/* Copyright (C) 2000 MySQL AB This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /* Written by Sinisa Milivojevic */ #include #ifdef HAVE_COMPRESS #include #ifndef SCO #include #endif #include /* This replaces the packet with a compressed packet SYNOPSIS my_compress() packet Data to compress. This is is replaced with the compressed data. len Length of data to compress at 'packet' complen out: 0 if packet was not compressed RETURN 1 error. 'len' is not changed' 0 ok. In this case 'len' contains the size of the compressed packet */ my_bool my_compress(uchar *packet, size_t *len, size_t *complen) { DBUG_ENTER("my_compress"); if (*len < MIN_COMPRESS_LENGTH) { *complen=0; DBUG_PRINT("note",("Packet too short: Not compressed")); } else { uchar *compbuf=my_compress_alloc(packet,len,complen); if (!compbuf) DBUG_RETURN(*complen ? 0 : 1); memcpy(packet,compbuf,*len); my_free(compbuf); } DBUG_RETURN(0); } /* Valgrind normally gives false alarms for zlib operations, in the form of "conditional jump depends on uninitialised values" etc. The reason is explained in the zlib FAQ (http://www.zlib.net/zlib_faq.html#faq36): "That is intentional for performance reasons, and the output of deflate is not affected." Also discussed on a blog (http://www.sirena.org.uk/log/2006/02/19/zlib-generating-valgrind-warnings/): "...loop unrolling in the zlib library causes the mentioned “Conditional jump or move depends on uninitialised value(s)” warnings. These are safe since the results of the comparison are subsequently ignored..." "the results of the calculations are discarded by bounds checking done after the loop exits" Fix by initializing the memory allocated by zlib when running under Valgrind. This fix is safe, since such memory is only used internally by zlib, so we will not hide any bugs in mysql this way. */ void *my_az_allocator(void *dummy __attribute__((unused)), unsigned int items, unsigned int size) { return my_malloc((size_t)items*(size_t)size, IF_VALGRIND(MY_ZEROFILL, MYF(0))); } void my_az_free(void *dummy __attribute__((unused)), void *address) { my_free(address); } /* This works like zlib compress(), but using custom memory allocators to work better with my_malloc leak detection and Valgrind. */ int my_compress_buffer(uchar *dest, size_t *destLen, const uchar *source, size_t sourceLen) { z_stream stream; int err; stream.next_in = (Bytef*)source; stream.avail_in = (uInt)sourceLen; stream.next_out = (Bytef*)dest; stream.avail_out = (uInt)*destLen; if ((size_t)stream.avail_out != *destLen) return Z_BUF_ERROR; stream.zalloc = (alloc_func)my_az_allocator; stream.zfree = (free_func)my_az_free; stream.opaque = (voidpf)0; err = deflateInit(&stream, Z_DEFAULT_COMPRESSION); if (err != Z_OK) return err; err = deflate(&stream, Z_FINISH); if (err != Z_STREAM_END) { deflateEnd(&stream); return err == Z_OK ? Z_BUF_ERROR : err; } *destLen = stream.total_out; err = deflateEnd(&stream); return err; } uchar *my_compress_alloc(const uchar *packet, size_t *len, size_t *complen) { uchar *compbuf; int res; *complen= *len * 120 / 100 + 12; if (!(compbuf= (uchar *) my_malloc(*complen, MYF(MY_WME)))) return 0; /* Not enough memory */ res= my_compress_buffer(compbuf, complen, packet, *len); if (res != Z_OK) { my_free(compbuf); return 0; } if (*complen >= *len) { *complen= 0; my_free(compbuf); DBUG_PRINT("note",("Packet got longer on compression; Not compressed")); return 0; } /* Store length of compressed packet in *len */ swap_variables(size_t, *len, *complen); return compbuf; } /* Uncompress packet SYNOPSIS my_uncompress() packet Compressed data. This is is replaced with the orignal data. len Length of compressed data complen Length of the packet buffer (must be enough for the original data) RETURN 1 error 0 ok. In this case 'complen' contains the updated size of the real data. */ my_bool my_uncompress(uchar *packet, size_t len, size_t *complen) { uLongf tmp_complen; DBUG_ENTER("my_uncompress"); if (*complen) /* If compressed */ { uchar *compbuf= (uchar *) my_malloc(*complen,MYF(MY_WME)); int error; if (!compbuf) DBUG_RETURN(1); /* Not enough memory */ tmp_complen= (uLongf) *complen; error= uncompress((Bytef*) compbuf, &tmp_complen, (Bytef*) packet, (uLong) len); *complen= tmp_complen; if (error != Z_OK) { /* Probably wrong packet */ DBUG_PRINT("error",("Can't uncompress packet, error: %d",error)); my_free(compbuf); DBUG_RETURN(1); } memcpy(packet, compbuf, *complen); my_free(compbuf); } else *complen= len; DBUG_RETURN(0); } /* Internal representation of the frm blob is: ver 4 bytes orglen 4 bytes complen 4 bytes */ #define BLOB_HEADER 12 /* packfrm is a method used to compress the frm file for storage in a handler. This method was developed for the NDB handler and has been moved here to serve also other uses. SYNOPSIS packfrm() data Data reference to frm file data. len Length of frm file data out:pack_data Reference to the pointer to the packed frm data out:pack_len Length of packed frm file data NOTES data is replaced with compressed content RETURN VALUES 0 Success >0 Failure */ int packfrm(uchar *data, size_t len, uchar **pack_data, size_t *pack_len) { int error; size_t org_len, comp_len, blob_len; uchar *blob; DBUG_ENTER("packfrm"); DBUG_PRINT("enter", ("data: 0x%lx len: %lu", (long) data, (ulong) len)); error= 1; org_len= len; if (my_compress((uchar*)data, &org_len, &comp_len)) goto err; DBUG_PRINT("info", ("org_len: %lu comp_len: %lu", (ulong) org_len, (ulong) comp_len)); DBUG_DUMP("compressed", data, org_len); error= 2; blob_len= BLOB_HEADER + org_len; if (!(blob= (uchar*) my_malloc(blob_len,MYF(MY_WME)))) goto err; /* Store compressed blob in machine independent format */ int4store(blob, 1); int4store(blob+4, (uint32) len); int4store(blob+8, (uint32) org_len); /* compressed length */ /* Copy frm data into blob, already in machine independent format */ memcpy(blob+BLOB_HEADER, data, org_len); *pack_data= blob; *pack_len= blob_len; error= 0; DBUG_PRINT("exit", ("pack_data: 0x%lx pack_len: %lu", (long) *pack_data, (ulong) *pack_len)); err: DBUG_RETURN(error); } /* unpackfrm is a method used to decompress the frm file received from a handler. This method was developed for the NDB handler and has been moved here to serve also other uses for other clustered storage engines. SYNOPSIS unpackfrm() pack_data Data reference to packed frm file data out:unpack_data Reference to the pointer to the unpacked frm data out:unpack_len Length of unpacked frm file data RETURN VALUES¨ 0 Success >0 Failure */ int unpackfrm(uchar **unpack_data, size_t *unpack_len, const uchar *pack_data) { uchar *data; size_t complen, orglen; ulong ver; DBUG_ENTER("unpackfrm"); DBUG_PRINT("enter", ("pack_data: 0x%lx", (long) pack_data)); ver= uint4korr(pack_data); orglen= uint4korr(pack_data+4); complen= uint4korr(pack_data+8); DBUG_PRINT("blob",("ver: %lu complen: %lu orglen: %lu", ver, (ulong) complen, (ulong) orglen)); DBUG_DUMP("blob->data", pack_data + BLOB_HEADER, complen); if (ver != 1) DBUG_RETURN(1); if (!(data= my_malloc(max(orglen, complen), MYF(MY_WME)))) DBUG_RETURN(2); memcpy(data, pack_data + BLOB_HEADER, complen); if (my_uncompress(data, complen, &orglen)) { my_free(data); DBUG_RETURN(3); } *unpack_data= data; *unpack_len= orglen; DBUG_PRINT("exit", ("frmdata: 0x%lx len: %lu", (long) *unpack_data, (ulong) *unpack_len)); DBUG_RETURN(0); } #endif /* HAVE_COMPRESS */