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diff --git a/web/c_cpp/cweb/common.w b/web/c_cpp/cweb/common.w new file mode 100644 index 0000000000..d8aacfb7b9 --- /dev/null +++ b/web/c_cpp/cweb/common.w @@ -0,0 +1,1418 @@ +% This file is part of CWEB. +% This program by Silvio Levy and Donald E. Knuth +% is based on a program by Knuth. +% It is distributed WITHOUT ANY WARRANTY, express or implied. +% Version 3.64 --- January 2002 + +% Copyright (C) 1987,1990,1993,2000 Silvio Levy and Donald E. Knuth + +% Permission is granted to make and distribute verbatim copies of this +% document provided that the copyright notice and this permission notice +% are preserved on all copies. + +% Permission is granted to copy and distribute modified versions of this +% document under the conditions for verbatim copying, provided that the +% entire resulting derived work is given a different name and distributed +% under the terms of a permission notice identical to this one. + +\def\v{\char'174} % vertical (|) in typewriter font + +\def\title{Common code for CTANGLE and CWEAVE (Version 3.64)} +\def\topofcontents{\null\vfill + \centerline{\titlefont Common code for {\ttitlefont CTANGLE} and + {\ttitlefont CWEAVE}} + \vskip 15pt + \centerline{(Version 3.64)} + \vfill} +\def\botofcontents{\vfill +\noindent +Copyright \copyright\ 1987, 1990, 1993, 2000 Silvio Levy and Donald E. Knuth +\bigskip\noindent +Permission is granted to make and distribute verbatim copies of this +document provided that the copyright notice and this permission notice +are preserved on all copies. + +\smallskip\noindent +Permission is granted to copy and distribute modified versions of this +document under the conditions for verbatim copying, provided that the +entire resulting derived work is given a different name and distributed +under the terms of a permission notice identical to this one. +} + +\pageno=\contentspagenumber \advance\pageno by 1 +\let\maybe=\iftrue +@s not_eq normal @q unreserve a C++ keyword @> + +@** Introduction. This file contains code common +to both \.{CTANGLE} and \.{CWEAVE}, which roughly concerns the following +problems: character uniformity, input routines, error handling and +parsing of command line. We have tried to concentrate in this file +all the system dependencies, so as to maximize portability. + +In the texts below we will +sometimes use \.{CWEB} to refer to either of the two component +programs, if no confusion can arise. + +The file begins with a few basic definitions. + +@c +@<Include files@>@/ +@h +@<Definitions that should agree with \.{CTANGLE} and \.{CWEAVE}@>@/ +@<Other definitions@>@/ +@<Predeclaration of procedures@>@/ + +@ In certain cases \.{CTANGLE} and \.{CWEAVE} should do almost, but not +quite, the same thing. In these cases we've written common code for +both, differentiating between the two by means of the global variable +|program|. + +@d ctangle 0 +@d cweave 1 + +@<Definitions...@>= +typedef short boolean; +boolean program; /* \.{CWEAVE} or \.{CTANGLE}? */ + +@ \.{CWEAVE} operates in three phases: First it inputs the source +file and stores cross-reference data, then it inputs the source once again and +produces the \TEX/ output file, and finally it sorts and outputs the index. +Similarly, \.{CTANGLE} operates in two phases. +The global variable |phase| tells which phase we are in. + +@<Other...@>= int phase; /* which phase are we in? */ + +@ There's an initialization procedure that gets both \.{CTANGLE} and +\.{CWEAVE} off to a good start. We will fill in the details of this +procedure later. + +@c +void +common_init() +{ + @<Initialize pointers@>; + @<Set the default options common to \.{CTANGLE} and \.{CWEAVE}@>; + @<Scan arguments and open output files@>; +} + +@* The character set. +\.{CWEB} uses the conventions of \CEE/ programs found in the standard +\.{ctype.h} header file. + +@<Include files@>= +#include <ctype.h> + +@ A few character pairs are encoded internally as single characters, +using the definitions below. These definitions are consistent with +an extension of ASCII code originally developed at MIT and explained in +Appendix~C of {\sl The \TEX/book\/}; thus, users who have such a +character set can type things like \.{\char'32} and \.{\char'4} instead +of \.{!=} and \.{\&\&}. (However, their files will not be too portable +until more people adopt the extended code.) + +If the character set is not ASCII, the definitions given here may conflict +with existing characters; in such cases, other arbitrary codes should be +substituted. The indexes to \.{CTANGLE} and \.{CWEAVE} mention every +case where similar codes may have to be changed in order to +avoid character conflicts. Look for the entry ``ASCII code dependencies'' +in those indexes. + +@^ASCII code dependencies@> +@^system dependencies@> + +@d and_and 04 /* `\.{\&\&}'\,; corresponds to MIT's {\tentex\char'4} */ +@d lt_lt 020 /* `\.{<<}'\,; corresponds to MIT's {\tentex\char'20} */ +@d gt_gt 021 /* `\.{>>}'\,; corresponds to MIT's {\tentex\char'21} */ +@d plus_plus 013 /* `\.{++}'\,; corresponds to MIT's {\tentex\char'13} */ +@d minus_minus 01 /* `\.{--}'\,; corresponds to MIT's {\tentex\char'1} */ +@d minus_gt 031 /* `\.{->}'\,; corresponds to MIT's {\tentex\char'31} */ +@d not_eq 032 /* `\.{!=}'\,; corresponds to MIT's {\tentex\char'32} */ +@d lt_eq 034 /* `\.{<=}'\,; corresponds to MIT's {\tentex\char'34} */ +@d gt_eq 035 /* `\.{>=}'\,; corresponds to MIT's {\tentex\char'35} */ +@d eq_eq 036 /* `\.{==}'\,; corresponds to MIT's {\tentex\char'36} */ +@d or_or 037 /* `\.{\v\v}'\,; corresponds to MIT's {\tentex\char'37} */ +@d dot_dot_dot 016 /* `\.{...}'\,; corresponds to MIT's {\tentex\char'16} */ +@d colon_colon 06 /* `\.{::}'\,; corresponds to MIT's {\tentex\char'6} */ +@d period_ast 026 /* `\.{.*}'\,; corresponds to MIT's {\tentex\char'26} */ +@d minus_gt_ast 027 /* `\.{->*}'\,; corresponds to MIT's {\tentex\char'27} */ + +@** Input routines. The lowest level of input to the \.{CWEB} programs +is performed by |input_ln|, which must be told which file to read from. +The return value of |input_ln| is 1 if the read is successful and 0 if +not (generally this means the file has ended). The conventions +of \TEX/ are followed; i.e., the characters of the next line of the file +are copied into the |buffer| array, +and the global variable |limit| is set to the first unoccupied position. +Trailing blanks are ignored. The value of |limit| must be strictly less +than |buf_size|, so that |buffer[buf_size-1]| is never filled. + +Since |buf_size| is strictly less than |long_buf_size|, +some of \.{CWEB}'s routines use the fact that it is safe to refer to +|*(limit+2)| without overstepping the bounds of the array. + +@d buf_size 100 /* for \.{CWEAVE} and \.{CTANGLE} */ +@d longest_name 10000 +@d long_buf_size (buf_size+longest_name) /* for \.{CWEAVE} */ +@d xisspace(c) (isspace(c)&&((unsigned char)c<0200)) +@d xisupper(c) (isupper(c)&&((unsigned char)c<0200)) + +@<Definitions...@>= +char buffer[long_buf_size]; /* where each line of input goes */ +char *buffer_end=buffer+buf_size-2; /* end of |buffer| */ +char *limit=buffer; /* points to the last character in the buffer */ +char *loc=buffer; /* points to the next character to be read from the buffer */ + +@ @<Include files@>= +#include <stdio.h> + +@ In the unlikely event that your standard I/O library does not +support |feof|, |getc|, and |ungetc| you may have to change things here. +@^system dependencies@> + +@c +int input_ln(fp) /* copies a line into |buffer| or returns 0 */ +FILE *fp; /* what file to read from */ +{ + register int c=EOF; /* character read; initialized so some compilers won't complain */ + register char *k; /* where next character goes */ + if (feof(fp)) return(0); /* we have hit end-of-file */ + limit = k = buffer; /* beginning of buffer */ + while (k<=buffer_end && (c=getc(fp)) != EOF && c!='\n') + if ((*(k++) = c) != ' ') limit = k; + if (k>buffer_end) + if ((c=getc(fp))!=EOF && c!='\n') { + ungetc(c,fp); loc=buffer; err_print("! Input line too long"); +@.Input line too long@> + } + if (c==EOF && limit==buffer) return(0); /* there was nothing after + the last newline */ + return(1); +} + +@ Now comes the problem of deciding which file to read from next. +Recall that the actual text that \.{CWEB} should process comes from two +streams: a |web_file|, which can contain possibly nested include +commands \.{@@i}, and a |change_file|, which might also contain +includes. The |web_file| together with the currently open include +files form a stack |file|, whose names are stored in a parallel stack +|file_name|. The boolean |changing| tells whether or not we're reading +from the |change_file|. + +The line number of each open file is also kept for error reporting and +for the benefit of \.{CTANGLE}. + +@f line x /* make |line| an unreserved word */ +@d max_include_depth 10 /* maximum number of source files open + simultaneously, not counting the change file */ +@d max_file_name_length 60 +@d cur_file file[include_depth] /* current file */ +@d cur_file_name file_name[include_depth] /* current file name */ +@d cur_line line[include_depth] /* number of current line in current file */ +@d web_file file[0] /* main source file */ +@d web_file_name file_name[0] /* main source file name */ + +@<Definitions...@>= +int include_depth; /* current level of nesting */ +FILE *file[max_include_depth]; /* stack of non-change files */ +FILE *change_file; /* change file */ +char file_name[max_include_depth][max_file_name_length]; + /* stack of non-change file names */ +char change_file_name[max_file_name_length]; /* name of change file */ +char alt_web_file_name[max_file_name_length]; /* alternate name to try */ +int line[max_include_depth]; /* number of current line in the stacked files */ +int change_line; /* number of current line in change file */ +int change_depth; /* where \.{@@y} originated during a change */ +boolean input_has_ended; /* if there is no more input */ +boolean changing; /* if the current line is from |change_file| */ +boolean web_file_open=0; /* if the web file is being read */ + +@ When |changing==0|, the next line of |change_file| is kept in +|change_buffer|, for purposes of comparison with the next +line of |cur_file|. After the change file has been completely input, we +set |change_limit=change_buffer|, +so that no further matches will be made. + +Here's a shorthand expression for inequality between the two lines: + +@d lines_dont_match (change_limit-change_buffer != limit-buffer || + strncmp(buffer, change_buffer, limit-buffer)) + +@<Other...@>= +char change_buffer[buf_size]; /* next line of |change_file| */ +char *change_limit; /* points to the last character in |change_buffer| */ + +@ Procedure |prime_the_change_buffer| +sets |change_buffer| in preparation for the next matching operation. +Since blank lines in the change file are not used for matching, we have +|(change_limit==change_buffer && !changing)| if and only if +the change file is exhausted. This procedure is called only when +|changing| is 1; hence error messages will be reported correctly. + +@c +void +prime_the_change_buffer() +{ + change_limit=change_buffer; /* this value is used if the change file ends */ + @<Skip over comment lines in the change file; |return| if end of file@>; + @<Skip to the next nonblank line; |return| if end of file@>; + @<Move |buffer| and |limit| to |change_buffer| and |change_limit|@>; +} + +@ While looking for a line that begins with \.{@@x} in the change file, we +allow lines that begin with \.{@@}, as long as they don't begin with \.{@@y}, +\.{@@z}, or \.{@@i} (which would probably mean that the change file is fouled up). + +@<Skip over comment lines in the change file...@>= +while(1) { + change_line++; + if (!input_ln(change_file)) return; + if (limit<buffer+2) continue; + if (buffer[0]!='@@') continue; + if (xisupper(buffer[1])) buffer[1]=tolower(buffer[1]); + if (buffer[1]=='x') break; + if (buffer[1]=='y' || buffer[1]=='z' || buffer[1]=='i') { + loc=buffer+2; + err_print("! Missing @@x in change file"); +@.Missing @@x...@> + } +} + +@ Here we are looking at lines following the \.{@@x}. + +@<Skip to the next nonblank line...@>= +do { + change_line++; + if (!input_ln(change_file)) { + err_print("! Change file ended after @@x"); +@.Change file ended...@> + return; + } +} while (limit==buffer); + +@ @<Move |buffer| and |limit| to |change_buffer| and |change_limit|@>= +{ + change_limit=change_buffer+(limit-buffer); + strncpy(change_buffer,buffer,limit-buffer+1); +} + +@ The following procedure is used to see if the next change entry should +go into effect; it is called only when |changing| is 0. +The idea is to test whether or not the current +contents of |buffer| matches the current contents of |change_buffer|. +If not, there's nothing more to do; but if so, a change is called for: +All of the text down to the \.{@@y} is supposed to match. An error +message is issued if any discrepancy is found. Then the procedure +prepares to read the next line from |change_file|. + +When a match is found, the current section is marked as changed unless +the first line after the \.{@@x} and after the \.{@@y} both start with +either |'@@*'| or |'@@ '| (possibly preceded by whitespace). + +This procedure is called only when |buffer<limit|, i.e., when the +current line is nonempty. + +@d if_section_start_make_pending(b) {@+*limit='!'; + for (loc=buffer;xisspace(*loc);loc++) ; + *limit=' '; + if (*loc=='@@' && (xisspace(*(loc+1)) || *(loc+1)=='*')) change_pending=b; +} + +@c +void +check_change() /* switches to |change_file| if the buffers match */ +{ + int n=0; /* the number of discrepancies found */ + if (lines_dont_match) return; + change_pending=0; + if (!changed_section[section_count]) { + if_section_start_make_pending(1); + if (!change_pending) changed_section[section_count]=1; + } + while (1) { + changing=1; print_where=1; change_line++; + if (!input_ln(change_file)) { + err_print("! Change file ended before @@y"); +@.Change file ended...@> + change_limit=change_buffer; changing=0; + return; + } + if (limit>buffer+1 && buffer[0]=='@@') { + char xyz_code=xisupper(buffer[1])? tolower(buffer[1]): buffer[1]; + @<If the current line starts with \.{@@y}, + report any discrepancies and |return|@>; + } + @<Move |buffer| and |limit|...@>; + changing=0; cur_line++; + while (!input_ln(cur_file)) { /* pop the stack or quit */ + if (include_depth==0) { + err_print("! CWEB file ended during a change"); +@.CWEB file ended...@> + input_has_ended=1; return; + } + include_depth--; cur_line++; + } + if (lines_dont_match) n++; + } +} + +@ @<If the current line starts with \.{@@y}...@>= +if (xyz_code=='x' || xyz_code=='z') { + loc=buffer+2; err_print("! Where is the matching @@y?"); +@.Where is the match...@> + } +else if (xyz_code=='y') { + if (n>0) { + loc=buffer+2; + printf("\n! Hmm... %d ",n); + err_print("of the preceding lines failed to match"); +@.Hmm... n of the preceding...@> + } + change_depth=include_depth; + return; +} + +@ The |reset_input| procedure, which gets \.{CWEB} ready to read the +user's \.{CWEB} input, is used at the beginning of phase one of \.{CTANGLE}, +phases one and two of \.{CWEAVE}. + +@c +void +reset_input() +{ + limit=buffer; loc=buffer+1; buffer[0]=' '; + @<Open input files@>; + include_depth=0; cur_line=0; change_line=0; + change_depth=include_depth; + changing=1; prime_the_change_buffer(); changing=!changing; + limit=buffer; loc=buffer+1; buffer[0]=' '; input_has_ended=0; +} + +@ The following code opens the input files. +@^system dependencies@> + +@<Open input files@>= +if ((web_file=fopen(web_file_name,"r"))==NULL) { + strcpy(web_file_name,alt_web_file_name); + if ((web_file=fopen(web_file_name,"r"))==NULL) + fatal("! Cannot open input file ", web_file_name); +} +@.Cannot open input file@> +@.Cannot open change file@> +web_file_open=1; +if ((change_file=fopen(change_file_name,"r"))==NULL) + fatal("! Cannot open change file ", change_file_name); + +@ The |get_line| procedure is called when |loc>limit|; it puts the next +line of merged input into the buffer and updates the other variables +appropriately. A space is placed at the right end of the line. +This procedure returns |!input_has_ended| because we often want to +check the value of that variable after calling the procedure. + +If we've just changed from the |cur_file| to the |change_file|, or if +the |cur_file| has changed, we tell \.{CTANGLE} to print this +information in the \CEE/ file by means of the |print_where| flag. + +@d max_sections 2000 /* number of identifiers, strings, section names; + must be less than 10240 */ + +@<Defin...@>= +typedef unsigned short sixteen_bits; +sixteen_bits section_count; /* the current section number */ +boolean changed_section[max_sections]; /* is the section changed? */ +boolean change_pending; /* if the current change is not yet recorded in + |changed_section[section_count]| */ +boolean print_where=0; /* should \.{CTANGLE} print line and file info? */ + +@ @c +int get_line() /* inputs the next line */ +{ + restart: + if (changing && include_depth==change_depth) + @<Read from |change_file| and maybe turn off |changing|@>; + if (! changing || include_depth>change_depth) { + @<Read from |cur_file| and maybe turn on |changing|@>; + if (changing && include_depth==change_depth) goto restart; + } + if (input_has_ended) return 0; + loc=buffer; *limit=' '; + if (buffer[0]=='@@' && (buffer[1]=='i' || buffer[1]=='I')) { + loc=buffer+2; *limit='"'; + while (*loc==' '||*loc=='\t') loc++; + if (loc>=limit) { + err_print("! Include file name not given"); +@.Include file name ...@> + goto restart; + } + if (include_depth>=max_include_depth-1) { + err_print("! Too many nested includes"); +@.Too many nested includes@> + goto restart; + } + include_depth++; /* push input stack */ + @<Try to open include file, abort push if unsuccessful, go to |restart|@>; + } + return 1; +} + +@ When an \.{@@i} line is found in the |cur_file|, we must temporarily +stop reading it and start reading from the named include file. The +\.{@@i} line should give a complete file name with or without +double quotes. +If the environment variable \.{CWEBINPUTS} is set, or if the compiler flag +of the same name was defined at compile time, +\.{CWEB} will look for include files in the directory thus named, if +it cannot find them in the current directory. +(Colon-separated paths are not supported.) +The remainder of the \.{@@i} line after the file name is ignored. + +@d too_long() {include_depth--; + err_print("! Include file name too long"); goto restart;} + +@<Include...@>= +#include <stdlib.h> /* declaration of |getenv| and |exit| */ + +@ @<Try to open...@>= { + char temp_file_name[max_file_name_length]; + char *cur_file_name_end=cur_file_name+max_file_name_length-1; + char *k=cur_file_name, *kk; + int l; /* length of file name */ + + if (*loc=='"') { + loc++; + while (*loc!='"' && k<=cur_file_name_end) *k++=*loc++; + if (loc==limit) k=cur_file_name_end+1; /* unmatched quote is `too long' */ + } else + while (*loc!=' '&&*loc!='\t'&&*loc!='"'&&k<=cur_file_name_end) *k++=*loc++; + if (k>cur_file_name_end) too_long(); +@.Include file name ...@> + *k='\0'; + if ((cur_file=fopen(cur_file_name,"r"))!=NULL) { + cur_line=0; print_where=1; + goto restart; /* success */ + } + kk=getenv("CWEBINPUTS"); + if (kk!=NULL) { + if ((l=strlen(kk))>max_file_name_length-2) too_long(); + strcpy(temp_file_name,kk); + } + else { +#ifdef CWEBINPUTS + if ((l=strlen(CWEBINPUTS))>max_file_name_length-2) too_long(); + strcpy(temp_file_name,CWEBINPUTS); +#else + l=0; +#endif /* |CWEBINPUTS| */ + } + if (l>0) { + if (k+l+2>=cur_file_name_end) too_long(); +@.Include file name ...@> + for (; k>= cur_file_name; k--) *(k+l+1)=*k; + strcpy(cur_file_name,temp_file_name); + cur_file_name[l]='/'; /* \UNIX/ pathname separator */ + if ((cur_file=fopen(cur_file_name,"r"))!=NULL) { + cur_line=0; print_where=1; + goto restart; /* success */ + } + } + include_depth--; err_print("! Cannot open include file"); goto restart; +} + +@ @<Read from |cur_file|...@>= { + cur_line++; + while (!input_ln(cur_file)) { /* pop the stack or quit */ + print_where=1; + if (include_depth==0) {input_has_ended=1; break;} + else { + fclose(cur_file); include_depth--; + if (changing && include_depth==change_depth) break; + cur_line++; + } + } + if (!changing && !input_has_ended) + if (limit-buffer==change_limit-change_buffer) + if (buffer[0]==change_buffer[0]) + if (change_limit>change_buffer) check_change(); +} + +@ @<Read from |change_file|...@>= { + change_line++; + if (!input_ln(change_file)) { + err_print("! Change file ended without @@z"); +@.Change file ended...@> + buffer[0]='@@'; buffer[1]='z'; limit=buffer+2; + } + if (limit>buffer) { /* check if the change has ended */ + if (change_pending) { + if_section_start_make_pending(0); + if (change_pending) { + changed_section[section_count]=1; change_pending=0; + } + } + *limit=' '; + if (buffer[0]=='@@') { + if (xisupper(buffer[1])) buffer[1]=tolower(buffer[1]); + if (buffer[1]=='x' || buffer[1]=='y') { + loc=buffer+2; + err_print("! Where is the matching @@z?"); +@.Where is the match...@> + } + else if (buffer[1]=='z') { + prime_the_change_buffer(); changing=!changing; print_where=1; + } + } + } +} + +@ At the end of the program, we will tell the user if the change file +had a line that didn't match any relevant line in |web_file|. + +@c +void +check_complete(){ + if (change_limit!=change_buffer) { /* |changing| is 0 */ + strncpy(buffer,change_buffer,change_limit-change_buffer+1); + limit=buffer+(int)(change_limit-change_buffer); + changing=1; change_depth=include_depth; loc=buffer; + err_print("! Change file entry did not match"); +@.Change file entry did not match@> + } +} + +@** Storage of names and strings. +Both \.{CWEAVE} and \.{CTANGLE} store identifiers, section names and +other strings in a large array of |char|s, called |byte_mem|. +Information about the names is kept in the array |name_dir|, whose +elements are structures of type |name_info|, containing a pointer into +the |byte_mem| array (the address where the name begins) and other data. +A |name_pointer| variable is a pointer into |name_dir|. + +@d max_bytes 90000 /* the number of bytes in identifiers, + index entries, and section names; must be less than $2^{24}$ */ +@d max_names 4000 /* number of identifiers, strings, section names; + must be less than 10240 */ + +@<Definitions that...@>= +typedef struct name_info { + char *byte_start; /* beginning of the name in |byte_mem| */ + @<More elements of |name_info| structure@>@; +} name_info; /* contains information about an identifier or section name */ +typedef name_info *name_pointer; /* pointer into array of |name_info|s */ +char byte_mem[max_bytes]; /* characters of names */ +char *byte_mem_end = byte_mem+max_bytes-1; /* end of |byte_mem| */ +name_info name_dir[max_names]; /* information about names */ +name_pointer name_dir_end = name_dir+max_names-1; /* end of |name_dir| */ + +@ The actual sequence of characters in the name pointed to by a |name_pointer +p| appears in positions |p->byte_start| to |(p+1)->byte_start-1|, inclusive. +The |print_id| macro prints this text on the user's terminal. + +@d length(c) (c+1)->byte_start-(c)->byte_start /* the length of a name */ +@d print_id(c) term_write((c)->byte_start,length((c))) /* print identifier */ + +@ The first unused position in |byte_mem| and |name_dir| is +kept in |byte_ptr| and |name_ptr|, respectively. Thus we +usually have |name_ptr->byte_start==byte_ptr|, and certainly +we want to keep |name_ptr<=name_dir_end| and |byte_ptr<=byte_mem_end|. + +@<Defini...@>= +name_pointer name_ptr; /* first unused position in |name_dir| */ +char *byte_ptr; /* first unused position in |byte_mem| */ + +@ @<Init...@>= +name_dir->byte_start=byte_ptr=byte_mem; /* position zero in both arrays */ +name_ptr=name_dir+1; /* |name_dir[0]| will be used only for error recovery */ +name_ptr->byte_start=byte_mem; /* this makes name 0 of length zero */ + +@ The names of identifiers are found by computing a hash address |h| and +then looking at strings of bytes signified by the |name_pointer|s +|hash[h]|, |hash[h]->link|, |hash[h]->link->link|, \dots, +until either finding the desired name or encountering the null pointer. + +@<More elements of |name...@>= +struct name_info *link; + +@ The hash table itself +consists of |hash_size| entries of type |name_pointer|, and is +updated by the |id_lookup| procedure, which finds a given identifier +and returns the appropriate |name_pointer|. The matching is done by the +function |names_match|, which is slightly different in +\.{CWEAVE} and \.{CTANGLE}. If there is no match for the identifier, +it is inserted into the table. + +@d hash_size 353 /* should be prime */ + +@<Defini...@>= +typedef name_pointer *hash_pointer; +name_pointer hash[hash_size]; /* heads of hash lists */ +hash_pointer hash_end = hash+hash_size-1; /* end of |hash| */ +hash_pointer h; /* index into hash-head array */ + +@ @<Predec...@>= +extern int names_match(); + +@ Initially all the hash lists are empty. + +@<Init...@>= +for (h=hash; h<=hash_end; *h++=NULL) ; + +@ Here is the main procedure for finding identifiers: + +@c +name_pointer +id_lookup(first,last,t) /* looks up a string in the identifier table */ +char *first; /* first character of string */ +char *last; /* last character of string plus one */ +char t; /* the |ilk|; used by \.{CWEAVE} only */ +{ + char *i=first; /* position in |buffer| */ + int h; /* hash code */ + int l; /* length of the given identifier */ + name_pointer p; /* where the identifier is being sought */ + if (last==NULL) for (last=first; *last!='\0'; last++); + l=last-first; /* compute the length */ + @<Compute the hash code |h|@>; + @<Compute the name location |p|@>; + if (p==name_ptr) @<Enter a new name into the table at position |p|@>; + return(p); +} + +@ A simple hash code is used: If the sequence of +character codes is $c_1c_2\ldots c_n$, its hash value will be +$$(2^{n-1}c_1+2^{n-2}c_2+\cdots+c_n)\,\bmod\,|hash_size|.$$ + +@<Compute the hash...@>= +h=(unsigned char)*i; +while (++i<last) h=(h+h+(int)((unsigned char)*i)) % hash_size; +@^high-bit character handling@> + +@ If the identifier is new, it will be placed in position |p=name_ptr|, +otherwise |p| will point to its existing location. + +@<Compute the name location...@>= +p=hash[h]; +while (p && !names_match(p,first,l,t)) p=p->link; +if (p==NULL) { + p=name_ptr; /* the current identifier is new */ + p->link=hash[h]; hash[h]=p; /* insert |p| at beginning of hash list */ +} + +@ The information associated with a new identifier must be initialized +in a slightly different way in \.{CWEAVE} than in \.{CTANGLE}; hence the +|init_p| procedure. + +@<Pred...@>= +void init_p(); + +@ @<Enter a new name...@>= { + if (byte_ptr+l>byte_mem_end) overflow("byte memory"); + if (name_ptr>=name_dir_end) overflow("name"); + strncpy(byte_ptr,first,l); + (++name_ptr)->byte_start=byte_ptr+=l; + if (program==cweave) init_p(p,t); +} + +@ The names of sections are stored in |byte_mem| together +with the identifier names, but a hash table is not used for them because +\.{CTANGLE} needs to be able to recognize a section name when given a prefix of +that name. A conventional binary search tree is used to retrieve section names, +with fields called |llink| and |rlink| (where |llink| takes the place +of |link|). The root of this tree is stored in |name_dir->rlink|; +this will be the only information in |name_dir[0]|. + +Since the space used by |rlink| has a different function for +identifiers than for section names, we declare it as a |union|. + +@d llink link /* left link in binary search tree for section names */ +@d rlink dummy.Rlink /* right link in binary search tree for section names */ +@d root name_dir->rlink /* the root of the binary search tree + for section names */ + +@<More elements of |name...@>= +union { + struct name_info *Rlink; /* right link in binary search tree for section + names */ + char Ilk; /* used by identifiers in \.{CWEAVE} only */ +} dummy; + +@ @<Init...@>= +root=NULL; /* the binary search tree starts out with nothing in it */ + +@ If |p| is a |name_pointer| variable, as we have seen, +|p->byte_start| is the beginning of the area where the name +corresponding to |p| is stored. However, if |p| refers to a section +name, the name may need to be stored in chunks, because it may +``grow'': a prefix of the section name may be encountered before +the full name. Furthermore we need to know the length of the shortest +prefix of the name that was ever encountered. + +We solve this problem by inserting two extra bytes at |p->byte_start|, +representing the length of the shortest prefix, when |p| is a +section name. Furthermore, the last byte of the name will be a blank +space if |p| is a prefix. In the latter case, the name pointer +|p+1| will allow us to access additional chunks of the name: +The second chunk will begin at the name pointer |(p+1)->link|, +and if it too is a prefix (ending with blank) its |link| will point +to additional chunks in the same way. Null links are represented by +|name_dir|. + +@d first_chunk(p) ((p)->byte_start+2) +@d prefix_length(p) (int)((unsigned char)*((p)->byte_start)*256 + + (unsigned char)*((p)->byte_start+1)) +@d set_prefix_length(p,m) (*((p)->byte_start)=(m)/256, + *((p)->byte_start+1)=(m)%256) + +@c +void +print_section_name(p) +name_pointer p; +{ + char *ss, *s = first_chunk(p); + name_pointer q = p+1; + while (p!=name_dir) { + ss = (p+1)->byte_start-1; + if (*ss==' ' && ss>=s) { + term_write(s,ss-s); p=q->link; q=p; + } else { + term_write(s,ss+1-s); p=name_dir; q=NULL; + } + s = p->byte_start; + } + if (q) term_write("...",3); /* complete name not yet known */ +} + +@ @c +void +sprint_section_name(dest,p) + char*dest; + name_pointer p; +{ + char *ss, *s = first_chunk(p); + name_pointer q = p+1; + while (p!=name_dir) { + ss = (p+1)->byte_start-1; + if (*ss==' ' && ss>=s) { + p=q->link; q=p; + } else { + ss++; p=name_dir; + } + strncpy(dest,s,ss-s), dest+=ss-s; + s = p->byte_start; + } + *dest='\0'; +} + +@ @c +void +print_prefix_name(p) +name_pointer p; +{ + char *s = first_chunk(p); + int l = prefix_length(p); + term_write(s,l); + if (s+l<(p+1)->byte_start) term_write("...",3); +} + +@ When we compare two section names, we'll need a function analogous to +|strcmp|. But we do not assume the strings +are null-terminated, and we keep an eye open for prefixes and extensions. + +@d less 0 /* the first name is lexicographically less than the second */ +@d equal 1 /* the first name is equal to the second */ +@d greater 2 /* the first name is lexicographically greater than the second */ +@d prefix 3 /* the first name is a proper prefix of the second */ +@d extension 4 /* the first name is a proper extension of the second */ + +@c +int web_strcmp(j,j_len,k,k_len) /* fuller comparison than |strcmp| */ + char *j, *k; /* beginning of first and second strings */ + int j_len, k_len; /* length of strings */ +{ + char *j1=j+j_len, *k1=k+k_len; + while (k<k1 && j<j1 && *j==*k) k++, j++; + if (k==k1) if (j==j1) return equal; + else return extension; + else if (j==j1) return prefix; + else if (*j<*k) return less; + else return greater; +} + +@ Adding a section name to the tree is straightforward if we know its +parent and whether it's the |rlink| or |llink| of the parent. As a +special case, when the name is the first section being added, we set the +``parent'' to |NULL|. When a section name is created, it has only one +chunk, which however may be just a prefix; the full name will +hopefully be unveiled later. Obviously, |prefix_length| starts +out as the length of the first chunk, though it may decrease later. + +The information associated with a new node must be initialized +differently in \.{CWEAVE} and \.{CTANGLE}; hence the +|init_node| procedure, which is defined differently in \.{cweave.w} +and \.{ctangle.w}. + +@<Prede...@>= +extern void init_node(); + +@ @c +name_pointer +add_section_name(par,c,first,last,ispref) /* install a new node in the tree */ +name_pointer par; /* parent of new node */ +int c; /* right or left? */ +char *first; /* first character of section name */ +char *last; /* last character of section name, plus one */ +int ispref; /* are we adding a prefix or a full name? */ +{ + name_pointer p=name_ptr; /* new node */ + char *s=first_chunk(p); + int name_len=last-first+ispref; /* length of section name */ + if (s+name_len>byte_mem_end) overflow("byte memory"); + if (name_ptr+1>=name_dir_end) overflow("name"); + (++name_ptr)->byte_start=byte_ptr=s+name_len; + if (ispref) { + *(byte_ptr-1)=' '; + name_len--; + name_ptr->link=name_dir; + (++name_ptr)->byte_start=byte_ptr; + } + set_prefix_length(p,name_len); + strncpy(s,first,name_len); + p->llink=NULL; + p->rlink=NULL; + init_node(p); + return par==NULL ? (root=p) : c==less ? (par->llink=p) : (par->rlink=p); +} + +@ @c +void +extend_section_name(p,first,last,ispref) +name_pointer p; /* name to be extended */ +char *first; /* beginning of extension text */ +char *last; /* one beyond end of extension text */ +int ispref; /* are we adding a prefix or a full name? */ +{ + char *s; + name_pointer q=p+1; + int name_len=last-first+ispref; + if (name_ptr>=name_dir_end) overflow("name"); + while (q->link!=name_dir) q=q->link; + q->link=name_ptr; + s=name_ptr->byte_start; + name_ptr->link=name_dir; + if (s+name_len>byte_mem_end) overflow("byte memory"); + (++name_ptr)->byte_start=byte_ptr=s+name_len; + strncpy(s,first,name_len); + if (ispref) *(byte_ptr-1)=' '; +} + +@ The |section_lookup| procedure is supposed to find a +section name that matches a new name, installing the new name if +it doesn't match an existing one. The new name is the string +between |first| and |last|; a ``match'' means that the new name +exactly equals or is a prefix or extension of a name in the tree. + +@c +name_pointer +section_lookup(first,last,ispref) /* find or install section name in tree */ +char *first, *last; /* first and last characters of new name */ +int ispref; /* is the new name a prefix or a full name? */ +{ + int c=0; /* comparison between two names; initialized so some compilers won't complain */ + name_pointer p=root; /* current node of the search tree */ + name_pointer q=NULL; /* another place to look in the tree */ + name_pointer r=NULL; /* where a match has been found */ + name_pointer par=NULL; /* parent of |p|, if |r| is |NULL|; + otherwise parent of |r| */ + int name_len=last-first+1; + @<Look for matches for new name among shortest prefixes, complaining + if more than one is found@>; + @<If no match found, add new name to tree@>; + @<If one match found, check for compatibility and return match@>; +} + +@ A legal new name matches an existing section name if and only if it +matches the shortest prefix of that section name. Therefore we can +limit our search for matches to shortest prefixes, which eliminates +the need for chunk-chasing at this stage. + +@<Look for matches for new name among...@>= +while (p) { /* compare shortest prefix of |p| with new name */ + c=web_strcmp(first,name_len,first_chunk(p),prefix_length(p)); + if (c==less || c==greater) { /* new name does not match |p| */ + if (r==NULL) /* no previous matches have been found */ + par=p; + p=(c==less?p->llink:p->rlink); + } else { /* new name matches |p| */ + if (r!=NULL) { /* and also |r|: illegal */ + printf("\n! Ambiguous prefix: matches <"); +@.Ambiguous prefix ... @> + print_prefix_name(p); + printf(">\n and <"); + print_prefix_name(r); + err_print(">"); + return name_dir; /* the unsection */ + } + r=p; /* remember match */ + p=p->llink; /* try another */ + q=r->rlink; /* we'll get back here if the new |p| doesn't match */ + } + if (p==NULL) + p=q, q=NULL; /* |q| held the other branch of |r| */ +} + +@ @<If no match ...@>= + if (r==NULL) /* no matches were found */ + return add_section_name(par,c,first,last+1,ispref); + +@ Although error messages are given in anomalous cases, we do return the +unique best match when a discrepancy is found, because users often +change a title in one place while forgetting to change it elsewhere. + +@<If one match found, check for compatibility and return match@>= +switch(section_name_cmp(&first,name_len,r)) { + /* compare all of |r| with new name */ + case prefix: + if (!ispref) { + printf("\n! New name is a prefix of <"); +@.New name is a prefix...@> + print_section_name(r); + err_print(">"); + } + else if (name_len<prefix_length(r)) set_prefix_length(r,name_len); + /* fall through */ + case equal: return r; + case extension: if (!ispref || first<=last) + extend_section_name(r,first,last+1,ispref); + return r; + case bad_extension: + printf("\n! New name extends <"); +@.New name extends...@> + print_section_name(r); + err_print(">"); + return r; + default: /* no match: illegal */ + printf("\n! Section name incompatible with <"); +@.Section name incompatible...@> + print_prefix_name(r); + printf(">,\n which abbreviates <"); + print_section_name(r); + err_print(">"); + return r; +} + +@ The return codes of |section_name_cmp|, which compares a string with +the full name of a section, are those of |web_strcmp| plus +|bad_extension|, used when the string is an extension of a +supposedly already complete section name. This function has a side +effect when the comparison string is an extension: It advances the +address of the first character of the string by an amount equal to +the length of the known part of the section name. + +The name \.{@@<foo...@@>} should be an acceptable ``abbreviation'' +for \.{@@<foo@@>}. If such an abbreviation comes after the complete +name, there's no trouble recognizing it. If it comes before the +complete name, we simply append a null chunk. This logic requires +us to regard \.{@@<foo...@@>} as an ``extension'' of itself. + +@d bad_extension 5 + +@<Predec...@>= +int section_name_cmp(); + +@ @c +int section_name_cmp(pfirst,len,r) +char **pfirst; /* pointer to beginning of comparison string */ +int len; /* length of string */ +name_pointer r; /* section name being compared */ +{ + char *first=*pfirst; /* beginning of comparison string */ + name_pointer q=r+1; /* access to subsequent chunks */ + char *ss, *s=first_chunk(r); + int c; /* comparison */ + int ispref; /* is chunk |r| a prefix? */ + while (1) { + ss=(r+1)->byte_start-1; + if (*ss==' ' && ss>=r->byte_start) ispref=1,q=q->link; + else ispref=0,ss++,q=name_dir; + switch(c=web_strcmp(first,len,s,ss-s)) { + case equal: if (q==name_dir) + if (ispref) { + *pfirst=first+(ss-s); + return extension; /* null extension */ + } else return equal; + else return (q->byte_start==(q+1)->byte_start)? equal: prefix; + case extension: + if (!ispref) return bad_extension; + first += ss-s; + if (q!=name_dir) {len -= ss-s; s=q->byte_start; r=q; continue;} + *pfirst=first; return extension; + default: return c; + } + } +} + +@ The last component of |name_info| is different for \.{CTANGLE} and +\.{CWEAVE}. In \.{CTANGLE}, if |p| is a pointer to a section name, +|p->equiv| is a pointer to its replacement text, an element of the +array |text_info|. In \.{CWEAVE}, on the other hand, if +|p| points to an identifier, |p->xref| is a pointer to its +list of cross-references, an element of the array |xmem|. The make-up +of |text_info| and |xmem| is discussed in the \.{CTANGLE} and \.{CWEAVE} +source files, respectively; here we just declare a common field +|equiv_or_xref| as a pointer to a |char|. + +@<More elements of |name...@>= +char *equiv_or_xref; /* info corresponding to names */ + +@** Reporting errors to the user. +A global variable called |history| will contain one of four values +at the end of every run: |spotless| means that no unusual messages were +printed; |harmless_message| means that a message of possible interest +was printed but no serious errors were detected; |error_message| means that +at least one error was found; |fatal_message| means that the program +terminated abnormally. The value of |history| does not influence the +behavior of the program; it is simply computed for the convenience +of systems that might want to use such information. + +@d spotless 0 /* |history| value for normal jobs */ +@d harmless_message 1 /* |history| value when non-serious info was printed */ +@d error_message 2 /* |history| value when an error was noted */ +@d fatal_message 3 /* |history| value when we had to stop prematurely */ +@d mark_harmless {if (history==spotless) history=harmless_message;} +@d mark_error history=error_message + +@<Definit...@>= +int history=spotless; /* indicates how bad this run was */ + +@ The command `|err_print("! Error message")|' will report a syntax error to +the user, by printing the error message at the beginning of a new line and +then giving an indication of where the error was spotted in the source file. +Note that no period follows the error message, since the error routine +will automatically supply a period. A newline is automatically supplied +if the string begins with |"!"|. + +@<Predecl...@>= +void err_print(); + +@ @c +void +err_print(s) /* prints `\..' and location of error message */ +char *s; +{ + char *k,*l; /* pointers into |buffer| */ + printf(*s=='!'? "\n%s" : "%s",s); + if(web_file_open) @<Print error location based on input buffer@>; + update_terminal; mark_error; +} + +@ The error locations can be indicated by using the global variables +|loc|, |cur_line|, |cur_file_name| and |changing|, +which tell respectively the first +unlooked-at position in |buffer|, the current line number, the current +file, and whether the current line is from |change_file| or |cur_file|. +This routine should be modified on systems whose standard text editor +has special line-numbering conventions. +@^system dependencies@> + +@<Print error location based on input buffer@>= +{if (changing && include_depth==change_depth) + printf(". (l. %d of change file)\n", change_line); +else if (include_depth==0) printf(". (l. %d)\n", cur_line); + else printf(". (l. %d of include file %s)\n", cur_line, cur_file_name); +l= (loc>=limit? limit: loc); +if (l>buffer) { + for (k=buffer; k<l; k++) + if (*k=='\t') putchar(' '); + else putchar(*k); /* print the characters already read */ + putchar('\n'); + for (k=buffer; k<l; k++) putchar(' '); /* space out the next line */ +} +for (k=l; k<limit; k++) putchar(*k); /* print the part not yet read */ +if (*limit=='|') putchar('|'); /* end of \CEE/ text in section names */ +putchar(' '); /* to separate the message from future asterisks */ +} + +@ When no recovery from some error has been provided, we have to wrap +up and quit as graciously as possible. This is done by calling the +function |wrap_up| at the end of the code. + +\.{CTANGLE} and \.{CWEAVE} have their own notions about how to +print the job statistics. + +@<Prede...@>= +int wrap_up(); +extern void print_stats(); + +@ Some implementations may wish to pass the |history| value to the +operating system so that it can be used to govern whether or not other +programs are started. Here, for instance, we pass the operating system +a status of 0 if and only if only harmless messages were printed. +@^system dependencies@> + +@c +int wrap_up() { + putchar('\n'); + if (show_stats) + print_stats(); /* print statistics about memory usage */ + @<Print the job |history|@>; + if (history > harmless_message) return(1); + else return(0); +} + +@ @<Print the job |history|@>= +switch (history) { +case spotless: if (show_happiness) printf("(No errors were found.)\n"); break; +case harmless_message: + printf("(Did you see the warning message above?)\n"); break; +case error_message: + printf("(Pardon me, but I think I spotted something wrong.)\n"); break; +case fatal_message: printf("(That was a fatal error, my friend.)\n"); +} /* there are no other cases */ + +@ When there is no way to recover from an error, the |fatal| subroutine is +invoked. This happens most often when |overflow| occurs. + +@<Predec...@>= +void fatal(), overflow(); + +@ The two parameters to |fatal| are strings that are essentially +concatenated to print the final error message. + +@c void +fatal(s,t) + char *s,*t; +{ + if (*s) printf(s); + err_print(t); + history=fatal_message; exit(wrap_up()); +} + +@ An overflow stop occurs if \.{CWEB}'s tables aren't large enough. + +@c void +overflow(t) + char *t; +{ + printf("\n! Sorry, %s capacity exceeded",t); fatal("",""); +} +@.Sorry, capacity exceeded@> + +@ Sometimes the program's behavior is far different from what it should be, +and \.{CWEB} prints an error message that is really for the \.{CWEB} +maintenance person, not the user. In such cases the program says +|confusion("indication of where we are")|. + +@d confusion(s) fatal("! This can't happen: ",s) +@.This can't happen@> + +@** Command line arguments. +The user calls \.{CWEAVE} and \.{CTANGLE} with arguments on the command line. +These are either file names or flags to be turned off (beginning with |"-"|) +or flags to be turned on (beginning with |"+"|). +The following globals are for communicating the user's desires to the rest +of the program. The various file name variables contain strings with +the names of those files. Most of the 128 flags are undefined but available +for future extensions. + +@d show_banner flags['b'] /* should the banner line be printed? */ +@d show_progress flags['p'] /* should progress reports be printed? */ +@d show_stats flags['s'] /* should statistics be printed at end of run? */ +@d show_happiness flags['h'] /* should lack of errors be announced? */ + +@<Defin...@>= +int argc; /* copy of |ac| parameter to |main| */ +char **argv; /* copy of |av| parameter to |main| */ +char C_file_name[max_file_name_length]; /* name of |C_file| */ +char tex_file_name[max_file_name_length]; /* name of |tex_file| */ +char idx_file_name[max_file_name_length]; /* name of |idx_file| */ +char scn_file_name[max_file_name_length]; /* name of |scn_file| */ +boolean flags[128]; /* an option for each 7-bit code */ + +@ The |flags| will be initially zero. Some of them are set to~1 before +scanning the arguments; if additional flags are 1 by default they +should be set before calling |common_init|. + +@<Set the default options common to \.{CTANGLE} and \.{CWEAVE}@>= +show_banner=show_happiness=show_progress=1; + +@ We now must look at the command line arguments and set the file names +accordingly. At least one file name must be present: the \.{CWEB} +file. It may have an extension, or it may omit the extension to get |".w"| or +|".web"| added. The \TEX/ output file name is formed by replacing the \.{CWEB} +file name extension by |".tex"|, and the \CEE/ file name by replacing +the extension by |".c"|, after removing the directory name (if any). + +If there is a second file name present among the arguments, it is the +change file, again either with an extension or without one to get |".ch"|. +An omitted change file argument means that |"/dev/null"| should be used, +when no changes are desired. +@^system dependencies@> + +If there's a third file name, it will be the output file. + +@<Pred...@>= +void scan_args(); + +@ @c +void +scan_args() +{ + char *dot_pos; /* position of |'.'| in the argument */ + char *name_pos; /* file name beginning, sans directory */ + register char *s; /* register for scanning strings */ + boolean found_web=0,found_change=0,found_out=0; + /* have these names been seen? */ + boolean flag_change; + + while (--argc > 0) { + if ((**(++argv)=='-'||**argv=='+')&&*(*argv+1)) @<Handle flag argument@>@; + else { + s=name_pos=*argv;@+dot_pos=NULL; + while (*s) { + if (*s=='.') dot_pos=s++; + else if (*s=='/') dot_pos=NULL,name_pos=++s; + else s++; + } + if (!found_web) @<Make + |web_file_name|, |tex_file_name|, and |C_file_name|@>@; + else if (!found_change) @<Make |change_file_name| from |fname|@>@; + else if (!found_out) @<Override |tex_file_name| and |C_file_name|@>@; + else @<Print usage error message and quit@>; + } + } + if (!found_web) @<Print usage error message and quit@>; + if (found_change<=0) strcpy(change_file_name,"/dev/null"); +} + +@ We use all of |*argv| for the |web_file_name| if there is a |'.'| in it, +otherwise we add |".w"|. If this file can't be opened, we prepare an +|alt_web_file_name| by adding |"web"| after the dot. +The other file names come from adding other things +after the dot. We must check that there is enough room in +|web_file_name| and the other arrays for the argument. + +@<Make |web_file_name|...@>= +{ + if (s-*argv > max_file_name_length-5) + @<Complain about argument length@>; + if (dot_pos==NULL) + sprintf(web_file_name,"%s.w",*argv); + else { + strcpy(web_file_name,*argv); + *dot_pos=0; /* string now ends where the dot was */ + } + sprintf(alt_web_file_name,"%s.web",*argv); + sprintf(tex_file_name,"%s.tex",name_pos); /* strip off directory name */ + sprintf(idx_file_name,"%s.idx",name_pos); + sprintf(scn_file_name,"%s.scn",name_pos); + sprintf(C_file_name,"%s.c",name_pos); + found_web=1; +} + +@ @<Make |change_file_name|...@>= +{ + if (strcmp(*argv,"-")==0) found_change=-1; + else { + if (s-*argv > max_file_name_length-4) + @<Complain about argument length@>; + if (dot_pos==NULL) + sprintf(change_file_name,"%s.ch",*argv); + else strcpy(change_file_name,*argv); + found_change=1; + } +} + +@ @<Override...@>= +{ + if (s-*argv > max_file_name_length-5) + @<Complain about argument length@>; + if (dot_pos==NULL) { + sprintf(tex_file_name,"%s.tex",*argv); + sprintf(idx_file_name,"%s.idx",*argv); + sprintf(scn_file_name,"%s.scn",*argv); + sprintf(C_file_name,"%s.c",*argv); + } else { + strcpy(tex_file_name,*argv); + strcpy(C_file_name,*argv); + if (flags['x']) { /* indexes will be generated */ + *dot_pos=0; + sprintf(idx_file_name,"%s.idx",*argv); + sprintf(scn_file_name,"%s.scn",*argv); + } + } + found_out=1; +} + +@ @<Handle flag...@>= +{ + if (**argv=='-') flag_change=0; + else flag_change=1; + for(dot_pos=*argv+1;*dot_pos>'\0';dot_pos++) + flags[*dot_pos]=flag_change; +} + +@ @<Print usage error message and quit@>= +{ +if (program==ctangle) + fatal( +"! Usage: ctangle [options] webfile[.w] [{changefile[.ch]|-} [outfile[.c]]]\n" + ,""); +@.Usage:@> +else fatal( +"! Usage: cweave [options] webfile[.w] [{changefile[.ch]|-} [outfile[.tex]]]\n" + ,""); +} + +@ @<Complain about arg...@>= fatal("! Filename too long\n", *argv); +@.Filename too long@> + +@** Output. Here is the code that opens the output file: +@^system dependencies@> + +@<Defin...@>= +FILE *C_file; /* where output of \.{CTANGLE} goes */ +FILE *tex_file; /* where output of \.{CWEAVE} goes */ +FILE *idx_file; /* where index from \.{CWEAVE} goes */ +FILE *scn_file; /* where list of sections from \.{CWEAVE} goes */ +FILE *active_file; /* currently active file for \.{CWEAVE} output */ + +@ @<Scan arguments and open output files@>= +scan_args(); +if (program==ctangle) { + if ((C_file=fopen(C_file_name,"w"))==NULL) + fatal("! Cannot open output file ", C_file_name); +@.Cannot open output file@> +} +else { + if ((tex_file=fopen(tex_file_name,"w"))==NULL) + fatal("! Cannot open output file ", tex_file_name); +} + +@ The |update_terminal| procedure is called when we want +to make sure that everything we have output to the terminal so far has +actually left the computer's internal buffers and been sent. +@^system dependencies@> + +@d update_terminal fflush(stdout) /* empty the terminal output buffer */ + +@ Terminal output uses |putchar| and |putc| when we have to +translate from \.{CWEB}'s code into the external character code, +and |printf| when we just want to print strings. +Several macros make other kinds of output convenient. +@^system dependencies@> +@d new_line putchar('\n') @d putxchar putchar +@d term_write(a,b) fflush(stdout),fwrite(a,sizeof(char),b,stdout) +@d C_printf(c,a) fprintf(C_file,c,a) +@d C_putc(c) putc(c,C_file) /* isn't \CEE/ wonderfully consistent? */ + +@ We predeclare several standard system functions here instead of including +their system header files, because the names of the header files are not as +standard as the names of the functions. (For example, some \CEE/ environments +have \.{<string.h>} where others have \.{<strings.h>}.) + +@<Predecl...@>= +extern int strlen(); /* length of string */ +extern int strcmp(); /* compare strings lexicographically */ +extern char* strcpy(); /* copy one string to another */ +extern int strncmp(); /* compare up to $n$ string characters */ +extern char* strncpy(); /* copy up to $n$ string characters */ + +@** Index. |