use compile_commands.json for Cppcheck (#1716)

* suppress memleak warnings only for u_scanner.c

.github/workflows/main.yml

@@ -132,16 +132,41 @@ jobs:
 
   cppcheck:
     name: Cppcheck
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
 
     steps:
       - name: Install dependencies
-        run: sudo apt-get update && sudo apt-get install cppcheck
+        run: |
+          sudo apt-get update
+          sudo apt-get install \
+            cppcheck \
+            ninja-build \
+            libsdl2-dev \
+            libsdl2-net-dev \
+            libopenal-dev \
+            libsndfile1-dev \
+            libfluidsynth-dev \
+            libxmp-dev
 
       - uses: actions/checkout@v4
 
-      - name: Run cppcheck
-        shell: bash
+      - name: Configure
         run: |
-          cppcheck --version
-          cppcheck --error-exitcode=1 -j4 -q --force -D__GNUC__ -U_MSC_VER -U_WIN32 -Isrc opl src setup textscreen
+          cmake -B build -G Ninja -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
+                -DCMAKE_FIND_PACKAGE_PREFER_CONFIG=OFF
+
+      - name: Run Cppcheck
+        run: |
+          mkdir cppcheck_cache
+          cppcheck -j4  --cppcheck-build-dir="cppcheck_cache" \
+            --quiet \
+            --error-exitcode=1 \
+            --check-level=exhaustive \
+            --inconclusive \
+            --inline-suppr \
+            --std=c99 \
+            --suppress="memleak:${{ github.workspace }}/src/u_scanner.c" \
+            --project="${{ github.workspace }}/build/compile_commands.json" \
+            -i"${{ github.workspace }}/miniz" \
+            -i"${{ github.workspace }}/spng" \
+            -D__GNUC__

opl/opl3.c

@@ -185,7 +185,7 @@ static Bit16s OPL3_EnvelopeCalcExp(Bit32u level)
     {
         level = 0x1fff;
     }
-    return (exprom[level & 0xff] << 1) >> (level >> 8);
+    return ((unsigned)(exprom[level & 0xff] << 1)) >> (level >> 8);
 }
 
 static Bit16s OPL3_EnvelopeCalcSin0(Bit16u phase, Bit16u envelope)

src/m_config.c

@@ -591,7 +591,8 @@ void M_LoadOptions(void)
 
     if (!M_CheckParm("-nooptions"))
     {
-        if ((lump = W_CheckNumForName("OPTIONS")) != -1)
+        lump = W_CheckNumForName("OPTIONS");
+        if (lump != -1)
         {
             int size = W_LumpLength(lump), buflen = 0;
             char *buf = NULL, *p,
@@ -605,7 +606,8 @@ void M_LoadOptions(void)
                 {
                     buf = I_Realloc(buf, buflen = len + 1);
                 }
-                strncpy(buf, p, len)[len] = 0;
+                strncpy(buf, p, len);
+                buf[len] = 0;
                 p += len;
                 size -= len;
                 M_ParseOption(buf, true);

src/r_draw.c

@@ -520,7 +520,7 @@ static void R_DrawFuzzColumn_orig(void)
       dest += linesize;             // killough 11/98
 
       // Clamp table lookup index.
-      fuzzpos &= (fuzzpos - FUZZTABLE) >> (8*sizeof fuzzpos-1); //killough 1/99
+      fuzzpos &= ((unsigned)(fuzzpos - FUZZTABLE)) >> (8*sizeof fuzzpos-1); //killough 1/99
     } 
   while (--count);
 
@@ -590,7 +590,7 @@ static void R_DrawFuzzColumn_block(void)
       }
 
       fuzzpos++;
-      fuzzpos &= (fuzzpos - FUZZTABLE) >> (8 * sizeof(fuzzpos) - 1);
+      fuzzpos &= ((unsigned)(fuzzpos - FUZZTABLE)) >> (8 * sizeof(fuzzpos) - 1);
     }
   while ((count -= ny) > 0);
 

src/u_mapinfo.c

@@ -18,7 +18,6 @@
 //
 //-----------------------------------------------------------------------------
 
-#include <ctype.h>
 #include <stdlib.h>
 #include <string.h>
 

textscreen/txt_fileselect.c

@@ -74,6 +74,7 @@ static char *ExecReadOutput(char **argv)
     // Wait until the program has completed and (if it was successful)
     // a full line has been read.
 
+    status = 0;
     result = NULL;
     result_len = 0;
     completed = 0;

win32/win_opendir.c

@@ -29,10 +29,6 @@
 // * Peters <colin@fu.is.saga-u.ac.jp>
 //
 
-#ifndef _MSC_VER
-#error i_opndir.c is for Microsoft Visual C++ only
-#endif
-
 #include <stdlib.h>
 #include <errno.h>
 #include <string.h>