scuffed-code/icu4c/source/common/ucnv_io.c

386 lines
12 KiB
C

/*
********************************************************************************
* *
* COPYRIGHT: *
* (C) Copyright International Business Machines Corporation, 1998, 1999 *
* Licensed Material - Program-Property of IBM - All Rights Reserved. *
* US Government Users Restricted Rights - Use, duplication, or disclosure *
* restricted by GSA ADP Schedule Contract with IBM Corp. *
* *
********************************************************************************
*
*
* ucnv_io.c:
* initializes global variables and defines functions pertaining to file access,
* and name resolution aspect of the library.
*
* new implementation:
*
* created on: 1999nov22
* created by: Markus W. Scherer
*
* Use the binary cnvalias.dat (created from convrtrs.txt) to work
* with aliases for converter names.
********************************************************************************
*/
#include "unicode/utypes.h"
#include "umutex.h"
#include "cstring.h"
#include "cmemory.h"
#include "ucnv_io.h"
#include "unicode/udata.h"
/* Format of cnvalias.dat ------------------------------------------------------
*
* cnvalias.dat is a binary, memory-mappable form of convrtrs.txt .
* It contains two sorted tables and a block of zero-terminated strings.
* Each table is preceded by the number of table entries.
*
* The first table maps from aliases to converter indexes.
* The converter names themselves are listed as aliases in this table.
* Each entry in this table has an offset to the alias and
* an index of the converter in the converter table.
*
* The second table lists only the converters themselves.
* Each entry in this table has an offset to the converter name and
* the number of aliases, including the converter itself.
* A count of 1 means that there is no alias, only the converter name.
*
* In the block of strings after the tables, each converter name is directly
* followed by its aliases. All offsets to strings are offsets from the
* beginning of the data.
*
* More formal file data structure (data format 2.0):
*
* uint16_t aliasCount;
* uint16_t aliasOffsets[aliasCount];
* uint16_t converterIndexes[aliasCount];
*
* uint16_t converterCount;
* struct {
* uint16_t converterOffset;
* uint16_t aliasCount;
* } converters[converterCount];
*
* char strings[]={
* "Converter0\0Alias1\0Alias2\0...Converter1\0Converter2\0Alias0\Alias1\0..."
* };
*/
#define DATA_NAME "cnvalias"
#define DATA_TYPE "dat"
static UDataMemory *aliasData=NULL;
static const uint16_t *aliasTable=NULL;
static bool_t
isAcceptable(void *context,
const char *type, const char *name,
UDataInfo *pInfo) {
return
pInfo->size>=20 &&
pInfo->isBigEndian==U_IS_BIG_ENDIAN &&
pInfo->charsetFamily==U_CHARSET_FAMILY &&
pInfo->dataFormat[0]==0x43 && /* dataFormat="CvAl" */
pInfo->dataFormat[1]==0x76 &&
pInfo->dataFormat[2]==0x41 &&
pInfo->dataFormat[3]==0x6c &&
pInfo->formatVersion[0]==2;
}
static bool_t
haveAliasData(UErrorCode *pErrorCode) {
if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
return FALSE;
}
/* load converter alias data from file if necessary */
if(aliasData==NULL) {
UDataMemory *data;
const uint16_t *table=NULL;
/* open the data outside the mutex block */
data=udata_openChoice(NULL, DATA_TYPE, DATA_NAME, isAcceptable, NULL, pErrorCode);
if(U_FAILURE(*pErrorCode)) {
return FALSE;
}
table=(const uint16_t *)udata_getMemory(data);
/* in the mutex block, set the data for this process */
umtx_lock(NULL);
if(aliasData==NULL) {
aliasData=data;
data=NULL;
aliasTable=table;
table=NULL;
}
umtx_unlock(NULL);
/* if a different thread set it first, then close the extra data */
if(data!=NULL) {
udata_close(data); /* NULL if it was set correctly */
}
}
return TRUE;
}
static bool_t
isAlias(const char *alias, UErrorCode *pErrorCode) {
if(alias==NULL) {
*pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
return FALSE;
} else if(*alias==0) {
return FALSE;
} else {
return TRUE;
}
}
/* compare lowercase str1 with mixed-case str2, ignoring case */
static int
strHalfCaseCmp(const char *str1, const char *str2) {
/* compare non-NULL strings lexically with lowercase */
int rc;
unsigned char c1, c2;
for(;;) {
c1=(unsigned char)*str1;
c2=(unsigned char)*str2;
if(c1==0) {
if(c2==0) {
return 0;
} else {
return -1;
}
} else if(c2==0) {
return 1;
} else {
/* compare non-zero characters with lowercase */
rc=(int)c1-(int)(unsigned char)uprv_tolower(c2);
if(rc!=0) {
return rc;
}
}
++str1;
++str2;
}
}
/*
* search for an alias
* return NULL or a pointer to the converter table entry
*/
static const uint16_t *
findAlias(const char *alias) {
char name[100];
const uint16_t *p=aliasTable;
uint16_t i, start, limit;
limit=*p++;
if(limit==0) {
/* there are no aliases */
return NULL;
}
/* convert the alias name to lowercase to do case-insensitive comparisons */
for(i=0; i<sizeof(name)-1 && *alias!=0; ++i) {
name[i]=uprv_tolower(*alias++);
}
name[i]=0;
/* do a binary search for the alias */
start=0;
while(start<limit-1) {
i=(start+limit)/2;
if(strHalfCaseCmp(name, (const char *)aliasTable+p[i])<0) {
limit=i;
} else {
start=i;
}
}
/* did we really find it? */
if(strHalfCaseCmp(name, (const char *)aliasTable+p[start])==0) {
limit=*(p-1); /* aliasCount */
p+=limit; /* advance to the second column of the alias table */
i=p[start]; /* converter index */
return
p+limit+ /* beginning of converter table */
1+ /* skip its count */
2*i; /* go to this converter's entry and return a pointer to it */
} else {
return NULL;
}
}
U_CFUNC const char *
ucnv_io_getConverterName(const char *alias, UErrorCode *pErrorCode) {
if(haveAliasData(pErrorCode) && isAlias(alias, pErrorCode)) {
const uint16_t *p=findAlias(alias);
if(p!=NULL) {
return (const char *)aliasTable+*p;
}
}
return NULL;
}
U_CFUNC uint16_t
ucnv_io_getAliases(const char *alias, const char **aliases, UErrorCode *pErrorCode) {
if(haveAliasData(pErrorCode) && isAlias(alias, pErrorCode)) {
const uint16_t *p=findAlias(alias);
if(p!=NULL) {
*aliases=(const char *)aliasTable+*p;
return *(p+1);
}
}
return 0;
}
U_CFUNC const char *
ucnv_io_getAlias(const char *alias, uint16_t index, UErrorCode *pErrorCode) {
if(haveAliasData(pErrorCode) && isAlias(alias, pErrorCode)) {
const uint16_t *p=findAlias(alias);
if(p!=NULL) {
uint16_t count=*(p+1);
if(index<count) {
const char *aliases=(const char *)aliasTable+*p;
while(index>0) {
/* skip a name, first the canonical converter name */
aliases+=uprv_strlen(aliases)+1;
--index;
}
return aliases;
}
}
}
return NULL;
}
U_CFUNC uint16_t
ucnv_io_countAvailableConverters(UErrorCode *pErrorCode) {
if(haveAliasData(pErrorCode)) {
return aliasTable[1+2*(*aliasTable)];
}
return 0;
}
U_CFUNC const char *
ucnv_io_getAvailableConverter(uint16_t index, UErrorCode *pErrorCode) {
if(haveAliasData(pErrorCode)) {
const uint16_t *p=aliasTable+1+2*(*aliasTable);
if(index<*p) {
return (const char *)aliasTable+p[1+2*index];
}
}
return NULL;
}
U_CFUNC void
ucnv_io_fillAvailableConverters(const char **aliases, UErrorCode *pErrorCode) {
if(haveAliasData(pErrorCode)) {
const uint16_t *p=aliasTable+1+2*(*aliasTable);
uint16_t count=*p++;
while(count>0) {
*aliases++=(const char *)aliasTable+*p;
p+=2;
--count;
}
}
}
U_CFUNC uint16_t
ucnv_io_countAvailableAliases(UErrorCode *pErrorCode) {
if(haveAliasData(pErrorCode)) {
return *aliasTable;
}
return 0;
}
U_CFUNC const char *
ucnv_io_getAvailableAlias(uint16_t index, UErrorCode *pErrorCode) {
if(haveAliasData(pErrorCode) && index<*aliasTable) {
return (const char *)aliasTable+*(aliasTable+1+index);
}
return NULL;
}
U_CFUNC void
ucnv_io_fillAvailableAliases(const char **aliases, UErrorCode *pErrorCode) {
if(haveAliasData(pErrorCode)) {
const uint16_t *p=aliasTable;
uint16_t count=*p++;
while(count>0) {
*aliases++=(const char *)aliasTable+*p;
++p;
--count;
}
}
}
/* default converter name --------------------------------------------------- */
/*
* In order to be really thread-safe, the get function would have to take
* a buffer parameter and copy the current string inside a mutex block.
* This implementation only tries to be really thread-safe while
* setting the name.
* It assumes that setting a pointer is atomic.
*/
static char defaultConverterNameBuffer[100];
static const char *defaultConverterName = NULL;
U_CFUNC const char *
ucnv_io_getDefaultConverterName() {
/* local variable to be thread-safe */
const char *name=defaultConverterName;
if(name==NULL) {
const char *codepage=uprv_getDefaultCodepage();
if(codepage!=NULL) {
UErrorCode errorCode=U_ZERO_ERROR;
name=ucnv_io_getConverterName(codepage, &errorCode);
if(U_FAILURE(errorCode) || name==NULL) {
name=codepage;
}
defaultConverterName=name;
}
}
return name;
}
U_CFUNC void
ucnv_io_setDefaultConverterName(const char *converterName) {
if(converterName==NULL) {
/* reset to the default codepage */
defaultConverterName=NULL;
} else {
UErrorCode errorCode=U_ZERO_ERROR;
const char *name=ucnv_io_getConverterName(converterName, &errorCode);
if(U_SUCCESS(errorCode) && name!=NULL) {
defaultConverterName=name;
} else {
/* do not set the name if the alias lookup failed and it is too long */
int32_t length=uprv_strlen(converterName);
if(length<sizeof(defaultConverterNameBuffer)) {
/* it was not found as an alias, so copy it - accept an empty name */
bool_t didLock;
if(defaultConverterName==defaultConverterNameBuffer) {
umtx_lock(NULL);
didLock=TRUE;
} else {
didLock=FALSE;
}
uprv_memcpy(defaultConverterNameBuffer, converterName, length);
defaultConverterNameBuffer[length]=0;
defaultConverterName=defaultConverterNameBuffer;
if(didLock) {
umtx_unlock(NULL);
}
}
}
}
}