Merge pull request merces#1 from UserXGnu/stdin_support

Adding /dev/stdin reading support

Author: UserXGnu

Makefile

@@ -1,5 +1,5 @@
 all:
-	gcc -Wall -Wextra -pedantic -ansi -o hdump hdump.c 
+	gcc -Wall -Wextra -pedantic -o hdump hdump.c
 
 install:
 	install -m 0755 hdump /usr/local/bin/hdump

hdump.c

@@ -19,6 +19,9 @@
 
 #ifdef __unix__
 #define _FILE_OFFSET_BITS 64
+
+#include <unistd.h>
+
 #endif /*__unix__ */
 
 #include <stdio.h>
@@ -90,20 +93,36 @@ int main(int argc, char *argv[])
 	if (!cols)
 		cols = 16;
 
-	buff = (unsigned char *) calloc (1, sizeof(unsigned char) * cols);
-	ascii = (unsigned char *) calloc (1, (sizeof(unsigned char) * cols) + 1);
+	if (!(file = fopen(argv[argc-1], "rb")))
+		fatal("file not found or not readable");
 
+#ifdef __unix__
 
-	if (!buff || !ascii)
-		fatal("not enough memory");
+ 	/*
+	 * Caso o arquivo de entrada seja na verdade uma
+	 * pseudo-tty como /dev/stdin.
+	 */
+	if (isatty (fileno (file))) {
+		for ( ;skip > 0; skip --) {
+			if (fgetc (file) == EOF) 
+				fatal ("skipping too much");
+		}
+	}
 
-	if (!(file = fopen(argv[argc-1], "rb")))
-		fatal("file not found or not readable");
+#else 
 
 	/* anda #skip posicoes para frente (-s) */
 	if (fseek(file, skip, SEEK_SET))
 		fatal("unable to seek through file");
 
+#endif /* __unix__ */
+
+	buff = (unsigned char *) calloc (1, sizeof(unsigned char) * cols);
+	ascii = (unsigned char *) calloc (1, (sizeof(unsigned char) * cols) + 1);
+
+	if (!buff || !ascii)
+		fatal("not enough memory");
+
 	do
 	{
 		bread = (int) fread(buff, sizeof(char), cols, file);
@@ -119,15 +138,12 @@ int main(int argc, char *argv[])
 			/* imprime os bytes separados por espaço */
 			printf("%02x%*c", (unsigned int) *(buff+i), (i+1 == cols/2) ? 2 : 1, ' ');
 
-			/* 
-			 * define o final do array asciii (será usado como string)
-			 * imprime os caracteres ascii 
-			 * */
-			if (i == bread-1) 
-			{
-			 	*(ascii+bread) = '\0';
+			/* define o fim do array ascii (sera usado como string) */
+			*(ascii+bread) = '\0';
+
+			/* imprime os caracteres ascii */
+			if (i == bread-1)
 				printf("%*c|%s|\n", get_spaces(bread, cols), ' ', ascii);
-			}
 		}
 		/* atualiza o numero de endereços lidos */
 		address += bread;