Float columns in PDBFile.set_structure() are not bounded

[padix-key]

Currently PDBFile.set_structure() does not restrict the upper bound of float values in the atom annotations (e.g. coordinates). However the fixed columns in PDB only allow for a certain value range: For example the value 10000 does not fit into a 4 character string.

Attempting to write such high values would currently lead to a shift in all following columns.
Hence, the created PDB file becomes invalid.
To fix this, the function should raise an exception if setting such an AtomArray is attempted.

Example:

import biotite.structure.io.pdb as pdb
import biotite.structure as struc


atoms = struc.AtomArray(10)
# Keep the first five ATOM records correct for comparison
atoms.coord[:5] = 100
atoms.coord[5:] = 1000000
pdb_file = pdb.PDBFile()
pdb_file.set_structure(atoms)
print(pdb_file)

Output:

ATOM      1             0      100.000 100.000 100.000  1.00  0.00              
ATOM      2             0      100.000 100.000 100.000  1.00  0.00              
ATOM      3             0      100.000 100.000 100.000  1.00  0.00              
ATOM      4             0      100.000 100.000 100.000  1.00  0.00              
ATOM      5             0      100.000 100.000 100.000  1.00  0.00              
ATOM      6             0     1000000.0001000000.0001000000.000  1.00  0.00              
ATOM      7             0     1000000.0001000000.0001000000.000  1.00  0.00              
ATOM      8             0     1000000.0001000000.0001000000.000  1.00  0.00              
ATOM      9             0     1000000.0001000000.0001000000.000  1.00  0.00              
ATOM     10             0     1000000.0001000000.0001000000.000  1.00  0.00

This affects the following atom annotations:

• coord
• b_factor
• occupancy

Note that negative value allow one numeric character less due to the added '-' character.