User:Rdebath/deadbeef

=Small and fast Brainfuck interpreter=

This interpreter uses byte cells and Ansi-C89. It does use the POSIX limits.h header but this can be easily substituted. It currently out performs all but four or five pure interpreters, however, C and assembler/JIT generators should be a lot faster. (But some of them aren't!)

This means that it's performance is still an order of magnitude below a really fast brainfuck interpreter.

/* This is the deadbeef brainfuck interpreter. * * Robert de Bath (2014/2015). * Released into the public domain. * Alternatively you may consider it released under the CC0 */ void run(void); struct bfi { int mov; int cmd; int arg; } *pgm = 0; int pgmlen = 0, on_eof = 1, debug = 0; int main(int argc, char **argv) {   FILE * ifd; int ch; int p= -1, n= -1, j= -1; for { if (argc < 2 || argv[1][0] != '-' || argv[1][1] == '\0') { break; } else if (!strcmp(argv[1], "-e")) { argc--; argv++; on_eof = -1; } else if (!strcmp(argv[1], "-z")) { argc--; argv++; on_eof = 0; } else if (!strcmp(argv[1], "-n")) { argc--; argv++; on_eof = 1; } else if (!strcmp(argv[1], "-d")) { argc--; argv++; debug = 1; } else if (argv[1][0] == '-') { fprintf(stderr, "Unknown option '%s'\n", argv[1]); exit(1); } else break; }   ifd = argc>1&&strcmp(argv[1],"-")?fopen(argv[1],"r"):stdin; if(!ifd) perror(argv[1]); else { while((ch = getc(ifd)) != EOF && (ifd!=stdin || ch != '!' || j>=0)) { int r = (ch == '<' || ch == '>' || ch == '+' || ch == '-'); if (r || (debug && ch == '#') || (ch == ']' && j>=0) ||               ch == '[' || ch == ',' || ch == '.') { if (ch == '<') {ch = '>'; r = -r;} if (ch == '-') {ch = '+'; r = -r;} if (r && p>=0 && pgm[p].cmd == ch) { pgm[p].arg += r; continue; } if (p>=0 && pgm[p].cmd == '=' && ch == '+') { pgm[p].arg += r; continue; } if (p>=0 && pgm[p].cmd == '>') { pgm[p].mov = pgm[p].arg; } else { n++; if (n>= pgmlen-2) pgm = realloc(pgm, (pgmlen=n+99)*sizeof*pgm); if (!pgm) { perror("realloc"); exit(1); } pgm[n].mov = 0; }            pgm[n].cmd = ch; pgm[n].arg = r; p = n;             if (pgm[n].cmd == '[') { pgm[n].arg=j; j = n; } else if (pgm[n].cmd == ']') { pgm[n].arg = j; j = pgm[j].arg; pgm[pgm[n].arg].arg = n;               if (  pgm[n].mov == 0 && pgm[n-1].mov == 0 &&                      pgm[n-1].cmd == '+' && (pgm[n-1].arg&1) == 1 &&                      pgm[n-2].cmd == '[') { n -= 2; pgm[p=n].cmd = '='; pgm[n].arg = 0; } else if (pgm[n-1].cmd == '[') { n--; pgm[p=n].cmd = '?'; pgm[n].arg = pgm[n+1].mov; }            }          }       }       while(j>=0) { p=j; j=pgm[j].arg; pgm[p].arg=0; pgm[p].cmd = '+'; } if (ifd!=stdin) fclose(ifd); setbuf(stdout, NULL); if (pgm) { pgm[n+1].cmd = 0; run; } }   return !ifd; } void run(void) { static unsigned char t[(sizeof(int)>sizeof(short))+USHRT_MAX]; unsigned short m = 0; int n, ch; for(n=0; ; n++) { m += pgm[n].mov; switch(pgm[n].cmd) {         case 0:    return; case '=': t[m] = pgm[n].arg; break; case '+': t[m] += pgm[n].arg; break; case '[': if (t[m] == 0) n=pgm[n].arg; break; case ']': if (t[m] != 0) n=pgm[n].arg; break; case '?': while(t[m]) m += pgm[n].arg; break; case '>': m += pgm[n].arg; break; case '.': putchar(t[m]); break; case ',': if((ch=getchar)!=EOF) t[m]=ch; else if (on_eof != 1) t[m]=on_eof; break; case '#': fprintf(stderr, "\n%3d %3d %3d %3d %3d %3d %3d %3d %3d %3d\n%*s\n",               t[0],t[1],t[2],t[3],t[4],t[5],t[6],t[7],t[8],t[9],4*m+3,"^"); break; }   } }
 * 1) include 
 * 2) include 
 * 3) include 
 * 4) include 