From f49fe3bbf0d52e2afcc1ace8c1f48dee9349d4f8 Mon Sep 17 00:00:00 2001
From: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Date: Thu, 25 Jul 2019 19:16:11 +0200
Subject: Cleanup sqfs_write_table

This commit attempts to make the generic table writer more readable.
A few changes are made, including heap allocation of the block list.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
---
 lib/sqfs/write_table.c | 71 +++++++++++++++++++++++++++++---------------------
 1 file changed, 42 insertions(+), 29 deletions(-)

(limited to 'lib/sqfs/write_table.c')

diff --git a/lib/sqfs/write_table.c b/lib/sqfs/write_table.c
index fc90a3f..23ba5a8 100644
--- a/lib/sqfs/write_table.c
+++ b/lib/sqfs/write_table.c
@@ -6,56 +6,69 @@
 #include "util.h"
 
 #include <endian.h>
+#include <stdlib.h>
 #include <stdio.h>
 
-int sqfs_write_table(int outfd, sqfs_super_t *super, const void *data,
-		     size_t entsize, size_t count, uint64_t *startblock,
-		     compressor_t *cmp)
+int sqfs_write_table(int outfd, sqfs_super_t *super, compressor_t *cmp,
+		     const void *data, size_t table_size, uint64_t *start)
 {
-	size_t ent_per_blocks = SQFS_META_BLOCK_SIZE / entsize;
-	uint64_t blocks[count / ent_per_blocks + 1], block;
-	size_t i, blkidx = 0, tblsize;
+	size_t block_count, list_size, diff, blkidx = 0;
+	uint64_t block, *locations;
 	meta_writer_t *m;
 	uint32_t offset;
+	int ret = -1;
 
-	/* Write actual data. Whenever we cross a block boundary, remember
-	   the block start offset */
+	block_count = table_size / SQFS_META_BLOCK_SIZE;
+	if ((table_size % SQFS_META_BLOCK_SIZE) != 0)
+		++block_count;
+
+	list_size = sizeof(uint64_t) * block_count;
+	locations = malloc(list_size);
+
+	if (locations == NULL) {
+		perror("writing table");
+		return -1;
+	}
+
+	/* Write actual data */
 	m = meta_writer_create(outfd, cmp, false);
 	if (m == NULL)
-		return -1;
+		goto out_idx;
 
-	for (i = 0; i < count; ++i) {
+	while (table_size > 0) {
 		meta_writer_get_position(m, &block, &offset);
+		locations[blkidx++] = htole64(super->bytes_used + block);
 
-		if (blkidx == 0 || block > blocks[blkidx - 1])
-			blocks[blkidx++] = block;
+		diff = SQFS_META_BLOCK_SIZE;
+		if (diff > table_size)
+			diff = table_size;
 
-		if (meta_writer_append(m, data, entsize))
-			goto fail;
+		if (meta_writer_append(m, data, diff))
+			goto out;
 
-		data = (const char *)data + entsize;
+		data = (const char *)data + diff;
+		table_size -= diff;
 	}
 
 	if (meta_writer_flush(m))
-		goto fail;
-
-	for (i = 0; i < blkidx; ++i)
-		blocks[i] = htole64(blocks[i] + super->bytes_used);
+		goto out;
 
 	meta_writer_get_position(m, &block, &offset);
 	super->bytes_used += block;
-	meta_writer_destroy(m);
 
-	/* write new index table */
-	*startblock = super->bytes_used;
-	tblsize = sizeof(blocks[0]) * blkidx;
+	/* write location list */
+	*start = super->bytes_used;
 
-	if (write_data("writing table index", outfd, blocks, tblsize))
-		return -1;
+	if (write_data("writing table locations", outfd, locations, list_size))
+		goto out;
+
+	super->bytes_used += list_size;
 
-	super->bytes_used += tblsize;
-	return 0;
-fail:
+	/* cleanup */
+	ret = 0;
+out:
 	meta_writer_destroy(m);
-	return -1;
+out_idx:
+	free(locations);
+	return ret;
 }
-- 
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