1 files changed, 60 insertions, 0 deletions
diff --git a/libsyscalls_to_tracee_endian.c b/libsyscalls_to_tracee_endian.c
new file mode 100644
index 0000000..94c44eb
--- /dev/null
+++ b/libsyscalls_to_tracee_endian.c
@@ -0,0 +1,60 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+
+
+/* XXX be smarter if using the same byteorder */
+enum libsyscalls_error
+libsyscalls_to_tracee_endian(unsigned long long int value_in,
+                             const struct libsyscalls_datatype_description *type,
+                             void *value_out, size_t out_offset)
+{
+	const unsigned long long int limit = sizeof(long long int) / sizeof(char) * CHAR_BIT;
+	unsigned long long int bytebits, bytemask, byte, remmask, valmask;
+	unsigned long long int offset, offset_byte, offset_bit;
+	unsigned char *out = value_out;
+	size_t i;
+
+	if (!type || !value_out || (unsigned long long int)type->width_in_bits > limit)
+		return LIBSYSCALLS_E_INVAL;
+
+	bytebits = (unsigned long long int)type->width_in_bits;
+	for (i = 0; !LIBSYSCALLS_IS_BYTEORDER_END_AT(type, i); i++)
+		if (type->byteorder[i] && (unsigned long long int)type->byteorder[i] < bytebits)
+			bytebits = (unsigned long long int)type->byteorder[i];
+
+	if (bytebits > limit)
+		return LIBSYSCALLS_E_INVAL;
+	else if (bytebits == limit)
+		bytemask = ~0ULL;
+	else
+		bytemask = (1ULL << bytebits) - 1ULL;
+
+	if ((unsigned long long int)type->width_in_bits == limit)
+		valmask = ~0ULL;
+	else
+		valmask = (1ULL << (unsigned long long int)type->width_in_bits) - 1ULL;
+
+	for (i = 0; !LIBSYSCALLS_IS_BYTEORDER_END_AT(type, i); i++) {
+		offset = out_offset;
+		offset_byte = offset / CHAR_BIT;
+		offset_bit = offset % CHAR_BIT;
+		out_offset += bytebits;
+
+		byte = value_in >> type->byteorder[i];
+		byte &= remmask = bytemask & (valmask >> type->byteorder[i]);
+
+		out[offset_byte] &= (unsigned char)~(remmask << offset_bit);
+		out[offset_byte] |= (unsigned char)(byte << offset_bit);
+		if (bytebits != limit && (remmask >>= CHAR_BIT - offset_bit)) {
+			byte >>= CHAR_BIT - offset_bit;
+			do {
+				offset_byte += 1;
+				out[offset_byte] &= (unsigned char)~remmask;
+				out[offset_byte] |= (unsigned char)byte;
+				byte >>= CHAR_BIT;
+			} while (remmask >>= CHAR_BIT);
+		}
+	}
+
+	return LIBSYSCALLS_E_OK;
+}