liblzma: Make the use of lzma_allocator const-correct.

There is a tiny risk of causing breakage: If an application
assigns lzma_stream.allocator to a non-const pointer, such
code won't compile anymore. I don't know why anyone would do
such a thing though, so in practice this shouldn't cause trouble.

Thanks to Jan Kratochvil for the patch.

36 files changed, 116 insertions, 105 deletions

diff --git a/src/liblzma/common/alone_decoder.c b/src/liblzma/common/alone_decoder.c
index 678c79e6..d35aff67 100644
--- a/src/liblzma/common/alone_decoder.c
+++ b/src/liblzma/common/alone_decoder.c
@@ -46,7 +46,7 @@ struct lzma_coder_s {
 
 static lzma_ret
 alone_decode(lzma_coder *coder,
-		lzma_allocator *allocator lzma_attribute((__unused__)),
+		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,
@@ -161,7 +161,7 @@ alone_decode(lzma_coder *coder,
 
 
 static void
-alone_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+alone_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	lzma_next_end(&coder->next, allocator);
 	lzma_free(coder, allocator);
@@ -188,7 +188,7 @@ alone_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
 
 
 extern lzma_ret
-lzma_alone_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+lzma_alone_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		uint64_t memlimit)
 {
 	lzma_next_coder_init(&lzma_alone_decoder_init, next, allocator);
diff --git a/src/liblzma/common/alone_decoder.h b/src/liblzma/common/alone_decoder.h
index 70d0d2a0..d819b3fb 100644
--- a/src/liblzma/common/alone_decoder.h
+++ b/src/liblzma/common/alone_decoder.h
@@ -17,6 +17,6 @@
 
 
 extern lzma_ret lzma_alone_decoder_init(lzma_next_coder *next,
-		lzma_allocator *allocator, uint64_t memlimit);
+		const lzma_allocator *allocator, uint64_t memlimit);
 
 #endif
diff --git a/src/liblzma/common/alone_encoder.c b/src/liblzma/common/alone_encoder.c
index eb1697e9..a2bc9eee 100644
--- a/src/liblzma/common/alone_encoder.c
+++ b/src/liblzma/common/alone_encoder.c
@@ -32,7 +32,7 @@ struct lzma_coder_s {
 
 static lzma_ret
 alone_encode(lzma_coder *coder,
-		lzma_allocator *allocator lzma_attribute((__unused__)),
+		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,
@@ -65,7 +65,7 @@ alone_encode(lzma_coder *coder,
 
 
 static void
-alone_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
+alone_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	lzma_next_end(&coder->next, allocator);
 	lzma_free(coder, allocator);
@@ -75,7 +75,7 @@ alone_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
 
 // At least for now, this is not used by any internal function.
 static lzma_ret
-alone_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+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);
@@ -137,7 +137,7 @@ alone_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
 
 /*
 extern lzma_ret
-lzma_alone_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+lzma_alone_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_options_alone *options)
 {
 	lzma_next_coder_init(&alone_encoder_init, next, allocator, options);
diff --git a/src/liblzma/common/auto_decoder.c b/src/liblzma/common/auto_decoder.c
index ae6c3e78..22e45189 100644
--- a/src/liblzma/common/auto_decoder.c
+++ b/src/liblzma/common/auto_decoder.c
@@ -30,7 +30,7 @@ struct lzma_coder_s {
 
 
 static lzma_ret
-auto_decode(lzma_coder *coder, lzma_allocator *allocator,
+auto_decode(lzma_coder *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, lzma_action action)
@@ -100,7 +100,7 @@ auto_decode(lzma_coder *coder, lzma_allocator *allocator,
 
 
 static void
-auto_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+auto_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	lzma_next_end(&coder->next, allocator);
 	lzma_free(coder, allocator);
@@ -143,7 +143,7 @@ auto_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
 
 
 static lzma_ret
-auto_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+auto_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		uint64_t memlimit, uint32_t flags)
 {
 	lzma_next_coder_init(&auto_decoder_init, next, allocator);
diff --git a/src/liblzma/common/block_buffer_decoder.c b/src/liblzma/common/block_buffer_decoder.c
index ff27a11c..b0ded90d 100644
--- a/src/liblzma/common/block_buffer_decoder.c
+++ b/src/liblzma/common/block_buffer_decoder.c
@@ -14,7 +14,7 @@
 
 
 extern LZMA_API(lzma_ret)
-lzma_block_buffer_decode(lzma_block *block, lzma_allocator *allocator,
+lzma_block_buffer_decode(lzma_block *block, const lzma_allocator *allocator,
 		const uint8_t *in, size_t *in_pos, size_t in_size,
 		uint8_t *out, size_t *out_pos, size_t out_size)
 {
diff --git a/src/liblzma/common/block_buffer_encoder.c b/src/liblzma/common/block_buffer_encoder.c
index 519c6a68..e678b30e 100644
--- a/src/liblzma/common/block_buffer_encoder.c
+++ b/src/liblzma/common/block_buffer_encoder.c
@@ -160,7 +160,7 @@ block_encode_uncompressed(lzma_block *block, const uint8_t *in, size_t in_size,
 
 
 static lzma_ret
-block_encode_normal(lzma_block *block, lzma_allocator *allocator,
+block_encode_normal(lzma_block *block, const lzma_allocator *allocator,
 		const uint8_t *in, size_t in_size,
 		uint8_t *out, size_t *out_pos, size_t out_size)
 {
@@ -222,7 +222,7 @@ block_encode_normal(lzma_block *block, lzma_allocator *allocator,
 
 
 extern LZMA_API(lzma_ret)
-lzma_block_buffer_encode(lzma_block *block, lzma_allocator *allocator,
+lzma_block_buffer_encode(lzma_block *block, const lzma_allocator *allocator,
 		const uint8_t *in, size_t in_size,
 		uint8_t *out, size_t *out_pos, size_t out_size)
 {
diff --git a/src/liblzma/common/block_decoder.c b/src/liblzma/common/block_decoder.c
index a3ce6f49..cee6c782 100644
--- a/src/liblzma/common/block_decoder.c
+++ b/src/liblzma/common/block_decoder.c
@@ -71,7 +71,7 @@ is_size_valid(lzma_vli size, lzma_vli reference)
 
 
 static lzma_ret
-block_decode(lzma_coder *coder, lzma_allocator *allocator,
+block_decode(lzma_coder *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, lzma_action action)
@@ -170,7 +170,7 @@ block_decode(lzma_coder *coder, lzma_allocator *allocator,
 
 
 static void
-block_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+block_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	lzma_next_end(&coder->next, allocator);
 	lzma_free(coder, allocator);
@@ -179,7 +179,7 @@ block_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
 
 
 extern lzma_ret
-lzma_block_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+lzma_block_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		lzma_block *block)
 {
 	lzma_next_coder_init(&lzma_block_decoder_init, next, allocator);
diff --git a/src/liblzma/common/block_decoder.h b/src/liblzma/common/block_decoder.h
index 7da9df63..718c5ced 100644
--- a/src/liblzma/common/block_decoder.h
+++ b/src/liblzma/common/block_decoder.h
@@ -17,6 +17,6 @@
 
 
 extern lzma_ret lzma_block_decoder_init(lzma_next_coder *next,
-		lzma_allocator *allocator, lzma_block *block);
+		const lzma_allocator *allocator, lzma_block *block);
 
 #endif
diff --git a/src/liblzma/common/block_encoder.c b/src/liblzma/common/block_encoder.c
index 1eeb502b..15f55f7a 100644
--- a/src/liblzma/common/block_encoder.c
+++ b/src/liblzma/common/block_encoder.c
@@ -45,7 +45,7 @@ struct lzma_coder_s {
 
 
 static lzma_ret
-block_encode(lzma_coder *coder, lzma_allocator *allocator,
+block_encode(lzma_coder *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, lzma_action action)
@@ -134,7 +134,7 @@ block_encode(lzma_coder *coder, lzma_allocator *allocator,
 
 
 static void
-block_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
+block_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	lzma_next_end(&coder->next, allocator);
 	lzma_free(coder, allocator);
@@ -143,7 +143,7 @@ block_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
 
 
 static lzma_ret
-block_encoder_update(lzma_coder *coder, lzma_allocator *allocator,
+block_encoder_update(lzma_coder *coder, const lzma_allocator *allocator,
 		const lzma_filter *filters lzma_attribute((__unused__)),
 		const lzma_filter *reversed_filters)
 {
@@ -156,7 +156,7 @@ block_encoder_update(lzma_coder *coder, lzma_allocator *allocator,
 
 
 extern lzma_ret
-lzma_block_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+lzma_block_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		lzma_block *block)
 {
 	lzma_next_coder_init(&lzma_block_encoder_init, next, allocator);
diff --git a/src/liblzma/common/block_encoder.h b/src/liblzma/common/block_encoder.h
index b9eff0be..bd97c186 100644
--- a/src/liblzma/common/block_encoder.h
+++ b/src/liblzma/common/block_encoder.h
@@ -42,6 +42,6 @@
 
 
 extern lzma_ret lzma_block_encoder_init(lzma_next_coder *next,
-		lzma_allocator *allocator, lzma_block *block);
+		const lzma_allocator *allocator, lzma_block *block);
 
 #endif
diff --git a/src/liblzma/common/block_header_decoder.c b/src/liblzma/common/block_header_decoder.c
index 2c9573ee..416642cd 100644
--- a/src/liblzma/common/block_header_decoder.c
+++ b/src/liblzma/common/block_header_decoder.c
@@ -15,7 +15,7 @@
 
 
 static void
-free_properties(lzma_block *block, lzma_allocator *allocator)
+free_properties(lzma_block *block, const lzma_allocator *allocator)
 {
 	// Free allocated filter options. The last array member is not
 	// touched after the initialization in the beginning of
@@ -32,7 +32,7 @@ free_properties(lzma_block *block, lzma_allocator *allocator)
 
 extern LZMA_API(lzma_ret)
 lzma_block_header_decode(lzma_block *block,
-		lzma_allocator *allocator, const uint8_t *in)
+		const lzma_allocator *allocator, const uint8_t *in)
 {
 	// NOTE: We consider the header to be corrupt not only when the
 	// CRC32 doesn't match, but also when variable-length integers
diff --git a/src/liblzma/common/common.c b/src/liblzma/common/common.c
index 85ae96a9..5d4d2408 100644
--- a/src/liblzma/common/common.c
+++ b/src/liblzma/common/common.c
@@ -36,7 +36,7 @@ lzma_version_string(void)
 ///////////////////////
 
 extern void * lzma_attribute((__malloc__)) lzma_attr_alloc_size(1)
-lzma_alloc(size_t size, lzma_allocator *allocator)
+lzma_alloc(size_t size, const lzma_allocator *allocator)
 {
 	// Some malloc() variants return NULL if called with size == 0.
 	if (size == 0)
@@ -54,7 +54,7 @@ lzma_alloc(size_t size, lzma_allocator *allocator)
 
 
 extern void
-lzma_free(void *ptr, lzma_allocator *allocator)
+lzma_free(void *ptr, const lzma_allocator *allocator)
 {
 	if (allocator != NULL && allocator->free != NULL)
 		allocator->free(allocator->opaque, ptr);
@@ -88,7 +88,7 @@ lzma_bufcpy(const uint8_t *restrict in, size_t *restrict in_pos,
 
 
 extern lzma_ret
-lzma_next_filter_init(lzma_next_coder *next, lzma_allocator *allocator,
+lzma_next_filter_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter_info *filters)
 {
 	lzma_next_coder_init(filters[0].init, next, allocator);
@@ -99,7 +99,7 @@ lzma_next_filter_init(lzma_next_coder *next, lzma_allocator *allocator,
 
 
 extern lzma_ret
-lzma_next_filter_update(lzma_next_coder *next, lzma_allocator *allocator,
+lzma_next_filter_update(lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter *reversed_filters)
 {
 	// Check that the application isn't trying to change the Filter ID.
@@ -117,7 +117,7 @@ lzma_next_filter_update(lzma_next_coder *next, lzma_allocator *allocator,
 
 
 extern void
-lzma_next_end(lzma_next_coder *next, lzma_allocator *allocator)
+lzma_next_end(lzma_next_coder *next, const lzma_allocator *allocator)
 {
 	if (next->init != (uintptr_t)(NULL)) {
 		// To avoid tiny end functions that simply call
diff --git a/src/liblzma/common/common.h b/src/liblzma/common/common.h
index 5c92af27..86c5f02c 100644
--- a/src/liblzma/common/common.h
+++ b/src/liblzma/common/common.h
@@ -96,7 +96,7 @@ typedef struct lzma_filter_info_s lzma_filter_info;
 
 /// Type of a function used to initialize a filter encoder or decoder
 typedef lzma_ret (*lzma_init_function)(
-		lzma_next_coder *next, lzma_allocator *allocator,
+		lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter_info *filters);
 
 /// Type of a function to do some kind of coding work (filters, Stream,
@@ -104,7 +104,7 @@ 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, lzma_allocator *allocator,
+		lzma_coder *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,
@@ -112,7 +112,7 @@ 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, lzma_allocator *allocator);
+		lzma_coder *coder, const lzma_allocator *allocator);
 
 
 /// Raw coder validates and converts an array of lzma_filter structures to
@@ -166,7 +166,7 @@ struct lzma_next_coder_s {
 
 	/// Update the filter-specific options or the whole filter chain
 	/// in the encoder.
-	lzma_ret (*update)(lzma_coder *coder, lzma_allocator *allocator,
+	lzma_ret (*update)(lzma_coder *coder, const lzma_allocator *allocator,
 			const lzma_filter *filters,
 			const lzma_filter *reversed_filters);
 };
@@ -220,11 +220,11 @@ struct lzma_internal_s {
 
 
 /// Allocates memory
-extern void *lzma_alloc(size_t size, lzma_allocator *allocator)
+extern void *lzma_alloc(size_t size, const lzma_allocator *allocator)
 		lzma_attribute((__malloc__)) lzma_attr_alloc_size(1);
 
 /// Frees memory
-extern void lzma_free(void *ptr, lzma_allocator *allocator);
+extern void lzma_free(void *ptr, const lzma_allocator *allocator);
 
 
 /// Allocates strm->internal if it is NULL, and initializes *strm and
@@ -236,17 +236,19 @@ extern lzma_ret lzma_strm_init(lzma_stream *strm);
 /// than the filter being initialized now. This way the actual filter
 /// initialization functions don't need to use lzma_next_coder_init macro.
 extern lzma_ret lzma_next_filter_init(lzma_next_coder *next,
-		lzma_allocator *allocator, const lzma_filter_info *filters);
+		const lzma_allocator *allocator,
+		const lzma_filter_info *filters);
 
 /// Update the next filter in the chain, if any. This checks that
 /// the application is not trying to change the Filter IDs.
 extern lzma_ret lzma_next_filter_update(
-		lzma_next_coder *next, lzma_allocator *allocator,
+		lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter *reversed_filters);
 
 /// Frees the memory allocated for next->coder either using next->end or,
 /// if next->end is NULL, using lzma_free.
-extern void lzma_next_end(lzma_next_coder *next, lzma_allocator *allocator);
+extern void lzma_next_end(lzma_next_coder *next,
+		const lzma_allocator *allocator);
 
 
 /// Copy as much data as possible from in[] to out[] and update *in_pos
diff --git a/src/liblzma/common/easy_buffer_encoder.c b/src/liblzma/common/easy_buffer_encoder.c
index c4be34cc..48eb56f5 100644
--- a/src/liblzma/common/easy_buffer_encoder.c
+++ b/src/liblzma/common/easy_buffer_encoder.c
@@ -15,8 +15,8 @@
 
 extern LZMA_API(lzma_ret)
 lzma_easy_buffer_encode(uint32_t preset, lzma_check check,
-		lzma_allocator *allocator, const uint8_t *in, size_t in_size,
-		uint8_t *out, size_t *out_pos, size_t out_size)
+		const lzma_allocator *allocator, const uint8_t *in,
+		size_t in_size, uint8_t *out, size_t *out_pos, size_t out_size)
 {
 	lzma_options_easy opt_easy;
 	if (lzma_easy_preset(&opt_easy, preset))
diff --git a/src/liblzma/common/filter_buffer_decoder.c b/src/liblzma/common/filter_buffer_decoder.c
index 2d35ef8e..6620986e 100644
--- a/src/liblzma/common/filter_buffer_decoder.c
+++ b/src/liblzma/common/filter_buffer_decoder.c
@@ -14,7 +14,8 @@
 
 
 extern LZMA_API(lzma_ret)
-lzma_raw_buffer_decode(const lzma_filter *filters, lzma_allocator *allocator,
+lzma_raw_buffer_decode(
+		const lzma_filter *filters, const lzma_allocator *allocator,
 		const uint8_t *in, size_t *in_pos, size_t in_size,
 		uint8_t *out, size_t *out_pos, size_t out_size)
 {
diff --git a/src/liblzma/common/filter_buffer_encoder.c b/src/liblzma/common/filter_buffer_encoder.c
index 646e1b30..dda18e3d 100644
--- a/src/liblzma/common/filter_buffer_encoder.c
+++ b/src/liblzma/common/filter_buffer_encoder.c
@@ -14,9 +14,10 @@
 
 
 extern LZMA_API(lzma_ret)
-lzma_raw_buffer_encode(const lzma_filter *filters, lzma_allocator *allocator,
-		const uint8_t *in, size_t in_size, uint8_t *out,
-		size_t *out_pos, size_t out_size)
+lzma_raw_buffer_encode(
+		const lzma_filter *filters, const lzma_allocator *allocator,
+		const uint8_t *in, size_t in_size,
+		uint8_t *out, size_t *out_pos, size_t out_size)
 {
 	// Validate what isn't validated later in filter_common.c.
 	if ((in == NULL && in_size != 0) || out == NULL
diff --git a/src/liblzma/common/filter_common.c b/src/liblzma/common/filter_common.c
index 7c95b05f..9ad5d5d8 100644
--- a/src/liblzma/common/filter_common.c
+++ b/src/liblzma/common/filter_common.c
@@ -123,7 +123,7 @@ static const struct {
 
 extern LZMA_API(lzma_ret)
 lzma_filters_copy(const lzma_filter *src, lzma_filter *dest,
-		lzma_allocator *allocator)
+		const lzma_allocator *allocator)
 {
 	if (src == NULL || dest == NULL)
 		return LZMA_PROG_ERROR;
@@ -239,7 +239,7 @@ validate_chain(const lzma_filter *filters, size_t *count)
 
 
 extern lzma_ret
-lzma_raw_coder_init(lzma_next_coder *next, lzma_allocator *allocator,
+lzma_raw_coder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter *options,
 		lzma_filter_find coder_find, bool is_encoder)
 {
diff --git a/src/liblzma/common/filter_common.h b/src/liblzma/common/filter_common.h
index cd61fc07..42a26a24 100644
--- a/src/liblzma/common/filter_common.h
+++ b/src/liblzma/common/filter_common.h
@@ -36,7 +36,7 @@ typedef const lzma_filter_coder *(*lzma_filter_find)(lzma_vli id);
 
 
 extern lzma_ret lzma_raw_coder_init(
-		lzma_next_coder *next, lzma_allocator *allocator,
+		lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter *filters,
 		lzma_filter_find coder_find, bool is_encoder);
 
diff --git a/src/liblzma/common/filter_decoder.c b/src/liblzma/common/filter_decoder.c
index 1ebbe2af..c75b0a89 100644
--- a/src/liblzma/common/filter_decoder.c
+++ b/src/liblzma/common/filter_decoder.c
@@ -35,7 +35,8 @@ typedef struct {
 	/// \return     - LZMA_OK: Properties decoded successfully.
 	///             - LZMA_OPTIONS_ERROR: Unsupported properties
 	///             - LZMA_MEM_ERROR: Memory allocation failed.
-	lzma_ret (*props_decode)(void **options, lzma_allocator *allocator,
+	lzma_ret (*props_decode)(
+			void **options, const lzma_allocator *allocator,
 			const uint8_t *props, size_t props_size);
 
 } lzma_filter_decoder;
@@ -136,7 +137,7 @@ lzma_filter_decoder_is_supported(lzma_vli id)
 
 
 extern lzma_ret
-lzma_raw_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+lzma_raw_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter *options)
 {
 	return lzma_raw_coder_init(next, allocator,
@@ -165,7 +166,7 @@ lzma_raw_decoder_memusage(const lzma_filter *filters)
 
 
 extern LZMA_API(lzma_ret)
-lzma_properties_decode(lzma_filter *filter, lzma_allocator *allocator,
+lzma_properties_decode(lzma_filter *filter, const lzma_allocator *allocator,
 		const uint8_t *props, size_t props_size)
 {
 	// Make it always NULL so that the caller can always safely free() it.
diff --git a/src/liblzma/common/filter_decoder.h b/src/liblzma/common/filter_decoder.h
index d5c68bdd..a2e255fe 100644
--- a/src/liblzma/common/filter_decoder.h
+++ b/src/liblzma/common/filter_decoder.h
@@ -17,7 +17,7 @@
 
 
 extern lzma_ret lzma_raw_decoder_init(
-		lzma_next_coder *next, lzma_allocator *allocator,
+		lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter *options);
 
 #endif
diff --git a/src/liblzma/common/filter_encoder.c b/src/liblzma/common/filter_encoder.c
index 4ba652b7..c5d8f397 100644
--- a/src/liblzma/common/filter_encoder.c
+++ b/src/liblzma/common/filter_encoder.c
@@ -196,7 +196,7 @@ lzma_filters_update(lzma_stream *strm, const lzma_filter *filters)
 
 
 extern lzma_ret
-lzma_raw_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+lzma_raw_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter *options)
 {
 	return lzma_raw_coder_init(next, allocator,
diff --git a/src/liblzma/common/filter_encoder.h b/src/liblzma/common/filter_encoder.h
index 82fb0d9e..f1d5683f 100644
--- a/src/liblzma/common/filter_encoder.h
+++ b/src/liblzma/common/filter_encoder.h
@@ -21,7 +21,7 @@ extern uint64_t lzma_mt_block_size(const lzma_filter *filters);
 
 
 extern lzma_ret lzma_raw_encoder_init(
-		lzma_next_coder *next, lzma_allocator *allocator,
+		lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter *filters);
 
 #endif
diff --git a/src/liblzma/common/filter_flags_decoder.c b/src/liblzma/common/filter_flags_decoder.c
index caae10ce..ddfb0859 100644
--- a/src/liblzma/common/filter_flags_decoder.c
+++ b/src/liblzma/common/filter_flags_decoder.c
@@ -15,7 +15,7 @@
 
 extern LZMA_API(lzma_ret)
 lzma_filter_flags_decode(
-		lzma_filter *filter, lzma_allocator *allocator,
+		lzma_filter *filter, const lzma_allocator *allocator,
 		const uint8_t *in, size_t *in_pos, size_t in_size)
 {
 	// Set the pointer to NULL so the caller can always safely free it.
diff --git a/src/liblzma/common/index.c b/src/liblzma/common/index.c
index 9af4bc19..11f45f40 100644
--- a/src/liblzma/common/index.c
+++ b/src/liblzma/common/index.c
@@ -191,8 +191,8 @@ index_tree_init(index_tree *tree)
 
 /// Helper for index_tree_end()
 static void
-index_tree_node_end(index_tree_node *node, lzma_allocator *allocator,
-		void (*free_func)(void *node, lzma_allocator *allocator))
+index_tree_node_end(index_tree_node *node, const lzma_allocator *allocator,
+		void (*free_func)(void *node, const lzma_allocator *allocator))
 {
 	// The tree won't ever be very huge, so recursion should be fine.
 	// 20 levels in the tree is likely quite a lot already in practice.
@@ -215,8 +215,8 @@ index_tree_node_end(index_tree_node *node, lzma_allocator *allocator,
 /// to free the Record groups from each index_stream before freeing
 /// the index_stream itself.
 static void
-index_tree_end(index_tree *tree, lzma_allocator *allocator,
-		void (*free_func)(void *node, lzma_allocator *allocator))
+index_tree_end(index_tree *tree, const lzma_allocator *allocator,
+		void (*free_func)(void *node, const lzma_allocator *allocator))
 {
 	if (tree->root != NULL)
 		index_tree_node_end(tree->root, allocator, free_func);
@@ -340,7 +340,7 @@ index_tree_locate(const index_tree *tree, lzma_vli target)
 static index_stream *
 index_stream_init(lzma_vli compressed_base, lzma_vli uncompressed_base,
 		lzma_vli stream_number, lzma_vli block_number_base,
-		lzma_allocator *allocator)
+		const lzma_allocator *allocator)
 {
 	index_stream *s = lzma_alloc(sizeof(index_stream), allocator);
 	if (s == NULL)
@@ -368,7 +368,7 @@ index_stream_init(lzma_vli compressed_base, lzma_vli uncompressed_base,
 
 /// Free the memory allocated for a Stream and its Record groups.
 static void
-index_stream_end(void *node, lzma_allocator *allocator)
+index_stream_end(void *node, const lzma_allocator *allocator)
 {
 	index_stream *s = node;
 	index_tree_end(&s->groups, allocator, NULL);
@@ -377,7 +377,7 @@ index_stream_end(void *node, lzma_allocator *allocator)
 
 
 static lzma_index *
-index_init_plain(lzma_allocator *allocator)
+index_init_plain(const lzma_allocator *allocator)
 {
 	lzma_index *i = lzma_alloc(sizeof(lzma_index), allocator);
 	if (i != NULL) {
@@ -395,7 +395,7 @@ index_init_plain(lzma_allocator *allocator)
 
 
 extern LZMA_API(lzma_index *)
-lzma_index_init(lzma_allocator *allocator)
+lzma_index_init(const lzma_allocator *allocator)
 {
 	lzma_index *i = index_init_plain(allocator);
 	if (i == NULL)
@@ -414,7 +414,7 @@ lzma_index_init(lzma_allocator *allocator)
 
 
 extern LZMA_API(void)
-lzma_index_end(lzma_index *i, lzma_allocator *allocator)
+lzma_index_end(lzma_index *i, const lzma_allocator *allocator)
 {
 	// NOTE: If you modify this function, check also the bottom
 	// of lzma_index_cat().
@@ -637,7 +637,7 @@ lzma_index_stream_padding(lzma_index *i, lzma_vli stream_padding)
 
 
 extern LZMA_API(lzma_ret)
-lzma_index_append(lzma_index *i, lzma_allocator *allocator,
+lzma_index_append(lzma_index *i, const lzma_allocator *allocator,
 		lzma_vli unpadded_size, lzma_vli uncompressed_size)
 {
 	// Validate.
@@ -765,7 +765,7 @@ index_cat_helper(const index_cat_info *info, index_stream *this)
 
 extern LZMA_API(lzma_ret)
 lzma_index_cat(lzma_index *restrict dest, lzma_index *restrict src,
-		lzma_allocator *allocator)
+		const lzma_allocator *allocator)
 {
 	const lzma_vli dest_file_size = lzma_index_file_size(dest);
 
@@ -859,7 +859,7 @@ lzma_index_cat(lzma_index *restrict dest, lzma_index *restrict src,
 
 /// Duplicate an index_stream.
 static index_stream *
-index_dup_stream(const index_stream *src, lzma_allocator *allocator)
+index_dup_stream(const index_stream *src, const lzma_allocator *allocator)
 {
 	// Catch a somewhat theoretical integer overflow.
 	if (src->record_count > PREALLOC_MAX)
@@ -919,7 +919,7 @@ index_dup_stream(const index_stream *src, lzma_allocator *allocator)
 
 
 extern LZMA_API(lzma_index *)
-lzma_index_dup(const lzma_index *src, lzma_allocator *allocator)
+lzma_index_dup(const lzma_index *src, const lzma_allocator *allocator)
 {
 	// Allocate the base structure (no initial Stream).
 	lzma_index *dest = index_init_plain(allocator);
diff --git a/src/liblzma/common/index_decoder.c b/src/liblzma/common/index_decoder.c
index 83c8a3af..795d1834 100644
--- a/src/liblzma/common/index_decoder.c
+++ b/src/liblzma/common/index_decoder.c
@@ -54,7 +54,7 @@ struct lzma_coder_s {
 
 
 static lzma_ret
-index_decode(lzma_coder *coder, lzma_allocator *allocator,
+index_decode(lzma_coder *coder, 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__)),
@@ -207,7 +207,7 @@ out:
 
 
 static void
-index_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+index_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	lzma_index_end(coder->index, allocator);
 	lzma_free(coder, allocator);
@@ -234,7 +234,7 @@ index_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
 
 
 static lzma_ret
-index_decoder_reset(lzma_coder *coder, lzma_allocator *allocator,
+index_decoder_reset(lzma_coder *coder, const lzma_allocator *allocator,
 		lzma_index **i, uint64_t memlimit)
 {
 	// Remember the pointer given by the application. We will set it
@@ -261,7 +261,7 @@ index_decoder_reset(lzma_coder *coder, lzma_allocator *allocator,
 
 
 static lzma_ret
-index_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+index_decoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		lzma_index **i, uint64_t memlimit)
 {
 	lzma_next_coder_init(&index_decoder_init, next, allocator);
@@ -299,8 +299,8 @@ lzma_index_decoder(lzma_stream *strm, lzma_index **i, uint64_t memlimit)
 
 
 extern LZMA_API(lzma_ret)
-lzma_index_buffer_decode(
-		lzma_index **i, uint64_t *memlimit, lzma_allocator *allocator,
+lzma_index_buffer_decode(lzma_index **i, uint64_t *memlimit,
+		const lzma_allocator *allocator,
 		const uint8_t *in, size_t *in_pos, size_t in_size)
 {
 	// Sanity checks
diff --git a/src/liblzma/common/index_encoder.c b/src/liblzma/common/index_encoder.c
index 45919f09..d25ac7d3 100644
--- a/src/liblzma/common/index_encoder.c
+++ b/src/liblzma/common/index_encoder.c
@@ -42,7 +42,7 @@ struct lzma_coder_s {
 
 static lzma_ret
 index_encode(lzma_coder *coder,
-		lzma_allocator *allocator lzma_attribute((__unused__)),
+		const lzma_allocator *allocator lzma_attribute((__unused__)),
 		const uint8_t *restrict in lzma_attribute((__unused__)),
 		size_t *restrict in_pos lzma_attribute((__unused__)),
 		size_t in_size lzma_attribute((__unused__)),
@@ -159,7 +159,7 @@ out:
 
 
 static void
-index_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
+index_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	lzma_free(coder, allocator);
 	return;
@@ -181,7 +181,7 @@ index_encoder_reset(lzma_coder *coder, const lzma_index *i)
 
 
 extern lzma_ret
-lzma_index_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+lzma_index_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_index *i)
 {
 	lzma_next_coder_init(&lzma_index_encoder_init, next, allocator);
diff --git a/src/liblzma/common/index_encoder.h b/src/liblzma/common/index_encoder.h
index a13c94dc..4d55cd10 100644
--- a/src/liblzma/common/index_encoder.h
+++ b/src/liblzma/common/index_encoder.h
@@ -17,7 +17,7 @@
 
 
 extern lzma_ret lzma_index_encoder_init(lzma_next_coder *next,
-		lzma_allocator *allocator, const lzma_index *i);
+		const lzma_allocator *allocator, const lzma_index *i);
 
 
 #endif
diff --git a/src/liblzma/common/index_hash.c b/src/liblzma/common/index_hash.c
index e3e9386a..d7a0344b 100644
--- a/src/liblzma/common/index_hash.c
+++ b/src/liblzma/common/index_hash.c
@@ -70,7 +70,8 @@ struct lzma_index_hash_s {
 
 
 extern LZMA_API(lzma_index_hash *)
-lzma_index_hash_init(lzma_index_hash *index_hash, lzma_allocator *allocator)
+lzma_index_hash_init(lzma_index_hash *index_hash,
+		const lzma_allocator *allocator)
 {
 	if (index_hash == NULL) {
 		index_hash = lzma_alloc(sizeof(lzma_index_hash), allocator);
@@ -101,7 +102,8 @@ lzma_index_hash_init(lzma_index_hash *index_hash, lzma_allocator *allocator)
 
 
 extern LZMA_API(void)
-lzma_index_hash_end(lzma_index_hash *index_hash, lzma_allocator *allocator)
+lzma_index_hash_end(lzma_index_hash *index_hash,
+		const lzma_allocator *allocator)
 {
 	lzma_free(index_hash, allocator);
 	return;
diff --git a/src/liblzma/common/outqueue.c b/src/liblzma/common/outqueue.c
index d7a87d9a..2dc8a38d 100644
--- a/src/liblzma/common/outqueue.c
+++ b/src/liblzma/common/outqueue.c
@@ -54,7 +54,7 @@ lzma_outq_memusage(uint64_t buf_size_max, uint32_t threads)
 
 
 extern lzma_ret
-lzma_outq_init(lzma_outq *outq, lzma_allocator *allocator,
+lzma_outq_init(lzma_outq *outq, const lzma_allocator *allocator,
 		uint64_t buf_size_max, uint32_t threads)
 {
 	uint64_t bufs_alloc_size;
@@ -98,7 +98,7 @@ lzma_outq_init(lzma_outq *outq, lzma_allocator *allocator,
 
 
 extern void
-lzma_outq_end(lzma_outq *outq, lzma_allocator *allocator)
+lzma_outq_end(lzma_outq *outq, const lzma_allocator *allocator)
 {
 	lzma_free(outq->bufs, allocator);
 	outq->bufs = NULL;
diff --git a/src/liblzma/common/outqueue.h b/src/liblzma/common/outqueue.h
index 154f91bc..079634de 100644
--- a/src/liblzma/common/outqueue.h
+++ b/src/liblzma/common/outqueue.h
@@ -87,12 +87,13 @@ extern uint64_t lzma_outq_memusage(uint64_t buf_size_max, uint32_t threads);
 /// \return     - LZMA_OK
 ///             - LZMA_MEM_ERROR
 ///
-extern lzma_ret lzma_outq_init(lzma_outq *outq, lzma_allocator *allocator,
+extern lzma_ret lzma_outq_init(
+		lzma_outq *outq, const lzma_allocator *allocator,
 		uint64_t buf_size_max, uint32_t threads);
 
 
 /// \brief      Free the memory associated with the output queue
-extern void lzma_outq_end(lzma_outq *outq, lzma_allocator *allocator);
+extern void lzma_outq_end(lzma_outq *outq, const lzma_allocator *allocator);
 
 
 /// \brief      Get a new buffer
diff --git a/src/liblzma/common/stream_buffer_decoder.c b/src/liblzma/common/stream_buffer_decoder.c
index ae753155..b9745b5d 100644
--- a/src/liblzma/common/stream_buffer_decoder.c
+++ b/src/liblzma/common/stream_buffer_decoder.c
@@ -15,7 +15,7 @@
 
 extern LZMA_API(lzma_ret)
 lzma_stream_buffer_decode(uint64_t *memlimit, uint32_t flags,
-		lzma_allocator *allocator,
+		const lzma_allocator *allocator,
 		const uint8_t *in, size_t *in_pos, size_t in_size,
 		uint8_t *out, size_t *out_pos, size_t out_size)
 {
diff --git a/src/liblzma/common/stream_buffer_encoder.c b/src/liblzma/common/stream_buffer_encoder.c
index 2450ee2e..af49554a 100644
--- a/src/liblzma/common/stream_buffer_encoder.c
+++ b/src/liblzma/common/stream_buffer_encoder.c
@@ -42,7 +42,8 @@ lzma_stream_buffer_bound(size_t uncompressed_size)
 
 extern LZMA_API(lzma_ret)
 lzma_stream_buffer_encode(lzma_filter *filters, lzma_check check,
-		lzma_allocator *allocator, const uint8_t *in, size_t in_size,
+		const lzma_allocator *allocator,
+		const uint8_t *in, size_t in_size,
 		uint8_t *out, size_t *out_pos_ptr, size_t out_size)
 {
 	// Sanity checks
diff --git a/src/liblzma/common/stream_decoder.c b/src/liblzma/common/stream_decoder.c
index 37ea71ed..5243e4c6 100644
--- a/src/liblzma/common/stream_decoder.c
+++ b/src/liblzma/common/stream_decoder.c
@@ -80,7 +80,7 @@ struct lzma_coder_s {
 
 
 static lzma_ret
-stream_decoder_reset(lzma_coder *coder, lzma_allocator *allocator)
+stream_decoder_reset(lzma_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);
@@ -96,7 +96,7 @@ stream_decoder_reset(lzma_coder *coder, lzma_allocator *allocator)
 
 
 static lzma_ret
-stream_decode(lzma_coder *coder, lzma_allocator *allocator,
+stream_decode(lzma_coder *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, lzma_action action)
@@ -366,7 +366,7 @@ stream_decode(lzma_coder *coder, lzma_allocator *allocator,
 
 
 static void
-stream_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
+stream_decoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	lzma_next_end(&coder->block_decoder, allocator);
 	lzma_index_hash_end(coder->index_hash, allocator);
@@ -401,7 +401,8 @@ stream_decoder_memconfig(lzma_coder *coder, uint64_t *memusage,
 
 
 extern lzma_ret
-lzma_stream_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+lzma_stream_decoder_init(
+		lzma_next_coder *next, const lzma_allocator *allocator,
 		uint64_t memlimit, uint32_t flags)
 {
 	lzma_next_coder_init(&lzma_stream_decoder_init, next, allocator);
diff --git a/src/liblzma/common/stream_decoder.h b/src/liblzma/common/stream_decoder.h
index e54ac28f..c13c6ba1 100644
--- a/src/liblzma/common/stream_decoder.h
+++ b/src/liblzma/common/stream_decoder.h
@@ -15,7 +15,8 @@
 
 #include "common.h"
 
-extern lzma_ret lzma_stream_decoder_init(lzma_next_coder *next,
-		lzma_allocator *allocator, uint64_t memlimit, uint32_t flags);
+extern lzma_ret lzma_stream_decoder_init(
+		lzma_next_coder *next, const lzma_allocator *allocator,
+		uint64_t memlimit, uint32_t flags);
 
 #endif
diff --git a/src/liblzma/common/stream_encoder.c b/src/liblzma/common/stream_encoder.c
index 2a975488..df072d91 100644
--- a/src/liblzma/common/stream_encoder.c
+++ b/src/liblzma/common/stream_encoder.c
@@ -59,7 +59,7 @@ struct lzma_coder_s {
 
 
 static lzma_ret
-block_encoder_init(lzma_coder *coder, lzma_allocator *allocator)
+block_encoder_init(lzma_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
@@ -78,7 +78,7 @@ block_encoder_init(lzma_coder *coder, lzma_allocator *allocator)
 
 
 static lzma_ret
-stream_encode(lzma_coder *coder, lzma_allocator *allocator,
+stream_encode(lzma_coder *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, lzma_action action)
@@ -208,7 +208,7 @@ stream_encode(lzma_coder *coder, lzma_allocator *allocator,
 
 
 static void
-stream_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
+stream_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	lzma_next_end(&coder->block_encoder, allocator);
 	lzma_next_end(&coder->index_encoder, allocator);
@@ -223,7 +223,7 @@ stream_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
 
 
 static lzma_ret
-stream_encoder_update(lzma_coder *coder, lzma_allocator *allocator,
+stream_encoder_update(lzma_coder *coder, const lzma_allocator *allocator,
 		const lzma_filter *filters,
 		const lzma_filter *reversed_filters)
 {
@@ -262,7 +262,7 @@ stream_encoder_update(lzma_coder *coder, lzma_allocator *allocator,
 
 
 static lzma_ret
-stream_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
+stream_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_filter *filters, lzma_check check)
 {
 	lzma_next_coder_init(&stream_encoder_init, next, allocator);
diff --git a/src/liblzma/common/stream_encoder_mt.c b/src/liblzma/common/stream_encoder_mt.c
index a4b28006..4c7e1bc2 100644
--- a/src/liblzma/common/stream_encoder_mt.c
+++ b/src/liblzma/common/stream_encoder_mt.c
@@ -69,7 +69,7 @@ struct worker_thread_s {
 	/// The allocator is set by the main thread. Since a copy of the
 	/// pointer is kept here, the application must not change the
 	/// allocator before calling lzma_end().
-	lzma_allocator *allocator;
+	const lzma_allocator *allocator;
 
 	/// Block encoder
 	lzma_next_coder block_encoder;
@@ -378,7 +378,7 @@ threads_stop(lzma_coder *coder, bool wait)
 /// Stop the threads and free the resources associated with them.
 /// Wait until the threads have exited.
 static void
-threads_end(lzma_coder *coder, lzma_allocator *allocator)
+threads_end(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	for (uint32_t i = 0; i < coder->threads_initialized; ++i) {
 		mythread_sync(coder->threads[i].mutex) {
@@ -400,7 +400,7 @@ threads_end(lzma_coder *coder, lzma_allocator *allocator)
 
 /// Initialize a new worker_thread structure and create a new thread.
 static lzma_ret
-initialize_new_thread(lzma_coder *coder, lzma_allocator *allocator)
+initialize_new_thread(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	worker_thread *thr = &coder->threads[coder->threads_initialized];
 
@@ -440,7 +440,7 @@ error_mutex:
 
 
 static lzma_ret
-get_thread(lzma_coder *coder, lzma_allocator *allocator)
+get_thread(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	// If there are no free output subqueues, there is no
 	// point to try getting a thread.
@@ -478,7 +478,7 @@ get_thread(lzma_coder *coder, lzma_allocator *allocator)
 
 
 static lzma_ret
-stream_encode_in(lzma_coder *coder, lzma_allocator *allocator,
+stream_encode_in(lzma_coder *coder, const lzma_allocator *allocator,
 		const uint8_t *restrict in, size_t *restrict in_pos,
 		size_t in_size, lzma_action action)
 {
@@ -593,7 +593,7 @@ wait_for_work(lzma_coder *coder, struct timespec *wait_abs,
 
 
 static lzma_ret
-stream_encode_mt(lzma_coder *coder, lzma_allocator *allocator,
+stream_encode_mt(lzma_coder *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, lzma_action action)
@@ -735,7 +735,7 @@ stream_encode_mt(lzma_coder *coder, lzma_allocator *allocator,
 
 
 static void
-stream_encoder_mt_end(lzma_coder *coder, lzma_allocator *allocator)
+stream_encoder_mt_end(lzma_coder *coder, const lzma_allocator *allocator)
 {
 	// Threads must be killed before the output queue can be freed.
 	threads_end(coder, allocator);
@@ -811,7 +811,7 @@ get_options(const lzma_mt *options, lzma_options_easy *opt_easy,
 
 
 static lzma_ret
-stream_encoder_mt_init(lzma_next_coder *next, lzma_allocator *allocator,
+stream_encoder_mt_init(lzma_next_coder *next, const lzma_allocator *allocator,
 		const lzma_mt *options)
 {
 	lzma_next_coder_init(&stream_encoder_mt_init, next, allocator);