diff --git a/thirdparty/misc/smaz.c b/thirdparty/misc/smaz.c
index aa674c3858..6f9ea20e67 100644
--- a/thirdparty/misc/smaz.c
+++ b/thirdparty/misc/smaz.c
@@ -1,7 +1,7 @@
 #include <string.h>
 
 /* Our compression codebook, used for compression */
-static char *Smaz_cb[241] = {
+static const char *Smaz_cb[241] = {
 "\002s,\266", "\003had\232\002leW", "\003on \216", "", "\001yS",
 "\002ma\255\002li\227", "\003or \260", "", "\002ll\230\003s t\277",
 "\004fromg\002mel", "", "\003its\332", "\001z\333", "\003ingF", "\001>\336",
@@ -76,7 +76,7 @@ static char *Smaz_rcb[254] = {
 "e, ", " it", "whi", " ma", "ge", "x", "e c", "men", ".com"
 };
 
-int smaz_compress(char *in, int inlen, char *out, int outlen) {
+int smaz_compress(const char *in, int inlen, char *out, int outlen) {
     unsigned int h1,h2,h3=0;
     int verblen = 0, _outlen = outlen;
     char verb[256], *_out = out;
@@ -154,7 +154,7 @@ out:
     return out-_out;
 }
 
-int smaz_decompress(char *in, int inlen, char *out, int outlen) {
+int smaz_decompress(const char *in, int inlen, char *out, int outlen) {
     unsigned char *c = (unsigned char*) in;
     char *_out = out;
     int _outlen = outlen;
@@ -179,7 +179,7 @@ int smaz_decompress(char *in, int inlen, char *out, int outlen) {
             inlen -= 2+len;
         } else {
             /* Codebook entry */
-            char *s = Smaz_rcb[*c];
+            const char *s = Smaz_rcb[*c];
             int len = strlen(s);
 
             if (outlen < len) return _outlen+1;
diff --git a/thirdparty/misc/smaz.h b/thirdparty/misc/smaz.h
index ce9c35d6b2..d8e1f8a6a5 100644
--- a/thirdparty/misc/smaz.h
+++ b/thirdparty/misc/smaz.h
@@ -1,7 +1,7 @@
 #ifndef _SMAZ_H
 #define _SMAZ_H
 
-int smaz_compress(char *in, int inlen, char *out, int outlen);
-int smaz_decompress(char *in, int inlen, char *out, int outlen);
+int smaz_compress(const char *in, int inlen, char *out, int outlen);
+int smaz_decompress(const char *in, int inlen, char *out, int outlen);
 
 #endif