libgedcom.so), to be linked in the
-application programgedcom.h), to be used in the sources
of the application programgedcom-tags.h) that is also installed,
- but that is automatically included via gedcom.hgedcom.hlibgedcom.so is also needed in this case, because the object model uses the callback parser internally):libgedcom_gom.so), to be linked in the application program, which implements the C object modelgom.h), to be used in the sources of the application program$PREFIX/share/gedcom-parse
that contains some additional stuff, but which is not immediately
important at first. I'll leave the description of the data directory
for later.gedcom.h header is assumed, as everywhere
in this manual):int result;
@@ -75,32 +78,43 @@ in this manual):
is parse the entire file and return the result. The function returns
0 on success and 1 on failure. No other information is available
using this function only.
-
- The call to gedcom_init() should be one of the first calls
+
+Alternatively, programs using the C object model should use the following (in this case, the inclusion of both gedcom.h and gom.h is required):
+
+int result;
+ ...
+ gedcom_init();
+ ...
+ result = gom_parse_file("myfamily.ged");
+
+The call to gom_parse_file will build the C object model, which is then a complete representation of the GEDCOM file.
+
+No matter which of the interfaces you use, the call to gedcom_init() should be one of the first calls
in your program. The requirement is that it should come before the first
call to iconv_open (part of the generic character set conversion
feature) in the program, either by your program itself, or indirectly by
the library calls it makes. Practically, it should e.g. come before
any calls to any GTK functions, because GTK uses iconv_open
- in its initialization. For the same reason it is also advised to put
-the -lgedcom option on the linking of the program as the last
-option, so that its initialization code is run first.
-
- The next sections will refine this piece of code to be able to have
+ in its initialization.
+
+For the same reason it is also advised to put
+the -lgedcom option
+on the linking of the program as the last option, so that its initialization
+code is run first. In the case of using the C object model, the linking
+options should be: -lgedcom_gom -lgedcom
+
The function gedcom_init() also initializes locale handling by calling setlocale(LC_ALL, ""), in case the application would not do this (it doesn't hurt for the application to do the same).
+
+The next sections will refine this piece of code to be able to have
meaningful errors and the actual data that is in the file.
-Error handling
- Since this is a relatively simple topic, it is discussed before the
- actual callback mechanism, although it also uses a callback...
-
- The library can be used in several different circumstances, both
+Error handling
The library can be used in several different circumstances, both
terminal-based as GUI-based. Therefore, it leaves the actual display
of the error message up to the application. For this, the application
needs to register a callback before parsing the GEDCOM file, which will
be called by the library on errors, warnings and messages.
- A typical piece of code would be:
+ A typical piece of code would be (gom_parse_file would be called in case the C object model is used):
void my_message_handler (Gedcom_msg_type type,
char *msg)
@@ -133,8 +147,7 @@ way it wants. Warnings are similar, but use "Warning" instead of "Error"
Data callback mechanism
The most important use of the parser is of course to get the data
-out of the GEDCOM file. As already mentioned, the parser uses a callback
- mechanism for that. In fact, the mechanism involves two levels.
+out of the GEDCOM file. This section focuses on the callback mechanism (see here for the C object model). In fact, the mechanism involves two levels.
The primary level is that each of the sections in a GEDCOM file is
notified to the application code via a "start element" callback and an
@@ -169,7 +182,8 @@ the information that comes via the default callback in plain textual format.
-Gedcom_ctxt my_header_start_cb (int level,
+Gedcom_ctxt my_header_start_cb (Gedcom_rec rec,
+ int level,
Gedcom_val xref,
@@ -185,7 +199,7 @@ of a GEDCOM file. First, have a look at the following piece of code:
}
- void my_header_end_cb (Gedcom_ctxt self)
+ void my_header_end_cb (Gedcom_rec rec, Gedcom_ctxt self)
{
printf("The header ends, context is %d\n", (int)self);
/* context will print as "1" */
@@ -203,7 +217,7 @@ callback. The end callback is optional: you can pass NULL
if you are not interested in the end callback. The identifiers
to use as first argument to the function (here REC_HEAD)
are described in the interface
-details .
+details . These are also passed as first argument in the callbacks (the Gedcom_rec argument).
From the name of the function it becomes clear that this function
is specific to complete records. For the separate elements in records
@@ -242,7 +256,9 @@ and included via gedcom.h (so no need to include gedcom-t
We will now retrieve the SOUR field (the name of the program that
wrote the file) from the header:
-Gedcom_ctxt my_header_source_start_cb(Gedcom_ctxt
+Gedcom_ctxt my_header_source_start_cb(Gedcom_elt elt,
+
+ Gedcom_ctxt
parent,
int
@@ -265,7 +281,8 @@ wrote the file) from the header:
return parent;
}
- void my_header_source_end_cb(Gedcom_ctxt parent,
+ void my_header_source_end_cb(Gedcom_elt elt,
+ Gedcom_ctxt parent,
Gedcom_ctxt self,
@@ -291,8 +308,7 @@ wrote the file) from the header:
can be its own context object of course. The end callback is called
with both the context of the parent and the context of itself, which in this
example will be the same. Again, the list of identifiers to use as
-a first argument for the subscription function are detailed in the interface details .
+a first argument for the subscription function are detailed in the interface details . Again, these are passed as first argument in the callback (the Gedcom_elt argument).
If we look at the other arguments of the start callback, we see the
level number (the initial number of the line in the GEDCOM file), the tag
@@ -305,8 +321,7 @@ in the section for record callbacks above.
The Gedcom_val type is meant to be an opaque type. The
only thing that needs to be known about it is that it can contain specific
data types, which have to be retrieved from it using pre-defined macros.
- These data types are described in the interface details.
+ These data types are described in the interface details.
Some extra notes:
@@ -334,7 +349,7 @@ in the section for record callbacks above.
applications. To preserve this extra data anyway, a default callback
can be registered by the application, as in the following example:
-void my_default_cb (Gedcom_ctxt parent, int level,
+void my_default_cb (Gedcom_elt elt, Gedcom_ctxt parent, int level,
char* tag, char* raw_value, int parsed_tag)
{
...
@@ -365,7 +380,7 @@ data is saved again in a GEDCOM file. To make it more specific, consider
char* extra_text;
};
- Gedcom_ctxt my_header_start_cb(int level, Gedcom_val xref, char* tag,
+ Gedcom_ctxt my_header_start_cb(Gedcom_rec rec, int level, Gedcom_val xref, char* tag,
char *raw_value,
int parsed_tag, Gedcom_val parsed_value)
@@ -374,7 +389,7 @@ data is saved again in a GEDCOM file. To make it more specific, consider
return (Gedcom_ctxt)head;
}
- void my_default_cb(Gedcom_ctxt parent, int level, char* tag, char*
+ void my_default_cb(Gedcom_elt elt, Gedcom_ctxt parent, int level, char* tag, char*
raw_value, int parsed_tag)
{
struct header head = (struct header)parent;
@@ -401,7 +416,8 @@ raw_value, int parsed_tag)
Other API functions
- Although the above describes the basic interface of libgedcom, there
+
+ Although the above describes the basic interface of the gedcom parser, there
are some other functions that allow to customize the behaviour of the library.
These will be explained in the current section.
@@ -500,17 +516,29 @@ controls the gettext mechanism in the application.
The source distribution of
-gedcom-parse contains an example implementation (utf8-locale.c
- and utf8-locale.h in the "t" subdirectory of the top directory).
- Feel free to use it in your source code (it is not part of the library,
-and it isn't installed anywhere, so you need to take over the source and
-header file in your application).
+gedcom-parse contains an a library implementing help functions for UTF-8 encoding (
- Its interface is:
+ Its interface contains first of all the following two help functions:
- char *convert_utf8_to_locale (char *input, int *conv_failures);
char *convert_locale_to_utf8 (char *input);
+ int is_utf8_string (char *input);
int utf8_strlen (char *input);
The
+first one returns 1 if the given input is a valid UTF-8 string, it returns
+0 otherwise, the second gives the number of UTF-8 characters in the given
+input. Note that the second function assumes that the input is valid
+UTF-8, and gives unpredictable results if it isn't.
+
+For conversion, the following functions are available:
+
+ char *convert_utf8_to_locale (char *input, int *conv_failures);
char *convert_locale_to_utf8 (char *input);
+
+
+
Both functions return a pointer to a static buffer that is overwritten
on each call. To function properly, the application must first set
the locale using the setlocale function (the second step detailed
@@ -538,8 +566,7 @@ because any locale can be converted to UTF-8.
implementation, the following steps need to be taken by the application
(more detailed info can be found in the info file of the GNU libc library
in the "Generic Charset Conversion" section under "Character Set Handling"
-or online
+or online
here):
@@ -626,8 +653,7 @@ and show an error. This is not very user friendly, of course.
- Skip over the character that
can't be converted and append a "?" to the output buffer, then call
iconv again. Skipping over a UTF-8 character is fairly simple,
- as follows from the encoding rules
+ as follows from the encoding rules
:
@@ -660,45 +686,38 @@ handle needs to be closed (when the program exits):
iconv_close(iconv_handle);
-
- The example implementation
- mentioned above grows the output buffer dynamically and outputs "?" for characters
+
+ The example implementation
+mentioned above grows the output buffer dynamically and outputs "?" for characters
that can't be converted.
-Support for configure.in
- Programs using the GEDCOM parser library and using autoconf to configure
- their sources can use the following statements in configure.in (the example
- is checking for gedcom-parse, version 1.34):
-
-AC_CHECK_LIB(gedcom, gedcom_parse_file,,
- AC_MSG_ERROR(Cannot
- find libgedcom: Please install gedcom-parse))
- AC_MSG_CHECKING(for libgedcom version)
- AC_TRY_RUN([
- #include <stdio.h>
- #include <stdlib.h>
- #include <gedcom.h>
- int
- main()
- {
- if (GEDCOM_PARSE_VERSION >= 1034) exit(0);
- exit(1);
- }],
- ac_gedcom_version_ok='yes',
- ac_gedcom_version_ok='no',
- ac_gedcom_version_ok='no')
- if test "$ac_gedcom_version_ok" = 'yes' ; then
- AC_MSG_RESULT(ok)
- else
- AC_MSG_RESULT(not ok)
- AC_MSG_ERROR(You need at least version 1.34 of gedcom-parse)
- fi
-
- There are three preprocessor symbols defined for version checks in the
- header:
+Support for configure.in
There
+is a macro available for use in configure.in for applications that are using
+autoconf to configure their sources. The following macro checks whether
+the Gedcom parser library is available and whether its version is high enough:
+AM_LIB_GEDCOM_PARSER([major,[minor,[patch]]])
+
+All the arguments are optional and default to 0. E.g. to check for
+version 1.34, you would put in configure.in the following statement:
+AM_LIB_GEDCOM_PARSER(1,34)
+
+To be able to use this macro in the sources of your application, you have three options:
+
+ - Put the file
m4/gedcom.m4 in your autoconf data directory (i.e. the path given by 'aclocal --print-ac-dir', usually /usr/share/aclocal). You can do this automatically by going into the m4 subdirectory and typing 'make install-m4'.
+
+
+ - If you're using autoconf, but not automake, copy the contents of
m4/gedcom.m4 in the aclocal.m4 file in your sources.
+
+
+ - If you're using automake, copy the contents of
m4/gedcom.m4 in the acinclude.m4 file in your sources.
+
+
+
+There are three preprocessor symbols defined for version checks in the
+ header (but their direct use is deprecated: please use the macro above):
GEDCOM_PARSE_VERSION_MAJOR
The last one is equal to (GEDCOM_PARSE_VERSION_MAJOR * 1000) + GEDCOM_PARSE_VERSION_MINOR.
+
@@ -717,5 +737,10 @@ handle needs to be closed (when the program exits):
-
-
+
+
+
+
+
+
+
\ No newline at end of file