int mcr_chunk_set(MCR *mcr, int x, int z, nbt_node *root)
{
assert(mcr && x < 32 && z < 32 && x >= 0 && z >= 0);
if (mcr->readonly) {
errno = EPERM;
return -1;
}
struct MCRChunk *chunk = &mcr->chunk[x][z];
if (root == NULL) {
// delete chunk
free(chunk->data);
chunk->data = NULL;
chunk->len = 0;
chunk->timestamp = 0;
} else {
// compress chunk
struct buffer compressed = nbt_dump_compressed(root, STRAT_INFLATE);
chunk->len = compressed.len+1;
uint8_t *data = (uint8_t*)malloc(chunk->len);
if (data == NULL) {
buffer_free(&compressed);
return -1;
}
data[0] = 2; // compression type
memcpy(data+1, compressed.data, compressed.len);
buffer_free(&compressed);
chunk->timestamp = mcr->last_timestamp;
free(chunk->data);
chunk->data = data;
}
return 0;
}
/*
* Once again, all we're doing is handing the actual compression off to
* nbt_dump_compressed, then dumping it into the file.
*/
nbt_status nbt_dump_file(const nbt_node* tree, FILE* fp, nbt_compression_strategy strat)
{
struct buffer compressed = nbt_dump_compressed(tree, strat);
if(compressed.data == NULL)
return (nbt_status)errno;
nbt_status ret = write_file(fp, compressed.data, compressed.len);
buffer_free(&compressed);
return ret;
}
int write_chunk(regionfile* region, int32_t cx, int32_t cz, chunk* chunk) {
if (region == NULL)
return -1;
if (chunk == NULL)
return -1;
cx &= 0x1f;
cz &= 0x1f;
uint32_t offset = region->offsets[cx + cz * 32];
if (offset == 0)
return -2;
uint32_t numSectors = offset & 0xff;
if (numSectors == 0)
return -3;
nbt_node* raw = new_chunk_data_to_nbt(chunk);
if (raw == NULL)
return -1;
uint32_t sectorStart = offset >> 8;
FILE* f;
if (region->keepopen == 1) {
if (region->file)
f = region->file;
else {
f = fopen(region->filename, "rb+");
region->file = f;
}
} else
f = fopen(region->filename, "rb+");
struct buffer buf = nbt_dump_compressed(raw, STRAT_INFLATE);
uint16_t sectorsNeeded = (buf.len + 5) / SECTOR_BYTES + 1;
if (sectorsNeeded >= 256)
goto error;
if (sectorStart != 0 && numSectors >= sectorsNeeded) {
if (fseek(f, sectorStart*SECTOR_BYTES, SEEK_SET) != 0)
goto error;
uint32_t size = htobe32(buf.len);
if (fwrite(&size, 1, sizeof(uint32_t), f) != sizeof(uint32_t))
goto error;
static const char COMPRESSION = 2;
if (fwrite(&COMPRESSION, 1, sizeof(COMPRESSION), f) != sizeof(COMPRESSION))
goto error;
if (fwrite(buf.data, 1, buf.len, f) != buf.len)
goto error;
goto success;
} else {
size_t i;
size_t runLength = 0;
uint32_t runStart = 0;
unsigned char* curSector = region->freeSectors;
for (i = 0; curSector[i] != 0x00; i++) {
if (runLength > 0) {
if (curSector[i] == 0x01)
runLength++;
else
runLength = 0;
} else if (curSector[i] == 0x01) {
runStart = i;
runLength = 1;
}
if (runLength >= sectorsNeeded)
break;
}
if (runLength >= sectorsNeeded) {
region->offsets[cx + cz * 32] = runStart << 8 | sectorsNeeded;
if (__region_write_offsets(region) != 0)
goto error;
if (fseek(f, runStart*SECTOR_BYTES, SEEK_SET) != 0)
goto error;
uint32_t size = htobe32(buf.len);
if (fwrite(&size, 1, sizeof(uint32_t), f) != sizeof(uint32_t))
goto error;
static const char COMPRESSION = 2;
if (fwrite(&COMPRESSION, 1, sizeof(COMPRESSION), f) != sizeof(COMPRESSION))
goto error;
if (fwrite(buf.data, 1, buf.len, f) != buf.len)
goto error;
goto success;
} else {
if (fseek(f, 0L, SEEK_END) != 0)
goto error;
long filesize = ftell(f);
uint32_t sectorNumber = filesize/SECTOR_BYTES;
filesize += sectorsNeeded * SECTOR_BYTES;
if (ftruncate(fileno(f), filesize) != 0)
goto error;
region->offsets[cx + cz * 32] = sectorNumber << 8 | sectorsNeeded;
if (__region_write_offsets(region) != 0)
goto error;
if (fseek(f, sectorNumber*SECTOR_BYTES, SEEK_SET) != 0)
goto error;
uint32_t size = htobe32(buf.len);
if (fwrite(&size, 1, sizeof(uint32_t), f) != sizeof(uint32_t))
goto error;
static const char COMPRESSION = 2;
if (fwrite(&COMPRESSION, 1, sizeof(COMPRESSION), f) != sizeof(COMPRESSION))
goto error;
if (fwrite(buf.data, 1, buf.len, f) != buf.len)
goto error;
uint32_t freeSectorsLength = filesize/SECTOR_BYTES;
region->freeSectors = realloc(region->freeSectors, sizeof(unsigned char) * (freeSectorsLength+1));
region->freeSectors[freeSectorsLength] = 0x00;
for (; sectorNumber < freeSectorsLength; sectorNumber++)
region->freeSectors[sectorNumber] = 0x02;
goto success;
}
}
error:
nbt_free(raw);
if (f && region->file != f)
fclose(f);
buffer_free(&buf);
return 1;
success:
nbt_free(raw);
buffer_free(&buf);
if (region->file != f)
fclose(f);
region->timestamps[cx + cz * 32] = time(NULL);
__region_write_timestamps(region);
return 0;
};
