libarchive: add capability to unpack to mem.buffer
The performance and number of processes for a "depmod -a" with gzipped modules was abysmal. This patch adds a code path without fork, benefiting all users of xmalloc_open_zipped_read_close. "modinfo radeon.ko.gz", a single-file reader, got 30% faster. "depmod -a", which used to fork over 800 times, got 20% faster. Heavily based on a patch by Lauri Kasanen <curaga@operamail.com> function old new delta setup_transformer_on_fd - 159 +159 transformer_write - 122 +122 fork_transformer - 112 +112 xmalloc_open_zipped_read_close 63 118 +55 read_bunzip 1866 1896 +30 xtransformer_write - 19 +19 unzip_main 2449 2462 +13 bbunpack 755 766 +11 unpack_lzma_stream 2717 2723 +6 unpack_xz_stream 2393 2397 +4 unpack_Z_stream 1173 1175 +2 inflate_unzip 111 105 -6 check_signature16 70 63 -7 unpack_bz2_stream 359 349 -10 unpack_unxz 12 - -12 unpack_unlzma 12 - -12 unpack_uncompress 12 - -12 unpack_gunzip 12 - -12 unpack_bunzip2 12 - -12 open_transformer 106 92 -14 inflate_unzip_internal 1945 1916 -29 unpack_gz_stream 693 655 -38 open_zipped 89 47 -42 setup_unzip_on_fd 142 53 -89 ------------------------------------------------------------------------------ (add/remove: 4/5 grow/shrink: 7/8 up/down: 533/-295) Total: 238 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
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@@ -731,7 +731,7 @@ void FAST_FUNC dealloc_bunzip(bunzip_data *bd)
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/* Decompress src_fd to dst_fd. Stops at end of bzip data, not end of file. */
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IF_DESKTOP(long long) int FAST_FUNC
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unpack_bz2_stream(transformer_state_t *xstate, int src_fd, int dst_fd)
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unpack_bz2_stream(transformer_state_t *xstate)
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{
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IF_DESKTOP(long long total_written = 0;)
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bunzip_data *bd;
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@@ -739,14 +739,14 @@ unpack_bz2_stream(transformer_state_t *xstate, int src_fd, int dst_fd)
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int i;
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unsigned len;
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if (check_signature16(xstate, src_fd, BZIP2_MAGIC))
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if (check_signature16(xstate, BZIP2_MAGIC))
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return -1;
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outbuf = xmalloc(IOBUF_SIZE);
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len = 0;
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while (1) { /* "Process one BZ... stream" loop */
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i = start_bunzip(&bd, src_fd, outbuf + 2, len);
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i = start_bunzip(&bd, xstate->src_fd, outbuf + 2, len);
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if (i == 0) {
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while (1) { /* "Produce some output bytes" loop */
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@@ -756,8 +756,7 @@ unpack_bz2_stream(transformer_state_t *xstate, int src_fd, int dst_fd)
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i = IOBUF_SIZE - i; /* number of bytes produced */
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if (i == 0) /* EOF? */
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break;
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if (i != full_write(dst_fd, outbuf, i)) {
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bb_error_msg("short write");
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if (i != transformer_write(xstate, outbuf, i)) {
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i = RETVAL_SHORT_WRITE;
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goto release_mem;
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}
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@@ -790,7 +789,7 @@ unpack_bz2_stream(transformer_state_t *xstate, int src_fd, int dst_fd)
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len = bd->inbufCount - bd->inbufPos;
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memcpy(outbuf, &bd->inbuf[bd->inbufPos], len);
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if (len < 2) {
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if (safe_read(src_fd, outbuf + len, 2 - len) != 2 - len)
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if (safe_read(xstate->src_fd, outbuf + len, 2 - len) != 2 - len)
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break;
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len = 2;
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}
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