Add optional padding data at the end to the bit source (is that the right place?...

[fjl] / dehuff.h

diff --git a/dehuff.h b/dehuff.h
index 69fc798ddd1f426186576e971126101734531b94..a6a431a8139440a7052ce1dadd39b182ee5566b4 100644 (file)
--- a/dehuff.h
+++ b/dehuff.h
@@ -51,9 +51,8 @@ unsigned read_huffman_symbol_slow_path(const struct huffman_table* table,
 static inline unsigned read_huffman_symbol(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];
@@ -61,7 +60,7 @@ 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;
 }
@@ -72,7 +71,7 @@ static inline unsigned read_huffman_symbol(const struct huffman_table* table,
 // 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)