#include <unistd.h>
#include <fcntl.h>
+#ifdef HAVE_ALLOCA_H
+# include <alloca.h>
+#endif
+
/* Write @n bytes from @buf to the file descriptor @fd, retrying on internupt
* and on short writes.
*
* Returns zero on success, nonzero on failure.
*/
static int
-read_compressed_resource(FILE *fp, u64 resource_compressed_size,
+read_compressed_resource(FILE *fp,
+ u64 resource_compressed_size,
u64 resource_uncompressed_size,
- u64 resource_offset, int resource_ctype,
- u64 len, u64 offset,
+ u64 resource_offset,
+ int resource_ctype,
+ u64 len,
+ u64 offset,
consume_data_callback_t cb,
void *ctx_or_buf)
{
* follows the chunk table and therefore must have an offset of 0.
*/
- /* Calculate how many chunks the resource conists of in its entirety. */
+ /* Calculate how many chunks the resource consists of in its entirety.
+ * */
u64 num_chunks = (resource_uncompressed_size + WIM_CHUNK_SIZE - 1) /
WIM_CHUNK_SIZE;
/* As mentioned, the first chunk has no entry in the chunk table. */
if (end_chunk != num_chunks - 1)
num_needed_chunks++;
- /* Declare the chunk table. It will only contain offsets for the chunks
- * that are actually needed for this read. */
- u64 chunk_offsets[num_needed_chunks];
+ /* Allocate the chunk table. It will only contain offsets for the
+ * chunks that are actually needed for this read. */
+ u64 *chunk_offsets;
+ bool chunk_offsets_malloced;
+ if (num_needed_chunks < 1000) {
+ chunk_offsets = alloca(num_needed_chunks * sizeof(u64));
+ chunk_offsets_malloced = false;
+ } else {
+ chunk_offsets = malloc(num_needed_chunks * sizeof(u64));
+ if (!chunk_offsets) {
+ ERROR("Failed to allocate chunk table "
+ "with %"PRIu64" entries", num_needed_chunks);
+ return WIMLIB_ERR_NOMEM;
+ }
+ chunk_offsets_malloced = true;
+ }
/* Set the implicit offset of the first chunk if it is included in the
* needed chunks.
/* Number of bytes we need to read from the chunk table. */
size_t size = num_needed_chunk_entries * chunk_entry_size;
- {
- u8 chunk_tab_buf[size];
+ /* Read the raw data into the end of the chunk_offsets array to
+ * avoid allocating another array. */
+ void *chunk_tab_buf = (void*)&chunk_offsets[num_needed_chunks] - size;
- if (fread(chunk_tab_buf, 1, size, fp) != size)
- goto read_error;
+ if (fread(chunk_tab_buf, 1, size, fp) != size)
+ goto read_error;
- /* Now fill in chunk_offsets from the entries we have read in
- * chunk_tab_buf. */
+ /* Now fill in chunk_offsets from the entries we have read in
+ * chunk_tab_buf. */
- u64 *chunk_tab_p = chunk_offsets;
- if (start_chunk == 0)
- chunk_tab_p++;
+ u64 *chunk_tab_p = chunk_offsets;
+ if (start_chunk == 0)
+ chunk_tab_p++;
- if (chunk_entry_size == 4) {
- u32 *entries = (u32*)chunk_tab_buf;
- while (num_needed_chunk_entries--)
- *chunk_tab_p++ = le32_to_cpu(*entries++);
- } else {
- u64 *entries = (u64*)chunk_tab_buf;
- while (num_needed_chunk_entries--)
- *chunk_tab_p++ = le64_to_cpu(*entries++);
- }
+ if (chunk_entry_size == 4) {
+ u32 *entries = (u32*)chunk_tab_buf;
+ while (num_needed_chunk_entries--)
+ *chunk_tab_p++ = le32_to_cpu(*entries++);
+ } else {
+ u64 *entries = (u64*)chunk_tab_buf;
+ while (num_needed_chunk_entries--)
+ *chunk_tab_p++ = le64_to_cpu(*entries++);
}
/* Done with the chunk table now. We must now seek to the first chunk
goto read_error;
/* Pointer to current position in the output buffer for uncompressed
- * data. */
+ * data. Alternatively, if using a callback function, we repeatedly
+ * fill a temporary buffer to feed data into the callback function. */
u8 *out_p;
if (cb)
- out_p = alloca(32768);
+ out_p = alloca(WIM_CHUNK_SIZE);
else
out_p = ctx_or_buf;
}
if (cb) {
/* Feed the data to the callback function */
- ret = cb(out_p, partial_chunk_size, ctx_or_buf);
+ ret = cb(out_p + start_offset,
+ partial_chunk_size, ctx_or_buf);
if (ret)
goto out;
} else {
ret = 0;
out:
+ if (chunk_offsets_malloced)
+ FREE(chunk_offsets);
return ret;
read_error:
wim = lte->wim;
- if (flags & WIMLIB_RESOURCE_FLAG_MULTITHREADED) {
+ if (flags & WIMLIB_RESOURCE_FLAG_THREADSAFE_READ) {
wim_fp = wim_get_fp(wim);
if (!wim_fp) {
ret = -1;
ERROR_WITH_ERRNO("Error reading data from WIM");
ret = WIMLIB_ERR_READ;
out_release_fp:
- if (flags & WIMLIB_RESOURCE_FLAG_MULTITHREADED)
+ if (flags & WIMLIB_RESOURCE_FLAG_THREADSAFE_READ)
ret |= wim_release_fp(wim, wim_fp);
out:
if (ret) {
bool threadsafe)
{
return read_partial_wim_resource(lte, size, NULL, buf,
- threadsafe ? WIMLIB_RESOURCE_FLAG_MULTITHREADED : 0,
+ threadsafe ? WIMLIB_RESOURCE_FLAG_THREADSAFE_READ : 0,
offset);
}
* When using a callback function, it is called with chunks up to 32768 bytes in
* size until the resource is exhausted.
*
- * If the resource is located in a WIM file, @flags can be
- * WIMLIB_RESOURCE_FLAG_MULTITHREADED if it must be safe to access the resource
- * concurrently by multiple threads, or WIMLIB_RESOURCE_FLAG_RAW if the raw
- * compressed data is to be supplied instead of the uncompressed data.
+ * If the resource is located in a WIM file, @flags can be:
+ * * WIMLIB_RESOURCE_FLAG_THREADSAFE_READ if it must be safe to access the resource
+ * concurrently by multiple threads.
+ * * WIMLIB_RESOURCE_FLAG_RAW if the raw compressed data is to be supplied
+ * instead of the uncompressed data.
+ * Otherwise, the @flags are ignored.
*/
int
read_resource_prefix(const struct wim_lookup_table_entry *lte,
return read_resource_prefix(lte,
wim_resource_size(lte),
NULL, buf,
- thread_safe ? WIMLIB_RESOURCE_FLAG_MULTITHREADED : 0);
+ thread_safe ? WIMLIB_RESOURCE_FLAG_THREADSAFE_READ : 0);
}
struct extract_ctx {
git://wimlib.net / wimlib / blobdiff