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Failed to connect to MySQL: (1203) User howardkn already has more than 'max_user_connections' active connectionsPath: ...!weretis.net!feeder6.news.weretis.net!i2pn.org!i2pn2.org!.POSTED!not-for-mail From: fir Newsgroups: comp.lang.c Subject: Re: macro for fir list? Date: Sat, 30 Mar 2024 15:54:18 +0100 Organization: i2pn2 (i2pn.org) Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Sat, 30 Mar 2024 14:54:14 -0000 (UTC) Injection-Info: i2pn2.org; logging-data="3726156"; mail-complaints-to="usenet@i2pn2.org"; posting-account="+ydHcGjgSeBt3Wz3WTfKefUptpAWaXduqfw5xdfsuS0"; User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:27.0) Gecko/20100101 Firefox/27.0 SeaMonkey/2.24 In-Reply-To: X-Spam-Checker-Version: SpamAssassin 4.0.0 Bytes: 5750 Lines: 135 fir wrote: > fir wrote: >> fir wrote: >>> bart wrote: >>>> On 30/03/2024 09:56, fir wrote: >>>> >>>>>> >>>>> yet other example >>>>> >>>>> //bytes container >>>>> char* bytes = NULL; int bytes_size = 0; >>>>> void bytes_add(char val) { >>>>> (bytes=(char*)realloc(bytes,++bytes_size*sizeof(char)))[bytes_size-1]=val; >>>>> >>>>> >>>>> >>>>> } >>>>> void bytes_load(char* name) { FILE *f = fopen(name, "rb"); int >>>>> c; while((c=getc(f))!=EOF) bytes_add(c); fclose(f); } >>>> >>>> This is pretty inefficient. Loading an 8MB file this way takes 3 >>>> seconds, vs. 50ms to load it in one go. >>>> >>>> Loading the same 90KB file 10,000 times took 120 seconds, vs. 0.8 >>>> seconds even using a scripting language. >>>> >>>> 80% of the inefficiency is growing the buffer one byte at a time. The >>>> other 20% is reading the file one byte at a time. >>>> >>>> >>> i know its inneficient but that was not the point - the point was more >>> about composition and utility >>> >>> i may revrite but the example would be much longer >>> >>> char* bytes = NULL; int bytes_size = 0; >>> char* bytes_resize(char size) {return >>> bytes=(char*)realloc(bytes,(bytes_size=size)*sizeof(char)); } >>> void bytes_add(char val) { >>> (bytes=(char*)realloc(bytes,++bytes_size*sizeof(char)))[bytes_size-1]=val; >>> >>> >>> } >>> void bytes_save(char* name) { FILE* f =fopen(name, "wb"); int >>> saved = fwrite (bytes , 1, bytes_size, f); fclose (f); } >>> >>> >>> int GetFileSize2(char *filename) >>> { >>> struct stat st; >>> if (stat(filename, &st)==0) return (int) st.st_size; >>> // ERROR_EXIT("error obtaining file size for &s", filename); >>> return -1; >>> } >>> >>> void bytes_load(char* name) >>> { >>> int flen = GetFileSize2(name); >>> FILE *f = fopen(name, "rb"); >>> int loaded = fread(bytes_resize(flen), 1, flen, f); >>> fclose(f); >>> } >>> >>> generally if some uses this bytes microcintainer (i call it also list, >>> though it is also resizable array) one may use thie add method which >>> callst reallock or call resize(1000) and use it by bytes[i] so its not >>> inefficient >>> >>> //@include "bytes.c" >>> for(int i=0;i<1000;i++) bytes_add(rand()&0xff); >>> >>> bytes_resize(1000); >>> for(int i=0;i<1000;i++) bytes[i]=rand()&0xff; >>> >> >> yoy may check how much it last to say insert 1M of bytes by add compared >> to resize and put it normall way - thic could measure overhead of this >> reallock... i may add this variable say _cached_size or what to name it, >> its a line of code ot wo and that will speed up but there still be a >> cost of if > > > i made some test with putting 1M by add it takes 160 ms > 10M by cahced add 45 ms and 10M stright 7 ms, 10M by firs approch may > take more than 10x 160 ms becouse i drwa a plot and if its plots so slow > i dont wait, > > if so it seems that this reallock is badly designed or what becouse > it shouldnt be so much slow imo - i vaguelly remember there was > iek already talko on this here..meybe becouse some multithreading > things or what (calling across dll barrier shouldnt be so slow per > se - it also seems i got some slight bug in the test > > if(_1_pressed) { bytes_size=0; for(int i=0; i<1*1024*1024; i++) > bytes_add(0x55); } > if(_2_pressed) { bytes_size=0; for(int i=0; i<10*1024*1024; i++) > bytes_add_cached(0x55); } > if(_3_pressed) { bytes_resize(10*1024*1024); for(int i=0; > i<10*1024*1024; i++) bytes[i]=0x55; } > > becouse all is okai untill i press 1 2 1 2 and now its segfault > but my head hurts today a bot and im not sure i even want to search fr > that bug now > ah, i know its obvious..i should use two separete seens as when i ussed thich cached one i may assume i reallocked cached amount and when i press 1 i reallock the same sid and i guess it reallocks it down so then cached one accesses above the limit > > char* bytes = NULL; int bytes_size = 0; > > char* bytes_resize(int size) > { > return bytes=(char*) realloc(bytes, (bytes_size=size)*sizeof(char)); > } > > void bytes_add(char val) { > (bytes=(char*)realloc(bytes,++bytes_size*sizeof(char)))[bytes_size-1]=val; > } > > void bytes_add_cached(char val) { > static int cached_size = 0; > bytes_size++; > if(bytes_size<=cached_size); > else > bytes=(char*)realloc(bytes,(cached_size=(bytes_size+100)*10)*sizeof(char)); > > bytes[bytes_size-1]=val; return; > > } > > >