diff --git a/backend/common.c b/backend/common.c
index e7ed58a6..9c5277cf 100644
--- a/backend/common.c
+++ b/backend/common.c
@@ -101,7 +101,7 @@ int is_sane(char test_string[], unsigned char source[], int length)
 			} 
 		}
 		if (!(latch)) { 
-			return ERROR_INVALID_DATA; 
+			return ZERROR_INVALID_DATA; 
 		}
 	}
 	
@@ -127,7 +127,7 @@ void lookup(char set_string[], char *table[], char data, char dest[])
 
 int module_is_set(struct zint_symbol *symbol, int y_coord, int x_coord)
 {
-	return (symbol->encoded_data[y_coord][x_coord / 7] & (1 << (x_coord % 7))) ? 1 : 0;
+	return (symbol->encoded_data[y_coord][x_coord / 7] >> (x_coord % 7)) & 1;
 #if 0	
 	switch(x_sub) {
 		case 0: if((symbol->encoded_data[y_coord][x_char] & 0x01) != 0) { result = 1; } break;
@@ -145,8 +145,7 @@ int module_is_set(struct zint_symbol *symbol, int y_coord, int x_coord)
 
 void set_module(struct zint_symbol *symbol, int y_coord, int x_coord)
 {
-        if(module_is_set(symbol, y_coord, x_coord)) { return; }
-	symbol->encoded_data[y_coord][x_coord / 7] += 1 << (x_coord % 7);
+	symbol->encoded_data[y_coord][x_coord / 7] |= 1 << (x_coord % 7);
 #if 0
 	int x_char, x_sub;
 	
@@ -168,8 +167,7 @@ void set_module(struct zint_symbol *symbol, int y_coord, int x_coord)
 
 void unset_module(struct zint_symbol *symbol, int y_coord, int x_coord)
 {
-        if(!(module_is_set(symbol, y_coord, x_coord))) { return; }
-	symbol->encoded_data[y_coord][x_coord / 7] -= 1 << (x_coord % 7);
+	symbol->encoded_data[y_coord][x_coord / 7] &= ~(1 << (x_coord % 7));
 #if 0
 	int x_char, x_sub;
 	
@@ -203,11 +201,8 @@ void expand(struct zint_symbol *symbol, char data[])
 			if(latch == '1') { set_module(symbol, symbol->rows, writer); }
 			writer++;
 		}
-		if(latch == '1') {
-			latch = '0';
-		} else {
-			latch = '1';
-		}
+
+		latch = (latch == '1' ? '0' : '1');
 	}
 	
 	if(symbol->symbology != BARCODE_PHARMA) {
@@ -315,7 +310,7 @@ int latin1_process(struct zint_symbol *symbol, unsigned char source[], unsigned
 		}
 		if(next == -1) {
 			strcpy(symbol->errtxt, "error: Invalid character in input string (only Latin-1 characters supported)");
-			return ERROR_INVALID_DATA;
+			return ZERROR_INVALID_DATA;
 		}
 		i = next;
 	} while(i < *length);
@@ -327,7 +322,7 @@ int latin1_process(struct zint_symbol *symbol, unsigned char source[], unsigned
 
 int utf8toutf16(struct zint_symbol *symbol, unsigned char source[], int vals[], int *length)
 {
-	int bpos, jpos, error_number, done;
+	int bpos, jpos, error_number;
 	int next;
 	
 	bpos = 0;
@@ -336,54 +331,36 @@ int utf8toutf16(struct zint_symbol *symbol, unsigned char source[], int vals[],
 	next = 0;
 	
 	do {
-		done = 0;
-		
 		if(source[bpos] <= 0x7f) {
 			/* 1 byte mode (7-bit ASCII) */
 			vals[jpos] = source[bpos];
 			next = bpos + 1;
 			jpos++;
-			done = 1;
-		}
-		
-		if(done == 0) {
+		} else {
 			if((source[bpos] >= 0x80) && (source[bpos] <= 0xbf)) {
 				strcpy(symbol->errtxt, "Corrupt Unicode data");
-				return ERROR_INVALID_DATA;
+				return ZERROR_INVALID_DATA;
 			}
-		}
-		
-		if(done == 0) {
 			if((source[bpos] >= 0xc0) && (source[bpos] <= 0xc1)) {
 				strcpy(symbol->errtxt, "Overlong encoding not supported");
-				return ERROR_INVALID_DATA;
+				return ZERROR_INVALID_DATA;
 			}
-		}
 		
-		if(done == 0) {
 			if((source[bpos] >= 0xc2) && (source[bpos] <= 0xdf)) {
 				/* 2 byte mode */
 				vals[jpos] = ((source[bpos] & 0x1f) << 6) + (source[bpos + 1] & 0x3f);
 				next = bpos + 2;
 				jpos++;
-				done = 1;
-			}
-		}
-		
-		if(done == 0) {
+			} else
 			if((source[bpos] >= 0xe0) && (source[bpos] <= 0xef)) {
 				/* 3 byte mode */
 				vals[jpos] = ((source[bpos] & 0x0f) << 12) + ((source[bpos + 1] & 0x3f) << 6) + (source[bpos + 2] & 0x3f);
 				next = bpos + 3;
 				jpos ++;
-				done = 1;
-			}
-		}
-		
-		if(done == 0) {
+			} else
 			if(source[bpos] >= 0xf0) {
 				strcpy(symbol->errtxt, "Unicode sequences of more than 3 bytes not supported");
-				return ERROR_INVALID_DATA;
+				return ZERROR_INVALID_DATA;
 			}
 		}