Print all status messages on stderr

All status messages should go out on stderr in case we're piping compressed data to other processes. Otherwise those errors might end up silently dumped into the data stream, and the error may go unnoticed.

heatshrink.c

@@ -154,7 +154,7 @@ static ssize_t handle_read(io_handle *io, size_t size, uint8_t **buf) {
     LOG("@ read %zd\n", size);
     if (buf == NULL) { return -1; }
     if (size > io->size) {
-        printf("size %zd, io->size %zd\n", size, io->size);
+        fprintf(stderr, "size %zd, io->size %zd\n", size, io->size);
         return -1;
     }
     if (io->mode != IO_READ) { return -1; }
@@ -289,7 +289,7 @@ static int encode(config *cfg) {
         uint8_t *input = NULL;
         read_sz = handle_read(in, window_sz, &input);
         if (input == NULL) {
-            printf("handle read failure\n");
+            fprintf(stderr, "handle read failure\n");
             die("read");
         }
         if (read_sz < 0) { die("read"); }
@@ -363,7 +363,7 @@ static int decode(config *cfg) {
         uint8_t *input = NULL;
         read_sz = handle_read(in, window_sz, &input);
         if (input == NULL) {
-            printf("handle read failure\n");
+            fprintf(stderr, "handle read failure\n");
             die("read");
         }
         if (read_sz == 0) {
@@ -446,7 +446,7 @@ int main(int argc, char **argv) {
 
     if (0 == strcmp(cfg.in_fname, cfg.out_fname)
         && (0 != strcmp("-", cfg.in_fname))) {
-        printf("Refusing to overwrite file '%s' with itself.\n", cfg.in_fname);
+        fprintf(stderr, "Refusing to overwrite file '%s' with itself.\n", cfg.in_fname);
         exit(1);
     }