1 % $Id: mp.w 597 2008-07-03 15:35:34Z taco $
3 % Copyright 2008 Taco Hoekwater.
5 % This program is free software: you can redistribute it and/or modify
6 % it under the terms of the GNU General Public License as published by
7 % the Free Software Foundation, either version 2 of the License, or
8 % (at your option) any later version.
10 % This program is distributed in the hope that it will be useful,
11 % but WITHOUT ANY WARRANTY; without even the implied warranty of
12 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 % GNU General Public License for more details.
15 % You should have received a copy of the GNU General Public License
16 % along with this program. If not, see <http://www.gnu.org/licenses/>.
18 % TeX is a trademark of the American Mathematical Society.
19 % METAFONT is a trademark of Addison-Wesley Publishing Company.
20 % PostScript is a trademark of Adobe Systems Incorporated.
22 % Here is TeX material that gets inserted after \input webmac
24 \font\tenlogo=logo10 % font used for the METAFONT logo
26 \def\MF{{\tenlogo META}\-{\tenlogo FONT}}
27 \def\MP{{\tenlogo META}\-{\tenlogo POST}}
29 \def\title{Reading TEX metrics files}
34 @ Needed headers and macros
36 @d qi(A) (quarterword)(A) /* to store eight bits in a quarterword */
37 @d null_font 0 /* the |font_number| for an empty font */
40 @d hlp1(A) mp->help_line[0]=A; }
41 @d hlp2(A,B) mp->help_line[1]=A; hlp1(B)
42 @d hlp3(A,B,C) mp->help_line[2]=A; hlp2(B,C)
43 @d help3 { mp->help_ptr=3; hlp3 /* use this with three help lines */
50 #include "mpmp.h" /* internal header */
53 @ The |font_ps_name| for a built-in font should be what PostScript expects.
54 A preliminary name is obtained here from the \.{TFM} name as given in the
55 |fname| argument. This gets updated later from an external table if necessary.
58 font_number mp_read_font_info (MP mp, char *fname) {
59 boolean file_opened; /* has |tfm_infile| been opened? */
60 font_number n; /* the number to return */
61 halfword lf,tfm_lh,bc,ec,nw,nh,nd; /* subfile size parameters */
62 size_t whd_size; /* words needed for heights, widths, and depths */
63 int i,ii; /* |font_info| indices */
64 int jj; /* counts bytes to be ignored */
65 scaled z; /* used to compute the design size */
66 fraction d; /* height, width, or depth as a fraction of design size times $2^{-8}$ */
67 int h_and_d; /* height and depth indices being unpacked */
68 int tfbyte = 0; /* a byte read from the file */
70 @<Open |tfm_infile| for input@>;
71 @<Read data from |tfm_infile|; if there is no room, say so and |goto done|;
72 otherwise |goto bad_tfm| or |goto done| as appropriate@>;
74 @<Complain that the \.{TFM} file is bad@>;
76 if ( file_opened ) (mp->close_file)(mp,mp->tfm_infile);
78 mp->font_ps_name[n]=mp_xstrdup(mp,fname);
79 mp->font_name[n]=mp_xstrdup(mp,fname);
84 @ \MP\ doesn't bother to check the entire \.{TFM} file for errors or explain
85 precisely what is wrong if it does find a problem. Programs called \.{TFtoPL}
87 and \.{PLtoTF} can be used to debug \.{TFM} files.
89 @<Complain that the \.{TFM} file is bad@>=
90 mp_print_err(mp,"Font ");
92 if ( file_opened ) mp_print(mp, " not usable: TFM file is bad");
93 else mp_print(mp, " not usable: TFM file not found");
94 help3("I wasn't able to read the size data for this font so this",
95 "`infont' operation won't produce anything. If the font name",
96 "is right, you might ask an expert to make a TFM file");
98 mp->help_line[0]="is right, try asking an expert to fix the TFM file";
101 @ @<Read data from |tfm_infile|; if there is no room, say so...@>=
102 @<Read the \.{TFM} size fields@>;
103 @<Use the size fields to allocate space in |font_info|@>;
104 @<Read the \.{TFM} header@>;
105 @<Read the character data and the width, height, and depth tables and
108 @ A bad \.{TFM} file can be shorter than it claims to be. The code given here
109 might try to read past the end of the file if this happens. Changes will be
110 needed if it causes a system error to refer to |tfm_infile^| or call
111 |get_tfm_infile| when |eof(tfm_infile)| is true. For example, the definition
112 @^system dependencies@>
113 of |tfget| could be changed to
114 ``|begin get(tfm_infile); if eof(tfm_infile) then goto bad_tfm; end|.''
118 void *tfbyte_ptr = &tfbyte;
119 (mp->read_binary_file)(mp,mp->tfm_infile, &tfbyte_ptr,&wanted);
120 if (wanted==0) goto BAD_TFM;
122 @d read_two(A) { (A)=tfbyte;
123 if ( (A)>127 ) goto BAD_TFM;
124 tfget; (A)=(A)*0400+tfbyte;
126 @d tf_ignore(A) { for (jj=(A);jj>=1;jj--) tfget; }
128 @<Read the \.{TFM} size fields@>=
130 tfget; read_two(tfm_lh);
133 if ( (bc>1+ec)||(ec>255) ) goto BAD_TFM;
137 whd_size=(size_t)((ec+1-bc)+nw+nh+nd);
138 if ( lf<(int)(6+tfm_lh+whd_size) ) goto BAD_TFM;
141 @ Offsets are added to |char_base[n]| and |width_base[n]| so that is not
142 necessary to apply the |so| and |qo| macros when looking up the width of a
143 character in the string pool. In order to ensure nonnegative |char_base|
144 values when |bc>0|, it may be necessary to reserve a few unused |font_info|
147 @<Use the size fields to allocate space in |font_info|@>=
148 if ( mp->next_fmem<(size_t)bc)
149 mp->next_fmem=(size_t)bc; /* ensure nonnegative |char_base| */
150 if (mp->last_fnum==mp->font_max)
151 mp_reallocate_fonts(mp,(mp->font_max+(mp->font_max/4)));
152 while (mp->next_fmem+whd_size>=mp->font_mem_size) {
153 size_t l = mp->font_mem_size+(mp->font_mem_size/4);
154 memory_word *font_info;
155 font_info = mp_xmalloc (mp,(l+1),sizeof(memory_word));
156 memset (font_info,0,sizeof(memory_word)*(l+1));
157 memcpy (font_info,mp->font_info,sizeof(memory_word)*(mp->font_mem_size+1));
158 mp_xfree(mp->font_info);
159 mp->font_info = font_info;
160 mp->font_mem_size = l;
164 mp->font_bc[n]=(eight_bits)bc;
165 mp->font_ec[n]=(eight_bits)ec;
166 mp->char_base[n]=(int)(mp->next_fmem-bc);
167 mp->width_base[n]=(int)(mp->next_fmem+ec-bc+1);
168 mp->height_base[n]=mp->width_base[n]+nw;
169 mp->depth_base[n]=mp->height_base[n]+nh;
170 mp->next_fmem=mp->next_fmem+whd_size;
173 @ @<Read the \.{TFM} header@>=
174 if ( tfm_lh<2 ) goto BAD_TFM;
177 tfget; z=z*0400+tfbyte;
178 tfget; z=z*0400+tfbyte; /* now |z| is 16 times the design size */
179 mp->font_dsize[n]=mp_take_fraction(mp, z,267432584);
180 /* times ${72\over72.27}2^{28}$ to convert from \TeX\ points */
181 tf_ignore(4*(tfm_lh-2))
183 @ @<Read the character data and the width, height, and depth tables...@>=
184 ii=mp->width_base[n];
185 i=mp->char_base[n]+bc;
187 tfget; mp->font_info[i].qqqq.b0=qi(tfbyte);
188 tfget; h_and_d=tfbyte;
189 mp->font_info[i].qqqq.b1=qi(h_and_d / 16);
190 mp->font_info[i].qqqq.b2=qi(h_and_d % 16);
194 while ( i<(int)mp->next_fmem ) {
195 @<Read a four byte dimension, scale it by the design size, store it in
196 |font_info[i]|, and increment |i|@>;
200 @ The raw dimension read into |d| should have magnitude at most $2^{24}$ when
201 interpreted as an integer, and this includes a scale factor of $2^{20}$. Thus
202 we can multiply it by sixteen and think of it as a |fraction| that has been
203 divided by sixteen. This cancels the extra scale factor contained in
206 @<Read a four byte dimension, scale it by the design size, store it in...@>=
209 if ( d>=0200 ) d=d-0400;
210 tfget; d=d*0400+tfbyte;
211 tfget; d=d*0400+tfbyte;
212 tfget; d=d*0400+tfbyte;
213 mp->font_info[i].cint=mp_take_fraction(mp, d*16,mp->font_dsize[n]);
217 @ This function does no longer use the file name parser, because |fname| is
220 @<Open |tfm_infile| for input@>=
222 mp_ptr_scan_file(mp, fname);
223 if ( strlen(mp->cur_area)==0 ) { mp_xfree(mp->cur_area); mp->cur_area=NULL; }
224 if ( strlen(mp->cur_ext)==0 ) {
225 mp_xfree(mp->cur_ext);
226 mp->cur_ext=mp_xstrdup(mp,".tfm");
228 mp_pack_file_name(mp, mp->cur_name,mp->cur_area,mp->cur_ext);
229 mp->tfm_infile = (mp->open_file)(mp, mp->name_of_file, "r",mp_filetype_metrics);
230 if ( !mp->tfm_infile ) goto BAD_TFM;