Я связался с Брайаном Мэдсеном, автором функции DBFREAD, которая была удалена из File Exchange, вероятно, потому, что Mathworks собирается включить эту функцию в MATLAB в каком-то будущем выпуске. Брайан любезно разрешил мне опубликовать эту функцию здесь. Вся информация об авторских правах сохранена. Я только изменил строки 33-38, чтобы позволить DBFREAD читать файл вне рабочего каталога.
function [dbfData, dbfFieldNames] = dbfread(filename, records2read, requestedFieldNames)
%DBFREAD Read the specified records and fields from a DBF file.
%
% [DATA, NAMES] = DBFREAD(FILE) reads numeric, float, character and date
% data and field names from a DBF file, FILE.
%
% [DATA, NAMES] = DBFREAD(FILE, RECORDS2READ) reads only the record
% numbers specified in RECORDS2READ, a scalar or vector.
%
% [DATA, NAMES] = DBFREAD(FILE, RECORDS2READ, REQUESTEDFIELDNAMES) reads
% the data from the fields, REQUESTEDFIELDNAMES, for the specified
% records. REQUESTEDFIELDNAMES must be a cell array. The fields in the
% output will follow the order given in REQUESTEDFIELDNAMES.
%
% Examples:
%
% % Get all records and a list of the field names from a DBF file.
% [DATA,NAMES] = dbfread('c:\matlab\work\mydbf')
%
% % Get data from records 3:5 and 10 from a DBF file.
% DATA = dbfread('c:\matlab\work\mydbf',[3:5,10])
%
% % Get data from records 1:10 for three of the fields in a DBF file.
% DATA = dbfread('c:\matlab\work\mydbf',1:10,{'FIELD1' 'FIELD3' 'FIELD5'})
%
% See also XLSREAD, DLMREAD, DLMWRITE, LOAD, FILEFORMATS, TEXTSCAN.
% Copyright 2008 The MathWorks, Inc.
% $Revision: 1.0 $ $Date: 2008/04/18 05:58:17 $
[pathstr,name,ext] = fileparts(filename);
dbfFileId = fopen(filename,'r','ieee-le');
if (dbfFileId == -1)
dbfFileId = fopen(fullfile(pathstr, [name '.dbf']),'r','ieee-le');
end
if (dbfFileId == -1)
dbfFileId = fopen(fullfile(pathstr, [name '.DBF']),'r','ieee-le');
end
if (dbfFileId == -1)
eid = sprintf('MATLAB:%s:missingDBF', mfilename);
msg = sprintf('Failed to open file %s.dbf or file %s.DBF.',...
name, name);
error(eid,'%s',msg)
end
info = dbfinfo(dbfFileId);
if ~exist('requestedFieldNames','var')
dbfFieldNames = {info.FieldInfo.Name};
requestedFieldNames = dbfFieldNames;
else
dbfFieldNames = (info.FieldInfo(matchFieldNames(info,requestedFieldNames)).Name);
end
fields2read = matchFieldNames(info,requestedFieldNames);
% The first byte in each record is a deletion indicator
lengthOfDeletionIndicator = 1;
if ~exist('records2read','var')
records2read = (1:info.NumRecords);
elseif max(records2read) > info.NumRecords
eid = sprintf('MATLAB:%s:invalidRecordNumber', mfilename);
msg = sprintf('Record number %d does not exist, please select from the range 1:%d.',...
max(records2read), info.NumRecords);
error(eid,'%s',msg)
end
% Loop over the requested fields, reading in the data
dbfData = cell(numel(records2read),numel(fields2read));
for k = 1:numel(fields2read),
n = fields2read(k);
fieldOffset = info.HeaderLength ...
+ sum([info.FieldInfo(1:(n-1)).Length]) ...
+ lengthOfDeletionIndicator;
fseek(dbfFileId,fieldOffset,'bof');
formatString = sprintf('%d*uint8=>char',info.FieldInfo(n).Length);
skip = info.RecordLength - info.FieldInfo(n).Length;
data = fread(dbfFileId,[info.FieldInfo(n).Length info.NumRecords],formatString,skip);
dbfData(:,k) = feval(info.FieldInfo(n).ConvFunc,(data(:,records2read)'));
% dbfData(:,k) = info.FieldInfo(n).ConvFunc(data(:,records2read)');
end
fclose(dbfFileId);
%--------------------------------------------------------------------------
function fields2read = matchFieldNames(info, requestedFieldNames)
% Determine which fields to read.
allFieldNames = {info.FieldInfo.Name};
if isempty(requestedFieldNames)
if ~iscell(requestedFieldNames)
% Default case: User omitted the parameter, return all fields.
fields2read = 1:info.NumFields;
else
% User supplied '{}', skip all fields.
fields2read = [];
end
else
% Match up field names to see which to return.
fields2read = [];
for k = 1:numel(requestedFieldNames)
index = strmatch(requestedFieldNames{k},allFieldNames,'exact');
if isempty(index)
wid = sprintf('MATLAB:%s:nonexistentDBFName',mfilename);
wrn = sprintf('DBF name ''%s'' %s\n%s',requestedFieldNames{k},...
'doesn''t match an existing DBF name.',...
' It will be ignored.');
warning(wid,wrn)
end
for l = 1:numel(index)
% Take them all in case of duplicate names.
fields2read(end+1) = index(l);
end
end
end
%--------------------------------------------------------------------------
function info = dbfinfo(fid)
%DBFINFO Read header information from DBF file.
% FID File identifier for an open DBF file.
% INFO is a structure with the following fields:
% Filename Char array containing the name of the file that was read
% DBFVersion Number specifying the file format version
% FileModDate A string containing the modification date of the file
% NumRecords A number specifying the number of records in the table
% NumFields A number specifying the number of fields in the table
% FieldInfo A 1-by-numFields structure array with fields:
% Name A string containing the field name
% Type A string containing the field type
% ConvFunc A function handle to convert from DBF to MATLAB type
% Length A number of bytes in the field
% HeaderLength A number specifying length of the file header in bytes
% RecordLength A number specifying length of each record in bytes
% Copyright 1996-2005 The MathWorks, Inc.
% $Revision: 1.1.10.4 $ $Date: 2005/11/15 01:07:13 $
[version, date, numRecords, headerLength, recordLength] = readFileInfo(fid);
fieldInfo = getFieldInfo(fid);
info.Filename = fopen(fid);
info.DBFVersion = version;
info.FileModDate = date;
info.NumRecords = numRecords;
info.NumFields = length(fieldInfo);
info.FieldInfo = fieldInfo;
info.HeaderLength = headerLength;
info.RecordLength = recordLength;
%----------------------------------------------------------------------------
function [version, date, numRecords, headerLength, recordLength] = readFileInfo(fid)
% Read from File Header.
fseek(fid,0,'bof');
version = fread(fid,1,'uint8');
year = fread(fid,1,'uint8') + 1900;
month = fread(fid,1,'uint8');
day = fread(fid,1,'uint8');
dateVector = datevec(sprintf('%d/%d/%d',month,day,year));
dateForm = 1;% dd-mmm-yyyy
date = datestr(dateVector,dateForm);
numRecords = fread(fid,1,'uint32');
headerLength = fread(fid,1,'uint16');
recordLength = fread(fid,1,'uint16');
%----------------------------------------------------------------------------
function fieldInfo = getFieldInfo(fid)
% Form FieldInfo by reading Field Descriptor Array.
%
% FieldInfo is a 1-by-numFields structure array with the following fields:
% Name A string containing the field name
% Type A string containing the field type
% ConvFunc A function handle to convert from DBF to MATLAB type
% Length A number equal to the length of the field in bytes
lengthOfLeadingBlock = 32;
lengthOfDescriptorBlock = 32;
lengthOfTerminator = 1;
fieldNameOffset = 16; % Within table field descriptor
fieldNameLength = 11;
% Get number of fields.
fseek(fid,8,'bof');
headerLength = fread(fid,1,'uint16');
numFields = (headerLength - lengthOfLeadingBlock - lengthOfTerminator)...
/ lengthOfDescriptorBlock;
% Read field lengths.
fseek(fid,lengthOfLeadingBlock + fieldNameOffset,'bof');
lengths = fread(fid,[1 numFields],'uint8',lengthOfDescriptorBlock - 1);
% Read the field names.
fseek(fid,lengthOfLeadingBlock,'bof');
data = fread(fid,[fieldNameLength numFields],...
sprintf('%d*uint8=>char',fieldNameLength),...
lengthOfDescriptorBlock - fieldNameLength);
data(data == 0) = ' '; % Replace nulls with blanks
names = cellstr(data')';
% Read field types.
fseek(fid,lengthOfLeadingBlock + fieldNameLength,'bof');
dbftypes = fread(fid,[numFields 1],'uint8=>char',lengthOfDescriptorBlock - 1);
% Convert DBF field types to MATLAB types.
typeConv = dbftype2matlab(upper(dbftypes));
% Return a struct array.
fieldInfo = cell2struct(...
[names; {typeConv.MATLABType}; {typeConv.ConvFunc}; num2cell(lengths)],...
{'Name', 'Type', 'ConvFunc', 'Length'},1)';
%----------------------------------------------------------------------------
function typeConv = dbftype2matlab(dbftypes)
% Construct struct array with MATLAB types & conversion function handles.
typeLUT = ...
{'N', 'double', @str2double2cell;... % DBF numeric
'F', 'double', @str2double2cell;... % DBF float
'C', 'char', @cellstr;... % DBF character
'D', 'char', @cellstr}; % DBF date
unsupported = struct('MATLABType', 'unsupported', ...
'ConvFunc', @cellstr);
% Unsupported types: Logical,Memo,N/ANameVariable,Binary,General,Picture
numFields = length(dbftypes);
if numFields ~= 0
typeConv(numFields) = struct('MATLABType',[],'ConvFunc',[]);
end
for k = 1:numFields
idx = strmatch(dbftypes(k),typeLUT(:,1));
if ~isempty(idx)
typeConv(k).MATLABType = typeLUT{idx,2};
typeConv(k).ConvFunc = typeLUT{idx,3};
else
typeConv(k) = unsupported;
end
end
%----------------------------------------------------------------------------
function out = str2double2cell(in)
% Translate IN, an M-by-N array of class char, to an M-by-1 column vector
% OUT, of class double. IN may be blank- or null-padded. If IN(k,:) does
% not represent a valid scalar value, then OUT(k) has value NaN.
if isempty(in)
out = {[NaN]};
return
end
% Use sprintf when possible, but fall back to str2double for unusual cases.
fmt = sprintf('%%%df',size(in,2));
[data count] = sscanf(reshape(in',[1 numel(in)]),fmt);
if count == size(in,1)
out = cell(count,1);
for k = 1:count
out{k} = data(k);
end
else
out = num2cell(str2double(cellstr(in)));
end
ОБНОВЛЕНИЕ
Подфункция STR2DOUBLE2CELL иногда работает некорректно, если количество цифр во входном параметре отличается (см. это обсуждение).
Вот моя версия STR2DOUBLE2CELL:
function out = str2double2cell(in)
% Translate IN, an M-by-N array of class char, to an M-by-1 column vector
% OUT, of class double. IN may be blank- or null-padded. If IN(k,:) does
% not represent a valid scalar value, then OUT(k) has value NaN.
if isempty(in)
out = {[NaN]};
return
end
out = cellfun(@str2double,cellstr(in),'UniformOutput',false);
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02.03.2010
