Refactor headers

[wimlib] / include / wimlib / compress.h

diff --git a/include/wimlib/compress.h b/include/wimlib/compress.h
new file mode 100644 (file)
index 0000000..764eee7
--- /dev/null
+++ b/include/wimlib/compress.h
@@ -0,0 +1,99 @@
+/*
+ * compress.h
+ *
+ * Functions useful for compression, mainly bitstreams.
+ */
+
+#ifndef _WIMLIB_COMPRESS_H
+#define _WIMLIB_COMPRESS_H
+
+#include "wimlib/endianness.h"
+#include "wimlib/types.h"
+
+typedef u16 output_bitbuf_t;
+
+/* Assuming that WIM chunks are at most 32768 bytes, 16 bits is enough for any
+ * symbol frequency. */
+typedef u16 freq_t;
+
+/* Structure to keep track of the current position in the compressed output. */
+struct output_bitstream {
+
+       /* A variable to buffer writing bits to the output and is flushed to the
+        * compressed output when full. */
+       output_bitbuf_t bitbuf;
+
+       /* Number of free bits in @bitbuf */
+       unsigned free_bits;
+
+       u8 *bit_output;
+       u8 *next_bit_output;
+
+       /* Pointer to the next byte in the compressed output. */
+       u8 *output;
+
+
+       /* Number of bytes left in the memory pointed to by @output. */
+       int num_bytes_remaining;
+};
+
+static inline int bitstream_put_byte(struct output_bitstream *ostream,
+                                    u8 n)
+{
+       if (ostream->num_bytes_remaining < 1)
+               return 1;
+       *ostream->output = n;
+       ostream->output++;
+       ostream->num_bytes_remaining--;
+       return 0;
+}
+
+static inline int bitstream_put_two_bytes(struct output_bitstream *ostream,
+                                         u16 n)
+{
+       if (ostream->num_bytes_remaining < 2)
+               return 1;
+       *(u16*)ostream->output = cpu_to_le16(n);
+       ostream->output += 2;
+       ostream->num_bytes_remaining -= 2;
+       return 0;
+}
+
+struct lz_params {
+       unsigned min_match;
+       unsigned max_match;
+       unsigned nice_match;
+       unsigned good_match;
+       unsigned max_chain_len;
+       unsigned max_lazy_match;
+       unsigned too_far;
+};
+
+typedef unsigned (*lz_record_match_t)(unsigned, unsigned, void *, void *);
+typedef unsigned (*lz_record_literal_t)(u8, void *);
+
+extern unsigned lz_analyze_block(const u8 uncompressed_data[],
+                                unsigned uncompressed_len,
+                                u32 match_tab[],
+                                lz_record_match_t record_match,
+                                lz_record_literal_t record_literal,
+                                void *record_match_arg1,
+                                void *record_match_arg2,
+                                void *record_literal_arg,
+                                const struct lz_params *params);
+
+extern int bitstream_put_bits(struct output_bitstream *ostream,
+                             output_bitbuf_t bits, unsigned num_bits);
+
+extern void init_output_bitstream(struct output_bitstream *ostream,
+                                 void *data, unsigned num_bytes);
+
+extern int flush_output_bitstream(struct output_bitstream *ostream);
+
+extern void make_canonical_huffman_code(unsigned num_syms,
+                                       unsigned max_codeword_len,
+                                       const freq_t freq_tab[],
+                                       u8 lens[],
+                                       u16 codewords[]);
+
+#endif /* _WIMLIB_COMPRESS_H */