X-Git-Url: https://wimlib.net/git/?a=blobdiff_plain;f=src%2Fxpress-compress.c;h=21118e7652b2e17d2287c085cc7e571c4bf88c3c;hb=34a91e36924e10b924117d91acd116ade58df0b4;hp=6d2836f050e6b3b02f86c3b0b3c6410a2324d292;hpb=a3bb2e86f2640f5d593d00250a627d3dcc9747a2;p=wimlib

diff --git a/src/xpress-compress.c b/src/xpress-compress.c
index 6d2836f0..21118e76 100644
--- a/src/xpress-compress.c
+++ b/src/xpress-compress.c
@@ -26,7 +26,9 @@
  */
 
 #include "xpress.h"
+#include "wimlib.h"
 #include "compress.h"
+
 #include <stdlib.h>
 #include <string.h>
 
@@ -139,28 +141,11 @@ static const struct lz_params xpress_lz_params = {
 	.too_far        = 4096,
 };
 
-/*
- * Performs XPRESS compression on a block of data.
- *
- * @__uncompressed_data:  Pointer to the data to be compressed.
- * @uncompressed_len:	Length, in bytes, of the data to be compressed.
- * @__compressed_data:	Pointer to a location at least (@uncompressed_len - 1)
- * 				bytes long into which the compressed data may be
- * 				written.
- * @compressed_len_ret:	A pointer to an unsigned int into which the length of
- * 				the compressed data may be returned.
- *
- * Returns zero if compression was successfully performed.  In that case
- * @compressed_data and @compressed_len_ret will contain the compressed data and
- * its length.  A return value of nonzero means that compressing the data did
- * not reduce its size, and @compressed_data will not contain the full
- * compressed data.
- */
-int
-xpress_compress(const void *__uncompressed_data, unsigned uncompressed_len,
-		void *__compressed_data, unsigned *compressed_len_ret)
+/* Documented in wimlib.h */
+WIMLIBAPI unsigned
+wimlib_xpress_compress(const void *__uncompressed_data,
+		       unsigned uncompressed_len, void *__compressed_data)
 {
-	const u8 *uncompressed_data = __uncompressed_data;
 	u8 *compressed_data = __compressed_data;
 	struct output_bitstream ostream;
 	u32 match_tab[uncompressed_len];
@@ -171,6 +156,12 @@ xpress_compress(const void *__uncompressed_data, unsigned uncompressed_len,
 	unsigned compressed_len;
 	unsigned i;
 	int ret;
+	u8 uncompressed_data[uncompressed_len + 8];
+
+	memcpy(uncompressed_data, __uncompressed_data, uncompressed_len);
+	memset(uncompressed_data + uncompressed_len, 0, 8);
+
+	wimlib_assert(uncompressed_len <= 32768);
 
 	/* XPRESS requires 256 bytes of overhead for the Huffman tables, so it's
 	 * impossible cannot compress 256 bytes or less of data to less than the
@@ -182,7 +173,7 @@ xpress_compress(const void *__uncompressed_data, unsigned uncompressed_len,
 	 * +4 to take into account that init_output_bitstream() requires at
 	 * least 4 bytes of data. */
 	if (uncompressed_len < XPRESS_NUM_SYMBOLS / 2 + 1 + 4)
-		return 1;
+		return 0;
 
 	ZERO_ARRAY(freq_tab);
 	num_matches = lz_analyze_block(uncompressed_data, uncompressed_len,
@@ -216,13 +207,13 @@ xpress_compress(const void *__uncompressed_data, unsigned uncompressed_len,
 
 	ret = xpress_write_compressed_literals(&ostream, match_tab,
 					       num_matches, codewords, lens);
-	if (ret != 0)
-		return ret;
+	if (ret)
+		return 0;
 
 	/* Flush any bits that are buffered. */
 	ret = flush_output_bitstream(&ostream);
-	if (ret != 0)
-		return ret;
+	if (ret)
+		return 0;
 
 	/* Assert that there are no output bytes between the ostream.output
 	 * pointer and the ostream.next_bit_output pointer.  This can only
@@ -242,20 +233,18 @@ xpress_compress(const void *__uncompressed_data, unsigned uncompressed_len,
 	 * they may precede a number of bytes embedded into the bitstream.) */
 	if (ostream.bit_output >
 	    (const u8*)__compressed_data + uncompressed_len - 3)
-		return 1;
+		return 0;
 	*(u16*)ostream.bit_output = cpu_to_le16(0);
 	compressed_len = ostream.next_bit_output - (const u8*)__compressed_data;
 
 	wimlib_assert(compressed_len <= uncompressed_len - 1);
 
-	*compressed_len_ret = compressed_len;
-
 #ifdef ENABLE_VERIFY_COMPRESSION
 	/* Verify that we really get the same thing back when decompressing. */
 	u8 buf[uncompressed_len];
-	ret = xpress_decompress(__compressed_data, compressed_len, buf,
-				uncompressed_len);
-	if (ret != 0) {
+	ret = wimlib_xpress_decompress(__compressed_data, compressed_len,
+				       buf, uncompressed_len);
+	if (ret) {
 		ERROR("xpress_compress(): Failed to decompress data we "
 		      "compressed");
 		abort();
@@ -269,5 +258,5 @@ xpress_compress(const void *__uncompressed_data, unsigned uncompressed_len,
 		}
 	}
 #endif
-	return 0;
+	return compressed_len;
 }