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Use heuristic to omit file index

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This commit is contained in:
Dave Vasilevsky 2012-11-05 02:39:20 -05:00
parent e20c330366
commit 09c60316cf
1 changed files with 55 additions and 3 deletions
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56
read.c
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@ -23,12 +23,16 @@ static void wanted_free(wanted_t *w);
#pragma mark DECLARE PIPELINE
typedef enum { BLOCK_SIZED, BLOCK_UNSIZED, BLOCK_CONTINUATION } block_type;
typedef struct {
uint8_t *input, *output;
size_t incap, outcap;
size_t insize, outsize;
off_t uoffset; // uncompressed offset
lzma_check check;
block_type btype;
} io_block_t;
static void *block_create(void);
@ -83,6 +87,9 @@ static void read_footer(void);
static lzma_vli gFileIndexOffset = 0;
static bool taste_tar(io_block_t *ib);
static bool taste_file_index(io_block_t *ib);
#pragma mark MAIN
@ -99,6 +106,7 @@ void pixz_read(bool verify, size_t nspecs, char **specs) {
debug("want: %s", w->name);
#endif
bool first = true;
pipeline_create(block_create, block_free,
gIndex ? read_thread : read_thread_noindex, decode_thread);
if (verify && gFileIndexOffset) {
@ -144,15 +152,36 @@ void pixz_read(bool verify, size_t nspecs, char **specs) {
wlast = w;
w = w->next;
}
archive_read_finish(ar);
if (w && w->name)
die("File %s missing in archive", w->name);
tar_write_last(); // write whatever's left
first = false;
}
if (!gExplicitFiles) {
pipeline_item_t *pi;
bool tar = false;
bool all_sized = true;
bool skipping = false;
pipeline_item_t *pi;
while ((pi = pipeline_merged())) {
io_block_t *ib = (io_block_t*)(pi->data);
fwrite(ib->output, ib->outsize, 1, gOutFile);
if (first) {
tar = taste_tar(ib);
first = false;
}
if (skipping && ib->btype != BLOCK_CONTINUATION) {
die("File index heuristic failed, retry with -t flag");
skipping = false;
}
if (verify && !skipping && !first && tar && all_sized
&& ib->btype == BLOCK_UNSIZED && taste_file_index(ib))
skipping = true;
if (ib->btype != BLOCK_SIZED)
all_sized = false;
if (!skipping)
fwrite(ib->output, ib->outsize, 1, gOutFile);
queue_push(gPipelineStartQ, PIPELINE_ITEM, pi);
}
}
@ -357,6 +386,7 @@ static bool read_block(bool force_stream, lzma_check check) {
block_capacity(gRbuf, 0, outsize);
gRbuf->outsize = outsize;
gRbuf->check = check;
gRbuf->btype = BLOCK_SIZED;
if (rbuf_read(lzma_block_total_size(&block)) != RBUF_FULL)
die("Error reading block contents");
@ -372,6 +402,7 @@ static void read_streaming(lzma_block *block) {
rbuf_cycle(&stream, true, block->header_size);
stream.avail_out = 0;
bool first = true;
pipeline_item_t *pi = NULL;
io_block_t *ib = NULL;
@ -384,9 +415,11 @@ static void read_streaming(lzma_block *block) {
if (ib) {
ib->outsize = ib->outcap;
pipeline_dispatch(pi, gPipelineMergeQ);
first = false;
}
queue_pop(gPipelineStartQ, (void**)&pi);
ib = (io_block_t*)pi->data;
ib->btype = (first ? BLOCK_UNSIZED : BLOCK_CONTINUATION);
block_capacity(ib, 0, STREAMSIZE);
stream.next_out = ib->output;
stream.avail_out = ib->outcap;
@ -512,6 +545,7 @@ static void read_thread(void) {
offset += bsize;
ib->uoffset = iter.block.uncompressed_file_offset;
ib->check = iter.stream.flags->check;
ib->btype = BLOCK_SIZED;
pipeline_split(pi);
}
@ -626,3 +660,21 @@ static ssize_t tar_read(struct archive *ar, void *ref, const void **bufp) {
*bufp = ib->output + off;
return size;
}
#pragma mark UTILS
static bool taste_tar(io_block_t *ib) {
struct archive *ar = archive_read_new();
archive_read_support_compression_none(ar);
archive_read_support_format_tar(ar);
archive_read_open_memory(ar, ib->output, ib->outsize);
struct archive_entry *entry;
bool ok = (archive_read_next_header(ar, &entry) == ARCHIVE_OK);
archive_read_finish(ar);
return ok;
}
static bool taste_file_index(io_block_t *ib) {
return xle64dec(ib->output) == PIXZ_INDEX_MAGIC;
}