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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-06-11 01:24:57 +0200
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2019-06-11 01:47:18 +0200
commit5038c4b33ea403203b8edd82b44a8db06464409b (patch)
treeb0d8b380601694f47a6dd45f4c6313fc7d9f0937
parentb45eead4dfd6e820b4c1634ae72398bf717193f9 (diff)
Major cleanup of mkfs block processor
This commit tries to make the block and fragment processing code a lot more readable by simplifying it as follows. The following pattern is used repeatedly: - Try to compress a block - Write the compressed if smaller (the original otherwise) to a file - Print errors on the way - Set the magic (1 << 24) flag if we wrote the original - Increment the super block byte counter => Move that to a seperate function called "write_compressed" => Move the code to grow the fragment table is moved to a seperate function. => Clearing the fragment buffer is pointless, so remove that The add_fragment/add_block functions are now trivial => Merge them into process_file => Global block counter no longer needed, so remove that too Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
-rw-r--r--mkfs/block.c117
-rw-r--r--mkfs/mkfs.h2
2 files changed, 46 insertions, 73 deletions
diff --git a/mkfs/block.c b/mkfs/block.c
index eba8c24..f023876 100644
--- a/mkfs/block.c
+++ b/mkfs/block.c
@@ -2,50 +2,43 @@
#include "mkfs.h"
#include "util.h"
-static int write_block(file_info_t *fi, sqfs_info_t *info)
+static int write_compressed(sqfs_info_t *info, const void *in, size_t size,
+ uint32_t *outsize)
{
- size_t idx, bs;
ssize_t ret;
- void *ptr;
- idx = info->file_block_count++;
- bs = info->super.block_size;
-
- ret = info->cmp->do_block(info->cmp, info->block, bs,
- info->scratch, bs);
+ ret = info->cmp->do_block(info->cmp, in, size, info->scratch,
+ info->super.block_size);
if (ret < 0)
return -1;
- if (ret > 0) {
- ptr = info->scratch;
- bs = ret;
- fi->blocksizes[idx] = bs;
+ if (ret > 0 && (size_t)ret < size) {
+ size = ret;
+ ret = write_retry(info->outfd, info->scratch, size);
+ *outsize = size;
} else {
- ptr = info->block;
- fi->blocksizes[idx] = bs | (1 << 24);
+ ret = write_retry(info->outfd, in, size);
+ *outsize = size | (1 << 24);
}
- ret = write_retry(info->outfd, ptr, bs);
if (ret < 0) {
perror("writing to output file");
return -1;
}
- if ((size_t)ret < bs) {
+ if ((size_t)ret < size) {
fputs("write to output file truncated\n", stderr);
return -1;
}
- info->super.bytes_used += bs;
+ info->super.bytes_used += ret;
return 0;
}
-static int flush_fragments(sqfs_info_t *info)
+static int grow_fragment_table(sqfs_info_t *info)
{
- size_t newsz, size;
- uint64_t offset;
- void *new, *ptr;
- ssize_t ret;
+ size_t newsz;
+ void *new;
if (info->num_fragments == info->max_fragments) {
newsz = info->max_fragments ? info->max_fragments * 2 : 16;
@@ -61,43 +54,27 @@ static int flush_fragments(sqfs_info_t *info)
info->fragments = new;
}
+ return 0;
+}
+
+static int flush_fragments(sqfs_info_t *info)
+{
+ uint64_t offset;
+ uint32_t out;
+
+ if (grow_fragment_table(info))
+ return -1;
+
offset = info->super.bytes_used;
- size = info->frag_offset;
- ret = info->cmp->do_block(info->cmp, info->fragment, size,
- info->scratch, info->super.block_size);
- if (ret < 0)
+ if (write_compressed(info, info->fragment, info->frag_offset, &out))
return -1;
info->fragments[info->num_fragments].start_offset = htole64(offset);
info->fragments[info->num_fragments].pad0 = 0;
-
- if (ret > 0) {
- ptr = info->scratch;
- size = ret;
- info->fragments[info->num_fragments].size = htole32(size);
- } else {
- ptr = info->fragment;
- info->fragments[info->num_fragments].size =
- htole32(size | (1 << 24));
- }
+ info->fragments[info->num_fragments].size = htole32(out);
info->num_fragments += 1;
-
- ret = write_retry(info->outfd, ptr, size);
- if (ret < 0) {
- perror("writing to output file");
- return -1;
- }
-
- if ((size_t)ret < size) {
- fputs("write to output file truncated\n", stderr);
- return -1;
- }
-
- memset(info->fragment, 0, info->super.block_size);
-
- info->super.bytes_used += size;
info->frag_offset = 0;
info->super.flags &= ~SQFS_FLAG_NO_FRAGMENTS;
@@ -105,25 +82,11 @@ static int flush_fragments(sqfs_info_t *info)
return 0;
}
-static int add_fragment(file_info_t *fi, sqfs_info_t *info, size_t size)
-{
- if (info->frag_offset + size > info->super.block_size) {
- if (flush_fragments(info))
- return -1;
- }
-
- fi->fragment_offset = info->frag_offset;
- fi->fragment = info->num_fragments;
-
- memcpy((char *)info->fragment + info->frag_offset, info->block, size);
- info->frag_offset += size;
- return 0;
-}
-
static int process_file(sqfs_info_t *info, file_info_t *fi)
{
+ int infd, ret, blk_idx = 0;
uint64_t count = fi->size;
- int infd, ret;
+ uint32_t out;
size_t diff;
infd = open(fi->input_file, O_RDONLY);
@@ -133,7 +96,6 @@ static int process_file(sqfs_info_t *info, file_info_t *fi)
}
fi->startblock = info->super.bytes_used;
- info->file_block_count = 0;
while (count != 0) {
diff = count > (uint64_t)info->super.block_size ?
@@ -146,11 +108,24 @@ static int process_file(sqfs_info_t *info, file_info_t *fi)
goto fail_trunc;
if (diff < info->super.block_size) {
- if (add_fragment(fi, info, diff))
- goto fail;
+ if (info->frag_offset + diff > info->super.block_size) {
+ if (flush_fragments(info))
+ goto fail;
+ }
+
+ fi->fragment_offset = info->frag_offset;
+ fi->fragment = info->num_fragments;
+
+ memcpy((char *)info->fragment + info->frag_offset,
+ info->block, diff);
+ info->frag_offset += diff;
} else {
- if (write_block(fi, info))
+ if (write_compressed(info, info->block,
+ info->super.block_size, &out)) {
goto fail;
+ }
+
+ fi->blocksizes[blk_idx++] = out;
}
count -= diff;
diff --git a/mkfs/mkfs.h b/mkfs/mkfs.h
index c4cd8a1..fe4123b 100644
--- a/mkfs/mkfs.h
+++ b/mkfs/mkfs.h
@@ -47,8 +47,6 @@ typedef struct {
sqfs_fragment_t *fragments;
size_t num_fragments;
size_t max_fragments;
-
- int file_block_count;
size_t frag_offset;
id_table_t idtbl;