Initial release

src/cmp.c

@@ -0,0 +1,129 @@
+/* cmp.c */
+
+
+
+#include <unistd.h>
+extern int optind;
+#include <stdio.h>
+#include <string.h>
+
+
+/* types */
+typedef enum _OutputType {
+	OT_NONE,
+	OT_LONG,
+	OT_DEFAULT
+} OutputType;
+
+
+/* cmp */
+static int _cmp_files(OutputType ot, char * file1, char * file2,
+		FILE * fp1, FILE * fp2);
+static int _cmp(OutputType ot, char * file1, char * file2)
+{
+	FILE * fp1;
+	FILE * fp2;
+
+	if(strcmp("-", file1) == 0)
+		fp1 = stdin;
+	else if((fp1 = fopen(file1, "r")) == NULL)
+	{
+		perror("fopen");
+		return 2;
+	}
+	if(strcmp("-", file2) == 0)
+		fp2 = stdin;
+	else if((fp2 = fopen(file2, "r")) == NULL)
+	{
+		perror("fopen");
+		if(fp1 != stdin)
+			fclose(fp1);
+		return 2;
+	}
+	return _cmp_files(ot, file1, file2, fp1, fp2);
+}
+
+static int _cmp_files(OutputType ot, char * file1, char * file2,
+		FILE * fp1, FILE * fp2)
+{
+	int c1;
+	int c2;
+	unsigned int byte = 1;
+	unsigned int line = 1;
+	int res = 0;
+
+	while(1)
+	{
+		c1 = fgetc(fp1);
+		c2 = fgetc(fp2);
+		if(c1 == EOF && c2 == EOF)
+			break;
+		if(c1 == EOF || c2 == EOF)
+		{
+			if(ot != OT_NONE)
+				fprintf(stderr, "%s%s\n",
+						"cmp: EOF on ",
+						c1 == EOF ? file1 : file2);
+			res = 1;
+			break;
+		}
+		if(c1 != c2)
+		{
+			res = 1;
+			if(ot == OT_DEFAULT)
+			{
+				printf("%s %s differ: char %u, line %u\n",
+						file1, file2, byte, line);
+				break;
+			}
+			else if(ot == OT_LONG)
+				printf("%d %o %o\n", byte, c1, c2);
+			else
+				break;
+		}
+		if(c1 == '\n')
+			line++;
+		byte++;
+	}
+	if(fp1 != stdin)
+		fclose(fp1);
+	if(fp2 != stdin)
+		fclose(fp2);
+	return res;
+}
+
+
+/* usage */
+static int _usage(void)
+{
+	fprintf(stderr, "%s", "Usage: cmp [-l|-s] file1 file2\n\
+  -l    write the byte number and the differing byte for each difference\n\
+  -s    write nothing for differing bytes\n");
+	return 2;
+}
+
+
+/* main */
+int main(int argc, char * argv[])
+{
+	OutputType ot = OT_DEFAULT;
+	int o;
+
+	while((o = getopt(argc, argv, "ls")) != -1)
+	{
+		switch(o)
+		{
+			case 'l':
+				ot = OT_LONG;
+				break;
+			case 's':
+				ot = OT_NONE;
+				break;
+			case '?':
+				return _usage();
+		}
+	}
+	if(argc - optind != 2)
+		return _usage();
+	return _cmp(ot, argv[optind], argv[optind+1]);
+}