X-Git-Url: https://git.sesse.net/?p=fjl;a=blobdiff_plain;f=dehuff.h;h=9243e101530018b346e80e2db8b64b96dee1db61;hp=69fc798ddd1f426186576e971126101734531b94;hb=8389f95d5750d6fcb202181005954829e64865b4;hpb=fc9f7affda0b0141099f8e91c1a36ddceed8319c

diff --git a/dehuff.h b/dehuff.h
index 69fc798..9243e10 100644
--- a/dehuff.h
+++ b/dehuff.h
@@ -48,12 +48,11 @@ void read_huffman_tables(huffman_tables_t* dst, input_func_t* input_func, void*
 unsigned read_huffman_symbol_slow_path(const struct huffman_table* table,
                                        struct bit_source* source);
 
-static inline unsigned read_huffman_symbol(const struct huffman_table* table,
-                                           struct bit_source* source)
+static inline unsigned read_huffman_symbol_no_refill(
+	const struct huffman_table* table,
+	struct bit_source* source)
 {
-	// FIXME: We can read past the end of the stream here in some edge
-	// cases. We need to define some guarantees in the layers above.
-	possibly_refill(source, DEHUF_TABLE_BITS);
+	assert(source->bits_available >= DEHUF_TABLE_BITS);
 	unsigned lookup = peek_bits(source, DEHUF_TABLE_BITS);
 	int code = table->lookup_table_codes[lookup];
 	int length = table->lookup_table_length[lookup];
@@ -61,18 +60,25 @@ static inline unsigned read_huffman_symbol(const struct huffman_table* table,
 	if (code == DEHUF_SLOW_PATH) {
 		return read_huffman_symbol_slow_path(table, source);
 	}
-
+		
 	read_bits(source, length);
 	return code;
 }
 
+static inline unsigned read_huffman_symbol(const struct huffman_table* table,
+                                           struct bit_source* source)
+{
+	possibly_refill(source, DEHUF_TABLE_BITS);
+	return read_huffman_symbol_no_refill(table, source);
+}
+
 // procedure EXTEND (figure F.12)
 
 // Fast lookup table for (1 << (bits - 1)).
 // The table actually helps, since the load can go in parallel with the shift
 // operation below.
 static const int bit_thresholds[16] = {
-	0, 1 << 0, 1 << 2, 1 << 3, 1 << 4, 1 << 5, 1 << 6, 1 << 7, 1 << 8, 1 << 9, 1 << 10, 1 << 11, 1 << 12, 1 << 13, 1 << 14, 1 << 15
+	0, 1 << 0, 1 << 1, 1 << 2, 1 << 3, 1 << 4, 1 << 5, 1 << 6, 1 << 7, 1 << 8, 1 << 9, 1 << 10, 1 << 11, 1 << 12, 1 << 13, 1 << 14
 };
 
 static inline unsigned extend(int val, int bits)