X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=lzma%2Fcommon%2Fstream_flags_encoder.c;fp=lzma%2Fcommon%2Fstream_flags_encoder.c;h=4e717159f1e7f17a528ae186b9c7186eeb462195;hb=32b8a6b26ed8843828e03e505d2256960bda0980;hp=0000000000000000000000000000000000000000;hpb=d48fc23a4bcf8ca3c406d6e8c8a6f8c6b0fa2f1e;p=zpackage

diff --git a/lzma/common/stream_flags_encoder.c b/lzma/common/stream_flags_encoder.c
new file mode 100644
index 0000000..4e71715
--- /dev/null
+++ b/lzma/common/stream_flags_encoder.c
@@ -0,0 +1,86 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       stream_flags_encoder.c
+/// \brief      Encodes Stream Header and Stream Footer for .xz files
+//
+//  Author:     Lasse Collin
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "stream_flags_common.h"
+
+
+static bool
+stream_flags_encode(const lzma_stream_flags *options, uint8_t *out)
+{
+	if ((unsigned int)(options->check) > LZMA_CHECK_ID_MAX)
+		return true;
+
+	out[0] = 0x00;
+	out[1] = options->check;
+
+	return false;
+}
+
+
+extern LZMA_API(lzma_ret)
+lzma_stream_header_encode(const lzma_stream_flags *options, uint8_t *out)
+{
+	assert(sizeof(lzma_header_magic) + LZMA_STREAM_FLAGS_SIZE
+			+ 4 == LZMA_STREAM_HEADER_SIZE);
+
+	if (options->version != 0)
+		return LZMA_OPTIONS_ERROR;
+
+	// Magic
+	memcpy(out, lzma_header_magic, sizeof(lzma_header_magic));
+
+	// Stream Flags
+	if (stream_flags_encode(options, out + sizeof(lzma_header_magic)))
+		return LZMA_PROG_ERROR;
+
+	// CRC32 of the Stream Header
+	const uint32_t crc = lzma_crc32(out + sizeof(lzma_header_magic),
+			LZMA_STREAM_FLAGS_SIZE, 0);
+
+	unaligned_write32le(out + sizeof(lzma_header_magic)
+			+ LZMA_STREAM_FLAGS_SIZE, crc);
+
+	return LZMA_OK;
+}
+
+
+extern LZMA_API(lzma_ret)
+lzma_stream_footer_encode(const lzma_stream_flags *options, uint8_t *out)
+{
+	assert(2 * 4 + LZMA_STREAM_FLAGS_SIZE + sizeof(lzma_footer_magic)
+			== LZMA_STREAM_HEADER_SIZE);
+
+	if (options->version != 0)
+		return LZMA_OPTIONS_ERROR;
+
+	// Backward Size
+	if (!is_backward_size_valid(options))
+		return LZMA_PROG_ERROR;
+
+	unaligned_write32le(out + 4, options->backward_size / 4 - 1);
+
+	// Stream Flags
+	if (stream_flags_encode(options, out + 2 * 4))
+		return LZMA_PROG_ERROR;
+
+	// CRC32
+	const uint32_t crc = lzma_crc32(
+			out + 4, 4 + LZMA_STREAM_FLAGS_SIZE, 0);
+
+	unaligned_write32le(out, crc);
+
+	// Magic
+	memcpy(out + 2 * 4 + LZMA_STREAM_FLAGS_SIZE,
+			lzma_footer_magic, sizeof(lzma_footer_magic));
+
+	return LZMA_OK;
+}