diff options
Diffstat (limited to 'src/projects.h')
| -rw-r--r-- | src/projects.h | 78 |
1 files changed, 73 insertions, 5 deletions
diff --git a/src/projects.h b/src/projects.h index c1bf1b3a..1c99506f 100644 --- a/src/projects.h +++ b/src/projects.h @@ -175,6 +175,7 @@ typedef struct { double u, v, w; } UVW; /* Forward declarations and typedefs for stuff needed inside the PJ object */ struct PJconsts; struct PJ_OBS; +union PJ_COORD; struct geod_geodesic; struct pj_opaque; struct ARG_list; @@ -190,6 +191,7 @@ enum pj_io_units { #ifndef PROJ_H typedef struct PJconsts PJ; /* the PJ object herself */ typedef struct PJ_OBS PJ_OBS; +typedef union PJ_COORD PJ_COORD; #endif struct PJ_REGION_S { @@ -208,11 +210,12 @@ struct PJconsts { /************************************************************************************* - G E N E R A L C O N T E X T + G E N E R A L P A R A M E T E R S T R U C T ************************************************************************************** TODO: Need some description here - especially about the thread context... + This is the struct behind the PJ typedef **************************************************************************************/ @@ -245,11 +248,67 @@ struct PJconsts { LPZ (*inv3d)(XYZ, PJ *); PJ_OBS (*fwdobs)(PJ_OBS, PJ *); PJ_OBS (*invobs)(PJ_OBS, PJ *); + PJ_COORD (*fwdcoord)(PJ_COORD, PJ *); + PJ_COORD (*invcoord)(PJ_COORD, PJ *); void (*spc)(LP, PJ *, struct FACTORS *); void (*pfree)(PJ *); + /************************************************************************************* + + E R R O R R E P O R T I N G + + ************************************************************************************** + + Currently, we're doing error reporting through the context->last_errno indicator. + + It is, however, not entirely sure this will be the right way to do it in all + cases: During allocation/initialization, it is certainly nice to have a higher + level error indicator, since we primarily signal "something went wrong", by + returning 0 from the pj_init family of functions - and with a null return we + cannot pass messages through internal state in the PJ object. + + Historically, the errno variable has been used for that kind of messages, but + apparently, thread safety was added to PROJ.4 at a time where it was not clear + that errno is actually thread local. + + Additionally, errno semantics has historically been misinterpreted in parts of + pj_init.c, a misinterpretation, that was mitigated by a hack in pj_malloc.c + some 15 years ago. + + This PJ-local errno is a first step towards a more structured approach to + error reporting, being implemented in the OBS_API (cf. pj_obs_api.[ch]), and + related plumbing efforts. + + In due course this will let us get rid of the pj_malloc.c hack, and allow us + to introduce a more layered error reporting structure, where errors are + reported where they occur, and bubble up to the higher levels (context->errno, + then thread local errno), so the highest level indicate "something went wrong + somewhere", then the more localized ones can be used for pinpointing: + + errno: "something went wrong somewhere on this thread", + context->last_errno: "something went wrong in some PROJ.4 related code", + PJ->last_errno: "It was in THIS PJ something went wrong", + pj_strerrno: "This was what went wrong". + + Which will be quite helpful, once fully implemented, especially for + debugging complex transformation pipelines, while still maintaining backward + compatibility in the messaging system. + + Note that there is even a global pj_errno, which is here and there accessed + without acquiring lock. This, and the practise of resetting the thread local + errno, should be given some consideration during the cleanup of the error + reporting system. + + The name "last_errno", rather than "errno" is used partially for alignment + with the context->last_errno, partially because in a multithreaded environment, + errno is a macro, and spurious spaces turning "errno" into a separate token + will expose it to macro expansion, to the tune of much confusion and agony. + + **************************************************************************************/ + int last_errno; + /************************************************************************************* @@ -345,6 +404,11 @@ struct PJconsts { D A T U M S A N D H E I G H T S Y S T E M S + ************************************************************************************** + + It may be possible, and meaningful, to move the list parts of this up to the + PJ_CONTEXT level. + **************************************************************************************/ int datum_type; /* PJD_UNKNOWN/3PARAM/7PARAM/GRIDSHIFT/WGS84 */ @@ -374,9 +438,15 @@ struct PJconsts { struct _pj_gi *last_after_grid; /* TODO: Description needed */ PJ_Region last_after_region; /* TODO: Description needed */ double last_after_date; /* TODO: Description needed */ -}; + /************************************************************************************* + + E N D O F G E N E R A L P A R A M E T E R S T R U C T + + **************************************************************************************/ + +}; @@ -389,7 +459,6 @@ struct ARG_list { }; - typedef union { double f; int i; char *s; } PROJVALUE; @@ -404,6 +473,7 @@ struct PJ_ELLPS { char *ell; /* elliptical parameter */ char *name; /* comments */ }; + struct PJ_UNITS { char *id; /* units keyword */ char *to_meter; /* multiply by value to get meters */ @@ -490,8 +560,6 @@ extern struct PJ_LIST pj_list[]; extern struct PJ_SELFTEST_LIST pj_selftest_list[]; #endif - - #ifndef PJ_ELLPS__ extern struct PJ_ELLPS pj_ellps[]; #endif |