4 files changed, 28 insertions, 19 deletions

diff --git a/src/liblzma/delta/delta_common.c b/src/liblzma/delta/delta_common.c
index 13dd4682..4768201d 100644
--- a/src/liblzma/delta/delta_common.c
+++ b/src/liblzma/delta/delta_common.c
@@ -15,8 +15,9 @@
 
 
 static void
-delta_coder_end(lzma_coder *coder, const lzma_allocator *allocator)
+delta_coder_end(void *coder_ptr, const lzma_allocator *allocator)
 {
+	lzma_delta_coder *coder = coder_ptr;
 	lzma_next_end(&coder->next, allocator);
 	lzma_free(coder, allocator);
 	return;
@@ -28,14 +29,17 @@ lzma_delta_coder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter_info *filters)
 {
 	// Allocate memory for the decoder if needed.
-	if (next->coder == NULL) {
-		next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
-		if (next->coder == NULL)
+	lzma_delta_coder *coder = next->coder;
+	if (coder == NULL) {
+		coder = lzma_alloc(sizeof(lzma_delta_coder), allocator);
+		if (coder == NULL)
 			return LZMA_MEM_ERROR;
 
+		next->coder = coder;
+
 		// End function is the same for encoder and decoder.
 		next->end = &delta_coder_end;
-		next->coder->next = LZMA_NEXT_CODER_INIT;
+		coder->next = LZMA_NEXT_CODER_INIT;
 	}
 
 	// Validate the options.
@@ -44,15 +48,14 @@ lzma_delta_coder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 
 	// Set the delta distance.
 	const lzma_options_delta *opt = filters[0].options;
-	next->coder->distance = opt->dist;
+	coder->distance = opt->dist;
 
 	// Initialize the rest of the variables.
-	next->coder->pos = 0;
-	memzero(next->coder->history, LZMA_DELTA_DIST_MAX);
+	coder->pos = 0;
+	memzero(coder->history, LZMA_DELTA_DIST_MAX);
 
 	// Initialize the next decoder in the chain, if any.
-	return lzma_next_filter_init(&next->coder->next,
-			allocator, filters + 1);
+	return lzma_next_filter_init(&coder->next, allocator, filters + 1);
 }
 
 
@@ -66,5 +69,5 @@ lzma_delta_coder_memusage(const void *options)
 			|| opt->dist > LZMA_DELTA_DIST_MAX)
 		return UINT64_MAX;
 
-	return sizeof(lzma_coder);
+	return sizeof(lzma_delta_coder);
 }
diff --git a/src/liblzma/delta/delta_decoder.c b/src/liblzma/delta/delta_decoder.c
index 726d0239..6859afa5 100644
--- a/src/liblzma/delta/delta_decoder.c
+++ b/src/liblzma/delta/delta_decoder.c
@@ -15,7 +15,7 @@
 
 
 static void
-decode_buffer(lzma_coder *coder, uint8_t *buffer, size_t size)
+decode_buffer(lzma_delta_coder *coder, uint8_t *buffer, size_t size)
 {
 	const size_t distance = coder->distance;
 
@@ -27,11 +27,13 @@ decode_buffer(lzma_coder *coder, uint8_t *buffer, size_t size)
 
 
 static lzma_ret
-delta_decode(lzma_coder *coder, const lzma_allocator *allocator,
+delta_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_delta_coder *coder = coder_ptr;
+
 	assert(coder->next.code != NULL);
 
 	const size_t out_start = *out_pos;
diff --git a/src/liblzma/delta/delta_encoder.c b/src/liblzma/delta/delta_encoder.c
index 5a842636..38416515 100644
--- a/src/liblzma/delta/delta_encoder.c
+++ b/src/liblzma/delta/delta_encoder.c
@@ -18,7 +18,7 @@
 /// is the first filter in the chain (and thus the last filter in the
 /// encoder's filter stack).
 static void
-copy_and_encode(lzma_coder *coder,
+copy_and_encode(lzma_delta_coder *coder,
 		const uint8_t *restrict in, uint8_t *restrict out, size_t size)
 {
 	const size_t distance = coder->distance;
@@ -35,7 +35,7 @@ copy_and_encode(lzma_coder *coder,
 /// Encodes the data in place. This is used when we are the last filter
 /// in the chain (and thus non-last filter in the encoder's filter stack).
 static void
-encode_in_place(lzma_coder *coder, uint8_t *buffer, size_t size)
+encode_in_place(lzma_delta_coder *coder, uint8_t *buffer, size_t size)
 {
 	const size_t distance = coder->distance;
 
@@ -49,11 +49,13 @@ encode_in_place(lzma_coder *coder, uint8_t *buffer, size_t size)
 
 
 static lzma_ret
-delta_encode(lzma_coder *coder, const lzma_allocator *allocator,
+delta_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_delta_coder *coder = coder_ptr;
+
 	lzma_ret ret;
 
 	if (coder->next.code == NULL) {
@@ -84,10 +86,12 @@ delta_encode(lzma_coder *coder, const lzma_allocator *allocator,
 
 
 static lzma_ret
-delta_encoder_update(lzma_coder *coder, const lzma_allocator *allocator,
+delta_encoder_update(void *coder_ptr, const lzma_allocator *allocator,
 		const lzma_filter *filters_null lzma_attribute((__unused__)),
 		const lzma_filter *reversed_filters)
 {
+	lzma_delta_coder *coder = coder_ptr;
+
 	// Delta doesn't and will never support changing the options in
 	// the middle of encoding. If the app tries to change them, we
 	// simply ignore them.
diff --git a/src/liblzma/delta/delta_private.h b/src/liblzma/delta/delta_private.h
index 46ce0c64..0d6cb386 100644
--- a/src/liblzma/delta/delta_private.h
+++ b/src/liblzma/delta/delta_private.h
@@ -15,7 +15,7 @@
 
 #include "delta_common.h"
 
-struct lzma_coder_s {
+typedef struct {
 	/// Next coder in the chain
 	lzma_next_coder next;
 
@@ -27,7 +27,7 @@ struct lzma_coder_s {
 
 	/// Buffer to hold history of the original data
 	uint8_t history[LZMA_DELTA_DIST_MAX];
-};
+} lzma_delta_coder;
 
 
 extern lzma_ret lzma_delta_coder_init(