add get_error_message error code return value mapping util function

gci_extract.c

@@ -146,7 +146,7 @@ int main(int argc, char *argv[]) {
 	GCI_DECRYPTED_DLQUEST_HEADER bin_gci_header;
 	result = get_quest_data(bin_gci_filename, &bin_data, &bin_data_size, &bin_gci_header);
 	if (result) {
-		printf("Error code %d reading quest .bin data.\n", result);
+		printf("Error code %d reading quest .bin data: %s\n", result, get_error_message(result));
 		goto error;
 	}
 
@@ -154,7 +154,7 @@ int main(int argc, char *argv[]) {
 	GCI_DECRYPTED_DLQUEST_HEADER dat_gci_header;
 	result = get_quest_data(dat_gci_filename, &dat_data, &dat_data_size, &dat_gci_header);
 	if (result) {
-		printf("Error code %d reading quest .dat data.\n", result);
+		printf("Error code %d reading quest .dat data: %s\n", result, get_error_message(result));
 		goto error;
 	}
 

utils.c

@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
 #include <malloc.h>
@@ -6,6 +7,17 @@
 #include "utils.h"
 #include "retvals.h"
 
+// from error codes defined in retvals.h
+static const char *error_messages[] = {
+		"No error",                    // SUCCESS
+		"Invalid parameter(s)",        // ERROR_INVALID_PARAMS
+		"File not found",              // ERROR_FILE_NOT_FOUND
+		"Cannot create file",          // ERROR_CREATING_FILE
+		"Bad data",                    // ERROR_BAD_DATA
+		"I/O error",                   // ERROR_IO
+		NULL
+};
+
 int read_file(const char *filename, uint8_t** out_file_data, uint32_t *out_file_size) {
 	if (!filename || !out_file_size || !out_file_data)
 		return ERROR_INVALID_PARAMS;
@@ -88,3 +100,16 @@ char* append_string(const char *a, const char *b) {
 	strcat(result, b);
 	return result;
 }
+
+const char* get_error_message(int retvals_error_code) {
+	retvals_error_code = abs(retvals_error_code);
+
+	int max_error_index;
+	for (max_error_index = 0; error_messages[max_error_index]; ++max_error_index) {}
+	max_error_index = max_error_index;
+
+	if (retvals_error_code >= max_error_index)
+		return "Unknown error";
+	else
+		return error_messages[retvals_error_code];
+}

utils.h

@@ -11,4 +11,6 @@ int get_filesize(const char *filename, size_t *out_size);
 const char* path_to_filename(const char *path);
 char* append_string(const char *a, const char *b);
 
+const char* get_error_message(int retvals_error_code);
+
 #endif