diff --git a/include/array.h b/include/array.h
new file mode 100644
index 0000000..9f0d4d2
--- /dev/null
+++ b/include/array.h
@@ -0,0 +1,27 @@
+#ifndef _ARRAY_H
+#define _ARRAY_H
+#include <ptr_store.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct array* array_t;
+
+array_t ar_create_file(S_LEXENV, FILE* from, size_t element_size, int owns_stream);
+array_t ar_create_memory_from(S_LEXENV, const void* from, size_t element_size, size_t count);
+array_t ar_create_memory(S_LEXENV, size_t size, size_t count, int init0);
+
+const void* ar_get(const array_t this, long i);
+void ar_set(array_t this, long i, const void* obj);
+long ar_size(const array_t this);
+long ar_full_size(const array_t this);
+long ar_type(const array_t this);
+int ar_get_into(const array_t this, long i, void* buffer);
+void ar_swap(array_t from, long i, long j);
+void ar_reinterpret(array_t from, size_t element);
+int ar_dump(const array_t from, void* buffer, size_t offset, size_t count);
+int ar_ndump(const array_t from, void* buffer, size_t bufsize, size_t offset, size_t count);
+
+#define ar_get_v(this, type, i) (*((const type*)ar_get(this, i)))
+#define ar_set_v(this, i, value) ar_set(this, i, &value)
+
+#endif /* _ARRAY_H */
diff --git a/include/ptr_store.h b/include/ptr_store.h
index a90875c..ca41d40 100644
--- a/include/ptr_store.h
+++ b/include/ptr_store.h
@@ -40,6 +40,7 @@ extern const object OBJ_PROTO;
 #define strack _store_first_empty(__internal_store, 0)->ptr = 
 #define strack_obj _store_first_empty(__internal_store, 1)->ptr =
 
+#define S_NAMED_LEXENV(n) store_t* n
 #define S_LEXENV store_t* __internal_store
 #define S_LEXCALL(f, ...) f(__internal_store, __VA_ARGS__)
 #define LEXENV __internal_store
@@ -51,8 +52,25 @@ extern const object OBJ_PROTO;
 #define MANAGED(var) { \
 				store_t * __internal_store = new_store(); \
 				var; \
+				goto __internal_breakpoint; /*to suppress unused warning*/ \
+				__internal_breakpoint: \
 				destroy_store(__internal_store); \
 			}
+#define MANAGED_RETURNABLE(type, var) { \
+						type __internal_retval; \
+						int __internal_has_set_return =0; \
+						store_t * __internal_store = new_store(); \
+						var; \
+						goto __internal_breakpoint; /*to suppress unused warning*/ \
+						__internal_breakpoint: \
+						destroy_store(__internal_store); \
+						if(__internal_has_set_return) return __internal_retval; \
+					}
+#define MANAGED_RETURN(value) __internal_retval = value; \
+				__internal_has_set_return = 1; \
+				MANAGED_BREAK
+
+#define MANAGED_BREAK goto __internal_breakpoint
 
 #define STORE_LEXBIND(type, name) type name = *((type*)store_malloc(__internal_store, sizeof(type)));
 
diff --git a/src/array.c b/src/array.c
new file mode 100644
index 0000000..046da45
--- /dev/null
+++ b/src/array.c
@@ -0,0 +1,241 @@
+#include <ptr_store.h>
+#include <array.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+struct array {
+	object* base;
+
+	size_t size;
+	size_t element;
+
+	size_t full_size;
+
+	void *tl_state;
+	void* state;
+	
+	int (*dump)(const array_t this, void* buffer, size_t buffermax, size_t offset, size_t count);
+	void* (*get)(struct array* this, long i);
+	void (*set)(struct array* this, long i, const void* item);
+
+	unsigned char data[];
+};
+
+static void* _ar_memory_get(struct array* this, long i)
+{
+	if(i< 0|| i>= this->size) return NULL;
+	return &this->data[i*this->element];
+}
+
+static const void _ar_memory_set(struct array* this, long i, const void* item)
+{
+	if(i<0 || i>= this->size) return;
+
+	memcpy(this->data+(i*this->element), item, this->element);
+}
+
+static int _ar_memory_dump(const array_t this, void* buffer, size_t bufsize, size_t offset, size_t count)
+{
+	if(offset+count > this->size) return 0;
+#define min(x, y) (x<y?x:y)
+	long fsz = count*this->element;
+	long wsz = min(fsz, bufsize);
+	memcpy(buffer, this->data+(offset*this->element), wsz);
+	return (wsz==fsz);
+#undef min
+}
+
+static void _ar_memory_destructor(object* this)
+{
+	free(this->state);
+	this->state=NULL;
+}
+
+array_t ar_create_memory(S_LEXENV, size_t size, size_t count, int init0)
+{
+	array_t mem = malloc(sizeof(struct array)+(size*count));
+	memset(mem,0,sizeof(struct array));
+	if(init0)
+		memset(mem->data, 0, size*count);
+
+	mem->size = count;
+	mem->element = size;
+	mem->full_size = size*count;
+
+	mem->get = &_ar_memory_get;
+	mem->set = &_ar_memory_set;
+	mem->dump = &_ar_memory_dump;
+
+	object obj = OBJ_PROTO;
+	
+	obj.state= mem;
+	obj.destructor = &_ar_memory_destructor;
+
+	return snew_obj(obj)->state;
+}
+
+array_t ar_create_memory_from(S_LEXENV, const void* from, size_t element_size, size_t count)
+{
+	array_t mem = ar_create_memory(LEXENV, element_size, count, 0);
+	memcpy(mem->data, from, element_size*count);
+	return mem;
+}
+
+static inline size_t filesize(FILE* file)
+{
+	size_t from = ftell(file);
+	fseek(file,0,SEEK_END);
+	size_t ret = ftell(file);
+	fseek(file,from, SEEK_SET);
+
+	return ret;
+}
+
+static void* _ar_file_get(struct array* this, long i)
+{
+	if(i<0 || i>=this->size) return NULL;
+
+	fseek(this->state, i*this->element, SEEK_SET);
+	if(this->tl_state != NULL)
+		free(this->tl_state);
+	void* buffer = malloc(this->element);
+	this->tl_state = buffer;
+	fread(buffer, this->element, 1, this->state);
+
+	return buffer;
+}
+
+static void _ar_file_set(struct array* this, long i, const void* from)
+{
+	if(i<0 || i>=this->size) return;
+
+	fseek(this->state, i*this->element, SEEK_SET);
+
+	fwrite(from, this->element, 1, this->state);
+}
+
+static void _ar_file_destructor(object* _this)
+{
+	array_t this = _this->state;
+
+	if(this->tl_state!=NULL)
+		free(this->tl_state);
+	if(this->data[0])
+		fclose(this->state);
+
+	this->state=NULL;
+	this->tl_state=NULL;
+
+	free(this);
+}
+
+array_t ar_create_file(S_LEXENV, FILE* from, size_t element_size, int owns_stream)
+{
+	array_t mem = malloc(sizeof(struct array)+1);
+
+	memset(mem,0, sizeof(struct array));
+
+	mem->data[0] = (unsigned char)owns_stream;
+
+	mem->state = from;
+
+	mem->element = element_size;
+	mem->full_size = filesize(from);
+	mem->size = mem->full_size/element_size;
+
+	mem->get = &_ar_file_get;
+	mem->set = &_ar_file_set;
+
+	object obj = OBJ_PROTO;
+
+	obj.state = mem;
+	obj.destructor = &_ar_file_destructor;	
+
+	return snew_obj(obj)->state;
+}
+
+///Generic accessor functions
+
+const void* ar_get(const array_t this, long i)
+{
+	return this->get(this, i);
+}
+
+void ar_set(array_t this, long i, const void* obj)
+{
+	this->set(this, i, obj);
+}
+
+long ar_size(const array_t this)
+{
+	return this->size;
+}
+
+long ar_full_size(const array_t this)
+{
+	return this->full_size;
+}
+
+long ar_type(const array_t this)
+{
+	return this->element;
+}
+
+int ar_get_into(const array_t this, long i, void* buffer)
+{
+	const void* ptr = ar_get(this, i);
+	if(!ptr) return 0;
+	memcpy(buffer,ptr,this->element);
+	return 1;
+}
+
+void ar_swap(array_t from, long i, long j)
+{
+	unsigned char temp[from->element];
+	ar_get_into(from, i, temp);
+	
+	ar_set(from, i, ar_get(from, j));
+	ar_set(from, j, temp);
+}
+
+void ar_reinterpret(array_t from, size_t element)
+{
+	long fsz = from->full_size;
+
+	from->element = element;
+	from->size = fsz/element;
+}
+
+int ar_dump(const array_t from, void* buffer, size_t offset, size_t count)
+{
+	if(from->dump)
+		return from->dump(from, buffer, from->full_size, offset,count);
+	else {
+		unsigned char* buf = buffer;
+		for(int i=0;i<count;i++)
+		{
+			if(!ar_get_into(from, offset+i, buf)) return 0;
+			buf+=from->element;
+		}
+		return 1;
+	}
+}
+
+int ar_ndump(const array_t from, void* buffer, size_t bufsize, size_t offset, size_t count)
+{
+	if(from->dump)
+		return from->dump(from, buffer, bufsize, offset,count);
+	else {
+		unsigned char* buf = buffer;
+		unsigned char* maxbuf = buf+bufsize;
+
+		for(int i=0;i<count;i++)
+		{
+			if(buf>=maxbuf) return 0;
+			if(!ar_get_into(from, offset+i, buf)) return 0;
+			buf+= from->element;
+		}
+		return 1;
+	}
+}
diff --git a/src/frng.c b/src/frng.c
index 0177a02..9ddc150 100644
--- a/src/frng.c
+++ b/src/frng.c
@@ -7,6 +7,7 @@ double vec[2];
 static void _seed(const void* from)
 {
 	memcpy(vec, from, sizeof(double)*2);
+
 }
 
 double fract(double x)
diff --git a/src/main.c b/src/main.c
index 63b2bcb..ed17d47 100644
--- a/src/main.c
+++ b/src/main.c
@@ -5,6 +5,7 @@
 #include <rng.h>
 #include <rng_algos.h>
 #include <ptr_store.h>
+#include <array.h>
 
 /*void test_destructor(object* ptr)
 {
@@ -23,78 +24,111 @@ RNG rng_object(S_LEXENV, RNG rng)
 	return snew_obj(proto)->state;
 }
 
-void shuffle_longs(RNG with, long *data, int n)
+void shuffle(RNG with, array_t data)
 {
-	register long temp;
-	for(register int i= n-1;i>0;i--)
+	printf("  -> shuffling %d objects...", (int)ar_size(data));
+	for(int i=ar_size(data)-1;i>0;i--)
 	{
 		int j = rng_next_int(with, i);
-		temp = data[i];
-		data[i] = data[j];
-		data[j] = temp;
+		ar_swap(data, i, j);
 	}
+	printf(" Okay\n");
 }
 
-void shuffle_floats(RNG with, float* data, int n)
+void unshuffle(RNG with, array_t data)
 {
-	register float temp;
-	for(register int i=n-1;i>0;i--)
+	int rng_values[ar_size(data)-1];
+	int k=0;
+	printf("  -> unshuffling %d objects...", (int)ar_size(data));
+	for(int i=ar_size(data)-1;i>0;i--)
+		rng_values[k++] = rng_next_int(with, i);
+
+	for(int i=1;i<ar_size(data);i++)
 	{
-		int j = rng_next_int(with,i);
-		temp = data[i];
-		data[i] = data[j];
-		data[j] = temp;
+		ar_swap(data, i, rng_values[--k]);
 	}
+	printf(" Okay\n");
 }
 
-void shuffle_bytes(RNG with, unsigned char* data, int n)
+void minmax_longs(long* min, long* max, const array_t data)
 {
-	register unsigned char temp;
-	for(int i=n-1;i>0;i--)
+	for(register int i=0;i<ar_size(data);i++)
 	{
-		int j = rng_next_int(with, i);
-		temp  = data[i];
-		data[i] = data[j];
-		data[j] = temp;
+		if(ar_get_v(data, long, i)  > *max) *max = ar_get_v(data, long, i);
+		if(ar_get_v(data, long, i) < *min) *min = ar_get_v(data, long, i);
 	}
 }
+int valid_float(float f)
+{
+	return !( (f!=f) || (f< -FLT_MAX || f> FLT_MAX));
 
-void minmax_longs(long* min, long* max, const long* data, int n)
+}
+void minmax_floats(float* min, float* max, const array_t data)
 {
-	for(register int i=0;i<n;i++)
+	for(register int i=0;i<ar_size(data);i++)
 	{
-		if(data[i] > *max) *max = data[i];
-		if(data[i] < *min) *min = data[i];
+		if(!valid_float(ar_get_v(data,float,i))) continue;
+		if(ar_get_v(data, float, i)  > *max) *max = ar_get_v(data, float, i);
+		if(ar_get_v(data, float, i) < *min) *min = ar_get_v(data, float, i);
 	}
 }
 
-void minmax_floats(float* min, float* max, const float* data, int n)
+void minmax_sbytes(signed char* min, signed char* max, const array_t data)
 {
-	for(register int i=0;i<n;i++)
+	for(register int i=0;i<ar_size(data);i++)
 	{
-		if(data[i] > *max) *max = data[i];
-		if(data[i] < *min) *min = data[i];
+		if(ar_get_v(data, signed char, i)  > *max) *max = ar_get_v(data, signed char, i);
+		if(ar_get_v(data, signed char, i) < *min) *min = ar_get_v(data, signed char, i);
 	}
 }
 
-void minmax_sbytes(signed char* min, signed char* max, const signed char* data,int n)
+void print_array(const array_t data)
 {
-	for(register int i=0;i<n;i++)
-	{
-		if(data[i] > *max) *max = data[i];
-		if(data[i] < *min) *min = data[i];
-	}
+	printf("---%d elements---\n", (int)ar_size(data));
+	for(register int i=0;i<ar_size(data);i++)
+		printf("%d ", (int)ar_get_v(data, unsigned char, i));
+	printf("\n---\n");
 }
 
-void print_array(unsigned char* data, int len)
+void unshuffle3(S_LEXENV, array_t data)
 {
-	for(register int i=0;i<len;i++)
-		printf("%d ", (int)data[i]);
-	printf("\n");
-}
+	if(ar_type(data)!=sizeof(signed char))
+		ar_reinterpret(data, sizeof(signed char));
+	RNG xoro = S_LEXCALL(rng_object, rng_new(RNG_ALGO(xoroshiro128plus)));
+	RNG frng = S_LEXCALL(rng_object, rng_new(RNG_ALGO(frng)));
+	RNG drng = S_LEXCALL(rng_object, rng_new(RNG_ALGO(drng)));
 
-void shuffle3(S_LEXENV, void* data, int raw_len)
+	signed char bmax = INT8_MIN;
+	signed char bmin = INT8_MAX;
+	minmax_sbytes(&bmin, &bmax, data);
+	unsigned int seed = (0xfffa << 16) | (bmin<<8) | bmax;
+	rng_seed(drng, &seed);
+	unshuffle(drng, data);
+
+	float fmin = (float)DBL_MAX;
+	float fmax = (float)-DBL_MAX;
+	ar_reinterpret(data, sizeof(float));
+	minmax_floats(&fmin, &fmax, data);
+	double fseed[2];
+	fseed[0] = fmin;
+	fseed[1] = fmax;
+	rng_seed(frng, fseed);
+	unshuffle(frng, data);
+	
+	long min = INT64_MAX;
+	long max = INT64_MIN;
+	ar_reinterpret(data, sizeof(long));
+	minmax_longs(&min, &max, data);
+	uint64_t xseed[2];
+	xseed[0] = min;
+	xseed[1] = max;
+	rng_seed(xoro, xseed);
+	unshuffle(xoro, data);
+}
+void shuffle3(S_LEXENV, array_t data)
 {
+	if(ar_type(data)!=sizeof(long))
+		ar_reinterpret(data, sizeof(long));
 	RNG xoro = S_LEXCALL(rng_object, rng_new(RNG_ALGO(xoroshiro128plus)));
 	RNG frng = S_LEXCALL(rng_object, rng_new(RNG_ALGO(frng)));
 	RNG drng = S_LEXCALL(rng_object, rng_new(RNG_ALGO(drng)));
@@ -108,52 +142,140 @@ void shuffle3(S_LEXENV, void* data, int raw_len)
 	signed char bmax = INT8_MIN;
 	signed char bmin = INT8_MAX;
 
-	minmax_longs(&min, &max, data, raw_len/sizeof(long));
+	minmax_longs(&min, &max, data);
 	uint64_t xseed[2];
 	xseed[0] = min;
 	xseed[1] = max;
 
 	rng_seed(xoro, xseed);
-	shuffle_longs(xoro, data, raw_len/sizeof(long));
+	shuffle(xoro, data);
+
+	ar_reinterpret(data, sizeof(float));
+	minmax_floats(&fmin, &fmax, data);
 
-	minmax_floats(&fmin, &fmax, data, raw_len/sizeof(float));
 	double fseed[2];
 	fseed[0] = fmin;
 	fseed[1] = fmax;
 	rng_seed(frng, fseed);
-	shuffle_floats(frng, data, raw_len/sizeof(float));
+	shuffle(frng, data);
 
-	minmax_sbytes(&bmin, &bmax, data, raw_len);
+	ar_reinterpret(data,sizeof(signed char));
+	minmax_sbytes(&bmin, &bmax, data);
 	unsigned int seed = (0xfffa << 16) | (bmin<<8) | bmax;
 	rng_seed(drng, &seed);
-	shuffle_bytes(drng, data, raw_len);
+	shuffle(drng, data);
 }
 
-int main()
+void print_usage(char** argv)
 {
+	printf("Usage: %s -[b]s <file> [<outfile>]\nUsage: %s -[b]u <file> [<outfile>]\n", argv[0], argv[0]);
+	printf(" <file>\t\tFile to shuffle\n");
+	printf(" <outfile>\tOutput file (only valid for buffered mode)\n");
+	printf("\ts\tShuffle\n");
+	printf("\tu\tReverse shuffle\n");
+	printf("\n\tb\tUse buffered mode instead of shuffling in place (must specify output file)\n");
+}
+
+array_t read_whole_file(S_NAMED_LEXENV(base), FILE* fp)
+{
+	fseek(fp,0,SEEK_END);
+	long sz = ftell(fp);
+	fseek(fp,0,SEEK_SET);
+
+	array_t ar;
 	MANAGED({
-		void * data = smalloc(255);
-		int raw_len = 255;
-		for(int i=0;i<raw_len;i++)
-			((unsigned char*)data)[i] = i;
-
-		print_array(data,raw_len);
-
-		shuffle3(LEXENV, data, raw_len);
-		
-		print_array(data,raw_len);
-
-		/*char* buffer = smalloc(32);
-		int* nw = snew(int);
-		object proto = OBJ_PROTO;
-		proto.destructor = &test_destructor;
-		proto.constructor = &test_destructor;
-		object* obj = snew_obj(proto);
-		*nw=22;
-		sprintf(buffer, "hello %d\n", *nw);
-		sdelete(nw);
-		sdelete(obj);
-		printf("%s", buffer);*/
+		void* buf = smalloc(sz);
+		fread(buf, 1, sz, fp);
+		ar = ar_create_memory_from(base, buf, 1, sz);
+	});
+	return ar;
+}
+
+int main(int argc, char** argv)
+{
+	int is_buffered=0;
+	int i=1;
+	int is_unshuffling =0;
+	if(!argv[1] || !argv[2] || argv[1][0] != '-')
+	{
+		print_usage(argv);
+		return 1;	
+	}
+	else {
+do_switch:
+		switch(argv[1][i])
+		{
+			case 'b':
+				if(is_buffered)
+				{
+					print_usage(argv);
+					return 1;
+				}
+				is_buffered = 1;
+				i+=1;
+				goto do_switch;
+			case 'u':
+				is_unshuffling=1;
+				break;
+			case 's':
+				break;
+			default:
+				print_usage(argv);
+				return 1;
+		}
+	}
+
+	if(is_buffered && !argv[3])
+	{
+		printf("Buffered option requires an output file\n");
+		return 1;
+	}
+
+	MANAGED_RETURNABLE(int ,{
+		array_t array;
+	       
+		if(is_buffered)
+		{
+			FILE* infile = fopen(argv[2], "rb");
+			if(!infile)
+			{
+				printf("! could not open file for reading\n");
+				MANAGED_RETURN(1);
+			}
+			array = read_whole_file(LEXENV, infile);
+			fclose(infile);	
+			printf("  buffered file (%ld bytes)\n", ar_size(array));
+		}
+		else {
+			FILE* infile = fopen(argv[2], "r+b");
+			if(!infile)
+			{
+				printf("! could not open file for reading+writing\n");
+				MANAGED_RETURN(1);
+			}
+			array = ar_create_file(LEXENV, infile, 1, 1);
+		}
+
+		//print_array(array);
+
+		if(is_unshuffling) unshuffle3(LEXENV, array);
+		else shuffle3(LEXENV, array);
+	
+		if(is_buffered)
+		{
+			FILE* outfile = fopen(argv[3], "wb");
+			if(!outfile)
+			{
+				printf("! could not open outfile for writing\n");
+				MANAGED_RETURN(1);
+			}
+			void* wbuf = smalloc(ar_full_size(array));
+			if(!ar_ndump(array, wbuf, ar_full_size(array), 0, ar_size(array)))
+				printf("W memory dump failed, continuing anyway\n");
+			fwrite(wbuf, 1, ar_full_size(array), outfile);
+			fclose(outfile);
+			printf("  write completed (%d bytes)\n", (int)ar_size(array));
+		}
 	});
 	return 0;
 }
diff --git a/src/rng.c b/src/rng.c
index 1484439..0303246 100644
--- a/src/rng.c
+++ b/src/rng.c
@@ -45,7 +45,8 @@ int rng_next_int_bounded(RNG algo, int min, int max)
 
 int rng_next_int(RNG algo, int max)
 {
-	return (int)floor(algo->sample() * (double)max);
+	double sample = algo->sample();
+	return (int)floor(sample * (double)max);
 }
 
 void* rng_next(RNG algo, void* data, int len)