initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644 (file)
index 0000000..292a768
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+bf

diff --git a/Makefile b/Makefile
new file mode 100644 (file)
index 0000000..a8f241a
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,7 @@
+PROGRAM:=bf
+CFLAGS:=-Wall -Werror -g
+
+all: $(PROGRAM)
+
+clean:
+       $(RM) -v $(PROGRAM)

diff --git a/bf.c b/bf.c
new file mode 100644 (file)
index 0000000..c095176
--- /dev/null
+++ b/bf.c
@@ -0,0 +1,87 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+struct nest {
+       long pos;
+       struct nest *next;
+};
+
+int main(int argc, char *argv[])
+{
+       size_t offset, stacksize = 1;
+       char *b = malloc(stacksize);
+       b[0] = 0;
+       char *ptr = b;
+       struct nest *t, *callstack = NULL;
+       FILE *in;
+
+       if(argc != 2){
+               fprintf(stderr, "Usage: %s PROGRAM\n", argv[0]);
+               return EXIT_FAILURE;
+       }
+       
+       if((in = fopen(argv[1], "r")) == NULL){
+               perror("fopen");
+               return EXIT_FAILURE;
+       }
+
+       while(1){
+               switch(fgetc(in)){
+                       case EOF:
+                               return EXIT_SUCCESS;
+                       case '>':
+                               ++ptr;
+                               if(ptr > b+stacksize){
+                                       offset = ptr-b;
+                                       b = realloc(b, stacksize *= 2);
+                                       ptr = b+offset;
+                                       memset(ptr, 0, stacksize/2);
+                               }
+                               break;
+                       case '<':
+                               if(ptr == b){
+                                       fprintf(stderr, "There is no stack position -1...\n");
+                                       return EXIT_FAILURE;
+                               }
+                               --ptr;
+                               break;
+                       case '+':
+                               ++*ptr;
+                               break;
+                       case '-':
+                               --*ptr;
+                               break;
+                       case '.':
+                               putchar(*ptr);
+                               break;
+                       case ',':
+                               *ptr = getchar();
+                               break;
+                       case '[':
+                               if(*ptr){
+                                       t = callstack;
+                                       callstack = malloc(sizeof(struct nest));
+                                       callstack->next = t;
+                                       if((callstack->pos = ftell(in)) == -1){
+                                               perror("ftell");
+                                               return EXIT_FAILURE;
+                                       }
+                               } else {
+                                       while(fgetc(in) != ']');
+                               }
+                               break;
+                       case ']':
+                               if(fseek(in, callstack->pos-1, SEEK_SET) == -1){
+                                       perror("fseek");
+                                       return EXIT_FAILURE;
+                               }
+                               t = callstack;
+                               callstack = callstack->next;
+                               free(t);
+                               break;
+                       default:
+                               break;
+               }
+       }
+}