read obj in matlab

function obj=read_obj(input_file_name)
[ node_num, face_num, normal_num, order_max ] = obj_size( input_file_name );
[ node_xyz, face_order, face_node, normal_vector, vertex_normal ] = ...
obj_read( input_file_name, node_num, face_num, normal_num, order_max );
obj.xyz=node_xyz;
obj.face_order=face_order;
obj.tri=face_node;
obj.normal=normal_vector;
obj.vertex_normal=vertex_normal;
obj.node_num=node_num;
obj.face_num=face_num;
obj.normal_num=normal_num;
obj.order_max=order_max;

vertex_mean_normal = zeros(3, node_num);
for i = 1:face_num
for j = 1:face_order(i)
node_index = face_node(j,i);
node_normal_index = vertex_normal(j,i);
node_normal = normal_vector(:,node_normal_index);
vertex_mean_normal(:,node_index) = vertex_mean_normal(:,node_index) + node_normal;
end
end

vertex_mean_normal = vertex_mean_normal./repmat(sqrt(sum(vertex_mean_normal.^2)),size(vertex_mean_normal,1),1);
obj.vertex_mean_normal = vertex_mean_normal;

end

function [ node_xyz, face_order, face_node, normal_vector, vertex_normal ] = ...
obj_read ( input_file_name, node_num, face_num, normal_num, order_max )

%*****************************************************************************80
%
% OBJ_READ reads graphics information from a Wavefront OBJ file.
%
%  Discussion:
%
%    It is intended that the information read from the file can
%    either start a whole new graphics object, or simply be added
%    to a current graphics object via the '<<' command.
%
%    This is controlled by whether the input values have been zeroed
%    out or not.  This routine simply tacks on the information it
%    finds to the current graphics object.
%
%  Example:
%
%    #  magnolia.obj
%
%    v -3.269770 -39.572201 0.876128
%    v -3.263720 -39.507999 2.160890
%    ...
%    v 0.000000 -9.988540 0.000000
%    vn 1.0 0.0 0.0
%    ...
%    vn 0.0 1.0 0.0
%
%    f 8 9 11 10
%    f 12 13 15 14
%    ...
%    f 788 806 774
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    27 September 2008
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, string INPUT_FILE_NAME, the name of the input file.
%
%    Input, integer NODE_NUM, the number of points.
%
%    Input, integer FACE_NUM, the number of faces.
%
%    Input, integer NORMAL_NUM, the number of normal vectors.
%
%    Input, integer ORDER_MAX, the maximum number of vertices per face.
%
%    Output, real ( kind = 8 ) NODE_XYZ(3,NODE_NUM), the coordinates of points.
%
%    Output, integer FACE_ORDER(FACE_NUM), the number of vertices per face.
%
%    Output, integer FACE_NODE(ORDER_MAX,FACE_NUM), the nodes making faces.
%
%    Output, real ( kind = 8 ) NORMAL_VECTOR(3,NORMAL_NUM), normal vectors.
%
%    Output, integer VERTEX_NORMAL(ORDER_MAX,FACE_NUM), the indices of normal
%    vectors per vertex.
%
ierror = 0;

face = 0;
node = 0;
normal = 0;
text_num = 0;

face_node = zeros ( order_max, face_num );
face_order = zeros ( face_num, 1 );
node_xyz = zeros ( 3, node_num );
normal_vector = zeros ( 3, normal_num );
vertex_normal = zeros ( order_max, face_num );
%
%  If no file input, try to get one from the user.
%
if ( nargin < 1 )
input_file_name = input ( 'Enter the name of the ASCII OBJ file.' );
if ( isempty ( input_file_name ) )
return
end
end
%
%  Open the file.
%
input_file_unit = fopen ( input_file_name, 'r' );

if ( input_file_unit < 0 )
fprintf ( 1, '\n' );
fprintf ( 1, 'OBJ_READ - Fatal error!\n' );
fprintf ( 1, '  Could not open the file "%s".\n', input_file_name );
error ( 'OBJ_READ - Fatal error!' );
return
end
%
%  Read a line of text from the file.
%
while ( 1 )

text = fgetl ( input_file_unit );

if ( text == -1 )
break
end

text_num = text_num + 1;
%
%  Replace any control characters (in particular, TAB's) by blanks.
%
s_control_blank ( text );

done = 1;
word_index = 0;
%
%  Read a word from the line.
%
[ word, done ] = word_next_read ( text, done );
%
%  If no more words in this line, read a new line.
%
if ( done )
continue
end
%
%  If this word begins with '#' or '$', then it's a comment.  Read a new line.
%
if ( word(1) == '#' || word(1) == '$' )
continue
end

word_index = word_index + 1;

if ( word_index == 1 )
word_one = word;
end
%
%  BEVEL
%  Bevel interpolation.
%
if ( s_eqi ( word_one, 'BEVEL' ) )
%
%  BMAT
%  Basis matrix.
%
elseif ( s_eqi ( word_one, 'BMAT' ) )
%
%  C_INTERP
%  Color interpolation.
%
elseif ( s_eqi ( word_one, 'C_INTERP' ) )
%
%  CON
%  Connectivity between free form surfaces.
%
elseif ( s_eqi ( word_one, 'CON' ) )
%
%  CSTYPE
%  Curve or surface type.
%
elseif ( s_eqi ( word_one, 'CSTYPE' ) )
%
%  CTECH
%  Curve approximation technique.
%
elseif ( s_eqi ( word_one, 'CTECH' ) )
%
%  CURV
%  Curve.
%
elseif ( s_eqi ( word_one, 'CURV' ) )
%
%  CURV2
%  2D curve.
%
elseif ( s_eqi ( word_one, 'CURV2' ) )
%
%  D_INTERP
%  Dissolve interpolation.
%
elseif ( s_eqi ( word_one, 'D_INTERP' ) )
%
%  DEG
%  Degree.
%
elseif ( s_eqi ( word_one, 'DEG' ) )
%
%  END
%  End statement.
%
elseif ( s_eqi ( word_one, 'END' ) )
%
%  F V1 V2 V3 ...
%    or
%  F V1/VT1/VN1 V2/VT2/VN2 ...
%    or
%  F V1//VN1 V2//VN2 ...
%
%  Face.
%  A face is defined by the vertices.
%  Optionally, slashes may be used to include the texture vertex
%  and vertex normal indices.
%
elseif ( s_eqi ( word_one, 'F' ) )

face = face + 1;

vertex = 0;

while ( 1 )

[ word, done ] = word_next_read ( text, done );

if ( done )
break
end

vertex = vertex + 1;
order_max = max ( order_max, vertex );
%
%  Locate the slash characters in the word, if any.
%
i1 = ch_index ( word, '/' );
if ( 0 < i1 )
i2 = ch_index ( word(i1+1:end), '/' ) + i1;
else
i2 = 0;
end
%
%  Read the vertex index.
%
itemp = s_to_i4 ( word );

face_node(vertex,face) = itemp;
face_order(face) = face_order(face) + 1;
%
%  If there are two slashes, then read the data following the second one.
%
if ( 0 < i2 )

itemp = s_to_i4 ( word(i2+1:end) );

vertex_normal(vertex,face) = itemp;

end

end
%
%  G
%  Group name.
%
elseif ( s_eqi ( word_one, 'G' ) )
%
%  HOLE
%  Inner trimming loop.
%
elseif ( s_eqi ( word_one, 'HOLE' ) )
%
%  L
%  A line, described by a sequence of vertex indices.
%  Are the vertex indices 0 based or 1 based?
%
elseif ( s_eqi ( word_one, 'L' ) )
%
%  LOD
%  Level of detail.
%
elseif ( s_eqi ( word_one, 'LOD' ) )
%
%  MG
%  Merging group.
%
elseif ( s_eqi ( word_one, 'MG' ) )
%
%  MTLLIB
%  Material library.
%
elseif ( s_eqi ( word_one, 'MTLLIB' ) )
%
%  O
%  Object name.
%
elseif ( s_eqi ( word_one, 'O' ) )
%
%  P
%  Point.
%
elseif ( s_eqi ( word_one, 'P' ) )
%
%  PARM
%  Parameter values.
%
elseif ( s_eqi ( word_one, 'PARM' ) )
%
%  S
%  Smoothing group.
%
elseif ( s_eqi ( word_one, 'S' ) )
%
%  SCRV
%  Special curve.
%
elseif ( s_eqi ( word_one, 'SCRV' ) )
%
%  SHADOW_OBJ
%  Shadow casting.
%
elseif ( s_eqi ( word_one, 'SHADOW_OBJ' ) )
%
%  SP
%  Special point.
%
elseif ( s_eqi ( word_one, 'SP' ) )
%
%  STECH
%  Surface approximation technique.
%
elseif ( s_eqi ( word_one, 'STECH' ) )
%
%  STEP
%  Stepsize.
%
elseif ( s_eqi ( word_one, 'STEP' ) )
%
%  SURF
%  Surface.
%
elseif ( s_eqi ( word_one, 'SURF' ) )
%
%  TRACE_OBJ
%  Ray tracing.
%
elseif ( s_eqi ( word_one, 'TRACE_OBJ' ) )
%
%  TRIM
%  Outer trimming loop.
%
elseif ( s_eqi ( word_one, 'TRIM' ) )
%
%  USEMTL
%  Material name.
%
elseif ( s_eqi ( word_one, 'USEMTL' ) )
%
%  V X Y Z
%  Geometric vertex.
%
elseif ( s_eqi ( word_one, 'V' ) )

node = node + 1;

for i = 1 : 3
[ word, done ] = word_next_read ( text, done );
temp = s_to_r8 ( word );
node_xyz(i,node) = temp;
end
%
%  VN
%  Vertex normals.
%
elseif ( s_eqi ( word_one, 'VN' ) )

normal = normal + 1;

for i = 1 : 3
[ word, done ] = word_next_read ( text, done );
temp = s_to_r8 ( word );
normal_vector(i,normal) = temp;
end
%
%  VT
%  Vertex texture.
%
elseif ( s_eqi ( word_one, 'VT' ) )
%
%  VP
%  Parameter space vertices.
%
elseif ( s_eqi ( word_one, 'VP' ) )
%
%  Unrecognized keyword.
%
else

end

end

fclose ( input_file_unit );

return
end

function [ node_num, face_num, normal_num, order_max ] = obj_size ( ...
input_file_name )
%*****************************************************************************80
%
% OBJ_SIZE determines sizes of graphics objects in an Alias OBJ file.
%
%  Discussion:
%
%    The only items of interest to this routine are vertices,
%    faces, and normal vectors.
%
%  Example:
%
%    #  magnolia.obj
%
%    v -3.269770 -39.572201 0.876128
%    v -3.263720 -39.507999 2.160890
%    ...
%    v 0.000000 -9.988540 0.000000
%
%    vn 1.0 0.0 0.0
%    ...
%    vn 0.0 1.0 0.0
%
%    f 8 9 11 10
%    f 12 13 15 14
%    ...
%    f 788 806 774
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    26 September 2008
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, string INPUT_FILE_NAME, the input file name.
%
%    Output, integer NODE_NUM, the number of points.
%
%    Output, integer FACE_NUM, the number of faces.
%
%    Output, integer NORMAL_NUM, the number of normal vectors.
%
%    Output, integer ORDER_MAX, the maximum face order.
%
ierror = 0;

face_num = 0;
node_num = 0;
normal_num = 0;
order_max = 0;
text_num = 0;
%
%  If no file input, try to get one from the user.
%
if ( nargin < 1 )
input_file_name = input ( 'Enter the name of the ASCII OBJ file.' );
if ( isempty ( input_file_name ) )
return
end
end
%
%  Open the file.
%
input_file_unit = fopen ( input_file_name, 'r' );

if ( input_file_unit < 0 )
fprintf ( 1, '\n' );
fprintf ( 1, 'OBJ_SIZE - Fatal error!\n' );
fprintf ( 1, '  Could not open the file "%s".\n', input_file_name );
error ( 'OBJ_SIZE - Fatal error!' );
return
end
%
%  Read a line of text from the file.
%
while ( 1 )

text = fgetl ( input_file_unit );

if ( text == -1 )
break
end

text_num = text_num + 1;
%
%  Replace any control characters (in particular, TABs) by blanks.
%
s_control_blank ( text );

done = 1;
word_index = 0;
%
%  Read a word from the line.
%
[ word, done ] = word_next_read ( text, done );
%
%  If no more words in this line, read a new line.
%
if ( done )
continue
end
%
%  If this word begins with '#' or '$', then it is a comment.  Read a new line.
%
if ( word(1) == '#' || word(1) == '$' )
continue
end

word_index = word_index + 1;

if ( word_index == 1 )
word_one = word;
end
%
%  F V1 V2 V3 ...
%    or
%  F V1/VT1/VN1 V2/VT2/VN2 ...
%    or
%  F V1//VN1 V2//VN2 ...
%
%  Face.
%  A face is defined by the vertices.
%  Optionally, slashes may be used to include the texture vertex
%  and vertex normal indices.
%
if ( s_eqi ( word_one, 'F' ) )

face_num = face_num + 1;

vertex = 0;

while ( 1 )

[ word, done ] = word_next_read ( text, done );

if ( done )
break
end

vertex = vertex + 1;
order_max = max ( order_max, vertex );
%
%  Locate the slash characters in the word, if any.
%
i1 = ch_index ( word, '/' );
if ( 0 < i1 )
i2 = ch_index ( word(i1+1), '/' ) + i1;
else
i2 = 0;
end
%
%  Read the vertex index.
%
itemp = s_to_i4 ( word );
%
%  If there are two slashes, then read the data following the second one.
%
if ( 0 < i2 )
itemp = s_to_i4 ( word(i2+1) );
end

end
%
%  V X Y Z W
%  Geometric vertex.
%
elseif ( s_eqi ( word_one, 'V' ) )

node_num = node_num + 1;
continue
%
%  VN
%  Vertex normals.
%
elseif ( s_eqi ( word_one, 'VN' ) )

normal_num = normal_num + 1;
continue

end

end

fclose ( input_file_unit );

return
end

function c2 = ch_cap ( c )

%*****************************************************************************80
%
% CH_CAP capitalizes a single character.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    22 November 2003
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, character C, the character to capitalize.
%
%    Output, character C2, the capitalized character.
%
if ( 'a' <= c & c <= 'z' )
c2 = c + 'A' - 'a';
else
c2 = c;
end

return
end

function truefalse = ch_eqi ( c1, c2 )

%*****************************************************************************80
%
% CH_EQI is a case insensitive comparison of two characters for equality.
%
%  Example:
%
%    CH_EQI ( 'A', 'a' ) is TRUE.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    28 July 2000
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, character C1, C2, the characters to compare.
%
%    Output, logical TRUEFALSE, is TRUE (1) if the characters are equal.
%
FALSE = 0;
TRUE = 1;

if ( ch_cap ( c1 ) == ch_cap ( c2 ) )
truefalse = TRUE;
else
truefalse = FALSE;
end

return
end

function value = ch_index ( s, c )
%*****************************************************************************80
%
% CH_INDEX is the first occurrence of a character in a string.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    01 May 2004
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, string S, the string to be searched.
%
%    Input, character C, the character to be searched for.
%
%    Output, integer VALUE, the location of the first occurrence of C
%    in the string, or 0 if C does not occur.
%
value = 0;

for i = 1 : length ( s )

if ( s(i:i) == c )
value = i;
return
end

end

return
end

function value = ch_is_control ( c )

%*****************************************************************************80
%
% CH_IS_CONTROL is TRUE if C is a control character.
%
%  Discussion:
%
%    A "control character" has ASCII code <= 31 or 127 <= ASCII code.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    26 September 2008
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, character C, the character to be tested.
%
%    Output, logical VALUE, TRUE if C is a control character, and
%    FALSE otherwise.
%
if ( c <= 31 || 127 <= c )
value = 1;
else
value = 0;
end

return
end

function truefalse = ch_is_digit ( c )

%*****************************************************************************80
%
% CH_IS_DIGIT returns TRUE if the character C is a digit.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    11 December 2003
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, character C, a character.
%
%    Output, integer TRUEFALSE, is TRUE (1) if C is a digit, FALSE (0) otherwise.
%
TRUE = 1;
FALSE = 0;

if ( '0' <= c & c <= '9' )
truefalse = TRUE;
else
truefalse = FALSE;
end

return
end

function digit = ch_to_digit ( c )

%*****************************************************************************80
%
% CH_TO_DIGIT returns the integer value of a base 10 digit.
%
%  Example:
%
%     C   DIGIT
%    ---  -----
%    '0'    0
%    '1'    1
%    ...  ...
%    '9'    9
%    ' '    0
%    'X'   -1
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    22 November 2003
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, character C, the decimal digit, '0' through '9' or blank
%    are legal.
%
%    Output, integer DIGIT, the corresponding integer value.  If C was
%    'illegal', then DIGIT is -1.
%
if ( '0' <= c & c <= '9' )

digit = c - '0';

elseif ( c == ' ' )

digit = 0;

else

digit = -1;

end

return
end

function v3 = r8vec_cross_product_3d ( v1, v2 )

%*****************************************************************************80
%
% R8VEC_CROSS_PRODUCT_3D computes the cross product of two R8VEC's in 3D.
%
%  Discussion:
%
%    The cross product in 3D can be regarded as the determinant of the
%    symbolic matrix:
%
%          |  i  j  k |
%      det | x1 y1 z1 |
%          | x2 y2 z2 |
%
%      = ( y1 * z2 - z1 * y2 ) * i
%      + ( z1 * x2 - x1 * z2 ) * j
%      + ( x1 * y2 - y1 * x2 ) * k
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    31 October 2005
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, real V1(3), V2(3), the two vectors.
%
%    Output, real V3(3), the cross product vector.
%
v3 = zeros ( 3, 1 );

v3(1) = v1(2) * v2(3) - v1(3) * v2(2);
v3(2) = v1(3) * v2(1) - v1(1) * v2(3);
v3(3) = v1(1) * v2(2) - v1(2) * v2(1);

return
end

function s3 = s_cat ( s1, s2 )

%*****************************************************************************80
%
% S_CAT concatenates two strings to make a third string.
%
%  Discussion:
%
%    MATLAB provides the STRCAT function, which you should
%    probably use instead of this function!
%
%    s3 = strcat ( s1, s2 )
%
%    Although STRCAT does not ignore trailing blanks.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    28 May 2007
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, string S1, the "prefix" string.
%
%    Input, string S2, the "postfix" string.
%
%    Output, string S3, the string made by
%    concatenating S1 and S2, ignoring any trailing blanks.
%
l1 = s_len_trim ( s1 );
l2 = s_len_trim ( s2 );
%
%  The following line essentially "declares" S3 to be a
%  character string.  Omitting this line would cause S3
%  to be regarded as a numeric array.
%
s3 = '';
%
%  Now copy the strings.
%
s3(   1:l1   ) = s1(1:l1);
s3(l1+1:l1+l2) = s2(1:l2);

return
end

function s = s_control_blank ( s )

%*****************************************************************************80
%
% S_CONTROL_BLANK replaces control characters with blanks.
%
%  Discussion:
%
%    A "control character" has ASCII code <= 31 or 127 <= ASCII code.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    27 September 2008
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input/output, string S, the string to be transformed.
%
s_length = s_len_trim ( s );

for i = 1 : s_length
if ( ch_is_control ( s(i) ) )
s(i) = ' ';
end
end

return
end

function value = s_eqi ( s1, s2 )

%*****************************************************************************80
%
% S_EQI is a case insensitive comparison of two strings for equality.
%
%  Example:
%
%    S_EQI ( 'Anjana', 'ANJANA' ) is TRUE.
%
%  Modified:
%
%    30 April 2004
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, string S1, S2, the strings to compare.
%
%    Output, logical VALUE, is TRUE if the strings are equal.
%
FALSE = 0;
TRUE = 1;

len1 = length ( s1 );
len2 = length ( s2 );
lenc = min ( len1, len2 );

value = FALSE;

for i = 1 : lenc

c1 = ch_cap ( s1(i) );
c2 = ch_cap ( s2(i) );

if ( c1 ~= c2 )
value = FALSE;
return
end

end

for i = lenc + 1 : len1
if ( s1(i) ~= ' ' )
value = FALSE;
return
end
end

for i = lenc + 1 : len2
if ( s2(i) ~= ' ' )
value = FALSE;
return
end
end

value = TRUE;
end

function len = s_len_trim ( s )

%*****************************************************************************80
%
% S_LEN_TRIM returns the length of a character string to the last nonblank.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    14 June 2003
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, string S, the string to be measured.
%
%    Output, integer LEN, the length of the string up to the last nonblank.
%
len = length ( s );

while ( 0 < len )
if ( s(len) ~= ' ' )
return
end
len = len - 1;
end

return
end

function ival = s_to_i4 ( s )

%*****************************************************************************80
%
% S_TO_I4 reads an integer value from a string.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    18 November 2003
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, string S, a string to be examined.
%
%    Output, integer IVAL, the integer value read from the string.
%
sgn = 1;
state = 0;
ival = 0;

i = 0;

while ( i < s_len_trim ( s ) )

i = i + 1;
c = s(i);

if ( state == 0 )

if ( c == ' ' )

elseif ( c == '-' )
state = 1;
sgn = -1;
elseif ( c == '+' )
state = 1;
sgn = +1;
elseif ( '0' <= c & c <= '9' )
state = 2;
ival = c - '0';
else
fprintf ( '\n' );
fprintf ( 'S_TO_I4 - Fatal error!\n' );
fprintf ( '  Illegal character %c while in state %d.\n', c, state );
return;
end
%
%  Have read the sign, now expecting the first digit.
%
elseif ( state == 1 )

if ( c == ' ' )

elseif ( '0' <= c & c <= '9' )
state = 2;
ival = c - '0';
else
fprintf ( '\n' );
fprintf ( 'S_TO_I4 - Fatal error!\n' );
fprintf ( '  Illegal character %c while in state %d.\n', c, state );
return
end
%
%  Have read at least one digit, expecting more.
%
elseif ( state == 2 )

if ( '0' <= c & c <= '9' )
ival = 10 * ival + c - '0';
else
ival = sgn * ival;
return;
end

end

end
%
%  If we read all the characters in the string, see if we're OK.
%
if ( state ~= 2 )
fprintf ( '\n' );
fprintf ( 'S_TO_I4 - Fatal error!\n' );
fprintf ( '  Did not read enough information to define an integer!\n' );
return;
end

ival = sgn * ival;

return
end

function [ r, lchar, ierror ] = s_to_r8 ( s )

%*****************************************************************************80
%
% S_TO_R8 reads an R8 from a string.
%
%  Discussion:
%
%    This routine will read as many characters as possible until it reaches
%    the end of the string, or encounters a character which cannot be
%    part of the real number.
%
%    Legal input is:
%
%       1 blanks,
%       2 '+' or '-' sign,
%       2.5 spaces
%       3 integer part,
%       4 decimal point,
%       5 fraction part,
%       6 'E' or 'e' or 'D' or 'd', exponent marker,
%       7 exponent sign,
%       8 exponent integer part,
%       9 exponent decimal point,
%      10 exponent fraction part,
%      11 blanks,
%      12 final comma or semicolon.
%
%    with most quantities optional.
%
%  Example:
%
%    S                 R
%
%    '1'               1.0
%    '     1   '       1.0
%    '1A'              1.0
%    '12,34,56'        12.0
%    '  34 7'          34.0
%    '-1E2ABCD'        -100.0
%    '-1X2ABCD'        -1.0
%    ' 2E-1'           0.2
%    '23.45'           23.45
%    '-4.2E+2'         -420.0
%    '17d2'            1700.0
%    '-14e-2'         -0.14
%    'e2'              100.0
%    '-12.73e-9.23'   -12.73 * 10.0**(-9.23)
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    22 November 2003
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, string S, the string containing the
%    data to be read.  Reading will begin at position 1 and
%    terminate at the end of the string, or when no more
%    characters can be read to form a legal real.  Blanks,
%    commas, or other nonnumeric data will, in particular,
%    cause the conversion to halt.
%
%    Output, real R, the value that was read from the string.
%
%    Output, integer LCHAR, the number of characters of S that were used to form R.
%
%    Output, integer IERROR, is 0 if no error occurred.
%
s_length = s_len_trim ( s );
ierror = 0;
r = 0.0;
lchar = -1;
isgn = 1;
rtop = 0.0;
rbot = 1.0;
jsgn = 1;
jtop = 0;
jbot = 1;
ihave = 1;
iterm = 0;

while ( 1 )

lchar = lchar + 1;
c = s(lchar+1);
%
%  Blank character.
%
if ( c == ' ' )

if ( ihave == 2 )

elseif ( ihave == 6 || ihave == 7 )
iterm = 1;
elseif ( 1 < ihave )
ihave = 11;
end
%
%  Comma.
%
elseif ( c == ',' || c == ';' )

if ( ihave ~= 1 )
iterm = 1;
ihave = 12;
lchar = lchar + 1;
end
%
%  Minus sign.
%
elseif ( c == '-' )

if ( ihave == 1 );
ihave = 2;
isgn = -1;
elseif ( ihave == 6 )
ihave = 7;
jsgn = -1;
else
iterm = 1;
end
%
%  Plus sign.
%
elseif ( c == '+' )

if ( ihave == 1 )
ihave = 2;
elseif ( ihave == 6 )
ihave = 7;
else
iterm = 1;
end
%
%  Decimal point.
%
elseif ( c == '.' )

if ( ihave < 4 )
ihave = 4;
elseif ( 6 <= ihave & ihave <= 8 )
ihave = 9;
else
iterm = 1;
end
%
%  Exponent marker.
%
elseif ( ch_eqi ( c, 'E' ) || ch_eqi ( c, 'D' ) )

if ( ihave < 6 )
ihave = 6;
else
iterm = 1;
end
%
%  Digit.
%
elseif ( ihave < 11 & ch_is_digit ( c ) )

if ( ihave <= 2 )
ihave = 3;
elseif ( ihave == 4 )
ihave = 5;
elseif ( ihave == 6 || ihave == 7 )
ihave = 8;
elseif ( ihave == 9 )
ihave = 10;
end

d = ch_to_digit ( c );

if ( ihave == 3 )
rtop = 10.0 * rtop + d;
elseif ( ihave == 5 )
rtop = 10.0 * rtop + d;
rbot = 10.0 * rbot;
elseif ( ihave == 8 )
jtop = 10 * jtop + d;
elseif ( ihave == 10 )
jtop = 10 * jtop + d;
jbot = 10 * jbot;
end
%
%  Anything else is regarded as a terminator.
%
else
iterm = 1;
end
%
%  If we haven't seen a terminator, and we haven't examined the
%  entire string, go get the next character.
%
if ( iterm == 1 || s_length <= lchar + 1 )
break;
end

end
%
%  If we haven't seen a terminator, and we have examined the
%  entire string, then we're done, and LCHAR is equal to S_LENGTH.
%
if ( iterm ~= 1 & lchar + 1 == s_length )
lchar = s_length;
end
%
%  Number seems to have terminated.  Have we got a legal number?
%  Not if we terminated in states 1, 2, 6 or 7!
%
if ( ihave == 1 || ihave == 2 || ihave == 6 || ihave == 7 )
ierror = ihave;
fprintf ( 1, '\n' );
fprintf ( 1, 'S_TO_R8 - Fatal error!\n' );
fprintf ( 1, '  IHAVE = %d\n', ihave );
error ( 'S_TO_R8 - Fatal error!' );
end
%
%  Number seems OK.  Form it.
%
if ( jtop == 0 )
rexp = 1.0;
else

if ( jbot == 1 )
rexp = 10.0^( jsgn * jtop );
else
rexp = jsgn * jtop;
rexp = rexp / jbot;
rexp = 10.0^rexp;
end

end

r = isgn * rexp * rtop / rbot;

return
end

function timestamp ( )

%*****************************************************************************80
%
% TIMESTAMP prints the current YMDHMS date as a timestamp.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    14 February 2003
%
%  Author:
%
%    John Burkardt
%
t = now;
c = datevec ( t );
s = datestr ( c, 0 );
fprintf ( 1, '%s\n', s );

return
end

function [ word, done ] = word_next_read ( s, done )

%*****************************************************************************80
%
% WORD_NEXT_READ "reads" words from a string, one at a time.
%
%  Special cases:
%
%    The following characters are considered to be a single word,
%    whether surrounded by spaces or not:
%
%      " ( ) { } [ ]
%
%    Also, if there is a trailing comma on the word, it is stripped off.
%    This is to facilitate the reading of lists.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    24 September 2005
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, string S, a string, presumably containing words
%    separated by spaces.
%
%    Input, logical DONE.
%    TRUE, if we are beginning a new string;
%    FALSE, if we are continuing to process the current string.
%
%    Output, string WORD.
%    If DONE is FALSE, then WORD contains the "next" word read.
%    If DONE is TRUE, then WORD is blank, because there was no more to read.
%
%    Output, logical DONE.
%      FALSE if another word was read,
%      TRUE if no more words could be read.
%
persistent lenc;
persistent next;

tab = char ( 9 );
%
%  We "remember" LENC and NEXT from the previous call.
%
%  An input value of DONE = TRUE signals a new line of text to examine.
%
if ( done )

next = 1;
done = 0;
lenc = s_len_trim ( s );

if ( lenc <= 0 )
done = 1;
word = ' ';
return
end

end
%
%  Beginning at index NEXT, search the string for the next nonblank,
%  which signals the beginning of a word.
%
ilo = next;
%
%  ...S(NEXT:) is blank.  Return with WORD = ' ' and DONE = TRUE.
%
while ( 1 )

if ( lenc < ilo )
word = ' ';
done = 1;
next = lenc + 1;
return
end
%
%  If the current character is blank, skip to the next one.
%
if ( s(ilo) ~= ' ' & s(ilo) ~= tab )
break
end

ilo = ilo + 1;

end
%
%  ILO is the index of the next nonblank character in the string.
%
%  If this initial nonblank is a special character,
%  then that's the whole word as far as we're concerned,
%  so return immediately.
%
if ( s(ilo) == '"' | ...
s(ilo) == '(' | ...
s(ilo) == ')' | ...
s(ilo) == '{' | ...
s(ilo) == '}' | ...
s(ilo) == '[' | ...
s(ilo) == ']' )

word = s(ilo);
next = ilo + 1;
return

end
%
%  Now search for the last contiguous character that is not a
%  blank, TAB, or special character.
%
next = ilo + 1;

while ( next <= lenc )

if ( s(next) == ' ' )
break;
elseif ( s(next) == tab )
break;
elseif ( s(next) == '"' )
break;
elseif ( s(next) == '(' )
break;
elseif ( s(next) == ')' )
break;
elseif ( s(next) == '{' )
break;
elseif ( s(next) == '}' )
break;
elseif ( s(next) == '[' )
break;
elseif ( s(next) == ']' )
break;
end

next = next + 1;

end

if ( s(next-1) == ',' )
word = s(ilo:next-2);
else
word = s(ilo:next-1);
end

return
end