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/*
* test_checksums.c
*
* Verify that libdeflate's Adler-32 and CRC-32 functions produce the same
* results as their zlib equivalents.
*/
#include <stdlib.h>
#include <time.h>
#include "test_util.h"
static unsigned int rng_seed;
typedef u32 (*cksum_fn_t)(u32, const void *, size_t);
static u32
adler32_libdeflate(u32 adler, const void *buf, size_t len)
{
return libdeflate_adler32(adler, buf, len);
}
static u32
crc32_libdeflate(u32 crc, const void *buf, size_t len)
{
return libdeflate_crc32(crc, buf, len);
}
static u32
adler32_zlib(u32 adler, const void *buf, size_t len)
{
return adler32(adler, buf, len);
}
static u32
crc32_zlib(u32 crc, const void *buf, size_t len)
{
return crc32(crc, buf, len);
}
static u32
select_initial_crc(void)
{
if (rand() & 1)
return 0;
return ((u32)rand() << 16) | rand();
}
static u32
select_initial_adler(void)
{
u32 lo, hi;
if (rand() & 1)
return 1;
lo = (rand() % 4 == 0 ? 65520 : rand() % 65521);
hi = (rand() % 4 == 0 ? 65520 : rand() % 65521);
return (hi << 16) | lo;
}
static void
test_initial_values(cksum_fn_t cksum, u32 expected)
{
ASSERT(cksum(0, NULL, 0) == expected);
if (cksum != adler32_zlib) /* broken */
ASSERT(cksum(0, NULL, 1) == expected);
ASSERT(cksum(0, NULL, 1234) == expected);
ASSERT(cksum(1234, NULL, 0) == expected);
ASSERT(cksum(1234, NULL, 1234) == expected);
}
static void
test_multipart(const u8 *buffer, size_t size, const char *name,
cksum_fn_t cksum, u32 v, u32 expected)
{
size_t division = rand() % (size + 1);
v = cksum(v, buffer, division);
v = cksum(v, buffer + division, size - division);
if (v != expected) {
fprintf(stderr, "%s checksum failed multipart test\n", name);
ASSERT(0);
}
}
static void
test_checksums(const void *buffer, size_t size, const char *name,
cksum_fn_t cksum1, cksum_fn_t cksum2, u32 initial_value)
{
u32 v1 = cksum1(initial_value, buffer, size);
u32 v2 = cksum2(initial_value, buffer, size);
if (v1 != v2) {
fprintf(stderr, "%s checksum mismatch\n", name);
fprintf(stderr, "initial_value=0x%08"PRIx32", buffer=%p, "
"size=%zu, buffer=", initial_value, buffer, size);
for (size_t i = 0; i < MIN(size, 256); i++)
fprintf(stderr, "%02x", ((const u8 *)buffer)[i]);
if (size > 256)
fprintf(stderr, "...");
fprintf(stderr, "\n");
ASSERT(0);
}
if ((rand() & 15) == 0) {
test_multipart(buffer, size, name, cksum1, initial_value, v1);
test_multipart(buffer, size, name, cksum2, initial_value, v1);
}
}
static void
test_crc32(const void *buffer, size_t size, u32 initial_value)
{
test_checksums(buffer, size, "CRC-32",
crc32_libdeflate, crc32_zlib, initial_value);
}
static void
test_adler32(const void *buffer, size_t size, u32 initial_value)
{
test_checksums(buffer, size, "Adler-32",
adler32_libdeflate, adler32_zlib, initial_value);
}
static void test_random_buffers(u8 *buffer, u8 *guarded_buf_end,
size_t limit, u32 num_iter)
{
for (u32 i = 0; i < num_iter; i++) {
size_t start = rand() % limit;
size_t len = rand() % (limit - start);
u32 a0 = select_initial_adler();
u32 c0 = select_initial_crc();
for (size_t j = start; j < start + len; j++)
buffer[j] = rand();
/* Test with chosen size and alignment */
test_adler32(&buffer[start], len, a0);
test_crc32(&buffer[start], len, c0);
/* Test with chosen size, with guard page after input buffer */
memcpy(guarded_buf_end - len, &buffer[start], len);
test_adler32(guarded_buf_end - len, len, a0);
test_crc32(guarded_buf_end - len, len, c0);
}
}
int
tmain(int argc, tchar *argv[])
{
u8 *buffer = xmalloc(32768);
u8 *guarded_buf_start, *guarded_buf_end;
begin_program(argv);
alloc_guarded_buffer(32768, &guarded_buf_start, &guarded_buf_end);
rng_seed = time(NULL);
srand(rng_seed);
test_initial_values(adler32_libdeflate, 1);
test_initial_values(adler32_zlib, 1);
test_initial_values(crc32_libdeflate, 0);
test_initial_values(crc32_zlib, 0);
/* Test different buffer sizes and alignments */
test_random_buffers(buffer, guarded_buf_end, 256, 5000);
test_random_buffers(buffer, guarded_buf_end, 1024, 500);
test_random_buffers(buffer, guarded_buf_end, 32768, 50);
/*
* Test Adler-32 overflow cases. For example, given all 0xFF bytes and
* the highest possible initial (s1, s2) of (65520, 65520), then s2 if
* stored as a 32-bit unsigned integer will overflow if > 5552 bytes are
* processed. Implementations must make sure to reduce s2 modulo 65521
* before that point. Also, some implementations make use of 16-bit
* counters which can overflow earlier.
*/
memset(buffer, 0xFF, 32768);
for (u32 i = 0; i < 20; i++) {
u32 initial_value;
if (i == 0)
initial_value = ((u32)65520 << 16) | 65520;
else
initial_value = select_initial_adler();
test_adler32(buffer, 5553, initial_value);
test_adler32(buffer, rand() % 32769, initial_value);
buffer[rand() % 32768] = 0xFE;
}
free(buffer);
free_guarded_buffer(guarded_buf_start, guarded_buf_end);
return 0;
}
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