Cleanup: Return combined return value from compressor id by name

Instead of returning the ID through a pointer and an error code as
return status, return a single int that could be a compressor ID
(positive values) or an error code (negative values).

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

4 files changed, 22 insertions, 28 deletions

diff --git a/include/sqfs/compressor.h b/include/sqfs/compressor.h
index 4f22b0d..5e0be5d 100644
--- a/include/sqfs/compressor.h
+++ b/include/sqfs/compressor.h
@@ -384,13 +384,11 @@ SQFS_API const char *sqfs_compressor_name_from_id(E_SQFS_COMPRESSOR id);
  * available.
  *
  * @param name The name of the compressor backend.
- * @param out Returns the coresponding @ref E_SQFS_COMPRESSOR identifier.
  *
- * @return Zero on success, @ref SQFS_ERROR_UNSUPPORTED if the backend
- *         is unknown.
+ * @return A positive, @ref E_SQFS_COMPRESSOR identifier on success
+ *         or @ref SQFS_ERROR_UNSUPPORTED if the backend is unknown.
  */
-SQFS_API
-int sqfs_compressor_id_from_name(const char *name, E_SQFS_COMPRESSOR *out);
+SQFS_API int sqfs_compressor_id_from_name(const char *name);
 
 #ifdef __cplusplus
 }
diff --git a/lib/sqfs/comp/compressor.c b/lib/sqfs/comp/compressor.c
index 0b8b5e9..8049ade 100644
--- a/lib/sqfs/comp/compressor.c
+++ b/lib/sqfs/comp/compressor.c
@@ -130,15 +130,13 @@ const char *sqfs_compressor_name_from_id(E_SQFS_COMPRESSOR id)
 	return names[id];
 }
 
-int sqfs_compressor_id_from_name(const char *name, E_SQFS_COMPRESSOR *out)
+int sqfs_compressor_id_from_name(const char *name)
 {
 	size_t i;
 
 	for (i = 0; i < sizeof(names) / sizeof(names[0]); ++i) {
-		if (names[i] != NULL && strcmp(names[i], name) == 0) {
-			*out = i;
-			return 0;
-		}
+		if (names[i] != NULL && strcmp(names[i], name) == 0)
+			return i;
 	}
 
 	return SQFS_ERROR_UNSUPPORTED;
diff --git a/mkfs/options.c b/mkfs/options.c
index 31b7731..4dce84e 100644
--- a/mkfs/options.c
+++ b/mkfs/options.c
@@ -146,7 +146,7 @@ const char *help_details =
 void process_command_line(options_t *opt, int argc, char **argv)
 {
 	bool have_compressor;
-	int i;
+	int i, ret;
 
 	memset(opt, 0, sizeof(*opt));
 	sqfs_writer_cfg_init(&opt->cfg);
@@ -159,25 +159,23 @@ void process_command_line(options_t *opt, int argc, char **argv)
 		switch (i) {
 		case 'c':
 			have_compressor = true;
+			ret = sqfs_compressor_id_from_name(optarg);
 
-			if (sqfs_compressor_id_from_name(optarg,
-							 &opt->cfg.comp_id)) {
+			if (ret < 0) {
 				have_compressor = false;
-			}
-
-			if (!sqfs_compressor_exists(opt->cfg.comp_id))
-				have_compressor = false;
-
 #ifdef WITH_LZO
-			if (opt->cfg.comp_id == SQFS_COMP_LZO)
-				have_compressor = true;
+				if (opt->cfg.comp_id == SQFS_COMP_LZO)
+					have_compressor = true;
 #endif
+			}
 
 			if (!have_compressor) {
 				fprintf(stderr, "Unsupported compressor '%s'\n",
 					optarg);
 				exit(EXIT_FAILURE);
 			}
+
+			opt->cfg.comp_id = ret;
 			break;
 		case 'b':
 			opt->cfg.block_size = strtol(optarg, NULL, 0);
diff --git a/tar/tar2sqfs.c b/tar/tar2sqfs.c
index 0076537..56ae5dc 100644
--- a/tar/tar2sqfs.c
+++ b/tar/tar2sqfs.c
@@ -97,7 +97,7 @@ static FILE *input_file = NULL;
 static void process_args(int argc, char **argv)
 {
 	bool have_compressor;
-	int i;
+	int i, ret;
 
 	sqfs_writer_cfg_init(&cfg);
 
@@ -120,23 +120,23 @@ static void process_args(int argc, char **argv)
 			break;
 		case 'c':
 			have_compressor = true;
+			ret = sqfs_compressor_id_from_name(optarg);
 
-			if (sqfs_compressor_id_from_name(optarg, &cfg.comp_id))
+			if (ret < 0) {
 				have_compressor = false;
-
-			if (!sqfs_compressor_exists(cfg.comp_id))
-				have_compressor = false;
-
 #ifdef WITH_LZO
-			if (cfg.comp_id == SQFS_COMP_LZO)
-				have_compressor = true;
+				if (cfg.comp_id == SQFS_COMP_LZO)
+					have_compressor = true;
 #endif
+			}
 
 			if (!have_compressor) {
 				fprintf(stderr, "Unsupported compressor '%s'\n",
 					optarg);
 				exit(EXIT_FAILURE);
 			}
+
+			cfg.comp_id = ret;
 			break;
 		case 'j':
 			cfg.num_jobs = strtol(optarg, NULL, 0);