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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* zstd.c
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#include "config.h"
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <zstd.h>
#include "internal.h"
#define ZSTD_DEFAULT_COMPRESSION_LEVEL 15
typedef struct {
compressor_t base;
ZSTD_CCtx *zctx;
int level;
} zstd_compressor_t;
typedef struct {
uint32_t level;
} zstd_options_t;
static int zstd_write_options(compressor_t *base, int fd)
{
zstd_compressor_t *zstd = (zstd_compressor_t *)base;
zstd_options_t opt;
(void)fd;
if (zstd->level == ZSTD_DEFAULT_COMPRESSION_LEVEL)
return 0;
opt.level = htole32(zstd->level);
return generic_write_options(fd, &opt, sizeof(opt));
}
static int zstd_read_options(compressor_t *base, int fd)
{
zstd_options_t opt;
(void)base;
if (generic_read_options(fd, &opt, sizeof(opt)))
return -1;
opt.level = le32toh(opt.level);
return 0;
}
static ssize_t zstd_comp_block(compressor_t *base, const uint8_t *in,
size_t size, uint8_t *out, size_t outsize)
{
zstd_compressor_t *zstd = (zstd_compressor_t *)base;
size_t ret;
ret = ZSTD_compressCCtx(zstd->zctx, out, outsize, in, size,
zstd->level);
if (ZSTD_isError(ret)) {
fprintf(stderr, "internal error in ZSTD compressor: %s\n",
ZSTD_getErrorName(ret));
return -1;
}
return ret < size ? ret : 0;
}
static ssize_t zstd_uncomp_block(compressor_t *base, const uint8_t *in,
size_t size, uint8_t *out, size_t outsize)
{
size_t ret;
(void)base;
ret = ZSTD_decompress(out, outsize, in, size);
if (ZSTD_isError(ret)) {
fprintf(stderr, "error uncompressing ZSTD compressed data: %s",
ZSTD_getErrorName(ret));
return -1;
}
return ret;
}
static void zstd_destroy(compressor_t *base)
{
zstd_compressor_t *zstd = (zstd_compressor_t *)base;
ZSTD_freeCCtx(zstd->zctx);
free(zstd);
}
compressor_t *create_zstd_compressor(bool compress, size_t block_size,
char *options)
{
zstd_compressor_t *zstd = calloc(1, sizeof(*zstd));
compressor_t *base = (compressor_t *)zstd;
size_t i;
(void)block_size;
if (zstd == NULL) {
perror("creating zstd compressor");
return NULL;
}
zstd->level = ZSTD_DEFAULT_COMPRESSION_LEVEL;
if (options != NULL) {
if (strncmp(options, "level=", 6) == 0) {
options += 6;
for (i = 0; isdigit(options[i]); ++i)
;
if (i == 0 || options[i] != '\0' || i > 6)
goto fail_level;
zstd->level = atoi(options);
if (zstd->level < 1 || zstd->level > ZSTD_maxCLevel())
goto fail_level;
} else {
goto fail_opt;
}
}
zstd->zctx = ZSTD_createCCtx();
if (zstd->zctx == NULL) {
fputs("error creating zstd compression context\n", stderr);
free(zstd);
return NULL;
}
base->destroy = zstd_destroy;
base->do_block = compress ? zstd_comp_block : zstd_uncomp_block;
base->write_options = zstd_write_options;
base->read_options = zstd_read_options;
return base;
fail_level:
fprintf(stderr, "zstd compression level must be a number in the range "
"1...%d\n", ZSTD_maxCLevel());
free(zstd);
return NULL;
fail_opt:
fputs("Unsupported extra options for zstd compressor\n", stderr);
free(zstd);
return NULL;
}
void compressor_zstd_print_help(void)
{
printf("Available options for zstd compressor:\n"
"\n"
" level=<value> Set compression level. Defaults to %d.\n"
" Maximum is %d.\n"
"\n",
ZSTD_DEFAULT_COMPRESSION_LEVEL, ZSTD_maxCLevel());
}
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