Adopt h2testw's file format

Now F3 and h2testw share the same file format.
Guenter Knauf has suggested this feature and
got the random-number generator used in h2testw from
Harald Bogeholz, the author of h2testw.

This change also addresses the issue that
the original random-number generator only fills
the first 32 bits of the 64 bits of the random numbers on
64-bit machines.
Besides the lower entropy on 64-bit machines, this issue was
making files generated on 32-bit and 64-bit machines incompatible.
Anselm Distelrath was the first to report this issue.

f3read.1

@@ -18,7 +18,7 @@ card and then checks if can read it. It will assure you haven't been
 sold a card with a smaller capacity than stated.
 .PP
 When writing to flash drive, \fBf3write\fP fills the filesystem with 1GB
-files named N.fff, where N is a number (i.e. /[0-9]+/).
+files named N.h2w, where N is a number (i.e. /[0-9]+/).
 .PP
 WARNING: all data on the tested disk might be lost!
 .SH OPTIONS

f3read.c

@@ -44,8 +44,6 @@ static void validate_file(const char *path, int number,
 	int offset_match, error_count;
 	size_t sectors_read;
 	uint64_t offset, expected_offset;
-	struct drand48_data state;
-	long int rand_int;
 	int final_errno;
 	struct timeval t1, t2;
 	/* Progress time. */
@@ -79,17 +77,19 @@ static void validate_file(const char *path, int number,
 	final_errno = errno;
 	expected_offset = (uint64_t)number * GIGABYTES;
 	while (sectors_read > 0) {
+		uint64_t rn;
+
 		assert(sectors_read == 1);
 		offset = *((uint64_t *) sector);
 		offset_match = offset == expected_offset;
 
-		srand48_r(offset, &state);
+		rn = offset;
 		p = sector + sizeof(offset);
 		error_count = 0;
 		for (; error_count <= TOLERANCE && p < ptr_end;
-			p += sizeof(long int)) {
-			lrand48_r(&state, &rand_int);
-			if (rand_int != *((long int *) p))
+			p += sizeof(rn)) {
+			rn = random_number(rn);
+			if (rn != *((typeof(rn) *) p))
 				error_count++;
 		}
 

f3write.c

@@ -18,20 +18,24 @@
 static uint64_t fill_buffer(void *buf, size_t size, uint64_t offset)
 {
 	uint8_t *p, *ptr_next_sector, *ptr_end;
-	struct drand48_data state;
+	uint64_t rn;
 
 	assert(size > 0);
 	assert(size % SECTOR_SIZE == 0);
+	assert(SECTOR_SIZE >= sizeof(offset) + sizeof(rn));
+	assert((SECTOR_SIZE - sizeof(offset)) % sizeof(rn) == 0);
 
 	p = buf;
 	ptr_end = p + size;
 	while (p < ptr_end) {
+		rn = offset;
 		memmove(p, &offset, sizeof(offset));
-		srand48_r(offset, &state);
 		ptr_next_sector = p + SECTOR_SIZE;
 		p += sizeof(offset);
-		for (; p < ptr_next_sector; p += sizeof(long int))
-			lrand48_r(&state, (long int *)p);
+		for (; p < ptr_next_sector; p += sizeof(rn)) {
+			rn = random_number(rn);
+			memmove(p, &rn, sizeof(rn));
+		}
 		assert(p == ptr_next_sector);
 		offset += SECTOR_SIZE;
 	}

utils.c

@@ -33,14 +33,14 @@ int is_my_file(const char *filename)
 		p++;
 	} while (isdigit(*p));
 
-	return	(p[0] == '.') && (p[1] == 'f') && (p[2] == 'f') &&
-		(p[3] == 'f') && (p[4] == '\0');
+	return	(p[0] == '.') && (p[1] == 'h') && (p[2] == '2') &&
+		(p[3] == 'w') && (p[4] == '\0');
 }
 
 void full_fn_from_number(char *full_fn, const char **filename,
 	const char *path, int num)
 {
-	assert(snprintf(full_fn, PATH_MAX, "%s/%i.fff", path, num + 1) <
+	assert(snprintf(full_fn, PATH_MAX, "%s/%i.h2w", path, num + 1) <
 		PATH_MAX);
 	*filename = full_fn + strlen(path) + 1;
 }
@@ -140,80 +140,3 @@ void print_header(FILE *f, char *name)
 	"This is free software; see the source for copying conditions.\n"
 	"\n", name);
 }
-
-#if defined(APPLE_MAC) || defined (CYGWIN)
-
-#include <stdio.h>
-#include <stdint.h>
-
-int srand48_r(long int seedval, struct drand48_data *buffer)
-{
-	/* The standards say we only have 32 bits.  */
-	if (sizeof(long int) > 4)
-		seedval &= 0xffffffffl;
-
-	buffer->__x[2] = seedval >> 16;
-	buffer->__x[1] = seedval & 0xffffl;
-	buffer->__x[0] = 0x330e;
-
-	buffer->__a = 0x5deece66dull;
-	buffer->__c = 0xb;
-	buffer->__init = 1;
-
-	return 0;
-}
-
-static int __drand48_iterate(unsigned short int xsubi[3],
-	struct drand48_data *buffer)
-{
-	uint64_t X;
-	uint64_t result;
-
-	/* Initialize buffer, if not yet done.  */
-	if (__builtin_expect(!buffer->__init, 0)) {
-		buffer->__a = 0x5deece66dull;
-		buffer->__c = 0xb;
-		buffer->__init = 1;
-	}
-
-	/* Do the real work.  We choose a data type which contains at least
-	   48 bits.  Because we compute the modulus it does not care how
-	   many bits really are computed.  */
-
-	X = (uint64_t) xsubi[2] << 32 | (uint32_t) xsubi[1] << 16 | xsubi[0];
-
-	result = X * buffer->__a + buffer->__c;
-
-	xsubi[0] = result & 0xffff;
-	xsubi[1] = (result >> 16) & 0xffff;
-	xsubi[2] = (result >> 32) & 0xffff;
-
-	return 0;
-}
-
-static int __nrand48_r(unsigned short int xsubi[3],
-		       struct drand48_data *buffer, long int *result)
-{
-	/* Compute next state.  */
-	if (__drand48_iterate(xsubi, buffer) < 0)
-		return -1;
-
-	/* Store the result.  */
-	if (sizeof(unsigned short int) == 2)
-		*result = xsubi[2] << 15 | xsubi[1] >> 1;
-	else
-		*result = xsubi[2] >> 1;
-
-	return 0;
-}
-
-int lrand48_r(struct drand48_data *buffer, long int *result)
-{
-	/* Be generous for the arguments, detect some errors.  */
-	if (buffer == NULL)
-		return -1;
-
-	return __nrand48_r(buffer->__x, buffer, result);
-}
-
-#endif	/* APPLE_MAC or CYGWIN */

utils.h

@@ -6,13 +6,14 @@
 #include <assert.h>
 #include <sys/time.h>
 #include <limits.h>
+#include <stdint.h>
 
 #define SECTOR_SIZE (512)
 #define GIGABYTES   (1024 * 1024 * 1024)
 
 const char *adjust_unit(double *ptr_bytes);
 
-/* Return true if @filename matches the regex /^[0-9]+\.fff$/ */
+/* Return true if @filename matches the regex /^[0-9]+\.h2w$/ */
 int is_my_file(const char *filename);
 
 /* @filename should be PATH_MAX long. */
@@ -35,6 +36,11 @@ const int *ls_my_files(const char *path, int start_at);
 
 void print_header(FILE *f, char *name);
 
+static inline uint64_t random_number(uint64_t prv_number)
+{
+	return prv_number * 4294967311ULL + 17;
+}
+
 #ifdef APPLE_MAC
 
 /* For function fcntl. */
@@ -66,33 +72,4 @@ static inline int posix_fadvise(int fd, off_t offset, off_t len, int advice)
 
 #endif	/* APPLE_MAC */
 
-#if defined(APPLE_MAC) || defined(CYGWIN)
-
-/*
- * The following functions were copied from GNU Library C to make F3
- * more portable.
- */
-
-/* Data structure for communication with thread safe versions.  This
- * type is to be regarded as opaque.  It's only exported because users
- * have to allocate objects of this type.
- */
-struct drand48_data {
-	unsigned short int __x[3];	/* Current state.		    */
-	unsigned short int __old_x[3];	/* Old state.			    */
-	unsigned short int __c;	/* Additive const. in congruential formula. */
-	unsigned short int __init;	/* Flag for initializing.	    */
-	unsigned long long int __a;	/* Factor in congruential formula.  */
-};
-
-/* Seed random number generator.  */
-extern int srand48_r(long int __seedval, struct drand48_data *__buffer)
-	__attribute__ ((nonnull(2)));
-
-/* Return non-negative, long integer in [0,2^31).  */
-extern int lrand48_r(struct drand48_data *__restrict __buffer,
-	long int *__restrict __result) __attribute__ ((nonnull(1, 2)));
-
-#endif	/* APPLE_MAC or CYGWIN */
-
 #endif	/* HEADER_UTILS_H */