helper interfaces: tpax_path_copy(): initial implementation.

1 files changed, 86 insertions, 0 deletions

diff --git a/src/helper/tpax_path_copy.c b/src/helper/tpax_path_copy.c
new file mode 100644
index 0000000..0df6c17
--- /dev/null
+++ b/src/helper/tpax_path_copy.c
@@ -0,0 +1,86 @@
+/******************************************************/
+/*  tpax: a topological pax implementation            */
+/*  Copyright (C) 2020  Z. Gilboa                     */
+/*  Released under GPLv2 and GPLv3; see COPYING.TPAX. */
+/******************************************************/
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+#include <tpax/tpax.h>
+#include "tpax_driver_impl.h"
+
+int tpax_path_copy(
+	char *          dstpath,
+	const char *    srcpath,
+	size_t          bufsize,
+	uint32_t        flags,
+	size_t *        nwritten)
+{
+	const char *    src;
+	char *          dst;
+	char *          cap;
+
+	if (!bufsize) {
+		errno = ENOBUFS;
+		return -1;
+	}
+
+	src = srcpath;
+	dst = dstpath;
+	cap = &dst[bufsize];
+
+	if ((src[0] == '/') && (src[1] == '/') && (src[2] != '/')) {
+		*dst++ = *src++;
+		*dst++ = *src++;
+	}
+
+	if (flags & TPAX_DRIVER_PURE_PATH_OUTPUT)
+		if ((src[0] == '.') && (src[1] == '/'))
+			for (++src; *src=='/'; src++)
+				(void)0;
+
+	for (; *src; ) {
+		if ((src[0] == '.') && (src[1] == '.')) {
+			if ((src[2] == '/') || (src[2] == '\0')) {
+				if (flags & TPAX_DRIVER_STRICT_PATH_INPUT) {
+					errno = EINVAL;
+					return -1;
+				}
+			}
+		}
+
+		if (flags & TPAX_DRIVER_PURE_PATH_OUTPUT) {
+			if ((src[0] == '.') && (src[1] == '/') && (src[-1] == '/')) {
+				for (++src; *src=='/'; src++)
+					(void)0;
+
+			} else if ((src[0] == '/')) {
+				for (src++; *src=='/'; src++)
+					(void)0;
+
+				*dst++ = '/';
+
+			} else {
+				*dst++ = *src++;
+			}
+		} else {
+			*dst++ = *src++;
+		}
+
+		if (dst == cap) {
+			errno = ENOBUFS;
+			return -1;
+		}
+	}
+
+	if (nwritten)
+		*nwritten = dst - dstpath;
+
+	*dst = '\0';
+
+	return 0;
+}