Subject:
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LDrawIni API (was: LDRAWPREDIRS LDRAWPOSTDIRS - additional search paths)
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Newsgroups:
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lugnet.cad.dev
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Date:
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Mon, 15 Mar 2004 23:30:28 GMT
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Viewed:
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5196 times
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Here are my ideas of an API for accessing the LDrawIni settings.
The basic idea is that it should be very simple to use, there are only four functions
and a data structure declaration.
First you call LDrawIniGet to read and initialize all relevant ldraw.ini data,
the LDrawDir, the search directories, the LGEO directory.
The data is initialized from environment variables and/or ini files
suitable for the platform you are running and in the agreed order.
L3P, as an example, will now look for the model in each of the search dirs.
When found L3P calls LDrawIniComputeRealDirs with the directory of the model.
This will recalculate the search dirs in the data structure to include those with <MODELDIR>.
L3P will now (probably) have an extra search dir to look in for the remaining loading of parts.
(directories marked with <SKIP> will of course be excluded from the search dirs)
For each search dir there may be a number of flags. The known ones are parsed into bit-flags
to speed up testing (e.g. LDSDF_HIDE|LDSDF_DEFPRIM), the remaining are available
as a string, e.g "<MyFlag><UnknownFlag>".
(or would you like a NULL terminated array of strings?)
When finding a file in one of the search dirs and the file has no official header
L3P can quickly determine whether the default filetype is e.g. Primitive.
When done L3P calls LDrawIniFree to release the data structure.
L3Lab works the same way, only it calls LDrawIniComputeRealDirs
whenever a new model is loaded.
The last function is LDrawIniResetSearchDirs, only to be called from the
LDrawSetup program - or if you wish to override the search to be the
standard one.
In C (not C++ for greatest compatibility) it may look like this, LDrawIni.h:
struct LDrawSearchDirS
{
int Flags; /* Parsed and known flags LDSDF_XXX */
char *UnknownFlags; /* Any unknown flags <XXX> */
char *Dir; /* The full path of a search dir */
};
struct LDrawIniS
{
/* The LDRAWDIR containing the P, PARTS and MODELS directories */
char *LDrawDir;
/* The LDrawSearch directories ready to use */
int nSearchDirs;
struct LDrawSearchDirS *SearchDirs;
/* The LGEODIR (named LGEO) containing the LGEO .inc files */
char *LgeoDir;
/* Private date for the LDrawIni routines */
struct LDrawIniPrivateDataS *PrivateData;
};
/* LDrawSearchDir Flags */
#define LDSDF_HIDE 0x0001 /* Hide directory */
#define LDSDF_DEFPART 0x0002 /* Default filetype: Part */
#define LDSDF_DEFPRIM 0x0004 /* Default filetype: Primitive */
#ifdef __cplusplus
extern "C" {
#endif
/*
Initialize and read all settings.
If the argument LDrawDir is not NULL
it will override the normal initialization of the LDraw directory.
If ErrorCode is not NULL it will return a code telling why
LDrawIniGet returned NULL.
If all is OK then a pointer to struct LDrawIniS is returned.
You should then call LDrawIniComputeRealDirs to obtain the search dirs.
Remember to free the struct by calling LDrawIniFree.
*/
struct LDrawIniS *LDrawIniGet(const char *LDrawDir, int *ErrorCode);
/*
Compute Real Dirs by substituting <LDRAWDIR> and <MODELDIR> in
the Symbolic Dirs read from the env vars or ini files.
If OnlyValidDirs is true then non-existing search dirs is skipped
If AddTrailingSlash is true then the search dirs will have a slash/backslash appended.
If ModelDir is NULL then search dir <MODELDIR> is skipped.
Returns 1 if OK, 0 on error
*/
int LDrawIniComputeRealDirs(struct LDrawIniS * LDrawIni,
int OnlyValidDirs,
int AddTrailingSlash,
const char *ModelDir);
/*
Reset search dirs to default if LDrawSearch is NULL
or to the dirs specified in LDrawSearch delimited by |.
Returns 1 if OK, 0 on error
*/
int LDrawIniResetSearchDirs(struct LDrawIniS * LDrawIni,
const char *LDrawSearch);
/*
Free the LDrawIni data
*/
void LDrawIniFree(struct LDrawIniS * LDrawIni);
#ifdef __cplusplus
}
#endif
/* Error codes returned by LDrawIniGet */
#define LDRAWINI_ERROR_OUT_OF_MEMORY 1
#define LDRAWINI_ERROR_LDRAWDIR_NOT_SET 2
(end of LDrawIni.h)
The LDrawSetup program would like to have access to the private data
and to some internal (static) functions for reading ini files and parsing,
so I am thinking of an additional include file, LDrawIniP.h:
struct LDrawIniPrivateDataS
{
/* The LDrawSearch directories as read */
int nSymbolicSearchDirs;
char **SymbolicSearchDirs;
};
some reading/parsing functions
(end of LDrawIniP.h)
I have currently tested the functions in L3P on Windows and will shortly test on Linux.
I had to rearrange some code in L3P now that you can't be sure
that the <MODELDIR> is the first search dir...
The L3P usage of the LDrawIni API is:
LDrawIni = LDrawIniGet(NULL, &LDrawIniErrorCode);
if (!LDrawIni)
{
if (LDrawIniErrorCode == LDRAWINI_ERROR_LDRAWDIR_NOT_SET)
{
/* Neither environment variable, nor ldraw.ini, simply try current dir */
if (IsDir("P") && IsDir("PARTS") && IsDir("MODELS"))
LDrawIni = LDrawIniGet(".", &LDrawIniErrorCode);
}
}
if (!LDrawIni)
{
Exit("\
Environment variable LDRAWDIR must be set to directory with P,PARTS,MODELS.\n\
e.g. 'set LDRAWDIR=c:\\Lego\\LDraw' (don't use long names)\n\
You may type the set command at the DOS prompt or put it into C:\\AUTOEXEC.BAT", NULL);
}
if (L3Pov.UseLgeoParts && !LDrawIni->LgeoDir)
{
Exit("\
Environment variable LGEODIR must be set to directory with LGEO parts.\n\
e.g. 'set LGEODIR=c:\\Lego\\LGEO' (don't use long names)\n\
You may type the set command at the DOS prompt or put it into C:\\AUTOEXEC.BAT", NULL);
}
i = LDrawIniComputeRealDirs(LDrawIni, 1, 1, NULL);
if (!i)
Exit("Failed to compute search dirs", NULL);
fp = OpenDatFile(ModelFilename, 1);
if (!fp)
Exit("Cannot find model file '%s'", ModelFilename);
fclose(fp);
Preparing load of model:
strcpy(ModelDir, lpszPathName);
for (i = strlen(ModelDir); --i >= 0;)
if (ModelDir[i] == '/' || ModelDir[i] == '\\')
break;
ModelDir[i<0? 0 : i] = '\0'; /* ModelDir may be empty. */
if (!LDrawIniComputeRealDirs(LDrawIni, 1, 1, ModelDir))
return -1;
And when loading DAT files:
static int FileIsFromP;
static int FileIsFromPARTS;
static FILE *OpenDatFile2(char *DatName, char *Extension)
{
FILE *fp;
register int i;
for (i = 0; i < LDrawIni->nSearchDirs; i++)
{
strcpy(DatPath, LDrawIni->SearchDirs[i].Dir); /* Has trailing \ */
strcat(DatPath, DatName);
strcat(DatPath, Extension);
FileIsFromP = (LDrawIni->SearchDirs[i].Flags & LDSDF_DEFPRIM) ? 1 : 0;
FileIsFromPARTS = (LDrawIni->SearchDirs[i].Flags & LDSDF_DEFPART) ? 1 : 0;
fp = fopeni(DatPath, "rb");
if (fp)
return fp;
}
return NULL;
}
FILE *OpenDatFile(char *DatName, int IsModel)
{
static char *Extensions[] = { "", ".ldr", ".dat", ".mpd" };
int i;
FILE *fp;
if (IsModel)
{
/* Be sure to load model; can't be sure <MODELDIR> is in search dirs */
strcpy(DatPath, ModelDir); /* ModelDir may be "" */
if (DatPath[0])
strcat(DatPath, BACKSLASH_STRING);
strcat(DatPath, DatName);
FileIsFromP = 0;
FileIsFromPARTS = 0;
fp = fopeni(DatPath, "rb");
if (fp)
return fp;
}
for (i = 0; i < sizeof(Extensions)/sizeof(char *); i++)
{
fp = OpenDatFile2(DatName, Extensions[i]);
if (fp)
return fp;
}
return NULL;
}
I hope the above gives you an idea of how to use the LDrawIni API in your program.
Let me know if you have other wishes I haven't thought of.
After a little more testing I'll soon publish LDrawIni.c.
I'll make an HTML page describing the functionlity,
the env var and ini file order, the format and the API.
/Lars
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Message has 2 Replies:
Message is in Reply To:
 | | LDRAWPREDIRS LDRAWPOSTDIRS - additional search paths
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| Several users have asked for an option to L3P for specifying additional search paths for parts. LDView already has implemented "Extra Search Dirs" to search after the usual ones. I think it would be of common interest and for the benefit of the (...) (21 years ago, 10-Feb-04, to lugnet.cad.dev)
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