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ICU-165 improve cnvalias.dat file format for binary search (CPU cache efficiency)

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X-SVN-Rev: 333
This commit is contained in:
Markus Scherer 1999-12-07 18:29:32 +00:00
parent 8cb97c75f3
commit 590d75d8ee
2 changed files with 17 additions and 18 deletions
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31
icu4c/source/common/ucnv_io.c
View file

@ -51,13 +51,11 @@
* followed by its aliases. All offsets to strings are offsets from the
* beginning of the data.
*
* More formal file data structure (data format 1.0):
* More formal file data structure (data format 2.0):
*
* uint16_t aliasCount;
* struct {
* uint16_t aliasOffset;
* uint16_t converterIndex;
* } aliases[aliasCount];
* uint16_t aliasOffsets[aliasCount];
* uint16_t converterIndexes[aliasCount];
*
* uint16_t converterCount;
* struct {
@ -88,7 +86,7 @@ isAcceptable(void *context,
pInfo->dataFormat[1]==0x76 &&
pInfo->dataFormat[2]==0x41 &&
pInfo->dataFormat[3]==0x6c &&
pInfo->formatVersion[0]==1;
pInfo->formatVersion[0]==2;
}
static bool_t
@ -197,7 +195,7 @@ findAlias(const char *alias) {
start=0;
while(start<limit-1) {
i=(start+limit)/2;
if(strHalfCaseCmp(name, (const char *)aliasTable+p[2*i])<0) {
if(strHalfCaseCmp(name, (const char *)aliasTable+p[i])<0) {
limit=i;
} else {
start=i;
@ -205,15 +203,14 @@ findAlias(const char *alias) {
}
/* did we really find it? */
if(icu_strcmp(name, (const char *)aliasTable+p[2*start])==0) {
/*
* turn p back to aliasTable and
* skip the entire alias table, both table counts,
* and point into the converter table
*/
i=p[2*start+1]; /* converter index */
--p;
return p+2*(*p+1+i);
if(icu_strcmp(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;
}
@ -301,7 +298,7 @@ ucnv_io_fillAvailableAliases(const char **aliases, UErrorCode *pErrorCode) {
* It assumes that setting a pointer is atomic.
*/
static const char *defaultConverterNameBuffer[100];
static char defaultConverterNameBuffer[100];
static const char *defaultConverterName = NULL;
U_CFUNC const char *

4
icu4c/source/tools/gencnval/gencnval.c
View file

@ -55,7 +55,7 @@ static const UDataInfo dataInfo={
0,
0x43, 0x76, 0x41, 0x6c, /* dataFormat="CvAl" */
1, 0, 0, 0, /* formatVersion */
2, 0, 0, 0, /* formatVersion */
1, 3, 1, 0 /* dataVersion */
};
@ -180,6 +180,8 @@ main(int argc, char *argv[]) {
udata_write16(out, aliasCount);
for(i=0; i<aliasCount; ++i) {
udata_write16(out, (uint16_t)(stringOffset+(aliases[i].alias-stringStore)));
}
for(i=0; i<aliasCount; ++i) {
udata_write16(out, aliases[i].converter);
}