From 5d9ce6f684956ba3859f9b1843b791f1b57b5664 Mon Sep 17 00:00:00 2001
From: Robin Stuart <rstuart114@gmail.com>
Date: Mon, 29 Feb 2016 19:42:32 +0000
Subject: [PATCH] Improvements from Oxy patch

Original email reads...
It does not contain any fundamental changes or new functions but a lot of improvements which I have done over time (added several const/static specifiers, replaced repeated if-conditions by if-else, removed some warnings).
---
 backend/auspost.c   |   2 +-
 backend/aztec.c     |  19 +++--
 backend/code.c      |  16 ++---
 backend/code1.c     |  12 ++--
 backend/code128.c   |  16 ++---
 backend/code16k.c   |  12 ++--
 backend/code49.c    |   4 +-
 backend/common.c    |  42 +++++------
 backend/common.h    |  32 ++++-----
 backend/composite.c |  42 +++++------
 backend/dmatrix.c   | 165 ++++++++++++++++++++++----------------------
 backend/gridmtx.c   |  18 ++---
 backend/gs1.c       |   4 +-
 backend/gs1.h       |   4 +-
 backend/library.c   |  14 ++--
 backend/qr.c        |  35 +++++-----
 backend/reedsol.c   |   8 +--
 backend/reedsol.h   |   8 +--
 backend/render.c    |  25 ++++---
 backend/zint.h      |   2 +-
 20 files changed, 244 insertions(+), 236 deletions(-)

diff --git a/backend/auspost.c b/backend/auspost.c
index ffb382c7..83bbdf43 100644
--- a/backend/auspost.c
+++ b/backend/auspost.c
@@ -109,7 +109,7 @@ int australia_post(struct zint_symbol *symbol, unsigned char source[], int lengt
     unsigned int loopey, reader, h;
 
     char data_pattern[200];
-    char fcc[3] = {0, 0}, dpid[10];
+    char fcc[3] = {0, 0, 0}, dpid[10];
     char localstr[30];
 
     error_number = 0;
diff --git a/backend/aztec.c b/backend/aztec.c
index 6def39b7..3a4370df 100644
--- a/backend/aztec.c
+++ b/backend/aztec.c
@@ -52,7 +52,7 @@ void mapshorten(int *charmap, int *typemap, int start, int length) {
  * Insert a character into the middle of a string at position posn
  */
 void insert(char binary_string[], int posn, char newbit) {
-    int i, end;
+    size_t i, end;
 
     end = strlen(binary_string);
     for (i = end; i > posn; i--) {
@@ -81,7 +81,7 @@ int aztec_text_process(unsigned char source[], const unsigned int src_len, char
     maplength = 0;
     debug = 0;
 
-    for (i = 0; i < src_len; i++) {
+    for (i = 0; i < (int) src_len; i++) {
         if (gs1 && (i == 0)) {
             /* Add FNC1 to beginning of GS1 messages */
             charmap[maplength] = 0;
@@ -109,7 +109,7 @@ int aztec_text_process(unsigned char source[], const unsigned int src_len, char
     /* Look for double character encoding possibilities */
     i = 0;
     do {
-        if (((charmap[i] == 300) && (charmap[i + 1] == 11)) 
+        if (((charmap[i] == 300) && (charmap[i + 1] == 11))
                 && ((typemap[i] == PUNC) && (typemap[i + 1] == PUNC))) {
             /* CR LF combination */
             charmap[i] = 2;
@@ -118,7 +118,7 @@ int aztec_text_process(unsigned char source[], const unsigned int src_len, char
             maplength--;
         }
 
-        if (((charmap[i] == 302) && (charmap[i + 1] == 1)) 
+        if (((charmap[i] == 302) && (charmap[i + 1] == 1))
                 && ((typemap[i] == 24) && (typemap[i + 1] == 23))) {
             /* . SP combination */
             charmap[i] = 3;
@@ -127,7 +127,7 @@ int aztec_text_process(unsigned char source[], const unsigned int src_len, char
             maplength--;
         }
 
-        if (((charmap[i] == 301) && (charmap[i + 1] == 1)) 
+        if (((charmap[i] == 301) && (charmap[i + 1] == 1))
                 && ((typemap[i] == 24) && (typemap[i + 1] == 23))) {
             /* , SP combination */
             charmap[i] = 4;
@@ -136,7 +136,7 @@ int aztec_text_process(unsigned char source[], const unsigned int src_len, char
             maplength--;
         }
 
-        if (((charmap[i] == 21) && (charmap[i + 1] == 1)) 
+        if (((charmap[i] == 21) && (charmap[i + 1] == 1))
                 && ((typemap[i] == PUNC) && (typemap[i + 1] == 23))) {
             /* : SP combination */
             charmap[i] = 5;
@@ -629,7 +629,7 @@ int aztec_text_process(unsigned char source[], const unsigned int src_len, char
                         if (bytes > 31) {
                             /* Put 00000 followed by 11-bit number of bytes less 31 */
                             concat(binary_string, "00000");
-                            
+
                             for (p = 0; p < 11; p++) {
                                 if ((bytes - 31) & (0x400 >> p)) {
                                     concat(binary_string, "1");
@@ -1000,8 +1000,7 @@ int aztec(struct zint_symbol *symbol, unsigned char source[], int length) {
                     break;
             }
 
-            if (layers == 0) {
-                /* Couldn't find a symbol which fits the data */
+            if (layers == 0) { /* Couldn't find a symbol which fits the data */
                 strcpy(symbol->errtxt, "Input too long (too many bits for selected ECC)");
                 return ZINT_ERROR_TOO_LONG;
             }
@@ -1299,7 +1298,7 @@ int aztec(struct zint_symbol *symbol, unsigned char source[], int length) {
             break;
         case 10:
             for (i = 0; i < data_blocks; i++) {
-                for(p = 0; p < 10; p++) {
+                for (p = 0; p < 10; p++) {
                     if (adjusted_string[i * codeword_size + p] == '1') {
                         data_part[i] += (0x200 >> p);
                     }
diff --git a/backend/code.c b/backend/code.c
index a6c035b6..53766a23 100644
--- a/backend/code.c
+++ b/backend/code.c
@@ -132,7 +132,7 @@ int code_11(struct zint_symbol *symbol, unsigned char source[], int length) { /*
     strcpy(dest, "112211");
 
     /* Draw main body of barcode */
-    for (i = 0; i < length; i++) {
+    for (i = 0; i < (unsigned int) length; i++) {
         lookup(SODIUM, C11Table, source[i], dest);
         if (source[i] == '-')
             weight[i] = 10;
@@ -187,7 +187,7 @@ int code_11(struct zint_symbol *symbol, unsigned char source[], int length) { /*
 }
 
 /* Code 39 */
-int c39(struct zint_symbol *symbol, unsigned char source[], int length) { 
+int c39(struct zint_symbol *symbol, unsigned char source[], int length) {
     unsigned int i;
     unsigned int counter;
     char check_digit;
@@ -219,7 +219,7 @@ int c39(struct zint_symbol *symbol, unsigned char source[], int length) {
     /* Start character */
     strcpy(dest, "1211212111");
 
-    for (i = 0; i < length; i++) {
+    for (i = 0; i < (unsigned int) length; i++) {
         lookup(SILVER, C39Table, source[i], dest);
         counter += posn(SILVER, source[i]);
     }
@@ -292,7 +292,7 @@ int c39(struct zint_symbol *symbol, unsigned char source[], int length) {
 }
 
 /* Pharmazentral Nummer (PZN) */
-int pharmazentral(struct zint_symbol *symbol, unsigned char source[], int length) { 
+int pharmazentral(struct zint_symbol *symbol, unsigned char source[], int length) {
 
     int i, error_number, zeroes;
     unsigned int count, check_digit;
@@ -338,7 +338,7 @@ int pharmazentral(struct zint_symbol *symbol, unsigned char source[], int length
 }
 
 /* Extended Code 39 - ISO/IEC 16388:2007 Annex A */
-int ec39(struct zint_symbol *symbol, unsigned char source[], int length) { 
+int ec39(struct zint_symbol *symbol, unsigned char source[], int length) {
 
     unsigned char buffer[150] = {0};
     unsigned int i;
@@ -352,7 +352,7 @@ int ec39(struct zint_symbol *symbol, unsigned char source[], int length) {
     }
 
     /* Creates a buffer string and places control characters into it */
-    for (i = 0; i < length; i++) {
+    for (i = 0; i < (unsigned int) length; i++) {
         if (source[i] > 127) {
             /* Cannot encode extended ASCII */
             strcpy(symbol->errtxt, "Invalid characters in input data");
@@ -364,7 +364,7 @@ int ec39(struct zint_symbol *symbol, unsigned char source[], int length) {
     /* Then sends the buffer to the C39 function */
     error_number = c39(symbol, buffer, ustrlen(buffer));
 
-    for (i = 0; i < length; i++)
+    for (i = 0; i < (unsigned int) length; i++)
         symbol->text[i] = source[i] ? source[i] : ' ';
     symbol->text[length] = '\0';
 
@@ -372,7 +372,7 @@ int ec39(struct zint_symbol *symbol, unsigned char source[], int length) {
 }
 
 /* Code 93 is an advancement on Code 39 and the definition is a lot tighter */
-int c93(struct zint_symbol *symbol, unsigned char source[], int length) { 
+int c93(struct zint_symbol *symbol, unsigned char source[], int length) {
 
     /* SILVER includes the extra characters a, b, c and d to represent Code 93 specific
        shift characters 1, 2, 3 and 4 respectively. These characters are never used by
diff --git a/backend/code1.c b/backend/code1.c
index 4efcc172..31fb3958 100644
--- a/backend/code1.c
+++ b/backend/code1.c
@@ -289,25 +289,25 @@ int c1_look_ahead_test(unsigned char source[], int sourcelen, int position, int
 
     if (sp == sourcelen) {
         /* Step K */
-        best_count = edi_count;
+		best_count = (int)edi_count;
 
         if (text_count <= best_count) {
-            best_count = text_count;
+			best_count = (int)text_count;
             best_scheme = C1_TEXT;
         }
 
         if (c40_count <= best_count) {
-            best_count = c40_count;
+			best_count = (int)c40_count;
             best_scheme = C1_C40;
         }
 
         if (ascii_count <= best_count) {
-            best_count = ascii_count;
+			best_count = (int)ascii_count;
             best_scheme = C1_ASCII;
         }
 
         if (byte_count <= best_count) {
-            best_count = byte_count;
+			best_count = (int)byte_count;
             best_scheme = C1_BYTE;
         }
     } else {
@@ -1052,7 +1052,7 @@ int c1_encode(struct zint_symbol *symbol, unsigned char source[], unsigned int t
 
                 strcpy(temp_binary, "");
                 if (strlen(decimal_binary) > 24) {
-                    for (i = 0; i <= (strlen(decimal_binary) - 24); i++) {
+					for(i = 0; i <= (int)(strlen(decimal_binary) - 24); i++) {
                         temp_binary[i] = decimal_binary[i + 24];
                     }
                     strcpy(decimal_binary, temp_binary);
diff --git a/backend/code128.c b/backend/code128.c
index 7db14441..c0b90404 100644
--- a/backend/code128.c
+++ b/backend/code128.c
@@ -75,7 +75,7 @@ static const char *C128Table[107] = {
 };
 
 /* Determine appropriate mode for a given character */
-int parunmodd(unsigned char llyth) {
+int parunmodd(const unsigned char llyth) {
     int modd;
     modd = 0;
 
@@ -281,7 +281,7 @@ void c128_set_b(unsigned char source, char dest[], int values[], int *bar_chars)
 /* Translate Code 128 Set C characters into barcodes
  * This set handles numbers in a compressed form
  */
-void c128_set_c(unsigned char source_a, unsigned char source_b, char dest[], int values[], int *bar_chars) { 
+void c128_set_c(unsigned char source_a, unsigned char source_b, char dest[], int values[], int *bar_chars) {
     int weight;
 
     weight = (10 * ctoi(source_a)) + ctoi(source_b);
@@ -291,7 +291,7 @@ void c128_set_c(unsigned char source_a, unsigned char source_b, char dest[], int
 }
 
 /* Handle Code 128 and NVE-18 */
-int code_128(struct zint_symbol *symbol, unsigned char source[], int length) { 
+int code_128(struct zint_symbol *symbol, unsigned char source[], int length) {
     int i, j, k, values[170] = {0}, bar_characters, read, total_sum;
     int error_number, indexchaine, indexliste, sourcelen, f_state;
     char set[170] = {' '}, fset[170] = {' '}, mode, last_set, current_set = ' ';
@@ -681,7 +681,7 @@ int code_128(struct zint_symbol *symbol, unsigned char source[], int length) {
 }
 
 /* Handle EAN-128 (Now known as GS1-128) */
-int ean_128(struct zint_symbol *symbol, unsigned char source[], int length) { 
+int ean_128(struct zint_symbol *symbol, unsigned char source[], int length) {
     int i, j, values[170], bar_characters, read, total_sum;
     int error_number, indexchaine, indexliste;
     char set[170], mode, last_set;
@@ -748,7 +748,7 @@ int ean_128(struct zint_symbol *symbol, unsigned char source[], int length) {
 
     do {
         list[1][indexliste] = mode;
-        while ((list[1][indexliste] == mode) && (indexchaine < strlen(reduced))) {
+        while ((list[1][indexliste] == mode) && (indexchaine < (int) strlen(reduced))) {
             list[0][indexliste]++;
             indexchaine++;
             mode = parunmodd(reduced[indexchaine]);
@@ -757,7 +757,7 @@ int ean_128(struct zint_symbol *symbol, unsigned char source[], int length) {
             }
         }
         indexliste++;
-    } while (indexchaine < strlen(reduced));
+    } while (indexchaine < (int) strlen(reduced));
 
     dxsmooth(&indexliste);
 
@@ -825,7 +825,7 @@ int ean_128(struct zint_symbol *symbol, unsigned char source[], int length) {
     being too long */
     last_set = ' ';
     glyph_count = 0.0;
-    for (i = 0; i < strlen(reduced); i++) {
+    for (i = 0; i < (int) strlen(reduced); i++) {
         if ((set[i] == 'a') || (set[i] == 'b')) {
             glyph_count = glyph_count + 1.0;
         }
@@ -919,7 +919,7 @@ int ean_128(struct zint_symbol *symbol, unsigned char source[], int length) {
             bar_characters++;
             read++;
         }
-    } while (read < strlen(reduced));
+    } while (read < (int) strlen(reduced));
 
     /* "...note that the linkage flag is an extra code set character between
     the last data character and the Symbol Check Character" (GS1 Specification) */
diff --git a/backend/code16k.c b/backend/code16k.c
index 5e1c923d..90708b54 100644
--- a/backend/code16k.c
+++ b/backend/code16k.c
@@ -113,7 +113,7 @@ void grwp16(int *indexliste) {
 }
 
 /* Implements rules from ISO 15417 Annex E */
-void dxsmooth16(int *indexliste) { 
+void dxsmooth16(int *indexliste) {
     int i, current, last, next, length;
 
     for (i = 0; i < *(indexliste); i++) {
@@ -285,7 +285,7 @@ int code16k(struct zint_symbol *symbol, unsigned char source[], int length) {
     bar_characters = 0;
 
     /* Detect extended ASCII characters */
-    for (i = 0; i < input_length; i++) {
+    for (i = 0; i < (unsigned int) input_length; i++) {
         if (source[i] >= 128) {
             fset[i] = 'f';
         }
@@ -293,7 +293,7 @@ int code16k(struct zint_symbol *symbol, unsigned char source[], int length) {
     fset[i] = '\0';
 
     /* Decide when to latch to extended mode */
-    for (i = 0; i < input_length; i++) {
+    for (i = 0; i < (unsigned int) input_length; i++) {
         j = 0;
         if (fset[i] == 'f') {
             do {
@@ -309,10 +309,10 @@ int code16k(struct zint_symbol *symbol, unsigned char source[], int length) {
 
     /* Decide if it is worth reverting to 646 encodation for a few characters */
     if (input_length > 1) {
-        for (i = 1; i < input_length; i++) {
+        for (i = 1; i < (unsigned int) input_length; i++) {
             if ((fset[i - 1] == 'F') && (fset[i] == ' ')) {
                 /* Detected a change from 8859-1 to 646 - count how long for */
-                for (j = 0; (fset[i + j] == ' ') && ((i + j) < input_length); j++);
+                for (j = 0; (fset[i + j] == ' ') && ((i + j) < (unsigned int) input_length); j++);
                 if ((j < 5) || ((j < 3) && ((i + j) == (input_length - 1)))) {
                     /* Change to shifting back rather than latching back */
                     for (k = 0; k < j; k++) {
@@ -543,7 +543,7 @@ int code16k(struct zint_symbol *symbol, unsigned char source[], int length) {
     current_set = set[0];
     f_state = 0;
     /* f_state remembers if we are in Extended ASCII mode (value 1) or
-	in ISO/IEC 646 mode (value 0) */
+        in ISO/IEC 646 mode (value 0) */
     if (fset[0] == 'F') {
         switch (current_set) {
             case 'A':
diff --git a/backend/code49.c b/backend/code49.c
index f71d22d6..386204b5 100644
--- a/backend/code49.c
+++ b/backend/code49.c
@@ -42,7 +42,7 @@
 
 int code_49(struct zint_symbol *symbol, unsigned char source[], int length) {
     int i, j, rows, M, x_count, y_count, z_count, posn_val, local_value, h;
-    char intermediate[170];
+    char intermediate[170] = "";
     int codewords[170], codeword_count;
     int c_grid[8][8]; /* Refers to table 3 */
     int w_grid[8][4]; /* Refets to table 2 */
@@ -195,7 +195,7 @@ int code_49(struct zint_symbol *symbol, unsigned char source[], int length) {
     } while (i < h);
 
     switch (codewords[0]) {
-        /* Set starting mode value */
+            /* Set starting mode value */
         case 48: M = 2;
             break;
         case 43: M = 4;
diff --git a/backend/common.c b/backend/common.c
index 154ef5ad..c9e86d6b 100644
--- a/backend/common.c
+++ b/backend/common.c
@@ -54,8 +54,8 @@ void ustrcpy(unsigned char target[], const unsigned char source[]) {
 }
 
 /* Concatinates dest[] with the contents of source[], copying /0 as well */
-void concat(char dest[], const char source[]) { 
-    unsigned int i, j, n;
+void concat(char dest[], const char source[]) {
+    size_t i, j, n;
 
     j = strlen(dest);
     n = strlen(source);
@@ -65,7 +65,7 @@ void concat(char dest[], const char source[]) {
 }
 
 /* Concatinates dest[] with the contents of source[], copying /0 as well */
-void uconcat(unsigned char dest[], const unsigned char source[]) { 
+void uconcat(unsigned char dest[], const unsigned char source[]) {
     unsigned int i, j;
 
     j = ustrlen(dest);
@@ -75,14 +75,14 @@ void uconcat(unsigned char dest[], const unsigned char source[]) {
 }
 
 /* Converts a character 0-9 to its equivalent integer value */
-int ctoi(char source) { 
+int ctoi(const char source) {
     if ((source >= '0') && (source <= '9'))
         return (source - '0');
     return (source - 'A' + 10);
 }
 
 /* Converts an integer value to its hexadecimal character */
-char itoc(int source) { 
+char itoc(const int source) {
     if ((source >= 0) && (source <= 9)) {
         return ('0' + source);
     } else {
@@ -91,7 +91,7 @@ char itoc(int source) {
 }
 
 /* Converts lower case characters to upper case in a string source[] */
-void to_upper(unsigned char source[]) { 
+void to_upper(unsigned char source[]) {
     unsigned int i, src_len = ustrlen(source);
 
     for (i = 0; i < src_len; i++) {
@@ -102,7 +102,7 @@ void to_upper(unsigned char source[]) {
 }
 
 /* Verifies that a string only uses valid characters */
-int is_sane(char test_string[], unsigned char source[], int length) { 
+int is_sane(char test_string[], const unsigned char source[], const int length) {
     unsigned int i, j, latch;
     unsigned int lt = strlen(test_string);
 
@@ -123,7 +123,7 @@ int is_sane(char test_string[], unsigned char source[], int length) {
 }
 
 /* Returns the position of data in set_string */
-int posn(char set_string[], char data) { 
+int posn(char set_string[], const char data) {
     unsigned int i, n = strlen(set_string);
 
     for (i = 0; i < n; i++) {
@@ -135,7 +135,7 @@ int posn(char set_string[], char data) {
 }
 
 /* Replaces huge switch statements for looking up in tables */
-void lookup(char set_string[], const char *table[], char data, char dest[]) { 
+void lookup(char set_string[], const char *table[], const char data, char dest[]) {
     unsigned int i, n = strlen(set_string);
 
     for (i = 0; i < n; i++) {
@@ -146,22 +146,22 @@ void lookup(char set_string[], const char *table[], char data, char dest[]) {
 }
 
 /* Return true (1) if a module is dark/black, orherwise false (0) */
-int module_is_set(struct zint_symbol *symbol, int y_coord, int x_coord) {
+int module_is_set(const struct zint_symbol *symbol, const int y_coord, const int x_coord) {
     return (symbol->encoded_data[y_coord][x_coord / 7] >> (x_coord % 7)) & 1;
 }
 
 /* Set a module to dark/black */
-void set_module(struct zint_symbol *symbol, int y_coord, int x_coord) {
+void set_module(struct zint_symbol *symbol, const int y_coord, const int x_coord) {
     symbol->encoded_data[y_coord][x_coord / 7] |= 1 << (x_coord % 7);
 }
 
 /* Set (or unset) a module to white */
-void unset_module(struct zint_symbol *symbol, int y_coord, int x_coord) {
+void unset_module(struct zint_symbol *symbol, const int y_coord, const int x_coord) {
     symbol->encoded_data[y_coord][x_coord / 7] &= ~(1 << (x_coord % 7));
 }
 
 /* Expands from a width pattern to a bit pattern */
-void expand(struct zint_symbol *symbol, char data[]) { 
+void expand(struct zint_symbol *symbol, char data[]) {
 
     unsigned int reader, n = strlen(data);
     int writer, i;
@@ -231,7 +231,7 @@ int is_stackable(int symbology) {
 }
 
 /* Indicates which symbols can have addon (EAN-2 and EAN-5) */
-int is_extendable(int symbology) {
+int is_extendable(const int symbology) {
     if (symbology == BARCODE_EANX) {
         return 1;
     }
@@ -257,21 +257,21 @@ int is_extendable(int symbology) {
     return 0;
 }
 
-int roundup(float input) {
+int roundup(const float input) {
     float remainder;
     int integer_part;
 
     integer_part = (int) input;
     remainder = input - integer_part;
 
-    if (remainder > 0.1) {
+    if (remainder > 0.1F) {
         integer_part++;
     }
 
     return integer_part;
 }
 
-int istwodigits(unsigned char source[], int position) {
+int istwodigits(const unsigned char source[], const int position) {
     if ((source[position] >= '0') && (source[position] <= '9')) {
         if ((source[position + 1] >= '0') && (source[position + 1] <= '9')) {
             return 1;
@@ -281,8 +281,8 @@ int istwodigits(unsigned char source[], int position) {
     return 0;
 }
 
-float froundup(float input) {
-    float fraction, output = 0.0;
+double froundup(const double input) {
+    double fraction, output = 0.0;
 
     fraction = input - (int) input;
     if (fraction > 0.01) {
@@ -295,7 +295,7 @@ float froundup(float input) {
 }
 
 /* Convert Unicode to Latin-1 for those symbologies which only support Latin-1 */
-int latin1_process(struct zint_symbol *symbol, unsigned char source[], unsigned char preprocessed[], int *length) {
+int latin1_process(struct zint_symbol *symbol, const unsigned char source[], unsigned char preprocessed[], int *length) {
     int j, i, next;
 
     j = 0;
@@ -330,7 +330,7 @@ int latin1_process(struct zint_symbol *symbol, unsigned char source[], unsigned
     return 0;
 }
 
-int utf8toutf16(struct zint_symbol *symbol, unsigned char source[], int vals[], int *length) {
+int utf8toutf16(struct zint_symbol *symbol, const unsigned char source[], int vals[], int *length) {
     int bpos, jpos, error_number;
     int next;
 
diff --git a/backend/common.h b/backend/common.h
index 9ff44ebc..97e586f5 100644
--- a/backend/common.h
+++ b/backend/common.h
@@ -55,24 +55,24 @@ extern "C" {
     extern void ustrcpy(unsigned char target[], const unsigned char source[]);
     extern void concat(char dest[], const char source[]);
     extern void uconcat(unsigned char dest[], const unsigned char source[]);
-    extern int ctoi(char source);
-    extern char itoc(int source);
+    extern int ctoi(const char source);
+    extern char itoc(const int source);
     extern void to_upper(unsigned char source[]);
-    extern int is_sane(char test_string[], unsigned char source[], int length);
-    extern void lookup(char set_string[], const char *table[], char data, char dest[]);
-    extern int posn(char set_string[], char data);
+    extern int is_sane(char test_string[], const unsigned char source[], const int length);
+    extern void lookup(char set_string[], const char *table[], const char data, char dest[]);
+    extern int posn(char set_string[], const char data);
     extern void expand(struct zint_symbol *symbol, char data[]);
-    extern int is_stackable(int symbology);
-    extern int is_extendable(int symbology);
-    extern int roundup(float input);
-    extern int module_is_set(struct zint_symbol *symbol, int y_coord, int x_coord);
-    extern void set_module(struct zint_symbol *symbol, int y_coord, int x_coord);
-    extern void unset_module(struct zint_symbol *symbol, int y_coord, int x_coord);
-    extern int istwodigits(unsigned char source[], int position);
-    extern float froundup(float input);
-    extern int parunmodd(unsigned char llyth);
-    extern int latin1_process(struct zint_symbol *symbol, unsigned char source[], unsigned char preprocessed[], int *length);
-    extern int utf8toutf16(struct zint_symbol *symbol, unsigned char source[], int vals[], int *length);
+    extern int is_stackable(const int symbology);
+    extern int is_extendable(const int symbology);
+    extern int roundup(const float input);
+    extern int module_is_set(const struct zint_symbol *symbol, const int y_coord, const int x_coord);
+    extern void set_module(struct zint_symbol *symbol, const int y_coord, const int x_coord);
+    extern void unset_module(struct zint_symbol *symbol, const int y_coord, const int x_coord);
+    extern int istwodigits(const unsigned char source[], const int position);
+    extern double froundup(const double input);
+    extern int parunmodd(const unsigned char llyth);
+    extern int latin1_process(struct zint_symbol *symbol, const unsigned char source[], unsigned char preprocessed[], int *length);
+    extern int utf8toutf16(struct zint_symbol *symbol, const unsigned char source[], int vals[], int *length);
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */
diff --git a/backend/composite.c b/backend/composite.c
index 3886be8e..9b045b48 100644
--- a/backend/composite.c
+++ b/backend/composite.c
@@ -129,7 +129,7 @@ int encode928(UINT bitString[], UINT codeWords[], int bitLng) {
 }
 
 /* CC-A 2D component */
-int cc_a(struct zint_symbol *symbol, char source[], int cc_width) { 
+int cc_a(struct zint_symbol *symbol, char source[], int cc_width) {
     int i, strpos, segment, bitlen, cwCnt, variant, rows;
     int k, offset, j, total, rsCodeWords[8];
     int LeftRAPStart, RightRAPStart, CentreRAPStart, StartCluster;
@@ -307,7 +307,7 @@ int cc_a(struct zint_symbol *symbol, char source[], int cc_width) {
         writer = 0;
         flip = 1;
         strcpy(pattern, "");
-        for (loop = 0; loop < strlen(codebarre); loop++) {
+        for (loop = 0; loop < (int) strlen(codebarre); loop++) {
             if ((codebarre[loop] >= '0') && (codebarre[loop] <= '9')) {
                 for (k = 0; k < ctoi(codebarre[loop]); k++) {
                     if (flip == 0) {
@@ -331,7 +331,7 @@ int cc_a(struct zint_symbol *symbol, char source[], int cc_width) {
         symbol->width = writer;
 
         /* so now pattern[] holds the string of '1's and '0's. - copy this to the symbol */
-        for (loop = 0; loop < strlen(pattern); loop++) {
+        for (loop = 0; loop < (int) strlen(pattern); loop++) {
             if (pattern[loop] == '1') {
                 set_module(symbol, i, loop);
             }
@@ -363,7 +363,7 @@ int cc_a(struct zint_symbol *symbol, char source[], int cc_width) {
 }
 
 /* CC-B 2D component */
-int cc_b(struct zint_symbol *symbol, char source[], int cc_width) { 
+int cc_b(struct zint_symbol *symbol, char source[], int cc_width) {
     int length, i, binloc;
 #ifndef _MSC_VER
     unsigned char data_string[(strlen(source) / 8) + 3];
@@ -591,7 +591,7 @@ int cc_b(struct zint_symbol *symbol, char source[], int cc_width) {
         writer = 0;
         flip = 1;
         strcpy(pattern, "");
-        for (loop = 0; loop < strlen(codebarre); loop++) {
+        for (loop = 0; loop < (int) strlen(codebarre); loop++) {
             if ((codebarre[loop] >= '0') && (codebarre[loop] <= '9')) {
                 for (k = 0; k < ctoi(codebarre[loop]); k++) {
                     if (flip == 0) {
@@ -615,7 +615,7 @@ int cc_b(struct zint_symbol *symbol, char source[], int cc_width) {
         symbol->width = writer;
 
         /* so now pattern[] holds the string of '1's and '0's. - copy this to the symbol */
-        for (loop = 0; loop < strlen(pattern); loop++) {
+        for (loop = 0; loop < (int) strlen(pattern); loop++) {
             if (pattern[loop] == '1') {
                 set_module(symbol, i, loop);
             }
@@ -646,7 +646,7 @@ int cc_b(struct zint_symbol *symbol, char source[], int cc_width) {
 }
 
 /* CC-C 2D component - byte compressed PDF417 */
-int cc_c(struct zint_symbol *symbol, char source[], int cc_width, int ecc_level) { 
+int cc_c(struct zint_symbol *symbol, char source[], int cc_width, int ecc_level) {
     int length, i, p, binloc;
 #ifndef _MSC_VER
     unsigned char data_string[(strlen(source) / 8) + 4];
@@ -765,12 +765,12 @@ int cc_c(struct zint_symbol *symbol, char source[], int cc_width, int ecc_level)
 
         for (j = 0; j <= cc_width + 1; j++) {
             switch (i % 3) {
-                case 1: offset = 929; /* cluster(3) */ 
+                case 1: offset = 929; /* cluster(3) */
                     break;
-                case 2: offset = 1858; /* cluster(6) */ 
+                case 2: offset = 1858; /* cluster(6) */
                     break;
                 default: offset = 0; /* cluster(0) */
-                     break;
+                    break;
             }
             concat(codebarre, codagemc[offset + dummy[j]]);
             concat(codebarre, "*");
@@ -778,10 +778,10 @@ int cc_c(struct zint_symbol *symbol, char source[], int cc_width, int ecc_level)
         concat(codebarre, "-");
 
         strcpy(pattern, "");
-        for (loop = 0; loop < strlen(codebarre); loop++) {
+        for (loop = 0; loop < (int) strlen(codebarre); loop++) {
             lookup(BRSET, PDFttf, codebarre[loop], pattern);
         }
-        for (loop = 0; loop < strlen(pattern); loop++) {
+        for (loop = 0; loop < (int) strlen(pattern); loop++) {
             if (pattern[loop] == '1') {
                 set_module(symbol, i, loop);
             }
@@ -914,7 +914,7 @@ int cc_binary_string(struct zint_symbol *symbol, const char source[], char binar
         alphanum = 0;
         numeric = 0;
 
-        for (i = 0; i < strlen(ninety); i++) {
+        for (i = 0; i < (int) strlen(ninety); i++) {
 
             if ((ninety[i] >= 'A') && (ninety[i] <= 'Z')) {
                 /* Character is alphabetic */
@@ -1217,7 +1217,7 @@ int cc_binary_string(struct zint_symbol *symbol, const char source[], char binar
         j++;
     }
 
-    for (i = read_posn; i < strlen(source); i++) {
+    for (i = read_posn; i < (int) strlen(source); i++) {
         general_field[j] = source[i];
         j++;
     }
@@ -1228,7 +1228,7 @@ int cc_binary_string(struct zint_symbol *symbol, const char source[], char binar
     }
 
     latch = 0;
-    for (i = 0; i < strlen(general_field); i++) {
+    for (i = 0; i < (int) strlen(general_field); i++) {
         /* Table 13 - ISO/IEC 646 encodation */
         if ((general_field[i] < ' ') || (general_field[i] > 'z')) {
             general_field_type[i] = INVALID_CHAR;
@@ -1301,13 +1301,13 @@ int cc_binary_string(struct zint_symbol *symbol, const char source[], char binar
         return ZINT_ERROR_INVALID_DATA;
     }
 
-    for (i = 0; i < strlen(general_field); i++) {
+    for (i = 0; i < (int) strlen(general_field); i++) {
         if ((general_field_type[i] == ISOIEC) && (general_field[i + 1] == '[')) {
             general_field_type[i + 1] = ISOIEC;
         }
     }
 
-    for (i = 0; i < strlen(general_field); i++) {
+    for (i = 0; i < (int) strlen(general_field); i++) {
         if ((general_field_type[i] == ALPHA_OR_ISO) && (general_field[i + 1] == '[')) {
             general_field_type[i + 1] = ALPHA_OR_ISO;
         }
@@ -1487,7 +1487,7 @@ int cc_binary_string(struct zint_symbol *symbol, const char source[], char binar
                 i++;
                 break;
         }
-    } while (i + latch < strlen(general_field));
+    } while (i + latch < (int) strlen(general_field));
 
     binary_length = strlen(binary_string);
     if (cc_mode == 1) {
@@ -2031,11 +2031,11 @@ int cc_binary_string(struct zint_symbol *symbol, const char source[], char binar
             concat(binary_string, "0000");
         }
 
-        while (strlen(binary_string) < target_bitsize) {
+        while (strlen(binary_string) < (unsigned int) target_bitsize) {
             concat(binary_string, "00100");
         }
 
-        if (strlen(binary_string) > target_bitsize) {
+        if (strlen(binary_string) > (unsigned int) target_bitsize) {
             binary_string[target_bitsize] = '\0';
         }
     }
@@ -2244,7 +2244,7 @@ int composite(struct zint_symbol *symbol, unsigned char source[], int length) {
     }
 
     switch (cc_mode) {
-        /* Note that ecc_level is only relevant to CC-C */
+            /* Note that ecc_level is only relevant to CC-C */
         case 1: error_number = cc_a(symbol, binary_string, cc_width);
             break;
         case 2: error_number = cc_b(symbol, binary_string, cc_width);
diff --git a/backend/dmatrix.c b/backend/dmatrix.c
index 5df83505..0cdf1e63 100755
--- a/backend/dmatrix.c
+++ b/backend/dmatrix.c
@@ -51,8 +51,8 @@
 #include "common.h"
 #include "dmatrix.h"
 
-// Annex M placement alorithm low level
-static void ecc200placementbit(int *array, int NR, int NC, int r, int c, int p, char b) {
+/* Annex M placement alorithm low level */
+static void ecc200placementbit(int *array, const int NR, const int NC, int r, int c, const int p, const char b) {
     if (r < 0) {
         r += NR;
         c += 4 - ((NR + 4) % 8);
@@ -86,7 +86,8 @@ static void ecc200placementbit(int *array, int NR, int NC, int r, int c, int p,
     array[r * NC + c] = (p << 3) + b;
 }
 
-static void ecc200placementblock(int *array, int NR, int NC, int r, int c, int p) {
+static void ecc200placementblock(int *array, const int NR, const int NC, const int r,
+        const int c, const int p) {
     ecc200placementbit(array, NR, NC, r - 2, c - 2, p, 7);
     ecc200placementbit(array, NR, NC, r - 2, c - 1, p, 6);
     ecc200placementbit(array, NR, NC, r - 1, c - 2, p, 5);
@@ -97,7 +98,7 @@ static void ecc200placementblock(int *array, int NR, int NC, int r, int c, int p
     ecc200placementbit(array, NR, NC, r - 0, c - 0, p, 0);
 }
 
-static void ecc200placementcornerA(int *array, int NR, int NC, int p) {
+static void ecc200placementcornerA(int *array, const int NR, const int NC, const int p) {
     ecc200placementbit(array, NR, NC, NR - 1, 0, p, 7);
     ecc200placementbit(array, NR, NC, NR - 1, 1, p, 6);
     ecc200placementbit(array, NR, NC, NR - 1, 2, p, 5);
@@ -108,7 +109,7 @@ static void ecc200placementcornerA(int *array, int NR, int NC, int p) {
     ecc200placementbit(array, NR, NC, 3, NC - 1, p, 0);
 }
 
-static void ecc200placementcornerB(int *array, int NR, int NC, int p) {
+static void ecc200placementcornerB(int *array, const int NR, const int NC, const int p) {
     ecc200placementbit(array, NR, NC, NR - 3, 0, p, 7);
     ecc200placementbit(array, NR, NC, NR - 2, 0, p, 6);
     ecc200placementbit(array, NR, NC, NR - 1, 0, p, 5);
@@ -119,7 +120,7 @@ static void ecc200placementcornerB(int *array, int NR, int NC, int p) {
     ecc200placementbit(array, NR, NC, 1, NC - 1, p, 0);
 }
 
-static void ecc200placementcornerC(int *array, int NR, int NC, int p) {
+static void ecc200placementcornerC(int *array, const int NR, const int NC, const int p) {
     ecc200placementbit(array, NR, NC, NR - 3, 0, p, 7);
     ecc200placementbit(array, NR, NC, NR - 2, 0, p, 6);
     ecc200placementbit(array, NR, NC, NR - 1, 0, p, 5);
@@ -130,7 +131,7 @@ static void ecc200placementcornerC(int *array, int NR, int NC, int p) {
     ecc200placementbit(array, NR, NC, 3, NC - 1, p, 0);
 }
 
-static void ecc200placementcornerD(int *array, int NR, int NC, int p) {
+static void ecc200placementcornerD(int *array, const int NR, const int NC, const int p) {
     ecc200placementbit(array, NR, NC, NR - 1, 0, p, 7);
     ecc200placementbit(array, NR, NC, NR - 1, NC - 1, p, 6);
     ecc200placementbit(array, NR, NC, 0, NC - 3, p, 5);
@@ -141,8 +142,8 @@ static void ecc200placementcornerD(int *array, int NR, int NC, int p) {
     ecc200placementbit(array, NR, NC, 1, NC - 1, p, 0);
 }
 
-// Annex M placement alorithm main function
-static void ecc200placement(int *array, int NR, int NC) {
+/* Annex M placement alorithm main function */
+static void ecc200placement(int *array, const int NR, const int NC) {
     int r, c, p;
     // invalidate
     for (r = 0; r < NR; r++)
@@ -186,8 +187,8 @@ static void ecc200placement(int *array, int NR, int NC) {
         array[NR * NC - 1] = array[NR * NC - NC - 2] = 1;
 }
 
-// calculate and append ecc code, and if necessary interleave
-static void ecc200(unsigned char *binary, int bytes, int datablock, int rsblock, int skew) {
+/* calculate and append ecc code, and if necessary interleave */
+static void ecc200(unsigned char *binary, const int bytes, const int datablock, const int rsblock, const int skew) {
     int blocks = (bytes + 2) / datablock, b;
     int n, p;
     rs_init_gf(0x12d);
@@ -217,7 +218,7 @@ static void ecc200(unsigned char *binary, int bytes, int datablock, int rsblock,
 }
 
 /* Return true (1) if a character is valid in X12 set */
-int isX12(unsigned char source) {
+static int isX12(const int source) {
     if (source == 13) {
         return 1;
     }
@@ -241,17 +242,17 @@ int isX12(unsigned char source) {
 }
 
 /* Insert a character into the middle of a string at position posn */
-void dminsert(char binary_string[], int posn, char newbit) { 
+static void dminsert(char binary_string[], const int posn, const char newbit) {
     int i, end;
 
-    end = strlen(binary_string);
+    end = (int) strlen(binary_string);
     for (i = end; i > posn; i--) {
         binary_string[i] = binary_string[i - 1];
     }
     binary_string[posn] = newbit;
 }
 
-void insert_value(unsigned char binary_stream[], int posn, int streamlen, char newbit) {
+static void insert_value(unsigned char binary_stream[], const int posn, const int streamlen, const int newbit) {
     int i;
 
     for (i = streamlen; i > posn; i--) {
@@ -260,7 +261,7 @@ void insert_value(unsigned char binary_stream[], int posn, int streamlen, char n
     binary_stream[posn] = newbit;
 }
 
-int p_r_6_2_1(unsigned char inputData[], int position, int sourcelen) {
+int p_r_6_2_1(const unsigned char inputData[], int position, const int sourcelen) {
     /* Annex P section (r)(6)(ii)(I)
        "If one of the three X12 terminator/separator characters first
         occurs in the yet to be processed data before a non-X12 character..."
@@ -297,7 +298,7 @@ int p_r_6_2_1(unsigned char inputData[], int position, int sourcelen) {
 }
 
 /* 'look ahead test' from Annex P */
-int look_ahead_test(unsigned char inputData[], int sourcelen, int position, int current_mode, int gs1) {
+static int look_ahead_test(const unsigned char inputData[], const int sourcelen, const int position, const int current_mode, const int gs1) {
     float ascii_count, c40_count, text_count, x12_count, edf_count, b256_count, best_count;
     int sp, best_scheme;
 
@@ -338,12 +339,12 @@ int look_ahead_test(unsigned char inputData[], int sourcelen, int position, int
     do {
         if (sp == (sourcelen - 1)) {
             /* At the end of data ... step (k) */
-            ascii_count = ceil(ascii_count);
-            b256_count = ceil(b256_count);
-            edf_count = ceil(edf_count);
-            text_count = ceil(text_count);
-            x12_count = ceil(x12_count);
-            c40_count = ceil(c40_count);
+            ascii_count = ceilf(ascii_count);
+            b256_count = ceilf(b256_count);
+            edf_count = ceilf(edf_count);
+            text_count = ceilf(text_count);
+            x12_count = ceilf(x12_count);
+            c40_count = ceilf(c40_count);
 
             best_count = c40_count;
             best_scheme = DM_C40; // (k)(7)
@@ -375,12 +376,12 @@ int look_ahead_test(unsigned char inputData[], int sourcelen, int position, int
 
             /* ascii ... step (l) */
             if ((inputData[sp] >= '0') && (inputData[sp] <= '9')) {
-                ascii_count += 0.5; // (l)(1)
+                ascii_count += 0.5F; // (l)(1)
             } else {
                 if (inputData[sp] > 127) {
-                    ascii_count = ceil(ascii_count) + 2.0; // (l)(2)
+                    ascii_count = ceilf(ascii_count) + 2.0F; // (l)(2)
                 } else {
-                    ascii_count = ceil(ascii_count) + 1.0; // (l)(3)
+                    ascii_count = ceilf(ascii_count) + 1.0F; // (l)(3)
                 }
             }
 
@@ -388,12 +389,12 @@ int look_ahead_test(unsigned char inputData[], int sourcelen, int position, int
             if ((inputData[sp] == ' ') ||
                     (((inputData[sp] >= '0') && (inputData[sp] <= '9')) ||
                     ((inputData[sp] >= 'A') && (inputData[sp] <= 'Z')))) {
-                c40_count += (2.0 / 3.0); // (m)(1)
+                c40_count += (2.0F / 3.0F); // (m)(1)
             } else {
                 if (inputData[sp] > 127) {
-                    c40_count += (8.0 / 3.0); // (m)(2)
+                    c40_count += (8.0F / 3.0F); // (m)(2)
                 } else {
-                    c40_count += (4.0 / 3.0); // (m)(3)
+                    c40_count += (4.0F / 3.0F); // (m)(3)
                 }
             }
 
@@ -401,45 +402,45 @@ int look_ahead_test(unsigned char inputData[], int sourcelen, int position, int
             if ((inputData[sp] == ' ') ||
                     (((inputData[sp] >= '0') && (inputData[sp] <= '9')) ||
                     ((inputData[sp] >= 'a') && (inputData[sp] <= 'z')))) {
-                text_count += (2.0 / 3.0); // (n)(1)
+                text_count += (2.0F / 3.0F); // (n)(1)
             } else {
                 if (inputData[sp] > 127) {
-                    text_count += (8.0 / 3.0); // (n)(2)
+                    text_count += (8.0F / 3.0F); // (n)(2)
                 } else {
-                    text_count += (4.0 / 3.0); // (n)(3)
+                    text_count += (4.0F / 3.0F); // (n)(3)
                 }
             }
 
             /* x12 ... step (o) */
             if (isX12(inputData[sp])) {
-                x12_count += (2.0 / 3.0); // (o)(1)
+                x12_count += (2.0F / 3.0F); // (o)(1)
             } else {
                 if (inputData[sp] > 127) {
-                    x12_count += (13.0 / 3.0); // (o)(2)
+                    x12_count += (13.0F / 3.0F); // (o)(2)
                 } else {
-                    x12_count += (10.0 / 3.0); // (o)(3)
+                    x12_count += (10.0F / 3.0F); // (o)(3)
                 }
             }
 
             /* edifact ... step (p) */
             if ((inputData[sp] >= ' ') && (inputData[sp] <= '^')) {
-                edf_count += (3.0 / 4.0); // (p)(1)
+                edf_count += (3.0F / 4.0F); // (p)(1)
             } else {
                 if (inputData[sp] > 127) {
-                    edf_count += (17.0 / 4.0); // (p)(2)
+                    edf_count += (17.0F / 4.0F); // (p)(2)
                 } else {
-                    edf_count += (13.0 / 4.0); // (p)(3)
+                    edf_count += (13.0F / 4.0F); // (p)(3)
                 }
             }
             if ((gs1 == 1) && (inputData[sp] == '[')) {
-                edf_count += 6.0;
+                edf_count += 6.0F;
             }
 
             /* base 256 ... step (q) */
             if ((gs1 == 1) && (inputData[sp] == '[')) {
-                b256_count += 4.0; // (q)(1)
+                b256_count += 4.0F; // (q)(1)
             } else {
-                b256_count += 1.0; // (q)(2)
+                b256_count += 1.0F; // (q)(2)
             }
         }
 
@@ -448,10 +449,10 @@ int look_ahead_test(unsigned char inputData[], int sourcelen, int position, int
             /* 4 data characters processed ... step (r) */
 
             /* step (r)(6) */
-            if (((c40_count + 1.0) < ascii_count) &&
-                    ((c40_count + 1.0) < b256_count) &&
-                    ((c40_count + 1.0) < edf_count) &&
-                    ((c40_count + 1.0) < text_count)) {
+            if (((c40_count + 1.0F) < ascii_count) &&
+                    ((c40_count + 1.0F) < b256_count) &&
+                    ((c40_count + 1.0F) < edf_count) &&
+                    ((c40_count + 1.0F) < text_count)) {
 
                 if (c40_count < x12_count) {
                     best_scheme = DM_C40;
@@ -468,47 +469,47 @@ int look_ahead_test(unsigned char inputData[], int sourcelen, int position, int
             }
 
             /* step (r)(5) */
-            if (((x12_count + 1.0) < ascii_count) &&
-                    ((x12_count + 1.0) < b256_count) &&
-                    ((x12_count + 1.0) < edf_count) &&
-                    ((x12_count + 1.0) < text_count) &&
-                    ((x12_count + 1.0) < c40_count)) {
+            if (((x12_count + 1.0F) < ascii_count) &&
+                    ((x12_count + 1.0F) < b256_count) &&
+                    ((x12_count + 1.0F) < edf_count) &&
+                    ((x12_count + 1.0F) < text_count) &&
+                    ((x12_count + 1.0F) < c40_count)) {
                 best_scheme = DM_X12;
             }
 
             /* step (r)(4) */
-            if (((text_count + 1.0) < ascii_count) &&
-                    ((text_count + 1.0) < b256_count) &&
-                    ((text_count + 1.0) < edf_count) &&
-                    ((text_count + 1.0) < x12_count) &&
-                    ((text_count + 1.0) < c40_count)) {
+            if (((text_count + 1.0F) < ascii_count) &&
+                    ((text_count + 1.0F) < b256_count) &&
+                    ((text_count + 1.0F) < edf_count) &&
+                    ((text_count + 1.0F) < x12_count) &&
+                    ((text_count + 1.0F) < c40_count)) {
                 best_scheme = DM_TEXT;
             }
 
             /* step (r)(3) */
-            if (((edf_count + 1.0) < ascii_count) &&
-                    ((edf_count + 1.0) < b256_count) &&
-                    ((edf_count + 1.0) < text_count) &&
-                    ((edf_count + 1.0) < x12_count) &&
-                    ((edf_count + 1.0) < c40_count)) {
+            if (((edf_count + 1.0F) < ascii_count) &&
+                    ((edf_count + 1.0F) < b256_count) &&
+                    ((edf_count + 1.0F) < text_count) &&
+                    ((edf_count + 1.0F) < x12_count) &&
+                    ((edf_count + 1.0F) < c40_count)) {
                 best_scheme = DM_EDIFACT;
             }
 
             /* step (r)(2) */
-            if (((b256_count + 1.0) <= ascii_count) ||
-                    (((b256_count + 1.0) < edf_count) &&
-                    ((b256_count + 1.0) < text_count) &&
-                    ((b256_count + 1.0) < x12_count) &&
-                    ((b256_count + 1.0) < c40_count))) {
+            if (((b256_count + 1.0F) <= ascii_count) ||
+                    (((b256_count + 1.0F) < edf_count) &&
+                    ((b256_count + 1.0F) < text_count) &&
+                    ((b256_count + 1.0F) < x12_count) &&
+                    ((b256_count + 1.0F) < c40_count))) {
                 best_scheme = DM_BASE256;
             }
 
             /* step (r)(1) */
-            if (((ascii_count + 1.0) <= b256_count) &&
-                    ((ascii_count + 1.0) <= edf_count) &&
-                    ((ascii_count + 1.0) <= text_count) &&
-                    ((ascii_count + 1.0) <= x12_count) &&
-                    ((ascii_count + 1.0) <= c40_count)) {
+            if (((ascii_count + 1.0F) <= b256_count) &&
+                    ((ascii_count + 1.0F) <= edf_count) &&
+                    ((ascii_count + 1.0F) <= text_count) &&
+                    ((ascii_count + 1.0F) <= x12_count) &&
+                    ((ascii_count + 1.0F) <= c40_count)) {
                 best_scheme = DM_ASCII;
             }
         }
@@ -1001,8 +1002,7 @@ int dm200encode_remainder(unsigned char target[], int target_length, unsigned ch
                 {
                     target[target_length] = source[inputlen - 1] + 1;
                     target_length++;
-                }
-                else if (process_p == 2) {
+                } else if (process_p == 2) {
                     target[target_length] = source[inputlen - 2] + 1;
                     target_length++;
                     target[target_length] = source[inputlen - 1] + 1;
@@ -1079,8 +1079,7 @@ int dm200encode_remainder(unsigned char target[], int target_length, unsigned ch
                 if (symbols_left < 3) {
                     target[target_length] = 31;
                     target_length++;
-                }
-                else
+                } else
                     target[target_length] = (31 << 2);
                 target_length++;
 
@@ -1179,17 +1178,17 @@ int data_matrix_200(struct zint_symbol *symbol, unsigned char source[], int leng
     }
 
     if (symbol->option_3 == DM_SQUARE) {
-        /* Skip rectangular symbols in square only mode */
+        /* Skip rectangular symbols in square only mode */
         while (matrixH[calcsize] != matrixW[calcsize]) {
             calcsize++;
-        }
+        }
     } else if (symbol->option_3 != DM_DMRE) {
-        /* Skip DMRE symbols */
-        while (isDMRE[calcsize]) {
-            calcsize++;
-        }
-    }
-
+        /* Skip DMRE symbols */
+        while (isDMRE[calcsize]) {
+            calcsize++;
+        }
+    }
+
     symbolsize = optionsize;
     if (calcsize > optionsize) {
         symbolsize = calcsize;
@@ -1297,7 +1296,7 @@ int data_matrix_200(struct zint_symbol *symbol, unsigned char source[], int leng
     return error_number;
 }
 
-int dmatrix(struct zint_symbol *symbol, unsigned char source[], int length) {
+int dmatrix(struct zint_symbol *symbol, unsigned char source[], const int length) {
     int error_number;
 
     if (symbol->option_1 <= 1) {
diff --git a/backend/gridmtx.c b/backend/gridmtx.c
index 1c26e81d..4b0f0893 100644
--- a/backend/gridmtx.c
+++ b/backend/gridmtx.c
@@ -312,9 +312,9 @@ int seek_forward(int gbdata[], int length, int position, int current_mode) {
 }
 
 /* Add the length indicator for byte encoded blocks */
-void add_byte_count(char binary[], int byte_count_posn, int byte_count) {
+static void add_byte_count(char binary[], const size_t byte_count_posn, const int byte_count) {
     int p;
-    
+
     for (p = 0; p < 8; p++) {
         if (byte_count & (0x100 >> p)) {
             binary[byte_count_posn + p] = '0';
@@ -352,13 +352,13 @@ int gm_encode(int gbdata[], int length, char binary[], int reader) {
     /* Create a binary stream representation of the input data.
        7 sets are defined - Chinese characters, Numerals, Lower case letters, Upper case letters,
        Mixed numerals and latters, Control characters and 8-bit binary data */
-    int sp, current_mode, next_mode, last_mode, glyph = 0;
+    int sp, current_mode, next_mode, last_mode, glyph = 0, q;
     int c1, c2, done;
     int p = 0, ppos;
     int numbuf[3], punt = 0;
-    int number_pad_posn, debug = 0;
-    int byte_count_posn = 0, byte_count = 0;
-    int shift, i, q;
+    size_t number_pad_posn, byte_count_posn = 0;
+    int byte_count = 0, debug = 0;
+    int shift, i;
 
     strcpy(binary, "");
 
@@ -830,7 +830,7 @@ int gm_encode(int gbdata[], int length, char binary[], int reader) {
     return 0;
 }
 
-void gm_add_ecc(char binary[], int data_posn, int layers, int ecc_level, int word[]) {
+static void gm_add_ecc(const char binary[], const size_t data_posn, const int layers, const int ecc_level, int word[]) {
     int data_cw, i, j, wp, p;
     int n1, b1, n2, b2, e1, b3, e2;
     int block_size, data_size, ecc_size;
@@ -854,7 +854,7 @@ void gm_add_ecc(char binary[], int data_posn, int layers, int ecc_level, int wor
 
     /* Add padding codewords */
     data[data_posn] = 0x00;
-    for (i = (data_posn + 1); i < data_cw; i++) {
+    for (i = (int) (data_posn + 1); i < data_cw; i++) {
         if (i & 1) {
             data[i] = 0x7e;
         } else {
@@ -1032,7 +1032,7 @@ void place_layer_id(char* grid, int size, int layers, int modules, int ecc_level
     }
 }
 
-int grid_matrix(struct zint_symbol *symbol, unsigned char source[], int length) {
+int grid_matrix(struct zint_symbol *symbol, const unsigned char source[], int length) {
     int size, modules, dark, error_number;
     int auto_layers, min_layers, layers, auto_ecc_level, min_ecc_level, ecc_level;
     int x, y, i, j, glyph;
diff --git a/backend/gs1.c b/backend/gs1.c
index e733b699..7bbad9f2 100644
--- a/backend/gs1.c
+++ b/backend/gs1.c
@@ -69,7 +69,7 @@ void itostr(char ai_string[], int ai_value) {
     concat(ai_string, ")");
 }
 
-int gs1_verify(struct zint_symbol *symbol, unsigned char source[], const unsigned int src_len, char reduced[]) {
+int gs1_verify(struct zint_symbol *symbol, const unsigned char source[], const unsigned int src_len, char reduced[]) {
     int i, j, last_ai, ai_latch;
     char ai_string[6];
     int bracket_level, max_bracket_level, ai_length, max_ai_length, min_ai_length;
@@ -335,7 +335,7 @@ int gs1_verify(struct zint_symbol *symbol, unsigned char source[], const unsigne
     return 0;
 }
 
-int ugs1_verify(struct zint_symbol *symbol, unsigned char source[], const unsigned int src_len, unsigned char reduced[]) {
+int ugs1_verify(struct zint_symbol *symbol, const unsigned char source[], const unsigned int src_len, unsigned char reduced[]) {
     /* Only to keep the compiler happy */
 #ifndef _MSC_VER
     char temp[src_len + 5];
diff --git a/backend/gs1.h b/backend/gs1.h
index 6c62409d..e097d564 100644
--- a/backend/gs1.h
+++ b/backend/gs1.h
@@ -36,8 +36,8 @@
 extern "C" {
 #endif /* __cplusplus */
 
-    extern int gs1_verify(struct zint_symbol *symbol, unsigned char source[], const unsigned int src_len, char reduced[]);
-    extern int ugs1_verify(struct zint_symbol *symbol, unsigned char source[], const unsigned int src_len, unsigned char reduced[]);
+    extern int gs1_verify(struct zint_symbol *symbol, const unsigned char source[], const unsigned int src_len, char reduced[]);
+    extern int ugs1_verify(struct zint_symbol *symbol, const unsigned char source[], const unsigned int src_len, unsigned char reduced[]);
 
 #ifdef __cplusplus
 }
diff --git a/backend/library.c b/backend/library.c
index 1566aa6c..846cab31 100755
--- a/backend/library.c
+++ b/backend/library.c
@@ -160,7 +160,7 @@ extern int australia_post(struct zint_symbol *symbol, unsigned char source[], in
 extern int code16k(struct zint_symbol *symbol, unsigned char source[], int length); /* Code 16k */
 extern int pdf417enc(struct zint_symbol *symbol, unsigned char source[], int length); /* PDF417 */
 extern int dmatrix(struct zint_symbol *symbol, unsigned char source[], int length); /* Data Matrix (IEC16022) */
-extern int qr_code(struct zint_symbol *symbol, unsigned char source[], int length); /* QR Code */
+extern int qr_code(struct zint_symbol *symbol, const unsigned char source[], int length); /* QR Code */
 extern int micro_pdf417(struct zint_symbol *symbol, unsigned char chaine[], int length); /* Micro PDF417 */
 extern int maxicode(struct zint_symbol *symbol, unsigned char source[], int length); /* Maxicode */
 extern int rss14(struct zint_symbol *symbol, unsigned char source[], int length); /* RSS-14 */
@@ -173,14 +173,14 @@ extern int code32(struct zint_symbol *symbol, unsigned char source[], int length
 extern int daft_code(struct zint_symbol *symbol, unsigned char source[], int length); /* DAFT Code */
 extern int ean_14(struct zint_symbol *symbol, unsigned char source[], int length); /* EAN-14 */
 extern int nve_18(struct zint_symbol *symbol, unsigned char source[], int length); /* NVE-18 */
-extern int microqr(struct zint_symbol *symbol, unsigned char source[], int length); /* Micro QR Code */
+extern int microqr(struct zint_symbol *symbol, const unsigned char source[], int length); /* Micro QR Code */
 extern int aztec_runes(struct zint_symbol *symbol, unsigned char source[], int length); /* Aztec Runes */
 extern int korea_post(struct zint_symbol *symbol, unsigned char source[], int length); /* Korea Post */
 extern int japan_post(struct zint_symbol *symbol, unsigned char source[], int length); /* Japanese Post */
-extern int code_49(struct zint_symbol *symbol, unsigned char source[], int length); /* Code 49 */
+extern int code_49(struct zint_symbol *symbol, unsigned char source[], const int length); /* Code 49 */
 extern int channel_code(struct zint_symbol *symbol, unsigned char source[], int length); /* Channel Code */
 extern int code_one(struct zint_symbol *symbol, unsigned char source[], int length); /* Code One */
-extern int grid_matrix(struct zint_symbol *symbol, unsigned char source[], int length); /* Grid Matrix */
+extern int grid_matrix(struct zint_symbol *symbol, const unsigned char source[], int length); /* Grid Matrix */
 
 #ifndef NO_PNG
 extern int png_handle(struct zint_symbol *symbol, int rotate_angle);
@@ -353,7 +353,7 @@ int hibc(struct zint_symbol *symbol, unsigned char source[], int length) {
     return error_number;
 }
 
-int gs1_compliant(int symbology) {
+static int gs1_compliant(const int symbology) {
     /* Returns 1 if symbology supports GS1 data */
 
     int result = 0;
@@ -480,7 +480,7 @@ int ZBarcode_ValidID(int symbol_id) {
     return result;
 }
 
-int extended_charset(struct zint_symbol *symbol, unsigned char *source, int length) {
+static int extended_charset(struct zint_symbol *symbol, const unsigned char *source, const int length) {
     int error_number = 0;
 
     /* These are the "elite" standards which can support multiple character sets */
@@ -496,7 +496,7 @@ int extended_charset(struct zint_symbol *symbol, unsigned char *source, int leng
     return error_number;
 }
 
-int reduced_charset(struct zint_symbol *symbol, unsigned char *source, int length) {
+static int reduced_charset(struct zint_symbol *symbol, const unsigned char *source, int length) {
     /* These are the "norm" standards which only support Latin-1 at most */
     int error_number = 0;
 
diff --git a/backend/qr.c b/backend/qr.c
index efbb9823..b46c369b 100644
--- a/backend/qr.c
+++ b/backend/qr.c
@@ -40,6 +40,7 @@
 #include "qr.h"
 #include "reedsol.h"
 #include <stdlib.h>     /* abs */
+#include <assert.h>
 
 /* Returns true if input glyph is in the Alphanumeric set */
 int in_alpha(int glyph) {
@@ -1297,16 +1298,12 @@ int tribus(int version, int a, int b, int c) {
 void applyOptimisation(int version, char inputMode[], int inputLength) {
     
 
-    int blockCount = 0;
+    int blockCount = 0, block;
     int i, j;
     char currentMode = ' '; // Null
-    int block;
+    int  *blockLength;
+    char *blockMode;
 
-#ifdef _MSC_VER
-    int* blockLength;
-    int* blockMode;
-#endif
-    
     for (i = 0; i < inputLength; i++) {
         if (inputMode[i] != currentMode) {
             currentMode = inputMode[i];
@@ -1314,13 +1311,16 @@ void applyOptimisation(int version, char inputMode[], int inputLength) {
         }
     }
 
-#ifndef _MSC_VER
-    int blockLength[blockCount];
-    char blockMode[blockCount];
-#else
-    blockLength = (int *) _alloca(blockCount * sizeof (int));
-    blockMode = (int *) _alloca(blockCount * sizeof(int));
-#endif
+    blockLength=(int*)malloc(sizeof(int)*blockCount);
+    assert(blockLength);
+    if (!blockLength) return;
+    blockMode=(char*)malloc(sizeof(char)*blockCount);
+    assert(blockMode);
+    if (!blockMode)
+    {   
+        free(blockLength);
+        return;
+    }
 
     j = -1;
     currentMode = ' '; // Null
@@ -1405,6 +1405,9 @@ void applyOptimisation(int version, char inputMode[], int inputLength) {
             j++;
         }
     }
+
+    free(blockLength);
+    free(blockMode);
 }
 
 int blockLength(int start, char inputMode[], int inputLength) {
@@ -1490,7 +1493,7 @@ int getBinaryLength(int version, char inputMode[], int inputData[], int inputLen
     return count;
 }
 
-int qr_code(struct zint_symbol *symbol, unsigned char source[], int length) {
+int qr_code(struct zint_symbol *symbol, const unsigned char source[], int length) {
     int error_number, i, j, glyph, est_binlen;
     int ecc_level, autosize, version, max_cw, target_binlen, blocks, size;
     int bitmask, gs1;
@@ -2757,7 +2760,7 @@ int micro_apply_bitmask(unsigned char *grid, int size) {
     return best_pattern;
 }
 
-int microqr(struct zint_symbol *symbol, unsigned char source[], int length) {
+int microqr(struct zint_symbol *symbol, const unsigned char source[], int length) {
     int i, j, glyph, size;
     char binary_stream[200];
     char full_stream[200];
diff --git a/backend/reedsol.c b/backend/reedsol.c
index fdac476a..09ad9da5 100644
--- a/backend/reedsol.c
+++ b/backend/reedsol.c
@@ -68,7 +68,7 @@ static int *logt = NULL, *alog = NULL, *rspoly = NULL;
 // polynomial.  e.g. for ECC200 (8-bit symbols) the polynomial is
 // a**8 + a**5 + a**3 + a**2 + 1, which translates to 0x12d.
 
-void rs_init_gf(int poly) {
+void rs_init_gf(const int poly) {
     int m, b, p, v;
 
     // Find the top bit, and hence the symbol size
@@ -100,7 +100,7 @@ void rs_init_gf(int poly) {
 // (x + 2**i)*(x + 2**(i+1))*...   [nsym terms]
 // For ECC200, index is 1.
 
-void rs_init_code(int nsym, int index) {
+void rs_init_code(const int nsym,int index) {
     int i, k;
 
     rspoly = (int *) malloc(sizeof (int) * (nsym + 1));
@@ -120,7 +120,7 @@ void rs_init_code(int nsym, int index) {
     }
 }
 
-void rs_encode(int len, unsigned char *data, unsigned char *res) {
+void rs_encode(const int len,const unsigned char *data, unsigned char *res) {
     int i, k, m;
     for (i = 0; i < rlen; i++)
         res[i] = 0;
@@ -140,7 +140,7 @@ void rs_encode(int len, unsigned char *data, unsigned char *res) {
 }
 
 /* The same as above but for larger bitlengths - Aztec code compatible */
-void rs_encode_long(int len, unsigned int *data, unsigned int *res) {
+void rs_encode_long(const int len,const unsigned int *data, unsigned int *res) { 
     int i, k, m;
     for (i = 0; i < rlen; i++)
         res[i] = 0;
diff --git a/backend/reedsol.h b/backend/reedsol.h
index 9afeee99..140f6586 100644
--- a/backend/reedsol.h
+++ b/backend/reedsol.h
@@ -37,10 +37,10 @@
 extern "C" {
 #endif /* __cplusplus */
 
-    extern void rs_init_gf(int poly);
-    extern void rs_init_code(int nsym, int index);
-    extern void rs_encode(int len, unsigned char *data, unsigned char *res);
-    extern void rs_encode_long(int len, unsigned int *data, unsigned int *res);
+extern void rs_init_gf(const int poly);
+extern void rs_init_code(const int nsym,int index);
+extern void rs_encode(const int len,const unsigned char *data, unsigned char *res);
+extern void rs_encode_long(const int len,const unsigned int *data, unsigned int *res);
     extern void rs_free(void);
 
 #ifdef __cplusplus
diff --git a/backend/render.c b/backend/render.c
index 591e9761..33659da5 100644
--- a/backend/render.c
+++ b/backend/render.c
@@ -56,7 +56,7 @@ int render_plot_add_hexagon(struct zint_symbol *symbol, struct zint_render_hexag
 
 int render_plot_add_string(struct zint_symbol *symbol, unsigned char *text, float x, float y, float fsize, float width, struct zint_render_string **last_string);
 
-int render_plot(struct zint_symbol *symbol, float width, float height) {
+int render_plot(struct zint_symbol *symbol,const float width,const  float height) {
     struct zint_render *render;
     struct zint_render_line *line, *last_line = NULL;
     struct zint_render_string *last_string = NULL;
@@ -173,7 +173,7 @@ int render_plot(struct zint_symbol *symbol, float width, float height) {
         }
     }
 
-    if (((symbol->symbology == BARCODE_UPCA) && (symbol->rows == 1)) || (symbol->symbology == BARCODE_UPCA_CC)) {
+	else if (((symbol->symbology == BARCODE_UPCA) && (symbol->rows == 1)) || (symbol->symbology == BARCODE_UPCA_CC)) {
         upceanflag = 12;
         if (symbol->whitespace_width < 10) {
             symbol->whitespace_width = 10;
@@ -191,7 +191,7 @@ int render_plot(struct zint_symbol *symbol, float width, float height) {
         }
     }
 
-    if (((symbol->symbology == BARCODE_UPCE) && (symbol->rows == 1)) || (symbol->symbology == BARCODE_UPCE_CC)) {
+	else if (((symbol->symbology == BARCODE_UPCE) && (symbol->rows == 1)) || (symbol->symbology == BARCODE_UPCE_CC)) {
         upceanflag = 6;
         if (symbol->whitespace_width == 0) {
             symbol->whitespace_width = 10;
@@ -228,7 +228,7 @@ int render_plot(struct zint_symbol *symbol, float width, float height) {
     if (large_bar_count == 0) {
         required_aspect = width / height;
         symbol_aspect = (total_symbol_width_x + (2 * xoffset)) / (preset_height + (2 * yoffset) + text_offset + text_height);
-        symbol->height = preset_height;
+        symbol->height = (int)preset_height;
         if (required_aspect > symbol_aspect) {
             /* the area is too wide */
             scaler = height / (preset_height + (2 * yoffset) + text_offset + text_height);
@@ -242,7 +242,7 @@ int render_plot(struct zint_symbol *symbol, float width, float height) {
         }
     } else {
         scaler = width / (total_symbol_width_x + (2 * xoffset));
-        symbol->height = (height / scaler) - ((2 * yoffset) + text_offset + text_height);
+        symbol->height = (int)((height / scaler) - ((2 * yoffset) + text_offset + text_height));
 
         render->width = width;
         render->height = height;
@@ -277,7 +277,7 @@ int render_plot(struct zint_symbol *symbol, float width, float height) {
         }
     }
 
-    if (symbol->symbology == BARCODE_CODE49) {
+	else if(symbol->symbology == BARCODE_CODE49) {
         /* The minimum X-dimension of Code 49 is 0.191mm */
         if (x_dimension < 0.191) {
             render->width = 0.191 * GL_CONST * total_area_width_x;
@@ -316,20 +316,20 @@ int render_plot(struct zint_symbol *symbol, float width, float height) {
         render->height = 4.064 * GL_CONST;
     }
 
-    if ((symbol->symbology == BARCODE_POSTNET) || (symbol->symbology == BARCODE_PLANET)) {
+	else if((symbol->symbology == BARCODE_POSTNET) || (symbol->symbology == BARCODE_PLANET)) {
         /* The size of PostNet and PLANET are fized */
         render->width = 0.508 * GL_CONST * total_area_width_x;
         render->height = 2.921 * GL_CONST;
     }
 
-    if (((symbol->symbology == BARCODE_AUSPOST) || (symbol->symbology == BARCODE_AUSREPLY)) ||
+	else if(((symbol->symbology == BARCODE_AUSPOST) || (symbol->symbology == BARCODE_AUSREPLY)) ||
             ((symbol->symbology == BARCODE_AUSROUTE) || (symbol->symbology == BARCODE_AUSREDIRECT))) {
         /* Australia Post use the same sizes as USPS */
         render->width = 0.508 * GL_CONST * total_area_width_x;
         render->height = 4.064 * GL_CONST;
     }
 
-    if ((symbol->symbology == BARCODE_RM4SCC) || (symbol->symbology == BARCODE_KIX)) {
+	else if((symbol->symbology == BARCODE_RM4SCC) || (symbol->symbology == BARCODE_KIX)) {
         /* Royal Mail and KIX Code uses 22 bars per inch */
         render->width = 0.577 * GL_CONST * total_area_width_x;
         render->height = 5.22 * GL_CONST;
@@ -680,6 +680,8 @@ struct zint_render_line *render_plot_create_line(float x, float y, float width,
     struct zint_render_line *line;
 
     line = (struct zint_render_line*) malloc(sizeof (struct zint_render_line));
+    if (!line) return NULL;
+
     line->next = NULL;
     line->x = x;
     line->y = y;
@@ -694,6 +696,7 @@ struct zint_render_line *render_plot_create_line(float x, float y, float width,
  * next value.
  */
 int render_plot_add_line(struct zint_symbol *symbol, struct zint_render_line *line, struct zint_render_line **last_line) {
+   if (!line) return ZINT_ERROR_MEMORY;
     if (*last_line)
         (*last_line)->next = line;
     else
@@ -707,6 +710,7 @@ struct zint_render_ring *render_plot_create_ring(float x, float y, float radius,
     struct zint_render_ring *ring;
 
     ring = (struct zint_render_ring *) malloc(sizeof (struct zint_render_ring));
+    if (!ring) return NULL;
     ring->next = NULL;
     ring->x = x;
     ring->y = y;
@@ -717,6 +721,7 @@ struct zint_render_ring *render_plot_create_ring(float x, float y, float radius,
 }
 
 int render_plot_add_ring(struct zint_symbol *symbol, struct zint_render_ring *ring, struct zint_render_ring **last_ring) {
+   if (!ring) return ZINT_ERROR_MEMORY;
     if (*last_ring)
         (*last_ring)->next = ring;
     else
@@ -730,6 +735,7 @@ struct zint_render_hexagon *render_plot_create_hexagon(float x, float y) {
     struct zint_render_hexagon *hexagon;
 
     hexagon = (struct zint_render_hexagon*) malloc(sizeof (struct zint_render_hexagon));
+    if (!hexagon) return NULL;
     hexagon->next = NULL;
     hexagon->x = x;
     hexagon->y = y;
@@ -738,6 +744,7 @@ struct zint_render_hexagon *render_plot_create_hexagon(float x, float y) {
 }
 
 int render_plot_add_hexagon(struct zint_symbol *symbol, struct zint_render_hexagon *hexagon, struct zint_render_hexagon **last_hexagon) {
+   if (!hexagon) return ZINT_ERROR_MEMORY;
     if (*last_hexagon)
         (*last_hexagon)->next = hexagon;
     else
diff --git a/backend/zint.h b/backend/zint.h
index 7fd94199..f9328442 100644
--- a/backend/zint.h
+++ b/backend/zint.h
@@ -235,7 +235,7 @@ extern "C" {
     ZINT_EXTERN int ZBarcode_Encode_and_Print(struct zint_symbol *symbol, unsigned char *input, int length, int rotate_angle);
     ZINT_EXTERN int ZBarcode_Encode_File_and_Print(struct zint_symbol *symbol, char *filename, int rotate_angle);
 
-    ZINT_EXTERN int ZBarcode_Render(struct zint_symbol *symbol, float width, float height);
+    ZINT_EXTERN int ZBarcode_Render(struct zint_symbol *symbol, const float width, const float height);
 
     ZINT_EXTERN int ZBarcode_Buffer(struct zint_symbol *symbol, int rotate_angle);
     ZINT_EXTERN int ZBarcode_Encode_and_Buffer(struct zint_symbol *symbol, unsigned char *input, int length, int rotate_angle);