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/* Decompressing store backend (common code for gunzip and bunzip2) |
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Copyright (C) 1998, 1999, 2002 Free Software Foundation, Inc. |
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Written by okuji@kuicr.kyoto-u.ac.jp <okuji@kuicr.kyoto-u.ac.jp> |
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This file is part of the GNU Hurd. |
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The GNU Hurd is free software; you can redistribute it and/or |
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modify it under the terms of the GNU General Public License as |
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published by the Free Software Foundation; either version 2, or (at |
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your option) any later version. |
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The GNU Hurd is distributed in the hope that it will be useful, but |
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WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */ |
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#include <stdio.h> |
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#include <string.h> |
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#include <setjmp.h> |
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#include <cthreads.h> |
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#include <sys/mman.h> |
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#include "store.h" |
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#define IN_BUFFERING (256*1024) |
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#define OUT_BUFFERING (512*1024) |
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static struct mutex unzip_lock = MUTEX_INITIALIZER; |
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#define STORE_UNZIP(name) STORE_UNZIP_1 (UNZIP, name) |
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#define STORE_UNZIP_1(unzip,name) STORE_UNZIP_2 (unzip, name) |
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#define STORE_UNZIP_2(unzip,name) store_##unzip##_##name |
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#define STORE_STD_CLASS_1(name) STORE_STD_CLASS(name) |
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#define STRINGIFY(name) STRINGIFY_1(name) |
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#define STRINGIFY_1(name) #name |
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/* Uncompress the contents of FROM, which should contain a valid bzip2 file, |
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into memory, returning the result buffer in BUF & BUF_LEN. */ |
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static error_t |
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unzip_store (struct store *from, void **buf, size_t *buf_len) |
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{ |
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/* Callbacks from decompression engine for I/O and error interface. */ |
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extern int (*unzip_read) (char *buf, size_t maxread); |
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extern void (*unzip_write) (const char *buf, size_t nwrite); |
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extern void (*unzip_read_error) (void); |
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extern void (*unzip_error) (const char *msg); |
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/* How we return errors from our hook functions. */ |
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jmp_buf zerr_jmp_buf; |
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error_t zerr; |
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/* vm_alloced buffer for the input store. */ |
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void *in_buf = 0; |
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size_t in_buf_len = 0; /* Amount of valid data in IN_BUF. */ |
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size_t in_buf_size = 0; /* Allocated space for IN_BUF. */ |
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size_t in_buf_offs = 0; /* Offset of read point in IN_BUF. */ |
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off_t in_buf_addr = 0; /* Address in FROM of *next* IN_BUF. */ |
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/* Buffer input in units that are least IN_BUFFERING bytes, but are also a |
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multiple of FROM's block size. */ |
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size_t in_addr_mask = ((1 << from->log2_block_size) - 1); |
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size_t in_buffering = ((IN_BUFFERING + in_addr_mask) & ~in_addr_mask); |
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/* Read at most MAXREAD (or 0 if eof) bytes into BUF from our current |
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position in FROM. */ |
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int zread (char *buf, size_t maxread) |
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{ |
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size_t did_read = 0; |
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while (maxread > 0) |
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{ |
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size_t left = in_buf_len - in_buf_offs; |
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if (left > 0) |
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/* Fill BUF with what we can from IN_BUF. */ |
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{ |
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if (left > maxread) |
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left = maxread; |
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bcopy (in_buf + in_buf_offs, buf, left); |
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in_buf_offs += left; |
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buf += left; |
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maxread -= left; |
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did_read += left; |
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} |
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/* Limit MAXREAD to the number of bytes left in the input. */ |
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if (maxread > (from->size - (in_buf_addr << from->log2_block_size))) |
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maxread = from->size - (in_buf_addr << from->log2_block_size); |
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if (maxread > 0) |
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/* Have to fill IN_BUF again. */ |
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{ |
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void *new_in_buf = in_buf; |
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size_t new_in_buf_len = in_buf_len; |
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zerr = store_read (from, in_buf_addr, in_buffering, |
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&new_in_buf, &new_in_buf_len); |
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if (zerr) |
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longjmp (zerr_jmp_buf, 1); |
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in_buf_addr += (new_in_buf_len >> from->log2_block_size); |
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if (new_in_buf != in_buf) |
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{ |
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if (in_buf_size > 0) |
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munmap (in_buf, in_buf_size); |
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in_buf = new_in_buf; |
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in_buf_size = new_in_buf_len; |
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} |
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in_buf_len = new_in_buf_len; |
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in_buf_offs = 0; |
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} |
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} |
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return did_read; |
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} |
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size_t out_buf_offs = 0; /* Position in the output buffer. */ |
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/* Write compress data to our output buffer. */ |
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void zwrite (const char *wbuf, size_t nwrite) |
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{ |
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size_t old_buf_len = *buf_len; |
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if (out_buf_offs + nwrite > old_buf_len) |
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/* Have to grow the output buffer. */ |
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{ |
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void *old_buf = *buf; |
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void *new_buf = old_buf + old_buf_len; /* First try. */ |
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size_t new_buf_len = round_page (old_buf_len + old_buf_len + nwrite); |
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/* Try to grow the buffer. */ |
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zerr = |
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vm_allocate (mach_task_self (), |
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(vm_address_t *)&new_buf, new_buf_len - old_buf_len, |
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0); |
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if (zerr) |
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/* Can't do that, try to make a bigger buffer elsewhere. */ |
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{ |
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new_buf = mmap (0, new_buf_len, PROT_READ|PROT_WRITE, |
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MAP_ANON, 0, 0); |
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zerr = (new_buf == (void *) -1) ? errno : 0; |
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if (zerr) |
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longjmp (zerr_jmp_buf, 1); |
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if (out_buf_offs > 0) |
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/* Copy the old buffer into the start of the new & free it. */ |
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bcopy (old_buf, new_buf, out_buf_offs); |
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munmap (old_buf, old_buf_len); |
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*buf = new_buf; |
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} |
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*buf_len = new_buf_len; |
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} |
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bcopy (wbuf, *buf + out_buf_offs, nwrite); |
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out_buf_offs += nwrite; |
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} |
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void zreaderr (void) |
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{ |
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zerr = EIO; |
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longjmp (zerr_jmp_buf, 1); |
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} |
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void zerror (const char *msg) |
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{ |
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zerr = EINVAL; |
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longjmp (zerr_jmp_buf, 2); |
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} |
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/* Try to guess a reasonable output buffer size. */ |
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*buf_len = round_page (from->size * 2); |
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*buf = mmap (0, *buf_len, PROT_READ|PROT_WRITE, MAP_ANON, 0, 0); |
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zerr = (*buf == (void *) -1) ? errno : 0; |
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if (zerr) |
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return zerr; |
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mutex_lock (&unzip_lock); |
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unzip_read = zread; |
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unzip_write = zwrite; |
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unzip_read_error = zreaderr; |
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unzip_error = zerror; |
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if (! setjmp (zerr_jmp_buf)) |
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{ |
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/* Call the decompression engine. */ |
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zerr = DO_UNZIP (); |
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} |
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mutex_unlock (&unzip_lock); |
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if (in_buf_size > 0) |
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munmap (in_buf, in_buf_size); |
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if (zerr) |
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{ |
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if (*buf_len > 0) |
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munmap (*buf, *buf_len); |
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} |
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else if (out_buf_offs < *buf_len) |
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/* Trim the output buffer to be the right length. */ |
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{ |
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size_t end = round_page (out_buf_offs); |
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if (end < *buf_len) |
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munmap (*buf + end, *buf_len - end); |
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*buf_len = out_buf_offs; |
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} |
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return zerr; |
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} |
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/* Return a new store in STORE which contains a snapshot of the uncompressed |
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contents of the store FROM; FROM is consumed. */ |
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error_t |
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STORE_UNZIP(create) (struct store *from, int flags, struct store **store) |
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{ |
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void *buf; |
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size_t buf_len; |
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error_t err = unzip_store (from, &buf, &buf_len); |
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if (! err) |
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{ |
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err = store_buffer_create (buf, buf_len, flags, store); |
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if (err) |
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munmap (buf, buf_len); |
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else |
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store_free (from); |
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} |
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return err; |
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} |
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/* Open the compressed store NAME -- which consists of another store-class |
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name, a ':', and a name for that store class to open -- and return the |
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corresponding store in STORE. CLASSES is used to select classes |
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specified by the type name; if it is 0, STORE_STD_CLASSES is used. */ |
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error_t |
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STORE_UNZIP(open) (const char *name, int flags, |
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const struct store_class *const *classes, |
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struct store **store) |
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{ |
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struct store *from; |
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error_t err = |
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store_typed_open (name, flags | STORE_HARD_READONLY, classes, &from); |
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if (! err) |
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{ |
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err = STORE_UNZIP(create) (from, flags, store); |
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if (err) |
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store_free (from); |
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} |
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return err; |
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} |
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const struct store_class STORE_UNZIP(class) = |
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{ -1, STRINGIFY(UNZIP), open: STORE_UNZIP(open) }; |
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STORE_STD_CLASS_1 (UNZIP); |