ini.h

Library: ini.h

Examples

Loading an ini file and retrieving values

#define INI_IMPLEMENTATION
#include "ini.h"

#include <stdio.h>
#include <stdlib.h>

int main()
	{
	FILE* fp = fopen( "test.ini", "r" );
	fseek( fp, 0, SEEK_END );
	int size = ftell( fp );
	fseek( fp, 0, SEEK_SET );
	char* data = (char*) malloc( size + 1 );
	fread( data, 1, size, fp );
	data[ size ] = '\0';
	fclose( fp );

	ini_t* ini = ini_load( data );
	free( data );
	int second_index = ini_find_property( ini, INI_GLOBAL_SECTION, "SecondSetting" );
	char const* second = ini_property_value( ini, INI_GLOBAL_SECTION, second_index );
	printf( "%s=%s\n", "SecondSetting", second );
	int section = ini_find_section( ini, "MySection" );
	int third_index = ini_find_property( ini, section, "ThirdSetting" );
	char const* third = ini_property_value( ini, section, third_index );
	printf( "%s=%s\n", "ThirdSetting", third );
	ini_destroy( ini );

	return 0;
	}

Creating a new ini file

#define INI_IMPLEMENTATION
#include "ini.h"

#include <stdio.h>
#include <stdlib.h>

int main()
	{       
	ini_t* ini = ini_create();
	ini_property_add( ini, INI_GLOBAL_SECTION, "FirstSetting", "Test" );
	ini_property_add( ini, INI_GLOBAL_SECTION, "SecondSetting", "2" );
	int section = ini_section_add( ini, "MySection" );
	ini_property_add( ini, section, "ThirdSetting", "Three" );

	int size = ini_save( ini, NULL, 0 ); // Find the size needed
	char* data = (char*) malloc( size );
	size = ini_save( ini, data, size ); // Actually save the file
	ini_destroy( ini );

	FILE* fp = fopen( "test.ini", "w" );
	fwrite( data, 1, size, fp );
	fclose( fp );
	free( data );

	return 0;
	}

API Documentation

ini.h is a small library for reading classic .ini files. It is a single-header library, and does not need any .lib files or other binaries, or any build scripts. To use it, you just include ini.h to get the API declarations. To get the definitions, you must include ini.h from one single C or C++ file, and #define the symbol INI_IMPLEMENTATION before you do.

Customization

There are a few different things in ini.h which are configurable by #defines. The customizations only affect the implementation, so will only need to be defined in the file where you have the #define INI_IMPLEMENTATION.

Note that if all customizations are utilized, ini.h will include no external files whatsoever, which might be useful if you need full control over what code is being built.

Custom memory allocators

To store the internal data structures, ini.h needs to do dynamic allocation by calling malloc. Programs might want to keep track of allocations done, or use custom defined pools to allocate memory from. ini.h allows for specifying custom memory allocation functions for malloc and free. This is done with the following code:

#define INI_IMPLEMENTATION
#define INI_MALLOC( ctx, size ) ( my_custom_malloc( ctx, size ) )
#define INI_FREE( ctx, ptr ) ( my_custom_free( ctx, ptr ) )
#include "ini.h"

where my_custom_malloc and my_custom_free are your own memory allocation/deallocation functions. The ctx parameter is an optional parameter of type void*. When ini_create or ini_load is called, you can pass in a memctx parameter, which can be a pointer to anything you like, and which will be passed through as the ctx parameter to every INI_MALLOC/INI_FREE call. For example, if you are doing memory tracking, you can pass a pointer to your tracking data as memctx, and in your custom allocation/deallocation function, you can cast the ctx param back to the right type, and access the tracking data.

If no custom allocator is defined, ini.h will default to malloc and free from the C runtime library.

Custom C runtime function

The library makes use of three additional functions from the C runtime library, and for full flexibility, it allows you to substitute them for your own. Here's an example:

#define INI_IMPLEMENTATION
#define INI_MEMCPY( dst, src, cnt ) ( my_memcpy_func( dst, src, cnt ) )
#define INI_STRLEN( s ) ( my_strlen_func( s ) )
#define INI_STRICMP( s1, s2 ) ( my_stricmp_func( s1, s2 ) )
#include "ini.h"

If no custom function is defined, ini.h will default to the C runtime library equivalent.

ini_create

ini_t* ini_create( void* memctx )

Instantiates a new, empty ini structure, which can be manipulated with other API calls, to fill it with data. To save it out to an ini-file string, use ini_save. When no longer needed, it can be destroyed by calling ini_destroy. memctx is a pointer to user defined data which will be passed through to the custom INI_MALLOC/INI_FREE calls. It can be NULL if no user defined data is needed.

ini_load

ini_t* ini_load( char const* data, void* memctx )

Parse the zero-terminated string data containing an ini-file, and create a new ini_t instance containing the data. The instance can be manipulated with other API calls to enumerate sections/properties and retrieve values. When no longer needed, it can be destroyed by calling ini_destroy. memctx is a pointer to user defined data which will be passed through to the custom INI_MALLOC/INI_FREE calls. It can be NULL if no user defined data is needed.

ini_save

int ini_save( ini_t const* ini, char* data, int size )

Saves an ini structure as a zero-terminated ini-file string, into the specified buffer. Returns the number of bytes written, including the zero terminator. If data is NULL, nothing is written, but ini_save still returns the number of bytes it would have written. If the size of data, as specified in the size parameter, is smaller than that required, only part of the ini-file string will be written. ini_save still returns the number of bytes it would have written had the buffer been large enough.

ini_destroy

void ini_destroy( ini_t* ini )

Destroy an ini_t instance created by calling ini_load or ini_create, releasing the memory allocated by it. No further API calls are valid on an ini_t instance after calling ini_destroy on it.

ini_section_count

int ini_section_count( ini_t const* ini )

Returns the number of sections in an ini file. There's at least one section in an ini file (the global section), but there can be many more, each specified in the file by the section name wrapped in square brackets [ ].

ini_section_name

char const* ini_section_name( ini_t const* ini, int section )

Returns the name of the section with the specified index. section must be non-negative and less than the value returned by ini_section_count, or ini_section_name will return NULL. The defined constant INI_GLOBAL_SECTION can be used to indicate the global section.

ini_property_count

int ini_property_count( ini_t const* ini, int section )

Returns the number of properties belonging to the section with the specified index. section must be non-negative and less than the value returned by ini_section_count, or ini_section_name will return 0. The defined constant INI_GLOBAL_SECTION can be used to indicate the global section. Properties are declared in the ini-file on he format name=value.

ini_property_name

char const* ini_property_name( ini_t const* ini, int section, int property )

Returns the name of the property with the specified index property in the section with the specified index section. section must be non-negative and less than the value returned by ini_section_count, and property must be non-negative and less than the value returned by ini_property_count, or ini_property_name will return NULL. The defined constant INI_GLOBAL_SECTION can be used to indicate the global section.

ini_property_value

char const* ini_property_value( ini_t const* ini, int section, int property )

Returns the value of the property with the specified index property in the section with the specified index section. section must be non-negative and less than the value returned by ini_section_count, and property must be non-negative and less than the value returned by ini_property_count, or ini_property_value will return NULL. The defined constant INI_GLOBAL_SECTION can be used to indicate the global section.

ini_find_section

int ini_find_section( ini_t const* ini, char const* name, int name_length )

Finds the section with the specified name, and returns its index. name_length specifies the number of characters in name, which does not have to be zero-terminated. If name_length is zero, the length is determined automatically, but in this case name has to be zero-terminated. If no section with the specified name could be found, the value INI_NOT_FOUND is returned.

ini_find_property

int ini_find_property( ini_t const* ini, int section, char const* name, int name_length )

Finds the property with the specified name, within the section with the specified index, and returns the index of the property. name_length specifies the number of characters in name, which does not have to be zero-terminated. If name_length is zero, the length is determined automatically, but in this case name has to be zero-terminated. If no property with the specified name could be found within the specified section, the value INI_NOT_FOUND is returned. section must be non-negative and less than the value returned by ini_section_count, or ini_find_property will return INI_NOT_FOUND. The defined constant INI_GLOBAL_SECTION can be used to indicate the global section.

ini_section_add

int ini_section_add( ini_t* ini, char const* name, int length )

Adds a section with the specified name, and returns the index it was added at. There is no check done to see if a section with the specified name already exists - multiple sections of the same name are allowed. length specifies the number of characters in name, which does not have to be zero-terminated. If length is zero, the length is determined automatically, but in this case name has to be zero-terminated.

ini_property_add

void ini_property_add( ini_t* ini, int section, char const* name, int name_length, char const* value, int value_length )

Adds a property with the specified name and value to the specified section, and returns the index it was added at. There is no check done to see if a property with the specified name already exists - multiple properties of the same name are allowed. name_length and value_length specifies the number of characters in name and value, which does not have to be zero-terminated. If name_length or value_length is zero, the length is determined automatically, but in this case name/value has to be zero-terminated. section must be non-negative and less than the value returned by ini_section_count, or the property will not be added. The defined constant INI_GLOBAL_SECTION can be used to indicate the global section.

ini_section_remove

void ini_section_remove( ini_t* ini, int section )

Removes the section with the specified index, and all properties within it. section must be non-negative and less than the value returned by ini_section_count. The defined constant INI_GLOBAL_SECTION can be used to indicate the global section. Note that removing a section will shuffle section indices, so that section indices you may have stored will no longer indicate the same section as it did before the remove. Use the find functions to update your indices.

ini_property_remove

void ini_property_remove( ini_t* ini, int section, int property )

Removes the property with the specified index from the specified section. section must be non-negative and less than the value returned by ini_section_count, and property must be non-negative and less than the value returned by ini_property_count. The defined constant INI_GLOBAL_SECTION can be used to indicate the global section. Note that removing a property will shuffle property indices within the specified section, so that property indices you may have stored will no longer indicate the same property as it did before the remove. Use the find functions to update your indices.

ini_section_name_set

void ini_section_name_set( ini_t* ini, int section, char const* name, int length )

Change the name of the section with the specified index. section must be non-negative and less than the value returned by ini_section_count. The defined constant INI_GLOBAL_SECTION can be used to indicate the global section. length specifies the number of characters in name, which does not have to be zero-terminated. If length is zero, the length is determined automatically, but in this case name has to be zero-terminated.

ini_property_name_set

void ini_property_name_set( ini_t* ini, int section, int property, char const* name, int length )

Change the name of the property with the specified index in the specified section. section must be non-negative and less than the value returned by ini_section_count, and property must be non-negative and less than the value returned by ini_property_count. The defined constant INI_GLOBAL_SECTION can be used to indicate the global section. length specifies the number of characters in name, which does not have to be zero-terminated. If length is zero, the length is determined automatically, but in this case name has to be zero-terminated.

ini_property_value_set

void ini_property_value_set( ini_t* ini, int section, int property, char const* value, int length  )

Change the value of the property with the specified index in the specified section. section must be non-negative and less than the value returned by ini_section_count, and property must be non-negative and less than the value returned by ini_property_count. The defined constant INI_GLOBAL_SECTION can be used to indicate the global section. length specifies the number of characters in value, which does not have to be zero-terminated. If length is zero, the length is determined automatically, but in this case value has to be zero-terminated.

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