source/texk/web2c/mplibdir/tfmin.w

   1 % Copyright 2008-2009 Taco Hoekwater.
   2 %
   3 % This program is free software: you can redistribute it and/or modify
   4 % it under the terms of the GNU Lesser General Public License as published by
   5 % the Free Software Foundation, either version 3 of the License, or
   6 % (at your option) any later version.
   7 %
   8 % This program is distributed in the hope that it will be useful,
   9 % but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 % GNU Lesser General Public License for more details.
  12 %
  13 % You should have received a copy of the GNU Lesser General Public License
  14 % along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15 %
  16 % TeX is a trademark of the American Mathematical Society.
  17 % METAFONT is a trademark of Addison-Wesley Publishing Company.
  18 % PostScript is a trademark of Adobe Systems Incorporated.
  19
  20 % Here is TeX material that gets inserted after \input webmac
  21
  22 \font\tenlogo=logo10 % font used for the METAFONT logo
  23 \font\logos=logosl10
  24 \def\MF{{\tenlogo META}\-{\tenlogo FONT}}
  25 \def\MP{{\tenlogo META}\-{\tenlogo POST}}
  26
  27 \def\title{Reading TEX metrics files}
  28 \pdfoutput=1
  29
  30 @ Introduction.
  31
  32 @ Needed headers and macros
  33
  34 @d qi(A) (quarterword)(A) /* to store eight bits in a quarterword */
  35 @d null_font 0 /* the |font_number| for an empty font */
  36 @d false 0
  37 @d true 1
  38 @d hlp1(A) mp->help_line[0]=A; }
  39 @d hlp2(A,B) mp->help_line[1]=A; hlp1(B)
  40 @d hlp3(A,B,C) mp->help_line[2]=A; hlp2(B,C)
  41 @d help3  { mp->help_ptr=3; hlp3 /* use this with three help lines */
  42
  43 @c
  44 #include <w2c/config.h>
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48 #include "mplib.h"
  49 #include "mpmp.h" /* internal header */
  50 #include "mpmath.h" /* internal header */
  51 #include "mpstrings.h" /* internal header */
  52 @<Declarations@>;
  53 @h
  54
  55 @ The |font_ps_name| for a built-in font should be what PostScript expects.
  56 A preliminary name is obtained here from the \.{TFM} name as given in the
  57 |fname| argument.  This gets updated later from an external table if necessary.
  58
  59 @<Declarations@>=
  60 font_number mp_read_font_info (MP mp, char *fname);
  61
  62 @ @c
  63 font_number mp_read_font_info (MP mp, char *fname) {
  64   boolean file_opened; /* has |tfm_infile| been opened? */
  65   font_number n; /* the number to return */
  66   halfword lf,tfm_lh,bc,ec,nw,nh,nd; /* subfile size parameters */
  67   size_t whd_size; /* words needed for heights, widths, and depths */
  68   int i,ii; /* |font_info| indices */
  69   int jj; /* counts bytes to be ignored */
  70   int z; /* used to compute the design size */
  71   int d; /* height, width, or depth as a fraction of design size times $2^{-8}$ */
  72   int h_and_d; /* height and depth indices being unpacked */
  73   int tfbyte = 0; /* a byte read from the file */
  74   n=null_font;
  75   @<Open |tfm_infile| for input@>;
  76   @<Read data from |tfm_infile|; if there is no room, say so and |goto done|;
  77     otherwise |goto bad_tfm| or |goto done| as appropriate@>;
  78 BAD_TFM:
  79   @<Complain that the \.{TFM} file is bad@>;
  80 DONE:
  81   if ( file_opened ) (mp->close_file)(mp,mp->tfm_infile);
  82   if ( n!=null_font ) {
  83     mp->font_ps_name[n]=mp_xstrdup(mp,fname);
  84     mp->font_name[n]=mp_xstrdup(mp,fname);
  85   }
  86   return n;
  87 }
  88
  89 @ \MP\ doesn't bother to check the entire \.{TFM} file for errors or explain
  90 precisely what is wrong if it does find a problem.  Programs called \.{TFtoPL}
  91 @.TFtoPL@> @.PLtoTF@>
  92 and \.{PLtoTF} can be used to debug \.{TFM} files.
  93
  94 @<Complain that the \.{TFM} file is bad@>=
  95 {
  96    char msg[256];
  97    const char *hlp[] = {
  98      "I wasn't able to read the size data for this font so this",
  99      "`infont' operation won't produce anything. If the font name",
 100      "is right, you might ask an expert to make a TFM file",
 101      NULL };
 102    if ( file_opened )
 103      hlp[2]="is right, try asking an expert to fix the TFM file";
 104    mp_snprintf(msg, 256, "Font %s not usable: TFM file %s", fname,
 105               ( file_opened ? "is bad" : "not found"));
 106    mp_error(mp, msg, hlp, true);
 107 }
 108
 109 @ @<Read data from |tfm_infile|; if there is no room, say so...@>=
 110 @<Read the \.{TFM} size fields@>;
 111 @<Use the size fields to allocate space in |font_info|@>;
 112 @<Read the \.{TFM} header@>;
 113 @<Read the character data and the width, height, and depth tables and
 114   |goto done|@>
 115
 116 @ A bad \.{TFM} file can be shorter than it claims to be.  The code given here
 117 might try to read past the end of the file if this happens.  Changes will be
 118 needed if it causes a system error to refer to |tfm_infile^| or call
 119 |get_tfm_infile| when |eof(tfm_infile)| is true.  For example, the definition
 120 @^system dependencies@>
 121 of |tfget| could be changed to
 122 ``|begin get(tfm_infile); if eof(tfm_infile) then goto bad_tfm; end|.''
 123
 124 @d tfget do {
 125   size_t wanted=1;
 126   unsigned char abyte=0;
 127   void *tfbyte_ptr = &abyte;
 128   (mp->read_binary_file)(mp,mp->tfm_infile, &tfbyte_ptr,&wanted);
 129   if (wanted==0) goto BAD_TFM;
 130   tfbyte = (int)abyte;
 131 } while (0)
 132 @d read_two(A) { (A)=tfbyte;
 133   if ( (A)>127 ) goto BAD_TFM;
 134   tfget; (A)=(A)*0400+tfbyte;
 135 }
 136 @d tf_ignore(A) { for (jj=(A);jj>=1;jj--) tfget; }
 137
 138 @<Read the \.{TFM} size fields@>=
 139 tfget; read_two(lf);
 140 tfget; read_two(tfm_lh);
 141 tfget; read_two(bc);
 142 tfget; read_two(ec);
 143 if ( (bc>1+ec)||(ec>255) ) goto BAD_TFM;
 144 tfget; read_two(nw);
 145 tfget; read_two(nh);
 146 tfget; read_two(nd);
 147 whd_size=(size_t)((ec+1-bc)+nw+nh+nd);
 148 if ( lf<(int)(6+(size_t)tfm_lh+whd_size) ) goto BAD_TFM;
 149 tf_ignore(10)
 150
 151 @ Offsets are added to |char_base[n]| and |width_base[n]| so that is not
 152 necessary to apply the |so|  and |qo| macros when looking up the width of a
 153 character in the string pool.  In order to ensure nonnegative |char_base|
 154 values when |bc>0|, it may be necessary to reserve a few unused |font_info|
 155 elements.
 156
 157 @<Use the size fields to allocate space in |font_info|@>=
 158 if ( mp->next_fmem<(size_t)bc)
 159   mp->next_fmem=(size_t)bc; /* ensure nonnegative |char_base| */
 160 if (mp->last_fnum==mp->font_max)
 161   mp_reallocate_fonts(mp,(mp->font_max+(mp->font_max/4)));
 162 while (mp->next_fmem+whd_size>=mp->font_mem_size) {
 163   size_t l = mp->font_mem_size+(mp->font_mem_size/4);
 164   font_data *font_info;
 165   font_info = mp_xmalloc (mp,(l+1),sizeof(font_data));
 166   memset (font_info,0,sizeof(font_data)*(l+1));
 167   memcpy (font_info,mp->font_info,sizeof(font_data)*(mp->font_mem_size+1));
 168   mp_xfree(mp->font_info);
 169   mp->font_info = font_info;
 170   mp->font_mem_size = l;
 171 }
 172 mp->last_fnum++;
 173 n=mp->last_fnum;
 174 mp->font_bc[n]=(eight_bits)bc;
 175 mp->font_ec[n]=(eight_bits)ec;
 176 mp->char_base[n]=(int)(mp->next_fmem-(size_t)bc);
 177 mp->width_base[n]=(int)(mp->next_fmem+(size_t)(ec-bc)+1);
 178 mp->height_base[n]=mp->width_base[n]+nw;
 179 mp->depth_base[n]=mp->height_base[n]+nh;
 180 mp->next_fmem=mp->next_fmem+whd_size;
 181
 182
 183 @ This macro is a bit odd, but it works.
 184
 185 @d integer_as_fraction(A) (int)(A)
 186
 187 @<Read the \.{TFM} header@>=
 188 if ( tfm_lh<2 ) goto BAD_TFM;
 189 tf_ignore(4);
 190 tfget; read_two(z);
 191 tfget; z=z*0400+tfbyte;
 192 tfget; z=z*0400+tfbyte; /* now |z| is 16 times the design size */
 193 mp->font_dsize[n]=mp_take_fraction(mp, z,integer_as_fraction(267432584));
 194   /* times ${72\over72.27}2^{28}$ to convert from \TeX\ points */
 195 tf_ignore(4*(tfm_lh-2))
 196
 197 @ @<Read the character data and the width, height, and depth tables...@>=
 198 ii=mp->width_base[n];
 199 i=mp->char_base[n]+bc;
 200 while ( i<ii ) {
 201   tfget; mp->font_info[i].qqqq.b0=qi(tfbyte);
 202   tfget; h_and_d=tfbyte;
 203   mp->font_info[i].qqqq.b1=qi(h_and_d / 16);
 204   mp->font_info[i].qqqq.b2=qi(h_and_d % 16);
 205   tfget; tfget;
 206   i++;
 207 }
 208 while ( i<(int)mp->next_fmem ) {
 209   @<Read a four byte dimension, scale it by the design size, store it in
 210     |font_info[i]|, and increment |i|@>;
 211 }
 212 goto DONE
 213
 214 @ The raw dimension read into |d| should have magnitude at most $2^{24}$ when
 215 interpreted as an integer, and this includes a scale factor of $2^{20}$.  Thus
 216 we can multiply it by sixteen and think of it as a |fraction| that has been
 217 divided by sixteen.  This cancels the extra scale factor contained in
 218 |font_dsize[n|.
 219
 220 @<Read a four byte dimension, scale it by the design size, store it in...@>=
 221 {
 222 tfget; d=tfbyte;
 223 if ( d>=0200 ) d=d-0400;
 224 tfget; d=d*0400+tfbyte;
 225 tfget; d=d*0400+tfbyte;
 226 tfget; d=d*0400+tfbyte;
 227 mp->font_info[i].sc=mp_take_fraction(mp, d*16,integer_as_fraction(mp->font_dsize[n]));
 228 i++;
 229 }
 230
 231 @ This function does no longer use the file name parser, because |fname| is
 232 a C string already.
 233
 234 @<Open |tfm_infile| for input@>=
 235 file_opened=false;
 236 mp_ptr_scan_file(mp, fname);
 237 if ( strlen(mp->cur_area)==0 ) { mp_xfree(mp->cur_area); mp->cur_area=NULL; }
 238 if ( strlen(mp->cur_ext)==0 )  {
 239     mp_xfree(mp->cur_ext);
 240     mp->cur_ext=mp_xstrdup(mp,".tfm");
 241 }
 242 mp_pack_file_name(mp, mp->cur_name,mp->cur_area,mp->cur_ext);
 243 mp->tfm_infile = (mp->open_file)(mp, mp->name_of_file, "r",mp_filetype_metrics);
 244 if ( !mp->tfm_infile  ) goto BAD_TFM;
 245 file_opened=true
 246
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