X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=include%2Fwimlib.h;h=d5194c17b71cba7b338c088df30c4d4c8990dd8e;hp=081dfca845aee487e5a2f64ec9df9e1db52abb84;hb=2254a0fc3f1d7af1151ee83f3458f44339b5028b;hpb=2159b8808998d2a75380ef6339147e48a39e3bae
diff --git a/include/wimlib.h b/include/wimlib.h
index 081dfca8..d5194c17 100644
--- a/include/wimlib.h
+++ b/include/wimlib.h
@@ -1501,6 +1501,13 @@ typedef int (*wimlib_iterate_lookup_table_callback_t)(const struct wimlib_resour
* already implied for wimlib_overwrite(). */
#define WIMLIB_WRITE_FLAG_STREAMS_OK 0x00000400
+/** Use the slow LZX compression algorithm (rather than the default fast LZX
+ * compression algorithm) to try to achieve a higher compression ratio. Only
+ * has an effect if the WIM uses LZX compression; not to be confused with "fast"
+ * (XPRESS) compression. This can be combined with
+ * ::WIMLIB_WRITE_FLAG_RECOMPRESS. */
+#define WIMLIB_WRITE_FLAG_COMPRESS_SLOW 0x00000800
+
/** @} */
/** @ingroup G_general
* @{ */
@@ -1642,6 +1649,97 @@ struct wimlib_extract_command {
int extract_flags;
};
+/** @} */
+/** @ingroup G_compression
+ * @{ */
+
+/** LZX compression parameters to pass to wimlib_lzx_alloc_context(). */
+struct wimlib_lzx_params {
+ /** Must be set to the size of this structure, in bytes. */
+ uint32_t size_of_this;
+
+ /** Relatively fast LZX compression algorithm with a decent compression
+ * ratio; the suggested default. */
+#define WIMLIB_LZX_ALGORITHM_FAST 0
+
+ /** Slower LZX compression algorithm that provides a better compression
+ * ratio. */
+#define WIMLIB_LZX_ALGORITHM_SLOW 1
+
+ /** Algorithm to use to perform the compression: either
+ * ::WIMLIB_LZX_ALGORITHM_FAST or ::WIMLIB_LZX_ALGORITHM_SLOW. The
+ * format is still LZX; this refers to the method the code will use to
+ * perform LZX-compatible compression. */
+ uint32_t algorithm : 3;
+
+ /** If set to 1, the default parameters for the specified algorithm are
+ * used rather than the ones specified in the following union. */
+ uint32_t use_defaults : 1;
+
+ union {
+ /** Parameters for the fast algorithm. */
+ struct wimlib_lzx_fast_params {
+ uint32_t fast_reserved1[10];
+ } fast;
+
+ /** Parameters for the slow algorithm. */
+ struct wimlib_lzx_slow_params {
+ /** If set to 1, the compressor can output length 2
+ * matches. If set 0, the compressor only outputs
+ * matches of length 3 or greater. Suggested value: 1
+ */
+ uint32_t use_len2_matches : 1;
+
+ uint32_t slow_reserved1 : 31;
+
+ /** This is the maximum match length to return from the
+ * binary tree match-finder. Any match reaching this
+ * limit is still extended as far as possible. Must be
+ * at least 3 and no more than 257. Suggested value:
+ * 32. */
+ uint32_t num_fast_bytes;
+
+ /** Number of passes to compute a match/literal sequence
+ * for each LZX block. This is for an iterative
+ * algorithm that attempts to minimize the cost of the
+ * match/literal sequence by using a cost model provided
+ * by the previous iteration. Must be at least 1.
+ * Suggested value: 3. */
+ uint32_t num_optim_passes;
+
+ /** The number of times to attempt to recursively split
+ * each LZX block. Up to (2**(num_split_passes)
+ * sub-blocks can be created for a given input. This
+ * parameter can be 0, in which case the full input is
+ * always output as one block. Suggested value: 3.
+ */
+ uint32_t num_split_passes;
+
+ uint32_t slow_reserved2[4];
+
+ /** Assumed cost of a main symbol with zero frequency.
+ * Must be at least 1 and no more than 16. Suggested
+ * value: 15. */
+ uint8_t main_nostat_cost;
+
+ /** Assumed cost of a length symbol with zero frequency.
+ * Must be at least 1 and no more than 16. Suggested
+ * value: 15. */
+ uint8_t len_nostat_cost;
+
+ /** Assumed cost of an aligned symbol with zero
+ * frequency. Must be at least 1 and no more than 8.
+ * Suggested value: 7. */
+ uint8_t aligned_nostat_cost;
+
+ uint8_t slow_reserved3[5];
+ } slow;
+ };
+};
+
+/** Opaque LZX compression context. */
+struct wimlib_lzx_context;
+
/** @} */
/** @ingroup G_general
* @{ */
@@ -2614,6 +2712,56 @@ wimlib_join(const wimlib_tchar * const *swms,
extern unsigned
wimlib_lzx_compress(const void *chunk, unsigned chunk_size, void *out);
+/**
+ * @ingroup G_compression
+ *
+ * Equivalent to wimlib_lzx_compress(), but uses the specified compression
+ * context, allocated by wimlib_lzx_alloc_context().
+ */
+extern unsigned
+wimlib_lzx_compress2(const void *chunk, unsigned chunk_size, void *out,
+ struct wimlib_lzx_context *ctx);
+
+/**
+ * @ingroup G_compression
+ *
+ * Allocate a LZX compression context using the specified parameters.
+ *
+ * This function is exported for convenience only and should only be used by
+ * library clients looking to make use of wimlib's compression code for another
+ * purpose.
+ *
+ * @param params
+ * Compression parameters to use, or @c NULL to use the default algorithm
+ * and parameters.
+ *
+ * @param ctx_ret
+ * A pointer to either @c NULL or an existing ::wimlib_lzx_context. If
+ * *ctx_ret == NULL, the new context is allocated. If
+ * *ctx_ret != NULL, the existing context is re-used if
+ * possible. Alternatively, this argument can itself be @c NULL to
+ * indicate that only parameter validation is to be performed.
+ *
+ * @return 0 on success; nonzero on error.
+ *
+ * @retval ::WIMLIB_ERR_INVALID_PARAM
+ * The compression parameters were invalid.
+ * @retval ::WIMLIB_ERR_NOMEM
+ * Not enough memory to allocate the compression context.
+ */
+extern int
+wimlib_lzx_alloc_context(const struct wimlib_lzx_params *params,
+ struct wimlib_lzx_context **ctx_pp);
+
+/**
+ * @ingroup G_compression
+ *
+ * Free the specified LZX compression context, allocated with
+ * wimlib_lzx_alloc_context().
+ */
+extern void
+wimlib_lzx_free_context(struct wimlib_lzx_context *ctx);
+
/**
* @ingroup G_compression
*