forked from kubo/snzip
/
framing-format.c
263 lines (245 loc) · 8.64 KB
/
framing-format.c
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/* -*- indent-tabs-mode: nil -*-
*
* Copyright 2012-2013 Kubo Takehiro <kubo@jiubao.org>
*
* Redistribution and use in source and binary forms, with or without modification, are
* permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list
* of conditions and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* The views and conclusions contained in the software and documentation are those of the
* authors and should not be interpreted as representing official policies, either expressed
* or implied, of the authors.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <snappy-c.h>
#include "snzip.h"
#include "crc32.h"
#define COMPRESSED_DATA_IDENTIFIER 0x00
#define UNCOMPRESSED_DATA_IDENTIFIER 0x01
/* 4.1. Stream identifier (0xff) */
static const char stream_header[9] = {0xff, 0x06, 0x00, 0x73, 0x4e, 0x61, 0x50, 0x70, 0x59};
#define MAX_DATA_LEN 65535 /* maximum chunk data length */
#define MAX_UNCOMPRESSED_DATA_LEN 32768 /* maximum uncompressed data length excluding checksum */
static int framing_format_compress(FILE *infp, FILE *outfp, size_t block_size)
{
const size_t max_uncompressed_data_len = MAX_UNCOMPRESSED_DATA_LEN;
const size_t max_compressed_data_len = snappy_max_compressed_length(max_uncompressed_data_len);
size_t uncompressed_data_len;
size_t compressed_data_len;
char *uncompressed_data = malloc(max_uncompressed_data_len);
char *compressed_data = malloc(max_compressed_data_len);
int err = 1;
if (uncompressed_data == NULL || compressed_data == NULL) {
print_error("out of memory\n");
goto cleanup;
}
/* write the steam header */
fwrite_unlocked(stream_header, sizeof(stream_header), 1, outfp);
/* write file body */
while ((uncompressed_data_len = fread_unlocked(uncompressed_data, 1, max_uncompressed_data_len, infp)) > 0) {
unsigned int crc32c = masked_crc32c(uncompressed_data, uncompressed_data_len);
char type_code;
size_t write_len;
const char *write_data;
/* compress the block. */
compressed_data_len = max_compressed_data_len;
snappy_compress(uncompressed_data, uncompressed_data_len, compressed_data, &compressed_data_len);
if (compressed_data_len >= (uncompressed_data_len - (uncompressed_data_len / 8))) {
/* uncompressed data */
type_code = UNCOMPRESSED_DATA_IDENTIFIER;
write_len = uncompressed_data_len;
write_data = uncompressed_data;
} else {
/* compressed data */
type_code = COMPRESSED_DATA_IDENTIFIER;
write_len = compressed_data_len;
write_data = compressed_data;
}
/* write block type */
putc_unlocked(type_code, outfp);
/* write data length */
putc_unlocked(((write_len + 4) >> 0), outfp);
putc_unlocked(((write_len + 4) >> 8), outfp);
/* write checksum */
putc_unlocked((crc32c >> 0), outfp);
putc_unlocked((crc32c >> 8), outfp);
putc_unlocked((crc32c >> 16), outfp);
putc_unlocked((crc32c >> 24), outfp);
/* write data */
if (fwrite_unlocked(write_data, write_len, 1, outfp) != 1) {
print_error("Failed to write a file: %s\n", strerror(errno));
goto cleanup;
}
}
/* check stream errors */
if (ferror_unlocked(infp)) {
print_error("Failed to read a file: %s\n", strerror(errno));
goto cleanup;
}
if (ferror_unlocked(outfp)) {
print_error("Failed to write a file: %s\n", strerror(errno));
goto cleanup;
}
err = 0;
cleanup:
free(uncompressed_data);
free(compressed_data);
return err;
}
static int read_data(char *buf, size_t buflen, FILE *fp)
{
if (fread_unlocked(buf, buflen, 1, fp) != 1) {
if (feof_unlocked(fp)) {
print_error("Unexpected end of file\n");
} else {
print_error("Failed to read a file: %s\n", strerror(errno));
}
return -1;
}
return 0;
}
/*
* Callers must ensure that the checksum pointer is aligned to a 4 byte boundary
* on little endian environment.
*/
static int check_crc32c(const char *data, size_t datalen, const char *checksum)
{
unsigned int actual_crc32c = masked_crc32c(data, datalen);
#ifdef WORDS_BIGENDIAN
unsigned int expected_crc32c = ((unsigned int)checksum[0] & 0xff)
| (((unsigned int)checksum[1] & 0xff) << 8)
| (((unsigned int)checksum[2] & 0xff) << 16)
| (((unsigned int)checksum[3] & 0xff) << 24);
#else
unsigned int expected_crc32c = *(unsigned int*)checksum;
#endif
if (actual_crc32c != expected_crc32c) {
print_error("CRC32C error! (expected 0x%08x but 0x%08x)\n", expected_crc32c, actual_crc32c);
return -1;
}
return 0;
}
static int framing_format_uncompress(FILE *infp, FILE *outfp, int skip_magic)
{
const size_t max_data_len = MAX_DATA_LEN;
const size_t max_uncompressed_data_len = MAX_UNCOMPRESSED_DATA_LEN;
size_t data_len;
size_t uncompressed_data_len;
char *data = malloc(max_data_len);
char *uncompressed_data = malloc(max_uncompressed_data_len);
int err = 1;
if (data == NULL || uncompressed_data == NULL) {
print_error("out of memory\n");
goto cleanup;
}
if (!skip_magic) {
/* read the steam header */
if (read_data(data, sizeof(stream_header), infp) != 0) {
goto cleanup;
}
if (memcmp(data, stream_header, sizeof(stream_header)) != 0) {
print_error("Invalid stream identfier\n");
goto cleanup;
}
}
for (;;) {
int id = getc_unlocked(infp);
if (id == EOF) {
break;
}
data_len = getc_unlocked(infp);
data_len |= getc_unlocked(infp) << 8;
if (data_len == (size_t)EOF) {
print_error("Unexpected end of file\n");
goto cleanup;
}
if (id == COMPRESSED_DATA_IDENTIFIER) {
/* 4.2. Compressed data (chunk type 0x00) */
if (data_len < 4) {
print_error("too short data length %lu\n", data_len);
goto cleanup;
}
if (read_data(data, data_len, infp) != 0) {
goto cleanup;
}
uncompressed_data_len = max_uncompressed_data_len;
if (snappy_uncompress(data + 4, data_len - 4, uncompressed_data, &uncompressed_data_len)) {
print_error("Invalid data: snappy_uncompress failed\n");
goto cleanup;
}
if (check_crc32c(uncompressed_data, uncompressed_data_len, data) != 0) {
goto cleanup;
}
if (fwrite_unlocked(uncompressed_data, uncompressed_data_len, 1, outfp) != 1) {
break;
}
} else if (id == UNCOMPRESSED_DATA_IDENTIFIER) {
/* 4.3. Uncompressed data (chunk type 0x01) */
if (data_len < 4) {
print_error("too short data length %lu\n", data_len);
goto cleanup;
}
if (read_data(data, data_len, infp) != 0) {
goto cleanup;
}
if (check_crc32c(data + 4, data_len - 4, data) != 0) {
goto cleanup;
}
if (fwrite_unlocked(data + 4, data_len - 4, 1, outfp) != 1) {
break;
}
} else if (id < 0x80) {
/* 4.4. Reserved unskippable chunks (chunk types 0x02-0x7f) */
print_error("Unsupported identifier 0x%02x\n", id);
goto cleanup;
} else {
/* 4.5. Reserved skippable chunks (chunk types 0x80-0xfe) */
fseek(infp, data_len, SEEK_CUR);
}
}
/* check stream errors */
if (ferror_unlocked(infp)) {
print_error("Failed to read a file: %s\n", strerror(errno));
goto cleanup;
}
if (ferror_unlocked(outfp)) {
print_error("Failed to write a file: %s\n", strerror(errno));
goto cleanup;
}
err = 0;
cleanup:
free(data);
free(uncompressed_data);
return err;
}
stream_format_t framing_format = {
"framing",
"http://code.google.com/p/snappy/source/browse/trunk/framing_format.txt?r=55",
"sz",
stream_header,
sizeof(stream_header),
framing_format_compress,
framing_format_uncompress,
};