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/* SPDX-License-Identifier: GPL-3.0-or-later */
#include "meta_writer.h"
#include "squashfs.h"
#include "util.h"
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
struct meta_writer_t {
/* A byte offset into the uncompressed data of the current block */
size_t offset;
/* The location of the current block in the file */
size_t block_offset;
/* The underlying file descriptor to write to */
int outfd;
/* A pointer to the compressor to use for compressing the data */
compressor_t *cmp;
/* The raw data chunk that data is appended to */
uint8_t data[SQFS_META_BLOCK_SIZE + 2];
/* Scratch buffer for compressing data */
uint8_t scratch[SQFS_META_BLOCK_SIZE + 2];
};
meta_writer_t *meta_writer_create(int fd, compressor_t *cmp)
{
meta_writer_t *m = calloc(1, sizeof(*m));
if (m == NULL) {
perror("creating meta data writer");
return NULL;
}
m->cmp = cmp;
m->outfd = fd;
return m;
}
void meta_writer_destroy(meta_writer_t *m)
{
free(m);
}
int meta_writer_flush(meta_writer_t *m)
{
ssize_t ret, count;
void *ptr;
if (m->offset == 0)
return 0;
ret = m->cmp->do_block(m->cmp, m->data + 2, m->offset,
m->scratch + 2, sizeof(m->scratch) - 2);
if (ret < 0)
return -1;
if (ret > 0) {
((uint16_t *)m->scratch)[0] = htole16(ret);
count = ret + 2;
ptr = m->scratch;
} else {
((uint16_t *)m->data)[0] = htole16(m->offset | 0x8000);
count = m->offset + 2;
ptr = m->data;
}
ret = write_retry(m->outfd, ptr, count);
if (ret < 0) {
perror("writing meta data");
return -1;
}
if (ret < count) {
fputs("meta data written to file was truncated\n", stderr);
return -1;
}
memset(m->data, 0, sizeof(m->data));
m->offset = 0;
m->block_offset += count;
return 0;
}
int meta_writer_append(meta_writer_t *m, const void *data, size_t size)
{
size_t diff;
while (size != 0) {
diff = sizeof(m->data) - 2 - m->offset;
if (diff == 0) {
if (meta_writer_flush(m))
return -1;
diff = sizeof(m->data) - 2;
}
if (diff > size)
diff = size;
memcpy(m->data + 2 + m->offset, data, diff);
m->offset += diff;
size -= diff;
data = (const char *)data + diff;
}
if (m->offset == (sizeof(m->data) - 2))
return meta_writer_flush(m);
return 0;
}
void meta_writer_get_position(const meta_writer_t *m, uint64_t *block_start,
uint32_t *offset)
{
*block_start = m->block_offset;
*offset = m->offset;
}
void meta_writer_reset(meta_writer_t *m)
{
m->block_offset = 0;
m->offset = 0;
}
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