1 files changed, 152 insertions, 0 deletions
diff --git a/src/liblzma/common/alone_encoder.c b/src/liblzma/common/alone_encoder.c
new file mode 100644
index 0000000..7d3812f
--- /dev/null
+++ b/src/liblzma/common/alone_encoder.c
@@ -0,0 +1,152 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       alone_encoder.c
+/// \brief      Encoder for LZMA_Alone files
+//
+//  Author:     Lasse Collin
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+#include "common.h"
+#include "lzma_encoder.h"
+
+
+#define ALONE_HEADER_SIZE (1 + 4 + 8)
+
+
+typedef struct {
+	lzma_next_coder next;
+
+	enum {
+		SEQ_HEADER,
+		SEQ_CODE,
+	} sequence;
+
+	size_t header_pos;
+	uint8_t header[ALONE_HEADER_SIZE];
+} lzma_alone_coder;
+
+
+static lzma_ret
+alone_encode(void *coder_ptr, const lzma_allocator *allocator,
+		const uint8_t *restrict in, size_t *restrict in_pos,
+		size_t in_size, uint8_t *restrict out,
+		size_t *restrict out_pos, size_t out_size,
+		lzma_action action)
+{
+	lzma_alone_coder *coder = coder_ptr;
+
+	while (*out_pos < out_size)
+	switch (coder->sequence) {
+	case SEQ_HEADER:
+		lzma_bufcpy(coder->header, &coder->header_pos,
+				ALONE_HEADER_SIZE,
+				out, out_pos, out_size);
+		if (coder->header_pos < ALONE_HEADER_SIZE)
+			return LZMA_OK;
+
+		coder->sequence = SEQ_CODE;
+		break;
+
+	case SEQ_CODE:
+		return coder->next.code(coder->next.coder,
+				allocator, in, in_pos, in_size,
+				out, out_pos, out_size, action);
+
+	default:
+		assert(0);
+		return LZMA_PROG_ERROR;
+	}
+
+	return LZMA_OK;
+}
+
+
+static void
+alone_encoder_end(void *coder_ptr, const lzma_allocator *allocator)
+{
+	lzma_alone_coder *coder = coder_ptr;
+	lzma_next_end(&coder->next, allocator);
+	lzma_free(coder, allocator);
+	return;
+}
+
+
+static lzma_ret
+alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
+		const lzma_options_lzma *options)
+{
+	lzma_next_coder_init(&alone_encoder_init, next, allocator);
+
+	lzma_alone_coder *coder = next->coder;
+
+	if (coder == NULL) {
+		coder = lzma_alloc(sizeof(lzma_alone_coder), allocator);
+		if (coder == NULL)
+			return LZMA_MEM_ERROR;
+
+		next->coder = coder;
+		next->code = &alone_encode;
+		next->end = &alone_encoder_end;
+		coder->next = LZMA_NEXT_CODER_INIT;
+	}
+
+	// Basic initializations
+	coder->sequence = SEQ_HEADER;
+	coder->header_pos = 0;
+
+	// Encode the header:
+	// - Properties (1 byte)
+	if (lzma_lzma_lclppb_encode(options, coder->header))
+		return LZMA_OPTIONS_ERROR;
+
+	// - Dictionary size (4 bytes)
+	if (options->dict_size < LZMA_DICT_SIZE_MIN)
+		return LZMA_OPTIONS_ERROR;
+
+	// Round up to the next 2^n or 2^n + 2^(n - 1) depending on which
+	// one is the next unless it is UINT32_MAX. While the header would
+	// allow any 32-bit integer, we do this to keep the decoder of liblzma
+	// accepting the resulting files.
+	uint32_t d = options->dict_size - 1;
+	d |= d >> 2;
+	d |= d >> 3;
+	d |= d >> 4;
+	d |= d >> 8;
+	d |= d >> 16;
+	if (d != UINT32_MAX)
+		++d;
+
+	write32le(coder->header + 1, d);
+
+	// - Uncompressed size (always unknown and using EOPM)
+	memset(coder->header + 1 + 4, 0xFF, 8);
+
+	// Initialize the LZMA encoder.
+	const lzma_filter_info filters[2] = {
+		{
+			.id = LZMA_FILTER_LZMA1,
+			.init = &lzma_lzma_encoder_init,
+			.options = (void *)(options),
+		}, {
+			.init = NULL,
+		}
+	};
+
+	return lzma_next_filter_init(&coder->next, allocator, filters);
+}
+
+
+extern LZMA_API(lzma_ret)
+lzma_alone_encoder(lzma_stream *strm, const lzma_options_lzma *options)
+{
+	lzma_next_strm_init(alone_encoder_init, strm, options);
+
+	strm->internal->supported_actions[LZMA_RUN] = true;
+	strm->internal->supported_actions[LZMA_FINISH] = true;
+
+	return LZMA_OK;
+}