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-rw-r--r--lib/src/unescape.c90
1 files changed, 90 insertions, 0 deletions
diff --git a/lib/src/unescape.c b/lib/src/unescape.c
new file mode 100644
index 0000000..7508e2f
--- /dev/null
+++ b/lib/src/unescape.c
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * Copyright (C) 2018 - David Oberhollenzer
+ *
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <stdlib.h>
+#include <ctype.h>
+#include <errno.h>
+
+#include "util.h"
+
+static int xdigit(int x)
+{
+ if (isupper(x))
+ return x - 'A' + 0x0A;
+ if (islower(x))
+ return x - 'a' + 0x0A;
+ return x - '0';
+}
+
+int unescape(char *src)
+{
+ char *dst = src;
+ int c;
+
+ for (;;) {
+ while (*src != '"' && *src != '\0')
+ *(dst++) = *(src++);
+
+ if (*src == '\0')
+ break;
+
+ ++src;
+
+ while ((c = *(src++)) != '"') {
+ if (c == '\0')
+ return -1;
+
+ if (c == '\\') {
+ c = *(src++);
+
+ switch (c) {
+ case 'a': c = '\a'; break;
+ case 'b': c = '\b'; break;
+ case 'f': c = '\f'; break;
+ case 'n': c = '\n'; break;
+ case 't': c = '\t'; break;
+ case '\\':
+ case '"':
+ break;
+ case 'x':
+ c = 0;
+ if (isxdigit(*src))
+ c = (c<<4) | xdigit(*(src++));
+ if (isxdigit(*src))
+ c = (c<<4) | xdigit(*(src++));
+ break;
+ case '0':
+ c = 0;
+ if (isdigit(*src) && *src < '8')
+ c = (c<<3) | (*(src++) - '0');
+ if (isdigit(*src) && *src < '8')
+ c = (c<<3) | (*(src++) - '0');
+ if (isdigit(*src) && *src < '8')
+ c = (c<<3) | (*(src++) - '0');
+ break;
+ default:
+ return -1;
+ }
+ }
+
+ *(dst++) = c;
+ }
+ }
+
+ *(dst++) = '\0';
+ return 0;
+}