1 files changed, 55 insertions, 0 deletions
diff --git a/lib/src/strexpand.c b/lib/src/strexpand.c
new file mode 100644
index 0000000..7e552eb
--- /dev/null
+++ b/lib/src/strexpand.c
@@ -0,0 +1,55 @@
+#include <string.h>
+#include <stdlib.h>
+#include <ctype.h>
+
+#include "util.h"
+
+char *strexpand(const char *inp, size_t argc, const char *const *argv)
+{
+	char *out, *dst;
+	const char *ptr;
+	size_t i, len;
+
+	ptr = inp;
+	len = 0;
+
+	while (*ptr != '\0') {
+		if (ptr[0] == '%' && isdigit(ptr[1])) {
+			i = ptr[1] - '0';
+			if (i < argc)
+				len += strlen(argv[i]);
+			ptr += 2;
+		} else if (ptr[0] == '%' && ptr[1] == '%') {
+			ptr += 2;
+			len += 1;
+		} else {
+			++ptr;
+			++len;
+		}
+	}
+
+	out = calloc(1, len + 1);
+	if (out == NULL)
+		return NULL;
+
+	dst = out;
+
+	while (*inp != '\0') {
+		if (inp[0] == '%' && isdigit(inp[1])) {
+			i = inp[1] - '0';
+			if (i < argc) {
+				len = strlen(argv[i]);
+				memcpy(dst, argv[i], len);
+				dst += len;
+			}
+			inp += 2;
+		} else if (inp[0] == '%' && inp[1] == '%') {
+			*(dst++) = '%';
+			inp += 2;
+		} else {
+			*(dst++) = *(inp++);
+		}
+	}
+
+	return out;
+}