1 files changed, 164 insertions, 0 deletions
diff --git a/c2bin.c b/c2bin.c
new file mode 100644
index 0000000..b15ee88
--- /dev/null
+++ b/c2bin.c
@@ -0,0 +1,164 @@
+#include <ctype.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+void usage(){
+	fprintf(stderr,
+		"Usage: c2bin [inputfile] [outputfile]\n"
+		"\n"
+		"Converts a C string to its parsed contents. The inverse of bin2c.\n"
+		"Default values for the arguments are stdin and stdout; also '-' indicates the\n"
+		"standard stream.\n");
+}
+
+int unhex(int c){
+	if(c>='0'&&c<='9'){
+		return c-'0';
+	} else if(c>='a'&&c<='f'){
+		return c-'a'+10;
+	} else if(c>='A'&&c<='F'){
+		return c-'A'+10;
+	} else {
+		return -1;
+	}
+}
+
+void c2bin(FILE *input,FILE *output){
+	bool stringmode=false;
+	int c;
+	while((c=fgetc(input))!=EOF){
+		if(c=='"'){
+			stringmode=!stringmode;
+		} else if(!stringmode){
+			if(!isspace(c)){
+				fprintf(stderr,"Characters outside string\n");
+				exit(1);
+			}
+		} else if(c=='\n'){
+			fprintf(stderr,"Invalid newline in string\n");
+			exit(1);
+		} else if(c!='\\'){
+			fputc(c,output);
+		} else {
+			c=fgetc(input);
+			if(c==EOF){
+				fprintf(stderr,"Invalid backslash at end of input\n");
+				exit(1);
+			} else if(c=='\n'){
+				continue;
+			} else if(c!='x'&&!isdigit(c)){
+				switch(c){
+					case 'a': fputc('\a',output); break;
+					case 'b': fputc('\b',output); break;
+					case 'f': fputc('\f',output); break;
+					case 'n': fputc('\n',output); break;
+					case 'r': fputc('\r',output); break;
+					case 't': fputc('\t',output); break;
+					case 'v': fputc('\v',output); break;
+					default: fputc(c,output); break;
+				}
+			} else if(c=='x'){
+				int c1=fgetc(input);
+				int c2=fgetc(input);
+				if(c1==-1||c2==-1){
+					fprintf(stderr,"Invalid end of input\n");
+					exit(1);
+				}
+				c1=unhex(c1);
+				c2=unhex(c2);
+				if(c1==-1){
+					fprintf(stderr,"Invalid hexadecimal escape\n");
+					exit(1);
+				}
+				if(c2==-1){
+					fputc(c1,output);
+				} else {
+					c=fgetc(input);
+					if(c==-1){
+						fprintf(stderr,"Invalid end of input\n");
+						exit(1);
+					}
+					if(unhex(c)!=-1){
+						fprintf(stderr,"Invalid wide hexadecimal escape\n");
+						exit(1);
+					}
+					ungetc(c,input);
+
+					fputc(16*c1+c2,output);
+				}
+			} else {
+				ungetc(c,input);
+				int res=0,i;
+				for(i=0;i<3;i++){
+					c=fgetc(input);
+					if(c==EOF){
+						fprintf(stderr,"Invalid end of input\n");
+						exit(1);
+					}
+					if(c<'0'||c>='8'){
+						ungetc(c,input);
+						break;
+					}
+					res=8*res+c-'0';
+				}
+				if(i==0){
+					fprintf(stderr,"Invalid octal escape\n");
+					exit(1);
+				}
+				fputc(res,output);
+			}
+		}
+		fflush(output);
+	}
+}
+
+int main(int argc,char **argv){
+	if(argc==1){
+		c2bin(stdin,stdout);
+	} else if(argc==2){
+		if(strcmp(argv[1],"-h")==0||strcmp(argv[1],"--help")==0){
+			usage();
+		} else if(strcmp(argv[1],"-")==0){
+			c2bin(stdin,stdout);
+		} else {
+			FILE *f=fopen(argv[1],"rb");
+			if(!f){
+				fprintf(stderr,"Could not open file '%s'\n",argv[1]);
+				return 1;
+			}
+			c2bin(f,stdout);
+			fclose(f);
+		}
+	} else if(argc==3){
+		FILE *fin,*fout;
+		if(strcmp(argv[1],"-")==0){
+			fin=stdin;
+		} else {
+			fin=fopen(argv[1],"rb");
+			if(!fin){
+				fprintf(stderr,"Could not open file '%s'\n",argv[1]);
+				return 1;
+			}
+		}
+
+		if(strcmp(argv[2],"-")==0){
+			fout=stdout;
+		} else {
+			fout=fopen(argv[2],"rb");
+			if(!fout){
+				fprintf(stderr,"Could not open file '%s'\n",argv[2]);
+				return 1;
+			}
+		}
+
+		c2bin(fin,fout);
+
+		fclose(fin);
+		fclose(fout);
+	} else {
+		usage();
+		return 1;
+	}
+}