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Simplify VHD write

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This commit is contained in:
shermp
2018-12-23 14:52:23 +13:00
parent d5f07def65
commit 809d7412a6
1 changed files with 15 additions and 28 deletions
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43
minivhd.c
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@@ -513,42 +513,29 @@ int vhd_write_sectors(VHDMeta *vhdm, FILE *f, int offset, int nr_sectors, void *
}
if (vhdm->type == VHD_DYNAMIC)
{
int start_blk = offset / vhdm->sparse_spb;
int end_blk = (offset + (transfer_sectors - 1)) / vhdm->sparse_spb;
int sbsz = vhdm->sparse_sb_sz / VHD_SECTOR_SZ;
/* Most common case. No need to access multiple data blocks. */
if (start_blk == end_blk)
int prev_blk, curr_blk;
prev_blk = -1;
uint32_t s, ls, sib;
uint8_t *buff_ptr = (uint8_t*)buffer;
ls = offset + (transfer_sectors - 1);
for (s = offset; s <= ls; s++)
{
uint32_t sib = offset % vhdm->sparse_spb;
curr_blk = s / vhdm->sparse_spb;
/* We need to create a data block if it does not yet exist. */
if (vhdm->sparse_bat_arr[start_blk] == VHD_SPARSE_BLK)
if (vhdm->sparse_bat_arr[curr_blk] == VHD_SPARSE_BLK)
{
vhd_create_blk(vhdm, f, start_blk);
vhd_create_blk(vhdm, f, curr_blk);
}
uint32_t file_sect_offs = vhdm->sparse_bat_arr[start_blk] + sbsz + sib;
fseeko64(f, (uint64_t)file_sect_offs * VHD_SECTOR_SZ, SEEK_SET);
fwrite(buffer, transfer_sectors * VHD_SECTOR_SZ, 1, f);
}
/* Sometimes writes cross data block boundries. We handle this case here. */
else
{
uint32_t s, ls;
ls = offset + (transfer_sectors - 1);
for (s = offset; s <= ls; s++)
if (curr_blk != prev_blk)
{
int blk = s / vhdm->sparse_spb;
uint32_t sib = s % vhdm->sparse_spb;
/* We need to create a data block if it does not yet exist. */
if (vhdm->sparse_bat_arr[blk] == VHD_SPARSE_BLK)
{
vhd_create_blk(vhdm, f, blk);
}
uint32_t file_sect_offs = vhdm->sparse_bat_arr[blk] + sbsz + sib;
sib = s % vhdm->sparse_spb;
uint32_t file_sect_offs = vhdm->sparse_bat_arr[curr_blk] + sbsz + sib;
fseeko64(f, (uint64_t)file_sect_offs * VHD_SECTOR_SZ, SEEK_SET);
fwrite(buffer, VHD_SECTOR_SZ, 1, f);
buffer = (uint8_t *)buffer + VHD_SECTOR_SZ;
prev_blk = curr_blk;
}
fwrite(buff_ptr, VHD_SECTOR_SZ, 1, f);
buff_ptr += VHD_SECTOR_SZ;
}
}
else