diff --git a/c_src/.gitignore b/c_src/.gitignore new file mode 100644 index 0000000..5761abc --- /dev/null +++ b/c_src/.gitignore @@ -0,0 +1 @@ +*.o diff --git a/c_src/egs_prs_drv.c b/c_src/egs_prs_drv.c new file mode 100644 index 0000000..d7d7d03 --- /dev/null +++ b/c_src/egs_prs_drv.c @@ -0,0 +1,74 @@ +/* + @author Loïc Hoguin + @copyright 2010 Loïc Hoguin. + @doc PRS Erlang driver for EGS. + + This file is part of EGS. + + EGS is free software: you can redistribute it and/or modify + it under the terms of the GNU Affero General Public License as + published by the Free Software Foundation, either version 3 of the + License, or (at your option) any later version. + + EGS 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 Affero General Public License for more details. + + You should have received a copy of the GNU Affero General Public License + along with EGS. If not, see . +*/ + +#include "/opt/erlang/lib/erlang/usr/include/erl_nif.h" + +extern unsigned long prs_compress(unsigned char* source, unsigned char* dest, unsigned long size); + +static ERL_NIF_TERM compress_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) +{ + ErlNifBinary srcbin; + ErlNifBinary destbin; + unsigned int size; + + if (argc != 1) + return enif_make_badarg(env); + + if (!enif_is_binary(env, argv[0])) + return enif_make_badarg(env); + + if (!enif_inspect_binary(env, argv[0], &srcbin)) + return enif_make_badarg(env); + + if (!enif_alloc_binary((9 * srcbin.size) / 8 + 2, &destbin)) + return enif_make_badarg(env); + + size = prs_compress(srcbin.data, destbin.data, srcbin.size); + enif_realloc_binary(&destbin, size); + + return enif_make_binary(env, &destbin); +} + +static int load(ErlNifEnv* env, void** priv, ERL_NIF_TERM load_info) +{ + return 0; +} + +static int reload(ErlNifEnv* env, void** priv, ERL_NIF_TERM load_info) +{ + return 0; +} + +static int upgrade(ErlNifEnv* env, void** priv, void** old_priv, ERL_NIF_TERM load_info) +{ + return 0; +} + +static void unload(ErlNifEnv* env, void* priv) +{ + return; +} + +static ErlNifFunc nif_funcs[] = { + {"compress", 1, compress_nif} +}; + +ERL_NIF_INIT(egs_prs, nif_funcs, load, reload, upgrade, unload) diff --git a/c_src/prs.c b/c_src/prs.c new file mode 100644 index 0000000..d2594e5 --- /dev/null +++ b/c_src/prs.c @@ -0,0 +1,173 @@ +/* + Original code from the PRSutil project. + http://www.fuzziqersoftware.com/projects.php +*/ + +#include + +typedef struct { + unsigned char bitpos; + unsigned char* controlbyteptr; + unsigned char* srcptr_orig; + unsigned char* dstptr_orig; + unsigned char* srcptr; + unsigned char* dstptr; } PRS_COMPRESSOR; + +void prs_put_control_bit(PRS_COMPRESSOR* pc,unsigned char bit) +{ + *pc->controlbyteptr = *pc->controlbyteptr >> 1; + *pc->controlbyteptr |= ((!!bit) << 7); + pc->bitpos++; + if (pc->bitpos >= 8) + { + pc->bitpos = 0; + pc->controlbyteptr = pc->dstptr; + pc->dstptr++; + } +} + +void prs_put_control_bit_nosave(PRS_COMPRESSOR* pc,unsigned char bit) +{ + *pc->controlbyteptr = *pc->controlbyteptr >> 1; + *pc->controlbyteptr |= ((!!bit) << 7); + pc->bitpos++; +} + +void prs_put_control_save(PRS_COMPRESSOR* pc) +{ + if (pc->bitpos >= 8) + { + pc->bitpos = 0; + pc->controlbyteptr = pc->dstptr; + pc->dstptr++; + } +} + +void prs_put_static_data(PRS_COMPRESSOR* pc,unsigned char data) +{ + *pc->dstptr = data; + pc->dstptr++; +} + +unsigned char prs_get_static_data(PRS_COMPRESSOR* pc) +{ + unsigned char data = *pc->srcptr; + pc->srcptr++; + return data; +} + +/* **************************************************** */ + +void prs_init(PRS_COMPRESSOR* pc,void* src,void* dst) +{ + pc->bitpos = 0; + pc->srcptr = (unsigned char*)src; + pc->srcptr_orig = (unsigned char*)src; + pc->dstptr = (unsigned char*)dst; + pc->dstptr_orig = (unsigned char*)dst; + pc->controlbyteptr = pc->dstptr; + pc->dstptr++; +} + +void prs_finish(PRS_COMPRESSOR* pc) +{ + prs_put_control_bit(pc,0); + prs_put_control_bit(pc,1); + if (pc->bitpos != 0) + { + *pc->controlbyteptr = ((*pc->controlbyteptr << pc->bitpos) >> 8); + } + prs_put_static_data(pc,0); + prs_put_static_data(pc,0); +} + +void prs_rawbyte(PRS_COMPRESSOR* pc) +{ + prs_put_control_bit_nosave(pc,1); + prs_put_static_data(pc,prs_get_static_data(pc)); + prs_put_control_save(pc); +} + +void prs_shortcopy(PRS_COMPRESSOR* pc,int offset,unsigned char size) +{ + size -= 2; + prs_put_control_bit(pc,0); + prs_put_control_bit(pc,0); + prs_put_control_bit(pc,(size >> 1) & 1); + prs_put_control_bit_nosave(pc,size & 1); + prs_put_static_data(pc,offset & 0xFF); + prs_put_control_save(pc); +} + +void prs_longcopy(PRS_COMPRESSOR* pc,int offset,unsigned char size) +{ + if (size <= 9) + { + prs_put_control_bit(pc,0); + prs_put_control_bit_nosave(pc,1); + prs_put_static_data(pc,((offset << 3) & 0xF8) | ((size - 2) & 0x07)); + prs_put_static_data(pc,(offset >> 5) & 0xFF); + prs_put_control_save(pc); + } else { + prs_put_control_bit(pc,0); + prs_put_control_bit_nosave(pc,1); + prs_put_static_data(pc,(offset << 3) & 0xF8); + prs_put_static_data(pc,(offset >> 5) & 0xFF); + prs_put_static_data(pc,size - 1); + prs_put_control_save(pc); + } +} + +void prs_copy(PRS_COMPRESSOR* pc,int offset,unsigned char size) +{ + if ((offset > -0x100) && (size <= 5)) + prs_shortcopy(pc,offset,size); + else + prs_longcopy(pc,offset,size); + pc->srcptr += size; +} + +/* **************************************************** */ + +unsigned long prs_compress(void* source,void* dest,unsigned long size) +{ + PRS_COMPRESSOR pc; + int x,y; + unsigned long xsize; + int lsoffset,lssize; + prs_init(&pc,source,dest); + for (x = 0; x < size; x++) + { + lsoffset = lssize = xsize = 0; + for (y = x - 3; (y > 0) && (y > (x - 0x1FF0)) && (xsize < 255); y--) + { + xsize = 3; + if (!memcmp((void*)((unsigned long)source + y),(void*)((unsigned long)source + x),xsize)) + { + do xsize++; + while (!memcmp((void*)((unsigned long)source + y), + (void*)((unsigned long)source + x), + xsize) && + (xsize < 256) && + ((y + xsize) < x) && + ((x + xsize) <= size) + ); + xsize--; + if (xsize > lssize) + { + lsoffset = -(x - y); + lssize = xsize; + } + } + } + if (lssize == 0) + { + prs_rawbyte(&pc); + } else { + prs_copy(&pc,lsoffset,lssize); + x += (lssize - 1); + } + } + prs_finish(&pc); + return pc.dstptr - pc.dstptr_orig; +} diff --git a/priv/.gitignore b/priv/.gitignore new file mode 100644 index 0000000..8f857fe --- /dev/null +++ b/priv/.gitignore @@ -0,0 +1 @@ +egs_drv.so diff --git a/src/egs_prs.erl b/src/egs_prs.erl new file mode 100644 index 0000000..b74b0a2 --- /dev/null +++ b/src/egs_prs.erl @@ -0,0 +1,28 @@ +%% @author Loïc Hoguin +%% @copyright 2010 Loïc Hoguin. +%% @doc EGS file creation functions. +%% +%% This file is part of EGS. +%% +%% EGS is free software: you can redistribute it and/or modify +%% it under the terms of the GNU Affero General Public License as +%% published by the Free Software Foundation, either version 3 of the +%% License, or (at your option) any later version. +%% +%% EGS 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 Affero General Public License for more details. +%% +%% You should have received a copy of the GNU Affero General Public License +%% along with EGS. If not, see . + +-module(egs_prs). +-export([init/0, compress/1]). +-on_load(init/0). + +init() -> + erlang:load_nif("priv/egs_drv", 0). + +compress(_SrcBin) -> + exit(nif_library_not_loaded).