general: suppress some CodeQL warnings

CODABLOCKF: tidy some comments

backend/codablock.c

@@ -69,7 +69,7 @@ typedef struct sCharacterSetTable {
 } CharacterSetTable;
 
 /* Find the possible Code-128 Character sets for a character
- * The result is an or of CodeA, CodeB, CodeC, CodeFNC1, CodeFNC4 depending on the
+ * The result is an OR of CodeA, CodeB, CodeC, CodeFNC1, CodeFNC4 depending on the
  * possible Code 128 character sets.
  */
 static int GetPossibleCharacterSet(unsigned char C) {
@@ -87,13 +87,11 @@ static int GetPossibleCharacterSet(unsigned char C) {
 }
 
 /* Create a Table with the following information for each Data character:
- *  int CharacterSet    is an or of CodeA, CodeB, CodeC, CodeFNC1, CodeFNC4,
+ *  int CharacterSet            is an OR of CodeA, CodeB, CodeC, CodeFNC1, CodeFNC4,
  *                              depending on which character set is applicable.
  *                              (Result of GetPossibleCharacterSet)
- *  int AFollowing,BFollowing   The number of source characters you still may encode
+ *  int AFollowing, BFollowing  The number of source characters you still may encode in this character set.
- *          in this character set.
+ *  int CFollowing              The number of characters encodable in CodeC if we start here.
- *  int CFollowing  The number of characters encodable in CodeC if we
- *          start here.
  */
 static void CreateCharacterSetTable(CharacterSetTable T[], unsigned char *data, const int dataLength) {
     int charCur;
@@ -260,6 +258,7 @@ static int Columns2Rows(struct zint_symbol *symbol, CharacterSetTable *T, const
                                     if (isFNC4) { /* So skip FNC4 and shift value instead */
                                         --emptyColumns;
                                         ++charCur;
+                                        assert(charCur < dataLength); /* FNC4s always followed by char */
                                     }
                                     pSet[charCur] |= CShift;
                                 } else {
@@ -292,6 +291,7 @@ static int Columns2Rows(struct zint_symbol *symbol, CharacterSetTable *T, const
                                     if (isFNC4) { /* So skip FNC4 and shift value instead */
                                         --emptyColumns;
                                         ++charCur;
+                                        assert(charCur < dataLength); /* FNC4s always followed by char */
                                     }
                                     pSet[charCur] |= CShift;
                                 } else {
@@ -684,7 +684,7 @@ INTERNAL int codablockf(struct zint_symbol *symbol, unsigned char source[], int
 
     /* >>> Build C128 code numbers */
     /* The C128 column count contains Start (2CW), Row ID, Checksum, Stop */
-    pOutput = (unsigned char *) z_alloca(columns * rows);
+    pOutput = (unsigned char *) z_alloca((size_t) columns * (size_t) rows);
     pOutPos = pOutput;
     charCur = 0;
     /* >> Loop over rows */
@@ -780,7 +780,7 @@ INTERNAL int codablockf(struct zint_symbol *symbol, unsigned char source[], int
                     --emptyColumns;
                 }
                 /* >> End Criteria */
-                if ((pSet[charCur] & CFill) || (pSet[charCur] & CEnd)) {
+                if (charCur < dataLength && ((pSet[charCur] & CFill) || (pSet[charCur] & CEnd))) {
                     /* Fill line but leave space for checks in last line */
                     if (rowCur == rows - 1) {
                         emptyColumns -= 2;

backend/dmatrix.c

@@ -1904,7 +1904,7 @@ static int dm_ecc200(struct zint_symbol *symbol, struct zint_seg segs[], const i
         const int NC = W - 2 * (W / FW);
         const int NR = H - 2 * (H / FH);
         int x, y, *places;
-        if (!(places = (int *) calloc(NC * NR, sizeof(int)))) {
+        if (!(places = (int *) calloc((size_t) NC * (size_t) NR, sizeof(int)))) {
             return errtxt(ZINT_ERROR_MEMORY, symbol, 718, "Insufficient memory for placement array");
         }
         dm_placement(places, NR, NC);

backend/dxfilmedge.c

@@ -138,7 +138,8 @@ static int dx_parse_code(struct zint_symbol *symbol, const unsigned char *source
         int dx_extract;
         /* DX format is either 4 digits (DX Extract, eg: 1271) or 6 digits (DX Full, eg: 012710) */
         if (debug_print) printf("No \"-\" separator, computing from DX Extract (4 digits) or DX Full (6 digits)\n");
-        if (dx_length == 5 || dx_length > 6) {
+        assert(dx_length <= 6); /* I.e. DX_MAX_DX_INFO_LENGTH, guaranteed above */
+        if (dx_length == 5) {
             return errtxtf(ZINT_ERROR_INVALID_DATA, symbol, 980,
                     "DX number \"%s\" is incorrect; expected 4 digits (DX extract) or 6 digits (DX full)", dx_info);
         }
@@ -154,7 +155,7 @@ static int dx_parse_code(struct zint_symbol *symbol, const unsigned char *source
         }
         /* Compute the DX parts 1 and 2 from the DX extract */
         dx_extract = to_int((const unsigned char *) dx_info, dx_length);
-        assert(dx_extract != -1);
+        assert(dx_extract != -1); /* All digits (no hyphen) & length 6 max - can't fail */
         if (dx_extract < 16 || dx_extract > 2047) {
             return errtxtf(ZINT_ERROR_INVALID_DATA, symbol, 981, "DX extract \"%d\" out of range (16 to 2047)",
                             dx_extract);

backend/gridmtx.c

@@ -875,8 +875,6 @@ static void gm_add_ecc(const char binary[], const int data_posn, const int layer
         }
         data_size = block_size - ecc_size;
 
-        /* printf("block %d/%d: data %d / ecc %d\n", i + 1, (b1 + b2), data_size, ecc_size);*/
-
         for (j = 0; j < data_size; j++) {
             data_block[j] = data[wp];
             wp++;

backend/library.c

@@ -1531,7 +1531,7 @@ int ZBarcode_Encode_File(struct zint_symbol *symbol, const char *filename) {
     }
 
     /* Allocate memory */
-    buffer = (unsigned char *) malloc(fileLen);
+    buffer = (unsigned char *) malloc((size_t) fileLen);
     if (!buffer) {
         if (file_opened) {
             (void) fclose(file);

backend/ultra.c

@@ -1141,7 +1141,7 @@ INTERNAL int ultra(struct zint_symbol *symbol, struct zint_seg segs[], const int
     total_width = columns + 6;
 
     /* Build symbol */
-    pattern = (char *) z_alloca(total_height * total_width);
+    pattern = (char *) z_alloca((size_t) total_height * (size_t) total_width);
 
     for (i = 0; i < (total_height * total_width); i++) {
         pattern[i] = 'W';