tidy-up: make conditional checks more consistent

... remove '== NULL' and '!= 0'

Closes #6912

src/tool_convert.c

@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2020, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -65,7 +65,7 @@ CURLcode convert_to_network(char *buffer, size_t length)
   in_bytes = out_bytes = length;
   res = iconv(outbound_cd, &input_ptr,  &in_bytes,
               &output_ptr, &out_bytes);
-  if((res == (size_t)-1) || (in_bytes != 0)) {
+  if((res == (size_t)-1) || (in_bytes)) {
     return CURLE_CONV_FAILED;
   }
 
@@ -95,7 +95,7 @@ CURLcode convert_from_network(char *buffer, size_t length)
   in_bytes = out_bytes = length;
   res = iconv(inbound_cd, &input_ptr,  &in_bytes,
               &output_ptr, &out_bytes);
-  if((res == (size_t)-1) || (in_bytes != 0)) {
+  if((res == (size_t)-1) || (in_bytes)) {
     return CURLE_CONV_FAILED;
   }
 

src/tool_metalink.c

@@ -534,7 +534,7 @@ int metalink_check_hash(struct GlobalConfig *config,
 {
   int rv;
   fprintf(config->errors, "Metalink: validating (%s)...\n", filename);
-  if(mlfile->checksum == NULL) {
+  if(!mlfile->checksum) {
     fprintf(config->errors,
             "Metalink: validating (%s) FAILED (digest missing)\n", filename);
     return -2;
@@ -649,7 +649,7 @@ static struct metalinkfile *new_metalinkfile(metalink_file_t *fileinfo)
          fileinfo->resources point to the target file. BitTorrent
          metainfo file URL may be appeared in fileinfo->metaurls.
       */
-      if((*p)->type == NULL ||
+      if(!(*p)->type ||
          curl_strequal((*p)->type, "http") ||
          curl_strequal((*p)->type, "https") ||
          curl_strequal((*p)->type, "ftp") ||
@@ -691,10 +691,10 @@ int parse_metalink(struct OperationConfig *config, struct OutStruct *outs,
   /* metlaink_parse_final deletes outs->metalink_parser */
   r = metalink_parse_final(outs->metalink_parser, NULL, 0, &metalink);
   outs->metalink_parser = NULL;
-  if(r != 0) {
+  if(r) {
     return -1;
   }
-  if(metalink->files == NULL) {
+  if(!metalink->files) {
     fprintf(config->global->errors, "Metalink: parsing (%s) WARNING "
             "(missing or invalid file name)\n",
             metalink_url);
@@ -824,7 +824,7 @@ static void delete_metalink_checksum(struct metalink_checksum *chksum)
 
 static void delete_metalink_resource(struct metalink_resource *res)
 {
-  if(res == NULL) {
+  if(!res) {
     return;
   }
   Curl_safefree(res->url);
@@ -834,7 +834,7 @@ static void delete_metalink_resource(struct metalink_resource *res)
 void delete_metalinkfile(struct metalinkfile *mlfile)
 {
   struct metalink_resource *res;
-  if(mlfile == NULL) {
+  if(!mlfile) {
     return;
   }
   Curl_safefree(mlfile->filename);

src/tool_operate.c

@@ -167,14 +167,14 @@ static curl_off_t vms_realfilesize(const char *name,
 
   /* !checksrc! disable FOPENMODE 1 */
   file = fopen(name, "r"); /* VMS */
-  if(file == NULL) {
+  if(!file) {
     return 0;
   }
   count = 0;
   ret_stat = 1;
   while(ret_stat > 0) {
     ret_stat = fread(buffer, 1, sizeof(buffer), file);
-    if(ret_stat != 0)
+    if(ret_stat)
       count += ret_stat;
   }
   fclose(file);
@@ -764,7 +764,7 @@ static CURLcode single_transfer(struct GlobalConfig *global,
     urlnode = config->state.urlnode;
     if(urlnode->flags & GETOUT_METALINK) {
       metalink = 1;
-      if(mlfile_last == NULL) {
+      if(!mlfile_last) {
         mlfile_last = config->metalinkfile_list;
       }
       mlfile = mlfile_last;
@@ -1979,7 +1979,7 @@ static CURLcode single_transfer(struct GlobalConfig *global,
         /* curl 7.17.1 */
         if(!config->nokeepalive) {
           my_setopt(curl, CURLOPT_TCP_KEEPALIVE, 1L);
-          if(config->alivetime != 0) {
+          if(config->alivetime) {
             my_setopt(curl, CURLOPT_TCP_KEEPIDLE, config->alivetime);
             my_setopt(curl, CURLOPT_TCP_KEEPINTVL, config->alivetime);
           }
@@ -2128,7 +2128,7 @@ static CURLcode single_transfer(struct GlobalConfig *global,
 #ifdef USE_METALINK
         if(!metalink && config->use_metalink) {
           outs->metalink_parser = metalink_parser_context_new();
-          if(outs->metalink_parser == NULL) {
+          if(!outs->metalink_parser) {
             result = CURLE_OUT_OF_MEMORY;
             break;
           }

src/tool_vms.c

@@ -56,7 +56,7 @@ int is_vms_shell(void)
   shell = getenv("SHELL");
 
   /* No shell, means DCL */
-  if(shell == NULL) {
+  if(!shell) {
     vms_shell = 1;
     return 1;
   }