Revert "ENH: Add writer for Siemens CSA header"

nibabel/nicom/csareader.py

@@ -1,7 +1,6 @@
 """CSA header reader from SPM spec"""
 
 import numpy as np
-import struct
 
 from .structreader import Unpacker
 from .utils import find_private_section
@@ -29,10 +28,6 @@ class CSAReadError(CSAError):
     pass
 
 
-class CSAWriteError(CSAError):
-    pass
-
-
 def get_csa_header(dcm_data, csa_type='image'):
     """Get CSA header information from DICOM header
 
@@ -166,96 +161,6 @@ def read(csa_str):
     return csa_dict
 
 
-def write(csa_header):
-    ''' Write string from CSA header `csa_header`
-
-    Parameters
-    ----------
-    csa_header : dict
-        header information as dict, where `header` has fields (at least)
-        ``type, n_tags, tags``.  ``header['tags']`` is also a dictionary
-        with one key, value pair for each tag in the header.
-
-    Returns
-    -------
-    csa_str : str
-        byte string containing CSA header information
-    '''
-    result = []
-    if csa_header['type'] == 2:
-        result.append(b'SV10')
-        result.append(csa_header['unused0'])
-    if not 0 < csa_header['n_tags'] <= 128:
-        raise CSAWriteError('Number of tags `t` should be '
-                            '0 < t <= 128')
-    result.append(struct.pack('2I',
-                              csa_header['n_tags'],
-                              csa_header['check'])
-                  )
-
-    # Build list of tags in correct order
-    tags = list(csa_header['tags'].items())
-    tags.sort(key=lambda x: x[1]['tag_no'])
-    tag0_n_items = tags[0][1]['n_items']
-
-    # Add the information for each tag
-    for tag_name, tag_dict in tags:
-        vm = tag_dict['vm']
-        vr = tag_dict['vr']
-        n_items = tag_dict['n_items']
-        assert n_items < 100
-        result.append(struct.pack('64si4s3i',
-                                  make_nt_str(tag_name),
-                                  vm,
-                                  make_nt_str(vr),
-                                  tag_dict['syngodt'],
-                                  n_items,
-                                  tag_dict['last3'])
-                      )
-
-        # Figure out the number of values for this tag
-        if vm == 0:
-            n_values = n_items
-        else:
-            n_values = vm
-
-        # Add each item for this tag
-        for item_no in range(n_items):
-            # Figure out the item length
-            if item_no >= n_values or tag_dict['items'][item_no] == '':
-                item_len = 0
-            else:
-                item = tag_dict['items'][item_no]
-                if not isinstance(item, str):
-                    item = str(item)
-                item_nt_str = make_nt_str(item)
-                item_len = len(item_nt_str)
-
-            # These values aren't actually preserved in the dict
-            # representation of the header. Best we can do is set the ones
-            # that determine the item length appropriately.
-            x0, x1, x2, x3 = 0, 0, 0, 0
-            if csa_header['type'] == 1:  # CSA1 - odd length calculation
-                x0 = tag0_n_items + item_len
-                if item_len < 0 or (ptr + item_len) > csa_len:
-                    if item_no < vm:
-                        items.append('')
-                    break
-            else:  # CSA2
-                x1 = item_len
-            result.append(struct.pack('4i', x0, x1, x2, x3))
-
-            if item_len == 0:
-                continue
-
-            result.append(item_nt_str)
-            # go to 4 byte boundary
-            plus4 = item_len % 4
-            if plus4 != 0:
-                result.append(b'\x00' * (4 - plus4))
-    return b''.join(result)
-
-
 def get_scalar(csa_dict, tag_name):
     try:
         items = csa_dict['tags'][tag_name]['items']
@@ -353,18 +258,3 @@ def nt_str(s):
     if zero_pos == -1:
         return s
     return s[:zero_pos].decode('latin-1')
-
-
-def make_nt_str(s):
-    ''' Create a null terminated byte string from a unicode object.
-
-    Parameters
-    ----------
-    s : unicode
-
-    Returns
-    -------
-    result : bytes
-       s encoded as latin-1 with a null char appended
-    '''
-    return s.encode('latin-1') + b'\x00'

nibabel/nicom/tests/test_csareader.py

@@ -130,14 +130,3 @@ def test_missing_csa_elem():
     del dcm[csa_tag]
     hdr = csa.get_csa_header(dcm, 'image')
     assert hdr is None
-
-
-def test_read_write_rt():
-    # Try doing a read-write-read round trip and make sure the dictionary
-    # representation of the header is the same. We can't exactly reproduce the
-    # original string representation currently.
-    for csa_str in (CSA2_B0, CSA2_B1000):
-        csa_info = csa.read(csa_str)
-        new_csa_str = csa.write(csa_info)
-        new_csa_info = csa.read(new_csa_str)
-        assert csa_info == new_csa_info