xpress_compress(): Initialize all data written

[wimlib] / src / comp.c

diff --git a/src/comp.c b/src/comp.c
index 7837a4614629f8b33fcde74051f676b76e7d220a..559abbe4016a57801f7f089914dd33c73656be0c 100644 (file)
--- a/src/comp.c
+++ b/src/comp.c
@@ -38,7 +38,7 @@ static inline void flush_bits(struct output_bitstream *ostream)
 
 /* Writes @num_bits bits, given by the @num_bits least significant bits of
  * @bits, to the output @ostream. */
-int bitstream_put_bits(struct output_bitstream *ostream, output_bitbuf_t bits, 
+int bitstream_put_bits(struct output_bitstream *ostream, output_bitbuf_t bits,
                       uint num_bits)
 {
        uint rem_bits;
@@ -49,7 +49,7 @@ int bitstream_put_bits(struct output_bitstream *ostream, output_bitbuf_t bits,
                ostream->free_bits -= num_bits;
        } else {
 
-               if (ostream->num_bytes_remaining + (ostream->output - 
+               if (ostream->num_bytes_remaining + (ostream->output -
                                                ostream->bit_output) < 2)
                        return 1;
 
@@ -75,7 +75,7 @@ int bitstream_put_bits(struct output_bitstream *ostream, output_bitbuf_t bits,
 /* Flushes any remaining bits in the output buffer to the output byte stream. */
 int flush_output_bitstream(struct output_bitstream *ostream)
 {
-       if (ostream->num_bytes_remaining + (ostream->output - 
+       if (ostream->num_bytes_remaining + (ostream->output -
                                        ostream->bit_output) < 2)
                return 1;
        if (ostream->free_bits != 16) {
@@ -87,9 +87,11 @@ int flush_output_bitstream(struct output_bitstream *ostream)
 
 /* Initializes an output bit buffer to write its output to the memory location
  * pointer to by @data. */
-void init_output_bitstream(struct output_bitstream *ostream, void *data, 
+void init_output_bitstream(struct output_bitstream *ostream, void *data,
                           uint num_bytes)
 {
+       wimlib_assert(num_bytes >= 4);
+
        ostream->bitbuf              = 0;
        ostream->free_bits           = 16;
        ostream->bit_output          = (u8*)data;
@@ -166,7 +168,7 @@ static void huffman_tree_compute_path_lengths(HuffmanNode *node, u16 cur_len)
        }
 }
 
-/* Creates a canonical Huffman code from an array of symbol frequencies. 
+/* Creates a canonical Huffman code from an array of symbol frequencies.
  *
  * The algorithm used is similar to the well-known algorithm that builds a
  * Huffman tree using a minheap.  In that algorithm, the leaf nodes are
@@ -217,12 +219,12 @@ static void huffman_tree_compute_path_lengths(HuffmanNode *node, u16 cur_len)
  *                     codewords for each symbol will be written.
  *
  * @codewords:    An array of @num_syms short integers into which the
- *                     codewords for each symbol will be written.  The first 
- *                     lens[i] bits of codewords[i] will contain the codeword 
+ *                     codewords for each symbol will be written.  The first
+ *                     lens[i] bits of codewords[i] will contain the codeword
  *                     for symbol i.
  */
-void make_canonical_huffman_code(uint num_syms, uint max_codeword_len, 
-                                const u32 freq_tab[], u8 lens[], 
+void make_canonical_huffman_code(uint num_syms, uint max_codeword_len,
+                                const u32 freq_tab[], u8 lens[],
                                 u16 codewords[])
 {
        /* We require at least 2 possible symbols in the alphabet to produce a
@@ -301,7 +303,7 @@ void make_canonical_huffman_code(uint num_syms, uint max_codeword_len,
         * most num_used_symbols - 1 intermediate nodes when creating a Huffman
         * code.  This is because if there were at least num_used_symbols nodes,
         * the code would be suboptimal because there would be at least one
-        * unnecessary intermediate node.  
+        * unnecessary intermediate node.
         *
         * The worst case (greatest number of intermediate nodes) would be if
         * all the intermediate nodes were chained together.  This results in
@@ -348,7 +350,7 @@ try_building_tree_again:
        while (1) {
 
                /* Lowest frequency node. */
-               HuffmanNode *f1 = NULL; 
+               HuffmanNode *f1 = NULL;
 
                /* Second lowest frequency node. */
                HuffmanNode *f2 = NULL;
@@ -357,14 +359,14 @@ try_building_tree_again:
                 * the remaining leaves or from the intermediate nodes.
                 * */
 
-               if (cur_leaf != end_leaf && (cur_inode == next_inode || 
+               if (cur_leaf != end_leaf && (cur_inode == next_inode ||
                                        cur_leaf->freq <= cur_inode->freq)) {
                        f1 = (HuffmanNode*)cur_leaf++;
                } else if (cur_inode != next_inode) {
                        f1 = cur_inode++;
                }
 
-               if (cur_leaf != end_leaf && (cur_inode == next_inode || 
+               if (cur_leaf != end_leaf && (cur_inode == next_inode ||
                                        cur_leaf->freq <= cur_inode->freq)) {
                        f2 = (HuffmanNode*)cur_leaf++;
                } else if (cur_inode != next_inode) {
@@ -403,7 +405,7 @@ try_building_tree_again:
                                if (leaves[i].freq > 1)
                                        leaves[i].freq >>= 1;
                        goto try_building_tree_again;
-               } 
+               }
                next_inode++;
        }