+// Serialize the given state to a file descriptor, and return the (still open)
+// descriptor.
+int make_tempfile(const CubemapStateProto &state)
+{
+ char tmpl[] = "/tmp/cubemapstate.XXXXXX";
+ int state_fd = mkstemp(tmpl);
+ if (state_fd == -1) {
+ perror("mkstemp");
+ exit(1);
+ }
+
+ string serialized;
+ state.SerializeToString(&serialized);
+
+ const char *ptr = serialized.data();
+ size_t to_write = serialized.size();
+ while (to_write > 0) {
+ ssize_t ret = write(state_fd, ptr, to_write);
+ if (ret == -1) {
+ perror("write");
+ exit(1);
+ }
+
+ ptr += ret;
+ to_write -= ret;
+ }
+
+ return state_fd;
+}
+
+// Read the state back from the file descriptor made by make_tempfile,
+// and close it.
+CubemapStateProto read_tempfile(int state_fd)
+{
+ if (lseek(state_fd, 0, SEEK_SET) == -1) {
+ perror("lseek");
+ exit(1);
+ }
+
+ string serialized;
+ char buf[4096];
+ for ( ;; ) {
+ ssize_t ret = read(state_fd, buf, sizeof(buf));
+ if (ret == -1) {
+ perror("read");
+ exit(1);
+ }
+ if (ret == 0) {
+ // EOF.
+ break;
+ }
+
+ serialized.append(string(buf, buf + ret));
+ }
+
+ close(state_fd); // Implicitly deletes the file.
+
+ CubemapStateProto state;
+ if (!state.ParseFromString(serialized)) {
+ fprintf(stderr, "PANIC: Failed deserialization of state.\n");
+ exit(1);
+ }
+
+ return state;
+}
+
+// Split a line on whitespace, e.g. "foo bar baz" -> {"foo", "bar", "baz"}.
+vector<string> split_tokens(const string &line)
+{
+ vector<string> ret;
+ string current_token;
+
+ for (size_t i = 0; i < line.size(); ++i) {
+ if (isspace(line[i])) {
+ if (!current_token.empty()) {
+ ret.push_back(current_token);
+ }
+ current_token.clear();
+ } else {
+ current_token.push_back(line[i]);
+ }
+ }
+ if (!current_token.empty()) {
+ ret.push_back(current_token);
+ }
+ return ret;
+}
+
+struct ConfigLine {
+ string keyword;
+ vector<string> arguments;
+ map<string, string> parameters;
+};
+
+// Parse the configuration file.
+vector<ConfigLine> parse_config(const string &filename)
+{
+ vector<ConfigLine> ret;
+
+ FILE *fp = fopen(filename.c_str(), "r");
+ if (fp == NULL) {
+ perror(filename.c_str());
+ exit(1);
+ }
+
+ char buf[4096];
+ while (!feof(fp)) {
+ if (fgets(buf, sizeof(buf), fp) == NULL) {
+ break;
+ }
+
+ // Chop off the string at the first #, \r or \n.
+ buf[strcspn(buf, "#\r\n")] = 0;
+
+ // Remove all whitespace from the end of the string.
+ size_t len = strlen(buf);
+ while (len > 0 && isspace(buf[len - 1])) {
+ buf[--len] = 0;
+ }
+
+ // If the line is now all blank, ignore it.
+ if (len == 0) {
+ continue;
+ }
+
+ vector<string> tokens = split_tokens(buf);
+ assert(!tokens.empty());
+
+ ConfigLine line;
+ line.keyword = tokens[0];
+
+ for (size_t i = 1; i < tokens.size(); ++i) {
+ // foo=bar is a parameter; anything else is an argument.
+ size_t equals_pos = tokens[i].find_first_of('=');
+ if (equals_pos == string::npos) {
+ line.arguments.push_back(tokens[i]);
+ } else {
+ string key = tokens[i].substr(0, equals_pos);
+ string value = tokens[i].substr(equals_pos + 1, string::npos);
+ line.parameters.insert(make_pair(key, value));
+ }
+ }
+
+ ret.push_back(line);
+ }
+
+ fclose(fp);
+ return ret;
+}
+