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#include "cache.h"
#include "chunk-format.h"
#include "csum-file.h"
/*
* When writing a chunk-based file format, collect the chunks in
* an array of chunk_info structs. The size stores the _expected_
* amount of data that will be written by write_fn.
*/
struct chunk_info {
uint32_t id;
uint64_t size;
chunk_write_fn write_fn;
};
struct chunkfile {
struct hashfile *f;
struct chunk_info *chunks;
size_t chunks_nr;
size_t chunks_alloc;
};
struct chunkfile *init_chunkfile(struct hashfile *f)
{
struct chunkfile *cf = xcalloc(1, sizeof(*cf));
cf->f = f;
return cf;
}
void free_chunkfile(struct chunkfile *cf)
{
if (!cf)
return;
free(cf->chunks);
free(cf);
}
int get_num_chunks(struct chunkfile *cf)
{
return cf->chunks_nr;
}
void add_chunk(struct chunkfile *cf,
uint32_t id,
size_t size,
chunk_write_fn fn)
{
ALLOC_GROW(cf->chunks, cf->chunks_nr + 1, cf->chunks_alloc);
cf->chunks[cf->chunks_nr].id = id;
cf->chunks[cf->chunks_nr].write_fn = fn;
cf->chunks[cf->chunks_nr].size = size;
cf->chunks_nr++;
}
int write_chunkfile(struct chunkfile *cf, void *data)
{
int i;
uint64_t cur_offset = hashfile_total(cf->f);
/* Add the table of contents to the current offset */
cur_offset += (cf->chunks_nr + 1) * CHUNK_TOC_ENTRY_SIZE;
for (i = 0; i < cf->chunks_nr; i++) {
hashwrite_be32(cf->f, cf->chunks[i].id);
hashwrite_be64(cf->f, cur_offset);
cur_offset += cf->chunks[i].size;
}
/* Trailing entry marks the end of the chunks */
hashwrite_be32(cf->f, 0);
hashwrite_be64(cf->f, cur_offset);
for (i = 0; i < cf->chunks_nr; i++) {
off_t start_offset = hashfile_total(cf->f);
int result = cf->chunks[i].write_fn(cf->f, data);
if (result)
return result;
if (hashfile_total(cf->f) - start_offset != cf->chunks[i].size)
BUG("expected to write %"PRId64" bytes to chunk %"PRIx32", but wrote %"PRId64" instead",
cf->chunks[i].size, cf->chunks[i].id,
hashfile_total(cf->f) - start_offset);
}
return 0;
}
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