X-Git-Url: https://wimlib.net/git/?p=wimlib;a=blobdiff_plain;f=src%2Flzx-compress.c;h=b23c2df088642ce2d9001ebeba130d8fbba504d8;hp=9a654b2d796586d1177adf234ff04b785e0d268f;hb=2a94ebd67e2a341208c4849a92442ecd511fb716;hpb=a3bb2e86f2640f5d593d00250a627d3dcc9747a2

diff --git a/src/lzx-compress.c b/src/lzx-compress.c
index 9a654b2d..b23c2df0 100644
--- a/src/lzx-compress.c
+++ b/src/lzx-compress.c
@@ -27,8 +27,8 @@
 
 
 /*
- * This file provides lzx_compress(), a function to compress an in-memory buffer
- * of data using LZX compression, as used in the WIM file format.
+ * This file provides wimlib_lzx_compress(), a function to compress an in-memory
+ * buffer of data using LZX compression, as used in the WIM file format.
  *
  * Please see the comments in lzx-decompress.c for more information about this
  * compression format.
@@ -57,6 +57,7 @@
  * blocks from one input chunk is not yet implemented.
  */
 
+#include "wimlib.h"
 #include "lzx.h"
 #include "compress.h"
 #include <stdlib.h>
@@ -566,7 +567,7 @@ lzx_write_compressed_tree(struct output_bitstream *out,
 
 /* Builds the canonical Huffman code for the main tree, the length tree, and the
  * aligned offset tree. */
-static void 
+static void
 lzx_make_huffman_codes(const struct lzx_freq_tables *freq_tabs,
 		       struct lzx_codes *codes)
 {
@@ -638,26 +639,10 @@ static const struct lz_params lzx_lz_params = {
 	.too_far        = 4096,
 };
 
-/*
- * Performs LZX 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
-lzx_compress(const void *__uncompressed_data, unsigned uncompressed_len,
-	     void *compressed_data, unsigned *compressed_len_ret)
+/* Documented in wimlib.h */
+WIMLIBAPI unsigned
+wimlib_lzx_compress(const void *__uncompressed_data, unsigned uncompressed_len,
+		    void *compressed_data)
 {
 	struct output_bitstream ostream;
 	u8 uncompressed_data[uncompressed_len + 8];
@@ -671,8 +656,10 @@ lzx_compress(const void *__uncompressed_data, unsigned uncompressed_len,
 	int ret;
 	int block_type = LZX_BLOCKTYPE_ALIGNED;
 
+	wimlib_assert(uncompressed_len <= 32768);
+
 	if (uncompressed_len < 100)
-		return 1;
+		return 0;
 
 	memset(&freq_tabs, 0, sizeof(freq_tabs));
 	queue.R0 = 1;
@@ -682,6 +669,7 @@ lzx_compress(const void *__uncompressed_data, unsigned uncompressed_len,
 	/* The input data must be preprocessed. To avoid changing the original
 	 * input, copy it to a temporary buffer. */
 	memcpy(uncompressed_data, __uncompressed_data, uncompressed_len);
+	memset(uncompressed_data + uncompressed_len, 0, 8);
 
 	/* Before doing any actual compression, do the call instruction (0xe8
 	 * byte) translation on the uncompressed data. */
@@ -728,55 +716,55 @@ lzx_compress(const void *__uncompressed_data, unsigned uncompressed_len,
 	 * main tree. */
 	ret = lzx_write_compressed_tree(&ostream, codes.main_lens,
 				        LZX_NUM_CHARS);
-	if (ret != 0)
-		return ret;
+	if (ret)
+		return 0;
 
 	/* Write the pre-tree and symbols for the rest of the main tree. */
 	ret = lzx_write_compressed_tree(&ostream, codes.main_lens +
 					LZX_NUM_CHARS,
 					LZX_MAINTREE_NUM_SYMBOLS -
 						LZX_NUM_CHARS);
-	if (ret != 0)
-		return ret;
+	if (ret)
+		return 0;
 
 	/* Write the pre-tree and symbols for the length tree. */
 	ret = lzx_write_compressed_tree(&ostream, codes.len_lens,
 					LZX_LENTREE_NUM_SYMBOLS);
-	if (ret != 0)
-		return ret;
+	if (ret)
+		return 0;
 
 	/* Write the compressed literals. */
 	ret = lzx_write_compressed_literals(&ostream, block_type,
 					    match_tab, num_matches, &codes);
-	if (ret != 0)
-		return ret;
+	if (ret)
+		return 0;
 
 	ret = flush_output_bitstream(&ostream);
-	if (ret != 0)
-		return ret;
+	if (ret)
+		return 0;
 
 	compressed_len = ostream.bit_output - (u8*)compressed_data;
 
-	*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 = lzx_decompress(compressed_data, compressed_len, buf,
-			     uncompressed_len);
-	if (ret != 0) {
-		ERROR("lzx_compress(): Failed to decompress data we compressed");
-		abort();
-	}
-
-	for (i = 0; i < uncompressed_len; i++) {
-		if (buf[i] != *((u8*)__uncompressed_data + i)) {
-			ERROR("lzx_compress(): Data we compressed didn't "
-			      "decompress to the original data (difference at "
-			      "byte %u of %u)", i + 1, uncompressed_len);
+	{
+		u8 buf[uncompressed_len];
+		ret = wimlib_lzx_decompress(compressed_data, compressed_len,
+					    buf, uncompressed_len);
+		if (ret != 0) {
+			ERROR("lzx_compress(): Failed to decompress data we compressed");
 			abort();
 		}
+
+		for (i = 0; i < uncompressed_len; i++) {
+			if (buf[i] != *((u8*)__uncompressed_data + i)) {
+				ERROR("lzx_compress(): Data we compressed didn't "
+				      "decompress to the original data (difference at "
+				      "byte %u of %u)", i + 1, uncompressed_len);
+				abort();
+			}
+		}
 	}
 #endif
-	return 0;
+	return compressed_len;
 }