Add limit of lc + lp <= 4. Now we can allocate the

literal coder as part of the main LZMA encoder or
decoder structure.

Make the LZMA decoder to rely on the current internal API
to free the allocated memory in case an error occurs.

1 files changed, 14 insertions, 43 deletions

diff --git a/src/liblzma/lzma/lzma_decoder.c b/src/liblzma/lzma/lzma_decoder.c
index d4cefe0b..68941021 100644
--- a/src/liblzma/lzma/lzma_decoder.c
+++ b/src/liblzma/lzma/lzma_decoder.c
@@ -115,7 +115,7 @@ struct lzma_coder_s {
 	uint32_t pos_mask;
 	uint32_t now_pos; // Lowest 32-bits are enough here.
 
-	lzma_literal_coder *literal_coder;
+	lzma_literal_coder literal_coder;
 
 	/// If 1, it's a match. Otherwise it's a single 8-bit literal.
 	probability is_match[STATES][POS_STATES_MAX];
@@ -651,7 +651,6 @@ lzma_decoder_end(lzma_coder *coder, lzma_allocator *allocator)
 {
 	lzma_next_coder_end(&coder->next, allocator);
 	lzma_lz_decoder_end(&coder->lz, allocator);
-	lzma_literal_end(&coder->literal_coder, allocator);
 	lzma_free(coder, allocator);
 	return;
 }
@@ -661,6 +660,9 @@ extern lzma_ret
 lzma_lzma_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
 		const lzma_filter_info *filters)
 {
+	// LZMA can only be the last filter in the chain.
+	assert(filters[1].init == NULL);
+
 	// Validate pos_bits. Other options are validated by the
 	// respective initialization functions.
 	const lzma_options_lzma *options = filters[0].options;
@@ -673,43 +675,25 @@ lzma_lzma_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
 		if (next->coder == NULL)
 			return LZMA_MEM_ERROR;
 
-		// Initialize variables so that we know later that we don't
-		// have an existing decoder initialized.
+		next->code = &lzma_lz_decode;
+		next->end = &lzma_decoder_end;
 		next->coder->next = LZMA_NEXT_CODER_INIT;
 		next->coder->lz = LZMA_LZ_DECODER_INIT;
-		next->coder->literal_coder = NULL;
 	}
 
 	// Store the pos_bits and calculate pos_mask.
 	next->coder->pos_bits = options->pos_bits;
 	next->coder->pos_mask = (1U << next->coder->pos_bits) - 1;
 
-	// Allocate (if needed) and initialize the literal decoder.
-	{
-		const lzma_ret ret = lzma_literal_init(
-				&next->coder->literal_coder, allocator,
+	// Initialize the literal decoder.
+	return_if_error(lzma_literal_init(&next->coder->literal_coder,
 				options->literal_context_bits,
-				options->literal_pos_bits);
-		if (ret != LZMA_OK) {
-			lzma_free(next->coder, allocator);
-			next->coder = NULL;
-			return ret;
-		}
-	}
+				options->literal_pos_bits));
 
 	// Allocate and initialize the LZ decoder.
-	{
-		const lzma_ret ret = lzma_lz_decoder_reset(
-				&next->coder->lz, allocator, &decode_real,
-				options->dictionary_size, MATCH_MAX_LEN);
-		if (ret != LZMA_OK) {
-			lzma_literal_end(&next->coder->literal_coder,
-					allocator);
-			lzma_free(next->coder, allocator);
-			next->coder = NULL;
-			return ret;
-		}
-	}
+	return_if_error(lzma_lz_decoder_reset(&next->coder->lz, allocator,
+			&decode_real, options->dictionary_size,
+			MATCH_MAX_LEN));
 
 	// State
 	next->coder->state = 0;
@@ -769,20 +753,6 @@ lzma_lzma_decoder_init(lzma_next_coder *next, lzma_allocator *allocator,
 
 	next->coder->has_produced_output = false;
 
-	// Initialize the next decoder in the chain, if any.
-	{
-		const lzma_ret ret = lzma_next_filter_init(&next->coder->next,
-				allocator, filters + 1);
-		if (ret != LZMA_OK) {
-			lzma_decoder_end(next->coder, allocator);
-			return ret;
-		}
-	}
-
-	// Initialization successful. Set the function pointers.
-	next->code = &lzma_lz_decode;
-	next->end = &lzma_decoder_end;
-
 	return LZMA_OK;
 }
 
@@ -808,5 +778,6 @@ lzma_lzma_decode_properties(lzma_options_lzma *options, uint8_t byte)
 	options->literal_pos_bits = byte / 9;
 	options->literal_context_bits = byte - options->literal_pos_bits * 9;
 
-	return false;
+	return options->literal_context_bits + options->literal_pos_bits
+			> LZMA_LITERAL_BITS_MAX;
 }