312 lines
10 KiB
C
Executable File
312 lines
10 KiB
C
Executable File
/* Codepage translation to Unicode, and UTF-8 support
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*
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* The translation is based on codepage mapping files that are distributed
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* by the Unicode consortium, see ftp://ftp.unicode.org/Public/MAPPINGS/.
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*
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* Character sets with a maximum of 256 codes are translated via a lookup
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* table (these are Single-Byte Character Sets). Character sets like Shift-JIS
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* with single-byte characters and multi-byte characters (introduced by a
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* leader byte) are split into two tables: the 256-entry lookup table for
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* the single-byte characters and an extended table for the multi-byte
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* characters. The extended table is allocated dynamically; the lookup table
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* is allocated statically, so loading SBCS tables cannot fail (if the tables
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* themselves are valid, of course).
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*
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* Copyright (c) ITB CompuPhase, 2004-2005
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*
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* This software is provided "as-is", without any express or implied warranty.
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* In no event will the authors be held liable for any damages arising from
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* the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software in
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* a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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#include <assert.h>
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#include <stdio.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include "sc.h"
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#if !defined TRUE
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#define FALSE 0
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#define TRUE 1
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#endif
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#if !defined _MAX_PATH
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#define _MAX_PATH 250
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#endif
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#if !defined DIRSEP_CHAR
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#if defined LINUX || defined __FreeBSD__ || defined __OpenBSD__ || defined __APPLE__
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#define DIRSEP_CHAR '/'
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#elif defined macintosh
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#define DIRSEP_CHAR ':'
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#else
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#define DIRSEP_CHAR '\\'
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#endif
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#endif
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#if !defined ELEMENTS
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#define ELEMENTS(array) (sizeof(array) / sizeof(array[0]))
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#endif
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#if !defined NO_CODEPAGE
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#if !defined MAXCODEPAGE
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#define MAXCODEPAGE 12 /* typically "cp" + 4 digits + ".txt" */
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#endif
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#define INVALID 0xffffu /* 0xffff and 0xfffe are invalid Unicode characters */
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#define LEADBYTE 0xfffeu
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struct wordpair {
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unsigned short index;
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wchar_t code;
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};
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static char cprootpath[_MAX_PATH] = { DIRSEP_CHAR, '\0' };
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static wchar_t bytetable[256];
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static struct wordpair *wordtable = NULL;
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static unsigned wordtablesize = 0;
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static unsigned wordtabletop = 0;
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/* read in a line delimited by '\r' or '\n'; do NOT store the '\r' or '\n' into
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* the string and ignore empty lines
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* returns 1 for success and 0 for failure
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*/
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static int cp_readline(FILE *fp,char *string,size_t size)
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{
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size_t count=0;
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int c;
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assert(size>1);
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while ((c=fgetc(fp))!=EOF && count<size-1) {
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if (c=='\r' || c=='\n') {
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if (count>0) /* '\r' or '\n' ends a string */
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break;
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/* if count==0, the line started with a '\r' or '\n', or perhaps line
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* ends in the file are '\r\n' and we read and stopped on the '\r' of
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* the preceding line
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*/
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} else {
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string[count++]=(char)c;
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} /* if */
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} /* while */
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string[count]='\0';
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return count>0;
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}
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/* cp_path() sets the directory where all codepage files must be found (if
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* the parameter to cp_set() specifies a full path, that is used instead).
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* The path is specified into two parts: root and directory; the full path
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* for the codepage direcory is just the concatenation of the two, with a
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* directory separator in between. The directory is given in two parts,
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* because often a program already retrieves its "home" directory and the
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* codepages are most conveniently stored in a subdirectory of this home
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* directory.
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*/
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SC_FUNC int cp_path(const char *root, const char *directory)
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{
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size_t len1,len2;
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int add_slash1,add_slash2;
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len1= (root!=NULL) ? strlen(root) : 0;
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add_slash1= (len1==0 || root[len1-1]!=DIRSEP_CHAR);
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len2= (directory!=NULL) ? strlen(directory) : 0;
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add_slash2= (len2>0 && root[len2-1]!=DIRSEP_CHAR);
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if (len1+add_slash1+len2+add_slash2>=(_MAX_PATH-MAXCODEPAGE))
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return FALSE; /* full filename may not fit */
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if (root!=NULL)
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strcpy(cprootpath,root);
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if (add_slash1) {
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assert(len1==0 || cprootpath[len1]=='\0');
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cprootpath[len1]=DIRSEP_CHAR;
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cprootpath[len1+1]='\0';
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} /* if */
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if (directory!=NULL)
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strcat(cprootpath,directory);
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if (add_slash2) {
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assert(cprootpath[len1+add_slash1+len2]=='\0');
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cprootpath[len1+add_slash1+len2]=DIRSEP_CHAR;
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cprootpath[len1+add_slash1+len2+1]='\0';
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} /* if */
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cp_set(NULL); /* start with a "linear" table (no translation) */
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return TRUE;
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}
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/* cp_set() loads a codepage from a file. The name parameter may be a
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* filename (including a full path) or it may be a partial codepage name.
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* If the name parameter is NULL, the codepage is cleared to be a "linear"
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* table (no translation).
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* The following files are attempted to open (where <name> specifies the
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* value of the parameter):
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* <name>
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* <cprootpath>/<name>
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* <cprootpath>/<name>.txt
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* <cprootpath>/cp<name>
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* <cprootpath>/cp<name>.txt
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*/
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SC_FUNC int cp_set(const char *name)
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{
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char filename[_MAX_PATH];
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FILE *fp=NULL;
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unsigned index;
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/* for name==NULL, set up an identity table */
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if (name==NULL || *name=='\0') {
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if (wordtable!=NULL) {
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free(wordtable);
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wordtable=NULL;
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wordtablesize=0;
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wordtabletop=0;
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} /* if */
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for (index=0; index<ELEMENTS(bytetable); index++)
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bytetable[index]=(wchar_t)index;
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return TRUE;
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} /* if */
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/* try to open the file as-is */
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if (strchr(name,DIRSEP_CHAR)!=NULL)
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fp=fopen(name,"rt");
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if (fp==NULL) {
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/* try opening the file in the "root path" for codepages */
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if (strlen(name)>MAXCODEPAGE)
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return 0;
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assert(strlen(name)+strlen(cprootpath)<_MAX_PATH);
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strcpy(filename,cprootpath);
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strcat(filename,name);
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fp=fopen(filename,"rt");
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} /* if */
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if (fp==NULL) {
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/* try opening the file in the "root path" for codepages, with a ".txt" extension */
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if (strlen(name)+4>=MAXCODEPAGE)
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return 0;
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assert(strlen(filename)+4<_MAX_PATH);
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strcat(filename,".txt");
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fp=fopen(filename,"rt");
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} /* if */
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if (fp==NULL) {
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/* try opening the file in the "root path" for codepages, with "cp" prefixed before the name */
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if (strlen(name)+2>MAXCODEPAGE)
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return 0;
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assert(2+strlen(name)+strlen(cprootpath)<_MAX_PATH);
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strcpy(filename,cprootpath);
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strcat(filename,"cp");
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strcat(filename,name);
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fp=fopen(filename,"rt");
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} /* if */
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if (fp==NULL) {
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/* try opening the file in the "root path" for codepages, with "cp" prefixed an ".txt" appended */
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if (strlen(name)+2+4>MAXCODEPAGE)
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return 0;
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assert(strlen(filename)+4<_MAX_PATH);
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strcat(filename,".txt");
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fp=fopen(filename,"rt");
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} /* if */
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if (fp==NULL)
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return FALSE; /* all failed */
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/* clear the tables */
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for (index=0; index<ELEMENTS(bytetable); index++)
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bytetable[index]=INVALID; /* special code meaning "not found" */
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assert(wordtablesize==0 && wordtabletop==0 && wordtable==NULL
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|| wordtablesize>0 && wordtable!=NULL);
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if (wordtable!=NULL) {
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free(wordtable);
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wordtable=NULL;
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wordtablesize=0;
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wordtabletop=0;
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} /* if */
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/* read in the table */
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while (cp_readline(fp,filename,sizeof filename)) {
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char *ptr;
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if ((ptr=strchr(filename,'#'))!=NULL)
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*ptr='\0'; /* strip of comment */
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for (ptr=filename; *ptr>0 && *ptr<' '; ptr++)
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/* nothing */; /* skip leading whitespace */
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if (*ptr!='\0') {
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/* content on line */
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unsigned code=LEADBYTE;
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int num=sscanf(ptr,"%i %i",&index,&code);
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/* if sscanf() returns 1 and the index is in range 0..255, then the
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* code is a DBCS lead byte; if sscanf() returns 2 and index>=256, this
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* is a double byte pair (lead byte + follower)
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*/
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if (num>=1 && index<256) {
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bytetable[index]=(wchar_t)code;
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} else if (num==2 && index>=256 && index<LEADBYTE) {
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/* store the DBCS character in wordtable */
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if (wordtabletop>=wordtablesize) {
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/* grow the list */
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int newsize;
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struct wordpair *newblock;
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newsize= (wordtablesize==0) ? 128 : 2*wordtablesize;
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newblock=(struct wordpair *)malloc(newsize*sizeof(*wordtable));
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if (newblock!=NULL) {
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memcpy(newblock,wordtable,wordtabletop*sizeof(*wordtable));
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free(wordtable);
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wordtable=newblock;
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wordtablesize=newsize;
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} /* if */
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} /* if */
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if (wordtabletop<wordtablesize) {
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/* insert at sorted position */
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int pos=wordtabletop;
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assert(wordtable!=NULL);
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while (pos>0 && (unsigned)wordtable[pos-1].index>index) {
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wordtable[pos]=wordtable[pos-1];
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pos--;
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} /* while */
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wordtable[pos].index=(unsigned short)index;
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wordtable[pos].code=(wchar_t)code;
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} /* if */
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} /* if */
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} /* if */
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} /* while */
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fclose(fp);
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return TRUE;
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}
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SC_FUNC cell cp_translate(const unsigned char *string,const unsigned char **endptr)
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{
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wchar_t result;
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result=bytetable[*string++];
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/* check whether this is a leader code */
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if ((unsigned)result==LEADBYTE && wordtable!=NULL) {
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/* look up the code via binary search */
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int low,high,mid;
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unsigned short index=(unsigned short)(((*(string-1)) << 8) | *string);
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string++;
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assert(wordtabletop>0);
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low=0;
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high=wordtabletop-1;
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while (low<high) {
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mid=(low+high)/2;
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assert(low<=mid && mid<high);
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if (index>wordtable[mid].index)
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low=mid+1;
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else
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high=mid;
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} /* while */
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assert(low==high);
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if (wordtable[low].index==index)
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result=wordtable[low].code;
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} /* if */
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if (endptr!=NULL)
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*endptr=string;
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return (cell)result;
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}
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#endif /* NO_CODEPAGE */
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