Initial import of the CDE 2.1.30 sources from the Open Group.
This commit is contained in:
Peter Howkins
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cde/programs/dthelp/parser/pass2/util/context.c
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cde/programs/dthelp/parser/pass2/util/context.c
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/* $XConsortium: context.c /main/3 1995/11/08 11:03:02 rswiston $ */
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/*
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Copyright 1986 Tandem Computers Incorporated.
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This product and information is proprietary of Tandem Computers Incorporated.
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Copyright (c) 1986, 1987, 1988, 1989 Hewlett-Packard Co.
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*/
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/*
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Context.c contains the main procedure for program CONTEXT.
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CONTEXT builds scanning and parsing tables for a simple
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state-transition recognizer. Input consists of two files, delimiter
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declarations in file "delim.dat" and state tables with corresponding
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actions in file "context.dat". If a parameter is present on the
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command line, a sparse matrix technique is used to encode some of the
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output arrays.
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Data lines in "delim.dat" contain the name of the delimiter followed
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by the text of the delimiter (one or more non-white space
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characters). The delimiter name must begin in the first column.
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Lines with white-space in the first column are considered comments.
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Data in "context.dat" consists of free-form multi-line declarations.
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Each declaration is terminated by a semi-colon. It begins with the
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name of a token followed by any number of pairs of contexts (parser
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states). The context pairs are separated by a colon and may
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optionally be followed by some C code enclosed in braces. In each
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pair, the first context is one in which the delimiter is recognized,
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the second is the state that will result from an occurrence of the
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delimiter in the first context. If code is specified, it is to be
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executed by the parser when the delimiter occurs in the first context
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of the pair. If successive pairs of contexts are separated by a
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comma, code which follows is common to all the pairs.
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The tokens specified in "context.dat" can either be delimiters defined in
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"delim.dat" or other tokens (e.g., number, name, end_of_file) that will
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be recognized by the user-defined scanner.
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For example, suppose "delim.dat" contains the line
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grpo (
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and "context.dat" includes
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grpo element:namegroup
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content:model {openmod() ;}
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excon:openex
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pcon:type ;
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name namegroup:namesep {eltname() ;}
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model:connector,
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model2:connector
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{storemod(nstring) ;}
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These declarations specify that the "grpo" delimiter is "(" and is
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recognized in contexts "element", "content", "excon", and "pcon".
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Procedure openmod() is called when "grpo" occurs in "content" and,
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beyond the state change, no code is executed in other contexts when
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"grpo" occurs. The "name" token is valid in contexts "namegroup",
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"model", and "model2"; in the first, the context is set to "namesep"
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and procedure eltname() is called, in the last two, the context is
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set to "connector" and storemod(nstring) is called.
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The program has several output files: case.c, delim.h, context.h, and
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error. Case.c contains nested switch statements to execute the code
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specified with the context transitions. Delim.h contains C
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declarations related to delimiters; context.h has declarations
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related to contexts. Programs that include delim.h should define
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M_DELIMDEF for definition form of the declarations and not define it
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for the declaration form. Programs that include context.h should
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define M_CONDEF analogously.
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The program numbers the delimiter names and the contexts as
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encountered and outputs corresponding #define instructions with all
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letters in the names forced to uppercase to delim.h and context.h.
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In addition, an array named for each delimiter (with all letters
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forced to lowercase) is initialized to the delimiter text. The first
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declaration in the above example, for instance, would result in the
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following lines written to delim.h:
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#define GRPO 1
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M_DELIMEXTERN char grpo[] M_DELIMINIT("(") ;
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These lines would be written to context.h:
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#define ELEMENT 1
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#define NAMEGROUP 2
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#define CONTENT 3
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#define MODEL 4
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#define EXCON 5
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#define OPENEX 6
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#define PCON 7
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#define TYPE 8
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#define NAMESEP 9
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#define CONNECTOR 10
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#define MODEL2 11
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Delim.h also contains an array, m_dlmptr, which contains pointers to the
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names of all the defined delimiters. In addition, delim.h contains the
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declaration of a tree representation of the delimiters allowed in each
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context. Internally, the program represents the delimiter strings with a
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tree. The children of the root of this tree represent the set of characters
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with which delimiters can start. Children of other nodes represent
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characters that can follow the character of their parent. Leaf nodes
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are associated with the null character, indicating the end of a
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delimiter. A path from the root to a leaf thus represents a valid
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delimiter.
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The form in which the tree is represented within this program is not
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quite the same as the output data structure. In the latter, each
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element consists of a flag called 'more' indicating whether it is the last
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child of its parent; a character, called 'symbol'; and an integer,
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called 'index'. All sons of a node are stored in adjacent elements
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ordered in increaing value of their 'symbol' fields. 'Symbol'
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contains the character associated with the node (0 if the node is a
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leaf node), with the sign bit turned on if the node is the last child
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of its parent. 'Index' contains the array index of the first son of
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the node, if the node is not a leaf. If the node is a leaf, 'index'
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is the number of the represented delimiter (i.e., 1 for "grpo" in the
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above example).
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As the tree is constructed, it is not feasible to store brothers in adjacent
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elements, so the internal data structure is different. It contains a 'next'
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field which points to the first brother of a given node. Because the 'next'
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field can be used to detect the last child of a parent, it is not necessary
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to use the sign bit of 'symbol' to indicate this special case.
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Two other arrays are written to context.h. Contree[i] points to the root
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of the delimiter tree for the ith context within the array tree whose
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declaration is in delim.h; nextcon[i][j] indicates the state
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resulting from an occurrence of delimiter j+1 in state i+1. Finally,
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a #define of MAXD to the length of the longest delimiter is written to
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delim.h.
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*/
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#include <stdio.h>
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#include <malloc.h>
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#if defined(MSDOS)
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#include <process.h>
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#endif
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#include "basic.h"
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#include "trie.h"
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#include "common.h"
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#include "chartype.h"
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#define CONTDEF 1
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#include "cont.h"
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/* Main procedure */
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void main(argc, argv)
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int argc ;
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char **argv ;
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{
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int n ;
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m_openchk(&delim, "delim.h", "w") ;
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m_openchk(&context, "context.h", "w") ;
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m_openchk(&fcase, "case.c", "w") ;
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m_openchk(&cdat, "context.dat", "r") ;
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m_openchk(&ddat, "delim.dat", "r") ;
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m_openchk(&m_errfile, "error", "w") ;
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fputs(" switch(m_token) {\n", fcase) ; /* keep the "}" balanced */
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fputs("#if defined(M_DELIMDEF)\n", delim) ;
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fputs("#define M_DELIMEXTERN\n", delim) ;
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fputs("#define M_DELIMINIT(a) = a\n", delim) ;
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fputs("#else\n", delim) ;
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fputs("#define M_DELIMEXTERN extern\n", delim) ;
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fputs("#define M_DELIMINIT(a)\n", delim) ;
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fputs("#endif\n\n", delim) ;
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fputs("#if defined(M_CONDEF)\n", context) ;
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fputs("#define M_CONEXTERN\n", context) ;
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fputs("#else\n", context) ;
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fputs("#define M_CONEXTERN extern\n", context) ;
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fputs("#endif\n\n", context) ;
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contree = (M_TRIE **) calloc(NUMCON, sizeof(M_TRIE *)) ;
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xtransit = (int *) calloc(NUMCON * NUMDELIM, sizeof(int)) ;
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contexts = (M_WCHAR **) calloc(NUMCON, sizeof(char *)) ;
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dlmptr = (char**) calloc(NUMDELIM, sizeof(char*)) ;
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loaddelim() ;
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while (getdname())
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{
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casestarted = FALSE ;
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while ((n = getContext()) >= 0)
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{
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if (withdelim) enterdelim(n) ;
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getcolon() ;
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if (transit(n, curdelim))
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{
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if (! withdelim)
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{
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char *mb_dname, *mb_contexts;
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mb_dname = MakeMByteString(dname);
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mb_contexts = MakeMByteString(contexts[n]);
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warning2(
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"Duplicate assignment to token \"%s\" in context \"%s\"",
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mb_dname,
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mb_contexts) ;
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m_free(mb_dname,"multi-byte string");
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m_free(mb_contexts,"multi-byte string");
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}
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}
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transit(n, curdelim) = getContext() + 1 ;
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getcode(n) ;
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}
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if (casestarted)
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{
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fprintf(fcase, " default:\n break ;\n") ;
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/* keep the "{" balanced */
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fprintf(fcase, " }\n break ;\n") ;
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}
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}
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/* keep the "{" balanced */
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fprintf(fcase, " default:\n break ;\n }\n") ;
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fprintf(context, "#define MAXD %d\n", maxd) ;
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dumptree((LOGICAL) (argc > 1)) ;
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fprintf(stderr, "NUMCON set to %d\n", NUMCON) ;
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fprintf(stderr, "NUMDELIM set to %d\n", NUMDELIM) ;
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exit(errexit) ;
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}
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