liblzma: Similar memlimit fix for stream_, alone_, and auto_decoder.

src/liblzma/api/lzma/container.h

@@ -520,7 +520,10 @@
  *
  * \param       strm        Pointer to properly prepared lzma_stream
  * \param       memlimit    Memory usage limit as bytes. Use UINT64_MAX
- *                          to effectively disable the limiter.
+ *                          to effectively disable the limiter. liblzma
+ *                          5.2.3 and earlier don't allow 0 here and return
+ *                          LZMA_PROG_ERROR; later versions treat 0 as if 1
+ *                          had been specified.
  * \param       flags       Bitwise-or of zero or more of the decoder flags:
  *                          LZMA_TELL_NO_CHECK, LZMA_TELL_UNSUPPORTED_CHECK,
  *                          LZMA_TELL_ANY_CHECK, LZMA_CONCATENATED
@@ -544,7 +547,10 @@
  *
  * \param       strm        Pointer to properly prepared lzma_stream
  * \param       memlimit    Memory usage limit as bytes. Use UINT64_MAX
- *                          to effectively disable the limiter.
+ *                          to effectively disable the limiter. liblzma
+ *                          5.2.3 and earlier don't allow 0 here and return
+ *                          LZMA_PROG_ERROR; later versions treat 0 as if 1
+ *                          had been specified.
  * \param       flags       Bitwise-or of flags, or zero for no flags.
  *
  * \return      - LZMA_OK: Initialization was successful.
@@ -560,4 +566,11 @@
 /**
  * \brief       Initialize .lzma decoder (legacy file format)
  *
+ * \param       strm        Pointer to properly prepared lzma_stream
+ * \param       memlimit    Memory usage limit as bytes. Use UINT64_MAX
+ *                          to effectively disable the limiter. liblzma
+ *                          5.2.3 and earlier don't allow 0 here and return
+ *                          LZMA_PROG_ERROR; later versions treat 0 as if 1
+ *                          had been specified.
+ *
  * Valid `action' arguments to lzma_code() are LZMA_RUN and LZMA_FINISH.
@@ -563,6 +576,6 @@
  * Valid `action' arguments to lzma_code() are LZMA_RUN and LZMA_FINISH.
- * There is no need to use LZMA_FINISH, but allowing it may simplify
- * certain types of applications.
+ * There is no need to use LZMA_FINISH, but it's allowed because it may
+ * simplify certain types of applications.
  *
  * \return      - LZMA_OK
  *              - LZMA_MEM_ERROR

src/liblzma/common/alone_decoder.c

@@ -203,9 +203,6 @@
 {
 	lzma_next_coder_init(&lzma_alone_decoder_init, next, allocator);
 
-	if (memlimit == 0)
-		return LZMA_PROG_ERROR;
-
 	lzma_alone_coder *coder = next->coder;
 
 	if (coder == NULL) {
@@ -227,7 +224,7 @@
 	coder->options.preset_dict = NULL;
 	coder->options.preset_dict_size = 0;
 	coder->uncompressed_size = 0;
-	coder->memlimit = memlimit;
+	coder->memlimit = my_max(1, memlimit);
 	coder->memusage = LZMA_MEMUSAGE_BASE;
 
 	return LZMA_OK;

src/liblzma/common/auto_decoder.c

@@ -155,9 +155,6 @@
 {
 	lzma_next_coder_init(&auto_decoder_init, next, allocator);
 
-	if (memlimit == 0)
-		return LZMA_PROG_ERROR;
-
 	if (flags & ~LZMA_SUPPORTED_FLAGS)
 		return LZMA_OPTIONS_ERROR;
 
@@ -175,7 +172,7 @@
 		coder->next = LZMA_NEXT_CODER_INIT;
 	}
 
-	coder->memlimit = memlimit;
+	coder->memlimit = my_max(1, memlimit);
 	coder->flags = flags;
 	coder->sequence = SEQ_INIT;
 

src/liblzma/common/stream_decoder.c

@@ -422,9 +422,6 @@
 {
 	lzma_next_coder_init(&lzma_stream_decoder_init, next, allocator);
 
-	if (memlimit == 0)
-		return LZMA_PROG_ERROR;
-
 	if (flags & ~LZMA_SUPPORTED_FLAGS)
 		return LZMA_OPTIONS_ERROR;
 
@@ -444,7 +441,7 @@
 		coder->index_hash = NULL;
 	}
 
-	coder->memlimit = memlimit;
+	coder->memlimit = my_max(1, memlimit);
 	coder->memusage = LZMA_MEMUSAGE_BASE;
 	coder->tell_no_check = (flags & LZMA_TELL_NO_CHECK) != 0;
 	coder->tell_unsupported_check