core: add minimal templating system

[elogind.git] / specifier.c

diff --git a/specifier.c b/specifier.c
new file mode 100644 (file)
index 0000000..a25f33a
--- /dev/null
+++ b/specifier.c
@@ -0,0 +1,110 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <string.h>
+
+#include "macro.h"
+#include "util.h"
+#include "specifier.h"
+
+/*
+ * Generic infrastructure for replacing %x style specifiers in
+ * strings. Will call a callback for each replacement.
+ *
+ */
+
+char *specifier_printf(const char *text, const Specifier table[], void *userdata) {
+        char *r, *t;
+        const char *f;
+        bool percent = false;
+        size_t l;
+
+        assert(text);
+        assert(table);
+
+        l = strlen(text);
+        if (!(r = new(char, l+1)))
+                return NULL;
+
+        t = r;
+
+        for (f = text; *f; f++, l--) {
+
+                if (percent) {
+                        if (*f == '%')
+                                *(t++) = '%';
+                        else {
+                                const Specifier *i;
+
+                                for (i = table; i->specifier; i++)
+                                        if (i->specifier == *f)
+                                                break;
+
+                                if (i->lookup) {
+                                        char *n, *w;
+                                        size_t k, j;
+
+                                        if (!(w = i->lookup(i->specifier, i->data, userdata))) {
+                                                free(r);
+                                                return NULL;
+                                        }
+
+                                        j = t - r;
+                                        k = strlen(w);
+
+                                        if (!(n = new(char, j + k + (l - (f - text)) + 1))) {
+                                                free(r);
+                                                free(w);
+                                                return NULL;
+                                        }
+
+                                        memcpy(n, r, j);
+                                        memcpy(n + j, w, k);
+
+                                        free(r);
+                                        free(w);
+
+                                        r = n;
+                                        t = n + j + k;
+                                } else {
+                                        *(t++) = '%';
+                                        *(t++) = *f;
+                                }
+                        }
+
+                        percent = false;
+                } else if (*f == '%')
+                        percent = true;
+                else
+                        *(t++) = *f;
+        }
+
+        *t = 0;
+        return r;
+}
+
+/* Generic handler for simple string replacements */
+
+char* specifier_string(char specifier, void *data, void *userdata) {
+        assert(data);
+
+        return strdup(strempty(data));
+}