liblzma: Avoid multiple definitions of lzma_coder structures.

Only one definition was visible in a translation unit.
It avoided a few casts and temp variables but seems that
this hack doesn't work with link-time optimizations in compilers
as it's not C99/C11 compliant.

Fixes:
http://www.mail-archive.com/xz-devel@tukaani.org/msg00279.html

11 files changed, 279 insertions, 212 deletions

diff --git a/src/liblzma/common/alone_decoder.c b/src/liblzma/common/alone_decoder.c
index c1360ca1..dd681765 100644
--- a/src/liblzma/common/alone_decoder.c
+++ b/src/liblzma/common/alone_decoder.c
@@ -15,7 +15,7 @@
 #include "lz_decoder.h"
 
 
-struct lzma_coder_s {
+typedef struct {
 	lzma_next_coder next;
 
 	enum {
@@ -46,17 +46,19 @@ struct lzma_coder_s {
 	/// Options decoded from the header needed to initialize
 	/// the LZMA decoder
 	lzma_options_lzma options;
-};
+} lzma_alone_coder;
 
 
 static lzma_ret
-alone_decode(lzma_coder *coder,
+alone_decode(void *coder_ptr,
 		const lzma_allocator *allocator lzma_attribute((__unused__)),
 		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
 			&& (coder->sequence == SEQ_CODE || *in_pos < in_size))
 	switch (coder->sequence) {
@@ -166,8 +168,9 @@ alone_decode(lzma_coder *coder,
 
 
 static void
-alone_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
+alone_decoder_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;
@@ -175,9 +178,11 @@ alone_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 
 
 static lzma_ret
-alone_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
+alone_decoder_memconfig(void *coder_ptr, uint64_t *memusage,
 		uint64_t *old_memlimit, uint64_t new_memlimit)
 {
+	lzma_alone_coder *coder = coder_ptr;
+
 	*memusage = coder->memusage;
 	*old_memlimit = coder->memlimit;
 
@@ -201,26 +206,29 @@ lzma_alone_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 	if (memlimit == 0)
 		return LZMA_PROG_ERROR;
 
-	if (next->coder == NULL) {
-		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
-		if (next->coder == NULL)
+	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_decode;
 		next->end = &alone_decoder_end;
 		next->memconfig = &alone_decoder_memconfig;
-		next->coder->next = LZMA_NEXT_CODER_INIT;
+		coder->next = LZMA_NEXT_CODER_INIT;
 	}
 
-	next->coder->sequence = SEQ_PROPERTIES;
-	next->coder->picky = picky;
-	next->coder->pos = 0;
-	next->coder->options.dict_size = 0;
-	next->coder->options.preset_dict = NULL;
-	next->coder->options.preset_dict_size = 0;
-	next->coder->uncompressed_size = 0;
-	next->coder->memlimit = memlimit;
-	next->coder->memusage = LZMA_MEMUSAGE_BASE;
+	coder->sequence = SEQ_PROPERTIES;
+	coder->picky = picky;
+	coder->pos = 0;
+	coder->options.dict_size = 0;
+	coder->options.preset_dict = NULL;
+	coder->options.preset_dict_size = 0;
+	coder->uncompressed_size = 0;
+	coder->memlimit = memlimit;
+	coder->memusage = LZMA_MEMUSAGE_BASE;
 
 	return LZMA_OK;
 }
diff --git a/src/liblzma/common/alone_encoder.c b/src/liblzma/common/alone_encoder.c
index a2bc9eee..4853cfd1 100644
--- a/src/liblzma/common/alone_encoder.c
+++ b/src/liblzma/common/alone_encoder.c
@@ -17,7 +17,7 @@
 #define ALONE_HEADER_SIZE (1 + 4 + 8)
 
 
-struct lzma_coder_s {
+typedef struct {
 	lzma_next_coder next;
 
 	enum {
@@ -27,17 +27,19 @@ struct lzma_coder_s {
 
 	size_t header_pos;
 	uint8_t header[ALONE_HEADER_SIZE];
-};
+} lzma_alone_coder;
 
 
 static lzma_ret
-alone_encode(lzma_coder *coder,
+alone_encode(void *coder_ptr,
 		const lzma_allocator *allocator lzma_attribute((__unused__)),
 		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:
@@ -65,8 +67,9 @@ alone_encode(lzma_coder *coder,
 
 
 static void
-alone_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
+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;
@@ -80,23 +83,26 @@ alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 {
 	lzma_next_coder_init(&alone_encoder_init, next, allocator);
 
-	if (next->coder == NULL) {
-		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
-		if (next->coder == NULL)
+	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;
-		next->coder->next = LZMA_NEXT_CODER_INIT;
+		coder->next = LZMA_NEXT_CODER_INIT;
 	}
 
 	// Basic initializations
-	next->coder->sequence = SEQ_HEADER;
-	next->coder->header_pos = 0;
+	coder->sequence = SEQ_HEADER;
+	coder->header_pos = 0;
 
 	// Encode the header:
 	// - Properties (1 byte)
-	if (lzma_lzma_lclppb_encode(options, next->coder->header))
+	if (lzma_lzma_lclppb_encode(options, coder->header))
 		return LZMA_OPTIONS_ERROR;
 
 	// - Dictionary size (4 bytes)
@@ -116,10 +122,10 @@ alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 	if (d != UINT32_MAX)
 		++d;
 
-	unaligned_write32le(next->coder->header + 1, d);
+	unaligned_write32le(coder->header + 1, d);
 
 	// - Uncompressed size (always unknown and using EOPM)
-	memset(next->coder->header + 1 + 4, 0xFF, 8);
+	memset(coder->header + 1 + 4, 0xFF, 8);
 
 	// Initialize the LZMA encoder.
 	const lzma_filter_info filters[2] = {
@@ -131,7 +137,7 @@ alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		}
 	};
 
-	return lzma_next_filter_init(&next->coder->next, allocator, filters);
+	return lzma_next_filter_init(&coder->next, allocator, filters);
 }
 
 
diff --git a/src/liblzma/common/auto_decoder.c b/src/liblzma/common/auto_decoder.c
index bf355070..09acd6dc 100644
--- a/src/liblzma/common/auto_decoder.c
+++ b/src/liblzma/common/auto_decoder.c
@@ -14,7 +14,7 @@
 #include "alone_decoder.h"
 
 
-struct lzma_coder_s {
+typedef struct {
 	/// Stream decoder or LZMA_Alone decoder
 	lzma_next_coder next;
 
@@ -26,15 +26,17 @@ struct lzma_coder_s {
 		SEQ_CODE,
 		SEQ_FINISH,
 	} sequence;
-};
+} lzma_auto_coder;
 
 
 static lzma_ret
-auto_decode(lzma_coder *coder, const lzma_allocator *allocator,
+auto_decode(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_auto_coder *coder = coder_ptr;
+
 	switch (coder->sequence) {
 	case SEQ_INIT:
 		if (*in_pos >= in_size)
@@ -100,8 +102,9 @@ auto_decode(lzma_coder *coder, const lzma_allocator *allocator,
 
 
 static void
-auto_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
+auto_decoder_end(void *coder_ptr, const lzma_allocator *allocator)
 {
+	lzma_auto_coder *coder = coder_ptr;
 	lzma_next_end(&coder->next, allocator);
 	lzma_free(coder, allocator);
 	return;
@@ -109,8 +112,10 @@ auto_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 
 
 static lzma_check
-auto_decoder_get_check(const lzma_coder *coder)
+auto_decoder_get_check(const void *coder_ptr)
 {
+	const lzma_auto_coder *coder = coder_ptr;
+
 	// It is LZMA_Alone if get_check is NULL.
 	return coder->next.get_check == NULL ? LZMA_CHECK_NONE
 			: coder->next.get_check(coder->next.coder);
@@ -118,9 +123,11 @@ auto_decoder_get_check(const lzma_coder *coder)
 
 
 static lzma_ret
-auto_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
+auto_decoder_memconfig(void *coder_ptr, uint64_t *memusage,
 		uint64_t *old_memlimit, uint64_t new_memlimit)
 {
+	lzma_auto_coder *coder = coder_ptr;
+
 	lzma_ret ret;
 
 	if (coder->next.memconfig != NULL) {
@@ -154,21 +161,23 @@ auto_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 	if (flags & ~LZMA_SUPPORTED_FLAGS)
 		return LZMA_OPTIONS_ERROR;
 
-	if (next->coder == NULL) {
-		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
-		if (next->coder == NULL)
+	lzma_auto_coder *coder = next->coder;
+	if (coder == NULL) {
+		coder = lzma_alloc(sizeof(lzma_auto_coder), allocator);
+		if (coder == NULL)
 			return LZMA_MEM_ERROR;
 
+		next->coder = coder;
 		next->code = &auto_decode;
 		next->end = &auto_decoder_end;
 		next->get_check = &auto_decoder_get_check;
 		next->memconfig = &auto_decoder_memconfig;
-		next->coder->next = LZMA_NEXT_CODER_INIT;
+		coder->next = LZMA_NEXT_CODER_INIT;
 	}
 
-	next->coder->memlimit = memlimit;
-	next->coder->flags = flags;
-	next->coder->sequence = SEQ_INIT;
+	coder->memlimit = memlimit;
+	coder->flags = flags;
+	coder->sequence = SEQ_INIT;
 
 	return LZMA_OK;
 }
diff --git a/src/liblzma/common/block_decoder.c b/src/liblzma/common/block_decoder.c
index 685c3b03..075bd279 100644
--- a/src/liblzma/common/block_decoder.c
+++ b/src/liblzma/common/block_decoder.c
@@ -15,7 +15,7 @@
 #include "check.h"
 
 
-struct lzma_coder_s {
+typedef struct {
 	enum {
 		SEQ_CODE,
 		SEQ_PADDING,
@@ -48,7 +48,7 @@ struct lzma_coder_s {
 
 	/// True if the integrity check won't be calculated and verified.
 	bool ignore_check;
-};
+} lzma_block_coder;
 
 
 static inline bool
@@ -74,11 +74,13 @@ is_size_valid(lzma_vli size, lzma_vli reference)
 
 
 static lzma_ret
-block_decode(lzma_coder *coder, const lzma_allocator *allocator,
+block_decode(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_block_coder *coder = coder_ptr;
+
 	switch (coder->sequence) {
 	case SEQ_CODE: {
 		const size_t in_start = *in_pos;
@@ -177,8 +179,9 @@ block_decode(lzma_coder *coder, const lzma_allocator *allocator,
 
 
 static void
-block_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
+block_decoder_end(void *coder_ptr, const lzma_allocator *allocator)
 {
+	lzma_block_coder *coder = coder_ptr;
 	lzma_next_end(&coder->next, allocator);
 	lzma_free(coder, allocator);
 	return;
@@ -198,27 +201,29 @@ lzma_block_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 			|| !lzma_vli_is_valid(block->uncompressed_size))
 		return LZMA_PROG_ERROR;
 
-	// Allocate and initialize *next->coder if needed.
-	if (next->coder == NULL) {
-		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
-		if (next->coder == NULL)
+	// Allocate *next->coder if needed.
+	lzma_block_coder *coder = next->coder;
+	if (coder == NULL) {
+		coder = lzma_alloc(sizeof(lzma_block_coder), allocator);
+		if (coder == NULL)
 			return LZMA_MEM_ERROR;
 
+		next->coder = coder;
 		next->code = &block_decode;
 		next->end = &block_decoder_end;
-		next->coder->next = LZMA_NEXT_CODER_INIT;
+		coder->next = LZMA_NEXT_CODER_INIT;
 	}
 
 	// Basic initializations
-	next->coder->sequence = SEQ_CODE;
-	next->coder->block = block;
-	next->coder->compressed_size = 0;
-	next->coder->uncompressed_size = 0;
+	coder->sequence = SEQ_CODE;
+	coder->block = block;
+	coder->compressed_size = 0;
+	coder->uncompressed_size = 0;
 
 	// If Compressed Size is not known, we calculate the maximum allowed
 	// value so that encoded size of the Block (including Block Padding)
 	// is still a valid VLI and a multiple of four.
-	next->coder->compressed_limit
+	coder->compressed_limit
 			= block->compressed_size == LZMA_VLI_UNKNOWN
 				? (LZMA_VLI_MAX & ~LZMA_VLI_C(3))
 					- block->header_size
@@ -228,14 +233,14 @@ lzma_block_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 	// Initialize the check. It's caller's problem if the Check ID is not
 	// supported, and the Block decoder cannot verify the Check field.
 	// Caller can test lzma_check_is_supported(block->check).
-	next->coder->check_pos = 0;
-	lzma_check_init(&next->coder->check, block->check);
+	coder->check_pos = 0;
+	lzma_check_init(&coder->check, block->check);
 
-	next->coder->ignore_check = block->version >= 1
+	coder->ignore_check = block->version >= 1
 			? block->ignore_check : false;
 
 	// Initialize the filter chain.
-	return lzma_raw_decoder_init(&next->coder->next, allocator,
+	return lzma_raw_decoder_init(&coder->next, allocator,
 			block->filters);
 }
 
diff --git a/src/liblzma/common/block_encoder.c b/src/liblzma/common/block_encoder.c
index def58641..168846ad 100644
--- a/src/liblzma/common/block_encoder.c
+++ b/src/liblzma/common/block_encoder.c
@@ -15,7 +15,7 @@
 #include "check.h"
 
 
-struct lzma_coder_s {
+typedef struct {
 	/// The filters in the chain; initialized with lzma_raw_decoder_init().
 	lzma_next_coder next;
 
@@ -41,15 +41,17 @@ struct lzma_coder_s {
 
 	/// Check of the uncompressed data
 	lzma_check_state check;
-};
+} lzma_block_coder;
 
 
 static lzma_ret
-block_encode(lzma_coder *coder, const lzma_allocator *allocator,
+block_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_block_coder *coder = coder_ptr;
+
 	// Check that our amount of input stays in proper limits.
 	if (LZMA_VLI_MAX - coder->uncompressed_size < in_size - *in_pos)
 		return LZMA_DATA_ERROR;
@@ -134,8 +136,9 @@ block_encode(lzma_coder *coder, const lzma_allocator *allocator,
 
 
 static void
-block_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
+block_encoder_end(void *coder_ptr, const lzma_allocator *allocator)
 {
+	lzma_block_coder *coder = coder_ptr;
 	lzma_next_end(&coder->next, allocator);
 	lzma_free(coder, allocator);
 	return;
@@ -143,10 +146,12 @@ block_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 
 
 static lzma_ret
-block_encoder_update(lzma_coder *coder, const lzma_allocator *allocator,
+block_encoder_update(void *coder_ptr, const lzma_allocator *allocator,
 		const lzma_filter *filters lzma_attribute((__unused__)),
 		const lzma_filter *reversed_filters)
 {
+	lzma_block_coder *coder = coder_ptr;
+
 	if (coder->sequence != SEQ_CODE)
 		return LZMA_PROG_ERROR;
 
@@ -178,30 +183,31 @@ lzma_block_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		return LZMA_UNSUPPORTED_CHECK;
 
 	// Allocate and initialize *next->coder if needed.
-	if (next->coder == NULL) {
-		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
-		if (next->coder == NULL)
+	lzma_block_coder *coder = next->coder;
+	if (coder == NULL) {
+		coder = lzma_alloc(sizeof(lzma_block_coder), allocator);
+		if (coder == NULL)
 			return LZMA_MEM_ERROR;
 
+		next->coder = coder;
 		next->code = &block_encode;
 		next->end = &block_encoder_end;
 		next->update = &block_encoder_update;
-		next->coder->next = LZMA_NEXT_CODER_INIT;
+		coder->next = LZMA_NEXT_CODER_INIT;
 	}
 
 	// Basic initializations
-	next->coder->sequence = SEQ_CODE;
-	next->coder->block = block;
-	next->coder->compressed_size = 0;
-	next->coder->uncompressed_size = 0;
-	next->coder->pos = 0;
+	coder->sequence = SEQ_CODE;
+	coder->block = block;
+	coder->compressed_size = 0;
+	coder->uncompressed_size = 0;
+	coder->pos = 0;
 
 	// Initialize the check
-	lzma_check_init(&next->coder->check, block->check);
+	lzma_check_init(&coder->check, block->check);
 
 	// Initialize the requested filters.
-	return lzma_raw_encoder_init(&next->coder->next, allocator,
-			block->filters);
+	return lzma_raw_encoder_init(&coder->next, allocator, block->filters);
 }
 
 
diff --git a/src/liblzma/common/common.h b/src/liblzma/common/common.h
index 955d784a..b3d3b7a0 100644
--- a/src/liblzma/common/common.h
+++ b/src/liblzma/common/common.h
@@ -88,10 +88,6 @@
 #define LZMA_TIMED_OUT 32
 
 
-/// Type of encoder/decoder specific data; the actual structure is defined
-/// differently in different coders.
-typedef struct lzma_coder_s lzma_coder;
-
 typedef struct lzma_next_coder_s lzma_next_coder;
 
 typedef struct lzma_filter_info_s lzma_filter_info;
@@ -107,7 +103,7 @@ typedef lzma_ret (*lzma_init_function)(
 /// input and output buffers, but for simplicity they still use this same
 /// function prototype.
 typedef lzma_ret (*lzma_code_function)(
-		lzma_coder *coder, const lzma_allocator *allocator,
+		void *coder, 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,
@@ -115,7 +111,7 @@ typedef lzma_ret (*lzma_code_function)(
 
 /// Type of a function to free the memory allocated for the coder
 typedef void (*lzma_end_function)(
-		lzma_coder *coder, const lzma_allocator *allocator);
+		void *coder, const lzma_allocator *allocator);
 
 
 /// Raw coder validates and converts an array of lzma_filter structures to
@@ -138,7 +134,7 @@ struct lzma_filter_info_s {
 /// Hold data and function pointers of the next filter in the chain.
 struct lzma_next_coder_s {
 	/// Pointer to coder-specific data
-	lzma_coder *coder;
+	void *coder;
 
 	/// Filter ID. This is LZMA_VLI_UNKNOWN when this structure doesn't
 	/// point to a filter coder.
@@ -160,21 +156,21 @@ struct lzma_next_coder_s {
 
 	/// Pointer to a function to get progress information. If this is NULL,
 	/// lzma_stream.total_in and .total_out are used instead.
-	void (*get_progress)(lzma_coder *coder,
+	void (*get_progress)(void *coder,
 			uint64_t *progress_in, uint64_t *progress_out);
 
 	/// Pointer to function to return the type of the integrity check.
 	/// Most coders won't support this.
-	lzma_check (*get_check)(const lzma_coder *coder);
+	lzma_check (*get_check)(const void *coder);
 
 	/// Pointer to function to get and/or change the memory usage limit.
 	/// If new_memlimit == 0, the limit is not changed.
-	lzma_ret (*memconfig)(lzma_coder *coder, uint64_t *memusage,
+	lzma_ret (*memconfig)(void *coder, uint64_t *memusage,
 			uint64_t *old_memlimit, uint64_t new_memlimit);
 
 	/// Update the filter-specific options or the whole filter chain
 	/// in the encoder.
-	lzma_ret (*update)(lzma_coder *coder, const lzma_allocator *allocator,
+	lzma_ret (*update)(void *coder, const lzma_allocator *allocator,
 			const lzma_filter *filters,
 			const lzma_filter *reversed_filters);
 };
diff --git a/src/liblzma/common/index_decoder.c b/src/liblzma/common/index_decoder.c
index 795d1834..1e33f0b0 100644
--- a/src/liblzma/common/index_decoder.c
+++ b/src/liblzma/common/index_decoder.c
@@ -14,7 +14,7 @@
 #include "check.h"
 
 
-struct lzma_coder_s {
+typedef struct {
 	enum {
 		SEQ_INDICATOR,
 		SEQ_COUNT,
@@ -50,11 +50,11 @@ struct lzma_coder_s {
 
 	/// CRC32 of the List of Records field
 	uint32_t crc32;
-};
+} lzma_index_coder;
 
 
 static lzma_ret
-index_decode(lzma_coder *coder, const lzma_allocator *allocator,
+index_decode(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 lzma_attribute((__unused__)),
@@ -62,6 +62,8 @@ index_decode(lzma_coder *coder, const lzma_allocator *allocator,
 		size_t out_size lzma_attribute((__unused__)),
 		lzma_action action lzma_attribute((__unused__)))
 {
+	lzma_index_coder *coder = coder_ptr;
+
 	// Similar optimization as in index_encoder.c
 	const size_t in_start = *in_pos;
 	lzma_ret ret = LZMA_OK;
@@ -207,8 +209,9 @@ out:
 
 
 static void
-index_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
+index_decoder_end(void *coder_ptr, const lzma_allocator *allocator)
 {
+	lzma_index_coder *coder = coder_ptr;
 	lzma_index_end(coder->index, allocator);
 	lzma_free(coder, allocator);
 	return;
@@ -216,9 +219,11 @@ index_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 
 
 static lzma_ret
-index_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
+index_decoder_memconfig(void *coder_ptr, uint64_t *memusage,
 		uint64_t *old_memlimit, uint64_t new_memlimit)
 {
+	lzma_index_coder *coder = coder_ptr;
+
 	*memusage = lzma_index_memusage(1, coder->count);
 	*old_memlimit = coder->memlimit;
 
@@ -234,7 +239,7 @@ index_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
 
 
 static lzma_ret
-index_decoder_reset(lzma_coder *coder, const lzma_allocator *allocator,
+index_decoder_reset(lzma_index_coder *coder, const lzma_allocator *allocator,
 		lzma_index **i, uint64_t memlimit)
 {
 	// Remember the pointer given by the application. We will set it
@@ -269,20 +274,22 @@ index_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 	if (i == NULL || memlimit == 0)
 		return LZMA_PROG_ERROR;
 
-	if (next->coder == NULL) {
-		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
-		if (next->coder == NULL)
+	lzma_index_coder *coder = next->coder;
+	if (coder == NULL) {
+		coder = lzma_alloc(sizeof(lzma_index_coder), allocator);
+		if (coder == NULL)
 			return LZMA_MEM_ERROR;
 
+		next->coder = coder;
 		next->code = &index_decode;
 		next->end = &index_decoder_end;
 		next->memconfig = &index_decoder_memconfig;
-		next->coder->index = NULL;
+		coder->index = NULL;
 	} else {
-		lzma_index_end(next->coder->index, allocator);
+		lzma_index_end(coder->index, allocator);
 	}
 
-	return index_decoder_reset(next->coder, allocator, i, memlimit);
+	return index_decoder_reset(coder, allocator, i, memlimit);
 }
 
 
@@ -309,7 +316,7 @@ lzma_index_buffer_decode(lzma_index **i, uint64_t *memlimit,
 		return LZMA_PROG_ERROR;
 
 	// Initialize the decoder.
-	lzma_coder coder;
+	lzma_index_coder coder;
 	return_if_error(index_decoder_reset(&coder, allocator, i, *memlimit));
 
 	// Store the input start position so that we can restore it in case
diff --git a/src/liblzma/common/index_encoder.c b/src/liblzma/common/index_encoder.c
index d25ac7d3..ac97d0ce 100644
--- a/src/liblzma/common/index_encoder.c
+++ b/src/liblzma/common/index_encoder.c
@@ -15,7 +15,7 @@
 #include "check.h"
 
 
-struct lzma_coder_s {
+typedef struct {
 	enum {
 		SEQ_INDICATOR,
 		SEQ_COUNT,
@@ -37,11 +37,11 @@ struct lzma_coder_s {
 
 	/// CRC32 of the List of Records field
 	uint32_t crc32;
-};
+} lzma_index_coder;
 
 
 static lzma_ret
-index_encode(lzma_coder *coder,
+index_encode(void *coder_ptr,
 		const lzma_allocator *allocator lzma_attribute((__unused__)),
 		const uint8_t *restrict in lzma_attribute((__unused__)),
 		size_t *restrict in_pos lzma_attribute((__unused__)),
@@ -50,6 +50,8 @@ index_encode(lzma_coder *coder,
 		size_t out_size,
 		lzma_action action lzma_attribute((__unused__)))
 {
+	lzma_index_coder *coder = coder_ptr;
+
 	// Position where to start calculating CRC32. The idea is that we
 	// need to call lzma_crc32() only once per call to index_encode().
 	const size_t out_start = *out_pos;
@@ -159,7 +161,7 @@ out:
 
 
 static void
-index_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
+index_encoder_end(void *coder, const lzma_allocator *allocator)
 {
 	lzma_free(coder, allocator);
 	return;
@@ -167,7 +169,7 @@ index_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 
 
 static void
-index_encoder_reset(lzma_coder *coder, const lzma_index *i)
+index_encoder_reset(lzma_index_coder *coder, const lzma_index *i)
 {
 	lzma_index_iter_init(&coder->iter, i);
 
@@ -190,7 +192,7 @@ lzma_index_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		return LZMA_PROG_ERROR;
 
 	if (next->coder == NULL) {
-		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
+		next->coder = lzma_alloc(sizeof(lzma_index_coder), allocator);
 		if (next->coder == NULL)
 			return LZMA_MEM_ERROR;
 
@@ -230,7 +232,7 @@ lzma_index_buffer_encode(const lzma_index *i,
 
 	// The Index encoder needs just one small data structure so we can
 	// allocate it on stack.
-	lzma_coder coder;
+	lzma_index_coder coder;
 	index_encoder_reset(&coder, i);
 
 	// Do the actual encoding. This should never fail, but store
diff --git a/src/liblzma/common/stream_decoder.c b/src/liblzma/common/stream_decoder.c
index 3ab938c9..7ae7a670 100644
--- a/src/liblzma/common/stream_decoder.c
+++ b/src/liblzma/common/stream_decoder.c
@@ -14,7 +14,7 @@
 #include "block_decoder.h"
 
 
-struct lzma_coder_s {
+typedef struct {
 	enum {
 		SEQ_STREAM_HEADER,
 		SEQ_BLOCK_HEADER,
@@ -80,11 +80,11 @@ struct lzma_coder_s {
 	/// Buffer to hold Stream Header, Block Header, and Stream Footer.
 	/// Block Header has biggest maximum size.
 	uint8_t buffer[LZMA_BLOCK_HEADER_SIZE_MAX];
-};
+} lzma_stream_coder;
 
 
 static lzma_ret
-stream_decoder_reset(lzma_coder *coder, const lzma_allocator *allocator)
+stream_decoder_reset(lzma_stream_coder *coder, const lzma_allocator *allocator)
 {
 	// Initialize the Index hash used to verify the Index.
 	coder->index_hash = lzma_index_hash_init(coder->index_hash, allocator);
@@ -100,11 +100,13 @@ stream_decoder_reset(lzma_coder *coder, const lzma_allocator *allocator)
 
 
 static lzma_ret
-stream_decode(lzma_coder *coder, const lzma_allocator *allocator,
+stream_decode(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_stream_coder *coder = coder_ptr;
+
 	// When decoding the actual Block, it may be able to produce more
 	// output even if we don't give it any new input.
 	while (true)
@@ -375,8 +377,9 @@ stream_decode(lzma_coder *coder, const lzma_allocator *allocator,
 
 
 static void
-stream_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
+stream_decoder_end(void *coder_ptr, const lzma_allocator *allocator)
 {
+	lzma_stream_coder *coder = coder_ptr;
 	lzma_next_end(&coder->block_decoder, allocator);
 	lzma_index_hash_end(coder->index_hash, allocator);
 	lzma_free(coder, allocator);
@@ -385,16 +388,19 @@ stream_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 
 
 static lzma_check
-stream_decoder_get_check(const lzma_coder *coder)
+stream_decoder_get_check(const void *coder_ptr)
 {
+	const lzma_stream_coder *coder = coder_ptr;
 	return coder->stream_flags.check;
 }
 
 
 static lzma_ret
-stream_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
+stream_decoder_memconfig(void *coder_ptr, uint64_t *memusage,
 		uint64_t *old_memlimit, uint64_t new_memlimit)
 {
+	lzma_stream_coder *coder = coder_ptr;
+
 	*memusage = coder->memusage;
 	*old_memlimit = coder->memlimit;
 
@@ -422,31 +428,33 @@ lzma_stream_decoder_init(
 	if (flags & ~LZMA_SUPPORTED_FLAGS)
 		return LZMA_OPTIONS_ERROR;
 
-	if (next->coder == NULL) {
-		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
-		if (next->coder == NULL)
+	lzma_stream_coder *coder = next->coder;
+	if (coder == NULL) {
+		coder = lzma_alloc(sizeof(lzma_stream_coder), allocator);
+		if (coder == NULL)
 			return LZMA_MEM_ERROR;
 
+		next->coder = coder;
 		next->code = &stream_decode;
 		next->end = &stream_decoder_end;
 		next->get_check = &stream_decoder_get_check;
 		next->memconfig = &stream_decoder_memconfig;
 
-		next->coder->block_decoder = LZMA_NEXT_CODER_INIT;
-		next->coder->index_hash = NULL;
+		coder->block_decoder = LZMA_NEXT_CODER_INIT;
+		coder->index_hash = NULL;
 	}
 
-	next->coder->memlimit = memlimit;
-	next->coder->memusage = LZMA_MEMUSAGE_BASE;
-	next->coder->tell_no_check = (flags & LZMA_TELL_NO_CHECK) != 0;
-	next->coder->tell_unsupported_check
+	coder->memlimit = memlimit;
+	coder->memusage = LZMA_MEMUSAGE_BASE;
+	coder->tell_no_check = (flags & LZMA_TELL_NO_CHECK) != 0;
+	coder->tell_unsupported_check
 			= (flags & LZMA_TELL_UNSUPPORTED_CHECK) != 0;
-	next->coder->tell_any_check = (flags & LZMA_TELL_ANY_CHECK) != 0;
-	next->coder->ignore_check = (flags & LZMA_IGNORE_CHECK) != 0;
-	next->coder->concatenated = (flags & LZMA_CONCATENATED) != 0;
-	next->coder->first_stream = true;
+	coder->tell_any_check = (flags & LZMA_TELL_ANY_CHECK) != 0;
+	coder->ignore_check = (flags & LZMA_IGNORE_CHECK) != 0;
+	coder->concatenated = (flags & LZMA_CONCATENATED) != 0;
+	coder->first_stream = true;
 
-	return stream_decoder_reset(next->coder, allocator);
+	return stream_decoder_reset(coder, allocator);
 }
 
 
diff --git a/src/liblzma/common/stream_encoder.c b/src/liblzma/common/stream_encoder.c
index a7663bc4..858cba47 100644
--- a/src/liblzma/common/stream_encoder.c
+++ b/src/liblzma/common/stream_encoder.c
@@ -14,7 +14,7 @@
 #include "index_encoder.h"
 
 
-struct lzma_coder_s {
+typedef struct {
 	enum {
 		SEQ_STREAM_HEADER,
 		SEQ_BLOCK_INIT,
@@ -55,11 +55,11 @@ struct lzma_coder_s {
 	/// Buffer to hold Stream Header, Block Header, and Stream Footer.
 	/// Block Header has biggest maximum size.
 	uint8_t buffer[LZMA_BLOCK_HEADER_SIZE_MAX];
-};
+} lzma_stream_coder;
 
 
 static lzma_ret
-block_encoder_init(lzma_coder *coder, const lzma_allocator *allocator)
+block_encoder_init(lzma_stream_coder *coder, const lzma_allocator *allocator)
 {
 	// Prepare the Block options. Even though Block encoder doesn't need
 	// compressed_size, uncompressed_size, and header_size to be
@@ -78,11 +78,13 @@ block_encoder_init(lzma_coder *coder, const lzma_allocator *allocator)
 
 
 static lzma_ret
-stream_encode(lzma_coder *coder, const lzma_allocator *allocator,
+stream_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_stream_coder *coder = coder_ptr;
+
 	// Main loop
 	while (*out_pos < out_size)
 	switch (coder->sequence) {
@@ -209,8 +211,10 @@ stream_encode(lzma_coder *coder, const lzma_allocator *allocator,
 
 
 static void
-stream_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
+stream_encoder_end(void *coder_ptr, const lzma_allocator *allocator)
 {
+	lzma_stream_coder *coder = coder_ptr;
+
 	lzma_next_end(&coder->block_encoder, allocator);
 	lzma_next_end(&coder->index_encoder, allocator);
 	lzma_index_end(coder->index, allocator);
@@ -224,10 +228,12 @@ stream_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 
 
 static lzma_ret
-stream_encoder_update(lzma_coder *coder, const lzma_allocator *allocator,
+stream_encoder_update(void *coder_ptr, const lzma_allocator *allocator,
 		const lzma_filter *filters,
 		const lzma_filter *reversed_filters)
 {
+	lzma_stream_coder *coder = coder_ptr;
+
 	if (coder->sequence <= SEQ_BLOCK_INIT) {
 		// There is no incomplete Block waiting to be finished,
 		// thus we can change the whole filter chain. Start by
@@ -271,30 +277,33 @@ stream_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 	if (filters == NULL)
 		return LZMA_PROG_ERROR;
 
-	if (next->coder == NULL) {
-		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
-		if (next->coder == NULL)
+	lzma_stream_coder *coder = next->coder;
+
+	if (coder == NULL) {
+		coder = lzma_alloc(sizeof(lzma_stream_coder), allocator);
+		if (coder == NULL)
 			return LZMA_MEM_ERROR;
 
+		next->coder = coder;
 		next->code = &stream_encode;
 		next->end = &stream_encoder_end;
 		next->update = &stream_encoder_update;
 
-		next->coder->filters[0].id = LZMA_VLI_UNKNOWN;
-		next->coder->block_encoder = LZMA_NEXT_CODER_INIT;
-		next->coder->index_encoder = LZMA_NEXT_CODER_INIT;
-		next->coder->index = NULL;
+		coder->filters[0].id = LZMA_VLI_UNKNOWN;
+		coder->block_encoder = LZMA_NEXT_CODER_INIT;
+		coder->index_encoder = LZMA_NEXT_CODER_INIT;
+		coder->index = NULL;
 	}
 
 	// Basic initializations
-	next->coder->sequence = SEQ_STREAM_HEADER;
-	next->coder->block_options.version = 0;
-	next->coder->block_options.check = check;
+	coder->sequence = SEQ_STREAM_HEADER;
+	coder->block_options.version = 0;
+	coder->block_options.check = check;
 
 	// Initialize the Index
-	lzma_index_end(next->coder->index, allocator);
-	next->coder->index = lzma_index_init(allocator);
-	if (next->coder->index == NULL)
+	lzma_index_end(coder->index, allocator);
+	coder->index = lzma_index_init(allocator);
+	if (coder->index == NULL)
 		return LZMA_MEM_ERROR;
 
 	// Encode the Stream Header
@@ -303,16 +312,15 @@ stream_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		.check = check,
 	};
 	return_if_error(lzma_stream_header_encode(
-			&stream_flags, next->coder->buffer));
+			&stream_flags, coder->buffer));
 
-	next->coder->buffer_pos = 0;
-	next->coder->buffer_size = LZMA_STREAM_HEADER_SIZE;
+	coder->buffer_pos = 0;
+	coder->buffer_size = LZMA_STREAM_HEADER_SIZE;
 
 	// Initialize the Block encoder. This way we detect unsupported
 	// filter chains when initializing the Stream encoder instead of
 	// giving an error after Stream Header has already written out.
-	return stream_encoder_update(
-			next->coder, allocator, filters, NULL);
+	return stream_encoder_update(coder, allocator, filters, NULL);
 }
 
 
diff --git a/src/liblzma/common/stream_encoder_mt.c b/src/liblzma/common/stream_encoder_mt.c
index 9780ed04..2efe44c2 100644
--- a/src/liblzma/common/stream_encoder_mt.c
+++ b/src/liblzma/common/stream_encoder_mt.c
@@ -44,6 +44,7 @@ typedef enum {
 
 } worker_state;
 
+typedef struct lzma_stream_coder_s lzma_stream_coder;
 
 typedef struct worker_thread_s worker_thread;
 struct worker_thread_s {
@@ -65,7 +66,7 @@ struct worker_thread_s {
 
 	/// Pointer to the main structure is needed when putting this
 	/// thread back to the stack of free threads.
-	lzma_coder *coder;
+	lzma_stream_coder *coder;
 
 	/// The allocator is set by the main thread. Since a copy of the
 	/// pointer is kept here, the application must not change the
@@ -96,7 +97,7 @@ struct worker_thread_s {
 };
 
 
-struct lzma_coder_s {
+struct lzma_stream_coder_s {
 	enum {
 		SEQ_STREAM_HEADER,
 		SEQ_BLOCK,
@@ -417,7 +418,7 @@ worker_start(void *thr_ptr)
 
 /// Make the threads stop but not exit. Optionally wait for them to stop.
 static void
-threads_stop(lzma_coder *coder, bool wait_for_threads)
+threads_stop(lzma_stream_coder *coder, bool wait_for_threads)
 {
 	// Tell the threads to stop.
 	for (uint32_t i = 0; i < coder->threads_initialized; ++i) {
@@ -446,7 +447,7 @@ threads_stop(lzma_coder *coder, bool wait_for_threads)
 /// Stop the threads and free the resources associated with them.
 /// Wait until the threads have exited.
 static void
-threads_end(lzma_coder *coder, const lzma_allocator *allocator)
+threads_end(lzma_stream_coder *coder, const lzma_allocator *allocator)
 {
 	for (uint32_t i = 0; i < coder->threads_initialized; ++i) {
 		mythread_sync(coder->threads[i].mutex) {
@@ -468,7 +469,8 @@ threads_end(lzma_coder *coder, const lzma_allocator *allocator)
 
 /// Initialize a new worker_thread structure and create a new thread.
 static lzma_ret
-initialize_new_thread(lzma_coder *coder, const lzma_allocator *allocator)
+initialize_new_thread(lzma_stream_coder *coder,
+		const lzma_allocator *allocator)
 {
 	worker_thread *thr = &coder->threads[coder->threads_initialized];
 
@@ -510,7 +512,7 @@ error_mutex:
 
 
 static lzma_ret
-get_thread(lzma_coder *coder, const lzma_allocator *allocator)
+get_thread(lzma_stream_coder *coder, const lzma_allocator *allocator)
 {
 	// If there are no free output subqueues, there is no
 	// point to try getting a thread.
@@ -548,7 +550,7 @@ get_thread(lzma_coder *coder, const lzma_allocator *allocator)
 
 
 static lzma_ret
-stream_encode_in(lzma_coder *coder, const lzma_allocator *allocator,
+stream_encode_in(lzma_stream_coder *coder, const lzma_allocator *allocator,
 		const uint8_t *restrict in, size_t *restrict in_pos,
 		size_t in_size, lzma_action action)
 {
@@ -616,7 +618,7 @@ stream_encode_in(lzma_coder *coder, const lzma_allocator *allocator,
 /// Wait until more input can be consumed, more output can be read, or
 /// an optional timeout is reached.
 static bool
-wait_for_work(lzma_coder *coder, mythread_condtime *wait_abs,
+wait_for_work(lzma_stream_coder *coder, mythread_condtime *wait_abs,
 		bool *has_blocked, bool has_input)
 {
 	if (coder->timeout != 0 && !*has_blocked) {
@@ -662,11 +664,13 @@ wait_for_work(lzma_coder *coder, mythread_condtime *wait_abs,
 
 
 static lzma_ret
-stream_encode_mt(lzma_coder *coder, const lzma_allocator *allocator,
+stream_encode_mt(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_stream_coder *coder = coder_ptr;
+
 	switch (coder->sequence) {
 	case SEQ_STREAM_HEADER:
 		lzma_bufcpy(coder->header, &coder->header_pos,
@@ -834,8 +838,10 @@ stream_encode_mt(lzma_coder *coder, const lzma_allocator *allocator,
 
 
 static void
-stream_encoder_mt_end(lzma_coder *coder, const lzma_allocator *allocator)
+stream_encoder_mt_end(void *coder_ptr, const lzma_allocator *allocator)
 {
+	lzma_stream_coder *coder = coder_ptr;
+
 	// Threads must be killed before the output queue can be freed.
 	threads_end(coder, allocator);
 	lzma_outq_end(&coder->outq, allocator);
@@ -907,10 +913,12 @@ get_options(const lzma_mt *options, lzma_options_easy *opt_easy,
 
 
 static void
-get_progress(lzma_coder *coder, uint64_t *progress_in, uint64_t *progress_out)
+get_progress(void *coder_ptr, uint64_t *progress_in, uint64_t *progress_out)
 {
+	lzma_stream_coder *coder = coder_ptr;
+
 	// Lock coder->mutex to prevent finishing threads from moving their
-	// progress info from the worker_thread structure to lzma_coder.
+	// progress info from the worker_thread structure to lzma_stream_coder.
 	mythread_sync(coder->mutex) {
 		*progress_in = coder->progress_in;
 		*progress_out = coder->progress_out;
@@ -962,24 +970,27 @@ stream_encoder_mt_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		return LZMA_UNSUPPORTED_CHECK;
 
 	// Allocate and initialize the base structure if needed.
-	if (next->coder == NULL) {
-		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
-		if (next->coder == NULL)
+	lzma_stream_coder *coder = next->coder;
+	if (coder == NULL) {
+		coder = lzma_alloc(sizeof(lzma_stream_coder), allocator);
+		if (coder == NULL)
 			return LZMA_MEM_ERROR;
 
+		next->coder = coder;
+
 		// For the mutex and condition variable initializations
 		// the error handling has to be done here because
 		// stream_encoder_mt_end() doesn't know if they have
 		// already been initialized or not.
-		if (mythread_mutex_init(&next->coder->mutex)) {
-			lzma_free(next->coder, allocator);
+		if (mythread_mutex_init(&coder->mutex)) {
+			lzma_free(coder, allocator);
 			next->coder = NULL;
 			return LZMA_MEM_ERROR;
 		}
 
-		if (mythread_cond_init(&next->coder->cond)) {
-			mythread_mutex_destroy(&next->coder->mutex);
-			lzma_free(next->coder, allocator);
+		if (mythread_cond_init(&coder->cond)) {
+			mythread_mutex_destroy(&coder->mutex);
+			lzma_free(coder, allocator);
 			next->coder = NULL;
 			return LZMA_MEM_ERROR;
 		}
@@ -989,76 +1000,76 @@ stream_encoder_mt_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		next->get_progress = &get_progress;
 // 		next->update = &stream_encoder_mt_update;
 
-		next->coder->filters[0].id = LZMA_VLI_UNKNOWN;
-		next->coder->index_encoder = LZMA_NEXT_CODER_INIT;
-		next->coder->index = NULL;
-		memzero(&next->coder->outq, sizeof(next->coder->outq));
-		next->coder->threads = NULL;
-		next->coder->threads_max = 0;
-		next->coder->threads_initialized = 0;
+		coder->filters[0].id = LZMA_VLI_UNKNOWN;
+		coder->index_encoder = LZMA_NEXT_CODER_INIT;
+		coder->index = NULL;
+		memzero(&coder->outq, sizeof(coder->outq));
+		coder->threads = NULL;
+		coder->threads_max = 0;
+		coder->threads_initialized = 0;
 	}
 
 	// Basic initializations
-	next->coder->sequence = SEQ_STREAM_HEADER;
-	next->coder->block_size = (size_t)(block_size);
-	next->coder->thread_error = LZMA_OK;
-	next->coder->thr = NULL;
+	coder->sequence = SEQ_STREAM_HEADER;
+	coder->block_size = (size_t)(block_size);
+	coder->thread_error = LZMA_OK;
+	coder->thr = NULL;
 
 	// Allocate the thread-specific base structures.
 	assert(options->threads > 0);
-	if (next->coder->threads_max != options->threads) {
-		threads_end(next->coder, allocator);
+	if (coder->threads_max != options->threads) {
+		threads_end(coder, allocator);
 
-		next->coder->threads = NULL;
-		next->coder->threads_max = 0;
+		coder->threads = NULL;
+		coder->threads_max = 0;
 
-		next->coder->threads_initialized = 0;
-		next->coder->threads_free = NULL;
+		coder->threads_initialized = 0;
+		coder->threads_free = NULL;
 
-		next->coder->threads = lzma_alloc(
+		coder->threads = lzma_alloc(
 				options->threads * sizeof(worker_thread),
 				allocator);
-		if (next->coder->threads == NULL)
+		if (coder->threads == NULL)
 			return LZMA_MEM_ERROR;
 
-		next->coder->threads_max = options->threads;
+		coder->threads_max = options->threads;
 	} else {
 		// Reuse the old structures and threads. Tell the running
 		// threads to stop and wait until they have stopped.
-		threads_stop(next->coder, true);
+		threads_stop(coder, true);
 	}
 
 	// Output queue
-	return_if_error(lzma_outq_init(&next->coder->outq, allocator,
+	return_if_error(lzma_outq_init(&coder->outq, allocator,
 			outbuf_size_max, options->threads));
 
 	// Timeout
-	next->coder->timeout = options->timeout;
+	coder->timeout = options->timeout;
 
 	// Free the old filter chain and copy the new one.
-	for (size_t i = 0; next->coder->filters[i].id != LZMA_VLI_UNKNOWN; ++i)
-		lzma_free(next->coder->filters[i].options, allocator);
+	for (size_t i = 0; coder->filters[i].id != LZMA_VLI_UNKNOWN; ++i)
+		lzma_free(coder->filters[i].options, allocator);
 
 	return_if_error(lzma_filters_copy(
-			filters, next->coder->filters, allocator));
+			filters, coder->filters, allocator));
 
 	// Index
-	lzma_index_end(next->coder->index, allocator);
-	next->coder->index = lzma_index_init(allocator);
-	if (next->coder->index == NULL)
+	lzma_index_end(coder->index, allocator);
+	coder->index = lzma_index_init(allocator);
+	if (coder->index == NULL)
 		return LZMA_MEM_ERROR;
 
 	// Stream Header
-	next->coder->stream_flags.version = 0;
-	next->coder->stream_flags.check = options->check;
+	coder->stream_flags.version = 0;
+	coder->stream_flags.check = options->check;
 	return_if_error(lzma_stream_header_encode(
-			&next->coder->stream_flags, next->coder->header));
+			&coder->stream_flags, coder->header));
 
-	next->coder->header_pos = 0;
+	coder->header_pos = 0;
 
 	// Progress info
-	next->coder->progress_in = 0;
-	next->coder->progress_out = LZMA_STREAM_HEADER_SIZE;
+	coder->progress_in = 0;
+	coder->progress_out = LZMA_STREAM_HEADER_SIZE;
 
 	return LZMA_OK;
 }
@@ -1111,7 +1122,8 @@ lzma_stream_encoder_mt_memusage(const lzma_mt *options)
 		return UINT64_MAX;
 
 	// Sum them with overflow checking.
-	uint64_t total_memusage = LZMA_MEMUSAGE_BASE + sizeof(lzma_coder)
+	uint64_t total_memusage = LZMA_MEMUSAGE_BASE
+			+ sizeof(lzma_stream_coder)
 			+ options->threads * sizeof(worker_thread);
 
 	if (UINT64_MAX - total_memusage < inbuf_memusage)