_NON_WRAPPING_OUTPUT_BUF) ? (size_t)-1 : ((pOut_buf_next - pOut_buf_start) + *pOut_buf_size) - 1, dist_from_out_buf_start;
 
     /* Ensure the output buffer's size is a power of 2, unless the output buffer is large enough to hold the entire output file (in which case it doesn't matter). */
+    if ((!pOut_buf_start) || (!pOut_buf_next) || (!pIn_buf_size) || (!pOut_buf_size))
+    {
+        return TINFL_STATUS_BAD_PARAM;
+    }
     if (((out_buf_size_mask + 1) & out_buf_size_mask) || (pOut_buf_next < pOut_buf_start))
     {
         *pIn_buf_size = *pOut_buf_size = 0;
diff --git a/miniz_zip.c b/miniz_zip.c
index 3fcff4e..3ed6a67 100644
--- a/miniz_zip.c
+++ b/miniz_zip.c
@@ -628,7 +628,7 @@ static mz_bool mz_zip_reader_locate_header_sig(mz_zip_archive *pZip, mz_uint32 r
         }
 
         /* Give up if we've searched the entire file, or we've gone back "too far" (~64kb) */
-        if ((!cur_file_ofs) || ((pZip->m_archive_size - cur_file_ofs) >= (MZ_UINT16_MAX + record_size)))
+        if ((!cur_file_ofs) || ((pZip->m_archive_size - cur_file_ofs) >= ((mz_uint64)(MZ_UINT16_MAX) + record_size)))
             return MZ_FALSE;
 
         cur_file_ofs = MZ_MAX(cur_file_ofs - (sizeof(buf_u32) - 3), 0);
@@ -1520,7 +1520,7 @@ mz_bool mz_zip_reader_extract_to_mem_no_alloc1(mz_zip_archive *pZip, mz_uint fil
     if (MZ_READ_LE32(pLocal_header) != MZ_ZIP_LOCAL_DIR_HEADER_SIG)
         return mz_zip_set_error(pZip, MZ_ZIP_INVALID_HEADER_OR_CORRUPTED);
 
-    cur_file_ofs += MZ_ZIP_LOCAL_DIR_HEADER_SIZE + MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_FILENAME_LEN_OFS) + MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_EXTRA_LEN_OFS);
+    cur_file_ofs += (mz_uint64)(MZ_ZIP_LOCAL_DIR_HEADER_SIZE) + MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_FILENAME_LEN_OFS) + MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_EXTRA_LEN_OFS);
     if ((cur_file_ofs + file_stat.m_comp_size) > pZip->m_archive_size)
         return mz_zip_set_error(pZip, MZ_ZIP_INVALID_HEADER_OR_CORRUPTED);
 
@@ -1732,7 +1732,7 @@ mz_bool mz_zip_reader_extract_to_callback(mz_zip_archive *pZip, mz_uint file_ind
     if (MZ_READ_LE32(pLocal_header) != MZ_ZIP_LOCAL_DIR_HEADER_SIG)
         return mz_zip_set_error(pZip, MZ_ZIP_INVALID_HEADER_OR_CORRUPTED);
 
-    cur_file_ofs += MZ_ZIP_LOCAL_DIR_HEADER_SIZE + MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_FILENAME_LEN_OFS) + MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_EXTRA_LEN_OFS);
+    cur_file_ofs += (mz_uint64)(MZ_ZIP_LOCAL_DIR_HEADER_SIZE) + MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_FILENAME_LEN_OFS) + MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_EXTRA_LEN_OFS);
     if ((cur_file_ofs + file_stat.m_comp_size) > pZip->m_archive_size)
         return mz_zip_set_error(pZip, MZ_ZIP_INVALID_HEADER_OR_CORRUPTED);
 
@@ -1974,7 +1974,7 @@ mz_zip_reader_extract_iter_state* mz_zip_reader_extract_iter_new(mz_zip_archive
         return NULL;
     }
 
-    pState->cur_file_ofs += MZ_ZIP_LOCAL_DIR_HEADER_SIZE + MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_FILENAME_LEN_OFS) + MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_EXTRA_LEN_OFS);
+    pState->cur_file_ofs += (mz_uint64)(MZ_ZIP_LOCAL_DIR_HEADER_SIZE) + MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_FILENAME_LEN_OFS) + MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_EXTRA_LEN_OFS);
     if ((pState->cur_file_ofs + pState->file_stat.m_comp_size) > pZip->m_archive_size)
     {
         mz_zip_set_error(pZip, MZ_ZIP_INVALID_HEADER_OR_CORRUPTED);
@@ -4052,7 +4052,7 @@ mz_bool mz_zip_writer_add_from_zip_reader(mz_zip_archive *pZip, mz_zip_archive *
     local_header_extra_len = MZ_READ_LE16(pLocal_header + MZ_ZIP_LDH_EXTRA_LEN_OFS);
     local_header_comp_size = MZ_READ_LE32(pLocal_header + MZ_ZIP_LDH_COMPRESSED_SIZE_OFS);
     local_header_uncomp_size = MZ_READ_LE32(pLocal_header + MZ_ZIP_LDH_DECOMPRESSED_SIZE_OFS);
-    src_archive_bytes_remaining = local_header_filename_size + local_header_extra_len + src_file_stat.m_comp_size;
+    src_archive_bytes_remaining = src_file_stat.m_comp_size + local_header_filename_size + local_header_extra_len ;
 
     /* Try to find a zip64 extended information field */
     if ((local_header_extra_len) && ((local_header_comp_size == MZ_UINT32_MAX) || (local_header_uncomp_size == MZ_UINT32_MAX)))