[coreboot-gerrit] New patch to review for coreboot: 887ba5d cbfstool: Add portable endian conversion helpers

[Alexandru Gagniuc]

Alexandru Gagniuc ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/4792

-gerrit

commit 887ba5dfcb3ee62c5cbf2ecd26bf9c743e6e77c0
Author: Alexandru Gagniuc 
Date:   Fri Jan 24 16:33:50 2014 -0600

cbfstool: Add portable endian conversion helpers

These helpers rely on the idea that external data is a stream with a
    known structure, and that the internal representation of data on the
    host is irrelevant. When properly used, these helpers eliminate the
    need to rely on the packed nature of structs.

This only adds the helpers. Changing the code to perform proper
    serialization and deserialization of data will be implemented in the
    future.

Change-Id: I697399193846ed741cda4801211b13f6c1e35742
    Signed-off-by: Alexandru Gagniuc 
---
 util/cbfstool/endian_stream.h | 112 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)

diff --git a/util/cbfstool/endian_stream.h b/util/cbfstool/endian_stream.h
new file mode 100644
index 0000000..cfc9149
--- /dev/null
+++ b/util/cbfstool/endian_stream.h
@@ -0,0 +1,112 @@
+/*
+ * Endian conversion helpers
+ *
+ * These helpers are based on the idea that outside data is a stream of well
+ * defined structure (including byte order), and that no assumptions are made
+ * about the internal representation of data on the host. For example, there is
+ * no notion of byte order, structure packing on the host.
+ *
+ * They allow the proper serialization and deserialization of data from host
+ * structs to data streams without relying on the notion of byte swaps.
+ *
+ * To enforce this philosophy, these endian conversion helpers always treat host
+ * data as standard integers types, and external data as streams identified by
+ * a pointer.
+ *
+ * So rather than extracting a structure in the following incorrect way:
+ *         memcpy(host_struct, src, size);
+ *         host_struct->member1 = ntoh(host_struct->member)
+ *         host_struct->member2 = ntohl(host_struct->member2)
+ *
+ * These helpers make the process more portable and less compiler-dependent:
+ *         host_struct->member1 = be16_to_h(src + 0);
+ *         host_struct->member2 = be32_to_h(src + 2);
+ *
+ * Copyright (C) 2014  Alexandru Gagniuc 
+ * Subject to the GNU GPL v2, or (at your option) any later version.
+ */
+
+#ifndef __CBFSTOOL_ENDIAN_STREAM_H
+#define __CBFSTOOL_ENDIAN_STREAM_H
+
+inline static uint8_t le8_to_h(void *src)
+{
+	uint8_t *b = src;
+	return b[0];
+};
+
+inline static uint16_t le16_to_h(void *src)
+{
+	uint8_t *b = src;
+	return ((b[1] << 8) | (b[0] << 0));
+};
+
+inline static uint32_t le32_to_h(void *src)
+{
+	uint8_t *b = src;
+	return ((b[3] << 24) | (b[2] << 16) | (b[1] << 8) | (b[0] << 0));
+};
+
+inline static void h_to_le8(uint8_t val8, void *dest)
+{
+	uint8_t *b = dest;
+	b[0] = val8;
+};
+
+inline static void h_to_le16(uint16_t val16, void *dest)
+{
+	uint8_t *b = dest;
+	b[0] = (val16 >> 0) & 0xff;
+	b[1] = (val16 >> 8) & 0xff;
+};
+
+inline static void h_to_le32(uint32_t val32, void *dest)
+{
+	uint8_t *b = dest;
+	b[0] = (val32 >> 0) & 0xff;
+	b[1] = (val32 >> 8) & 0xff;
+	b[2] = (val32 >> 16) & 0xff;
+	b[3] = (val32 >> 24) & 0xff;
+};
+
+inline static uint8_t be8_to_h(void *src)
+{
+	uint8_t *b = src;
+	return b[0];
+};
+
+inline static uint16_t be16_to_h(void *src)
+{
+	uint8_t *b = src;
+	return ((b[1] << 0) | (b[0] << 16));
+};
+
+inline static uint32_t be32_to_h(void *src)
+{
+	uint8_t *b = src;
+	return ((b[3] << 0) | (b[2] << 8) | (b[1] << 16) | (b[0] << 24));
+};
+
+inline static void h_to_be8(uint8_t val8, void *dest)
+{
+	uint8_t *b = dest;
+	b[0] = val8;
+};
+
+inline static void h_to_be16(uint16_t val16, void *dest)
+{
+	uint8_t *b = dest;
+	b[0] = (val16 >> 8) & 0xff;
+	b[1] = (val16 >> 0) & 0xff;
+};
+
+inline static void h_to_be32(uint32_t val32, void *dest)
+{
+	uint8_t *b = dest;
+	b[0] = (val32 >> 24) & 0xff;
+	b[1] = (val32 >> 16) & 0xff;
+	b[2] = (val32 >> 8) & 0xff;
+	b[3] = (val32 >> 0) & 0xff;
+};
+
+#endif				/* __CBFSTOOL_ENDIAN_STREAM_H */