initial commit

.gitignore

@@ -0,0 +1 @@
+obj/

Makefile

@@ -0,0 +1,44 @@
+SRC = $(wildcard src/*.c)
+INCLUDE=include
+
+PROJECT=fcmp
+
+OPT_FLAGS+= -fgraphite -fno-strict-aliasing
+
+RELEASE_CFLAGS?=  -O3 -march=native -flto $(OPT_FLAGS)
+RELEASE_LDFLAGS?= -O3 -flto
+
+DEBUG_CFLAGS?=  -O0 -g
+DEBUG_LDFLAGS?= -O0
+
+CFLAGS+= -Wall -pedantic --std=gnu11 $(addprefix -I,$(INCLUDE))
+LDFLAGS+= 
+
+OBJ = $(addprefix obj/,$(SRC:.c=.o))
+
+.PHONY: release
+release: | dirs $(PROJECT)-release
+
+.PHONY: debug
+debug: | dirs $(PROJECT)-debug
+
+dirs:
+	@mkdir -p obj/src
+
+%.o: %.c
+	$(CC) -c $< $(CFLAGS) -o $@ $(LDFLAGS)
+
+$(PROJECT)-release: CFLAGS := $(RELEASE_CFLAGS) $(CFLAGS)
+$(PROJECT)-release: LDFLAGS := $(RELEASE_LDFLAGS) $(LDFLAGS)
+$(PROJECT)-release: $(OBJ)
+	$(CC) $^ $(CFLAGS) -o $@ $(LDFLAGS)
+	strip $@
+
+$(PROJECT)-debug: CFLAGS := $(DEBUG_CFLAGS) $(CFLAGS)
+$(PROJECT)-debug: LDFLAGS := $(DEBUG_LDFLAGS) $(LDFLAGS)
+$(PROJECT)-debug: $(OBJ)
+	$(CC) $^ $(CFLAGS) -o $@ $(LDFLAGS)
+
+clean:
+	rm -rf obj
+	rm -f $(PROJECT)-{release,debug}

include/map.h

@@ -0,0 +1,26 @@
+#ifndef _MAP_H
+#define _MAP_H
+
+#ifdef __cplusplus
+extern "C" {
+#define restrict __restrict__
+#endif
+
+#include <stddef.h>
+
+typedef struct mmap {
+	int fd;
+
+	void* ptr;
+	size_t len;
+} mmap_t;
+
+int open_and_map(const char* file, mmap_t* restrict ptr);
+int unmap_and_close(mmap_t map);
+
+#ifdef _cplusplus
+}
+#undef restrict
+#endif
+
+#endif /* _MAP_H */

src/main.c

@@ -0,0 +1,55 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <map.h>
+
+static const char* _prog_name = "fcmp";
+
+__attribute__((noreturn)) void usage() 
+{
+	fprintf(stderr, "usage: %s <file1> <file2>\n", _prog_name);
+	exit(-1);
+}
+
+__attribute__((always_inline)) static inline const void* die_if_null(const void* ptr)
+{
+	if (!ptr) usage();
+	else return ptr;
+}
+
+int main(int argc, char** argv)
+{
+	_prog_name = argv[0];
+
+	const char* f1 = die_if_null(argv[1]);
+	const char* f2 = die_if_null(argv[2]);
+
+	mmap_t map1, map2;
+	if (!open_and_map(f1, &map1)) {
+		fprintf(stderr, "Failed to open or map %s\n", f1);
+		return -1;
+	}
+	if (!open_and_map(f2, &map2)) {
+		fprintf(stderr, "Failed to open or map %s\n", f2);
+		unmap_and_close(map1);
+		return -1;
+	}
+
+	if (map1.len != map2.len) return 2;
+
+	if (memcmp(map1.ptr, map2.ptr, map1.len) != 0) return 1;
+
+	register int rval=0;
+	if(!unmap_and_close(map1)) {
+		fprintf(stderr, "Failed to unmap and close %s", f1);
+		rval=-1;
+	}
+
+	if(!unmap_and_close(map2)) {
+		fprintf(stderr, "Failed to unmap and close %s", f2);
+		rval=-1;
+	}
+
+	return rval;
+}

src/map.c

@@ -0,0 +1,55 @@
+#define _GNU_SOURCE
+#include<stdio.h>
+#include<stdlib.h>
+#include<string.h>
+#include<unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include<sys/mman.h>
+#include<fcntl.h>
+
+#define FILEMODE S_IRWXU | S_IRGRP | S_IROTH
+
+#include <map.h>
+
+int open_and_map(const char* file, mmap_t* restrict ptr)
+{
+	int fd;
+	struct stat st;
+	if ((fd = open(file, O_RDONLY, FILEMODE)) < 0) {
+		perror("Failed to open file");
+		return 0;
+	}
+
+	if (fstat(fd, &st) < 0) {
+		perror("Failed to stat file");
+		close(fd);
+		return 0;
+	}
+
+	register struct mmap map = { .fd = fd, .ptr = NULL, .len = st.st_size };
+
+	if ((map.ptr = mmap(NULL, map.len, PROT_READ, MAP_SHARED,fd, 0)) == MAP_FAILED) {
+		perror("mmam() failed");
+		close(fd);
+		return 0;
+	}
+
+	*ptr = map;
+
+	return 1;
+}
+
+int unmap_and_close(mmap_t map)
+{
+	if (munmap(map.ptr, map.len) < 0) {
+		perror("munmap() failed");
+		return 0;
+	}
+	if (close(map.fd) <0) {
+		perror("Failed to close fd");
+		return 0;
+	}
+
+	return 1;
+}