1 files changed, 129 insertions, 0 deletions
diff --git a/debug/known_sizes.c b/debug/known_sizes.c
new file mode 100644
index 0000000..6c3641f
--- /dev/null
+++ b/debug/known_sizes.c
@@ -0,0 +1,129 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       known_sizes.c
+/// \brief      Encodes .lzma Stream with sizes known in Block Header
+///
+/// The input file is encoded in RAM, and the known Compressed Size
+/// and/or Uncompressed Size values are stored in the Block Header.
+/// As of writing there's no such Stream encoder in liblzma.
+//
+//  Author:     Lasse Collin
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "sysdefs.h"
+#include "lzma.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/unistd.h>
+#include <stdio.h>
+
+
+// Support file sizes up to 1 MiB. We use this for output space too, so files
+// close to 1 MiB had better compress at least a little or we have a buffer
+// overflow.
+#define BUFFER_SIZE (1U << 20)
+
+
+int
+main(void)
+{
+	// Allocate the buffers.
+	uint8_t *in = malloc(BUFFER_SIZE);
+	uint8_t *out = malloc(BUFFER_SIZE);
+	if (in == NULL || out == NULL)
+		return 1;
+
+	// Fill the input buffer.
+	const size_t in_size = fread(in, 1, BUFFER_SIZE, stdin);
+
+	// Filter setup
+	lzma_options_lzma opt_lzma;
+	if (lzma_lzma_preset(&opt_lzma, 1))
+		return 1;
+
+	lzma_filter filters[] = {
+		{
+			.id = LZMA_FILTER_LZMA2,
+			.options = &opt_lzma
+		},
+		{
+			.id = LZMA_VLI_UNKNOWN
+		}
+	};
+
+	lzma_block block = {
+		.check = LZMA_CHECK_CRC32,
+		.compressed_size = BUFFER_SIZE, // Worst case reserve
+		.uncompressed_size = in_size,
+		.filters = filters,
+	};
+
+	lzma_stream strm = LZMA_STREAM_INIT;
+	if (lzma_block_encoder(&strm, &block) != LZMA_OK)
+		return 1;
+
+	// Reserve space for Stream Header and Block Header. We need to
+	// calculate the size of the Block Header first.
+	if (lzma_block_header_size(&block) != LZMA_OK)
+		return 1;
+
+	size_t out_size = LZMA_STREAM_HEADER_SIZE + block.header_size;
+
+	strm.next_in = in;
+	strm.avail_in = in_size;
+	strm.next_out = out + out_size;
+	strm.avail_out = BUFFER_SIZE - out_size;
+
+	if (lzma_code(&strm, LZMA_FINISH) != LZMA_STREAM_END)
+		return 1;
+
+	out_size += strm.total_out;
+
+	if (lzma_block_header_encode(&block, out + LZMA_STREAM_HEADER_SIZE)
+			!= LZMA_OK)
+		return 1;
+
+	lzma_index *idx = lzma_index_init(NULL);
+	if (idx == NULL)
+		return 1;
+
+	if (lzma_index_append(idx, NULL, block.header_size + strm.total_out,
+			strm.total_in) != LZMA_OK)
+		return 1;
+
+	if (lzma_index_encoder(&strm, idx) != LZMA_OK)
+		return 1;
+
+	if (lzma_code(&strm, LZMA_RUN) != LZMA_STREAM_END)
+		return 1;
+
+	out_size += strm.total_out;
+
+	lzma_end(&strm);
+
+	lzma_index_end(idx, NULL);
+
+	// Encode the Stream Header and Stream Footer. backwards_size is
+	// needed only for the Stream Footer.
+	lzma_stream_flags sf = {
+		.backward_size = strm.total_out,
+		.check = block.check,
+	};
+
+	if (lzma_stream_header_encode(&sf, out) != LZMA_OK)
+		return 1;
+
+	if (lzma_stream_footer_encode(&sf, out + out_size) != LZMA_OK)
+		return 1;
+
+	out_size += LZMA_STREAM_HEADER_SIZE;
+
+	// Write out the file.
+	fwrite(out, 1, out_size, stdout);
+
+	return 0;
+}