/* gb_ini.h - v0.93 - public domain ini file loader library - no warranty implied; use at your own risk
	A Simple Ini File Loader Library for C and C++

		Version History:
			0.93  - C90 support
			0.92  - ??
			0.91  - New styling
			0.91a - Error handling fix
			0.91  - Add extern "C" if compiling as C++
			0.90  - Initial Version

		LICENSE
		This software is in the public domain. Where that dedication is not
		recognized, you are granted a perpetual, irrevocable license to copy,
		distribute, and modify this file as you see fit.

		How to use:
		Do this:
		    #define GB_INI_IMPLEMENTATION
		before you include this file in *one* C++ file to create the implementation

		i.e. it should look like this:
		#include ...
		#include ...
		#include ...
		#define GB_INI_IMPLEMENTATION
		#include "gb_ini.h"

		If you prefer to use C++, you can use all the same functions in a
		namespace instead, do this:
			#define GB_INI_CPP
		before you include the header file

			i.e it should look like this:
			#define GB_INI_CPP
			#include "gb_ini.h"
*/

/* Examples: */
/* test.ini contents*/
#if 0
; This is a Comment
# This is also

name=gb_ini.h
version = 01337 # Look mum, a comment!

[license]
name = Public Domain

[author]
name = Ginger Bill
#endif
/* C example */
#if 0
#define GB_INI_IMPLEMENTATION
#include "gb_ini.h"

#include <stdio.h>
#include <stdlib.h>
struct Library {
	char const *name;
	int         version;
	char const *license;
	char const *author;
};

// The below macro expands to this:
// static test_ini_handlerchar const *data, char const *section, char const *name, char const *value)
static GB_INI_HANDLER(test_ini_handler)
{
	struct Library *lib = (struct Library *)data;

	#define TEST(s, n) (strcmp(section, s) == 0 && strcmp(name, n) == 0)

	if (TEST("", "name"))
		lib->name    = strdup(value);
	else if (TEST("", "version"))
		lib->version = atoi(value);
	else if (TEST("license", "name"))
		lib->license = strdup(value);
	else if (TEST("author", "name"))
		lib->author  = strdup(value);
	else
		return 0;

	#undef TEST

	return 1;
}

int main(int argc, char **argv)
{
	struct Library lib = {0};
	gbIniError err = gb_ini_parse("test.ini", &test_ini_handler, &lib);
	if (err.type != GB_INI_ERROR_NONE) {
		if (err.line_num > 0)
			printf("Line (%d): ", err.line_num);
		printf("%s\n", gb_ini_error_string(err));

		return 1;
	}

	printf("Name    : %s\n", lib.name);    // Name    : gb_init.h
	printf("Version : %d\n", lib.version); // Version : 1337
	printf("License : %s\n", lib.license); // License : Public Domain
	printf("Author  : %s\n", lib.author);  // Author  : Ginger Bill

	return 0;
}
#endif

/* C++ example */
#if 0
#define GB_INI_CPP
#define GB_INI_IMPLEMENTATION
#include "gb_ini.h"

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

struct Library {
	char const *name;
	int         version;
	char const *license;
	char const *author;
};

// The below macro expands to this:
// static test_ini_handler(void *data, char const *section, char const *name, char const *value)
static GB_INI_HANDLER(test_ini_handler)
{
	Library* lib = (Library*)data;

	#define TEST(s, n) (strcmp(section, s) == 0 && strcmp(name, n) == 0)

	if (TEST("", "name"))
		lib->name    = strdup(value);
	else if (TEST("", "version"))
		lib->version = atoi(value);
	else if (TEST("license", "name"))
		lib->license = strdup(value);
	else if (TEST("author", "name"))
		lib->author  = strdup(value);
	else
		return 0;

	#undef TEST

	return 1;
}

int main(int argc, char** argv)
{
	Library lib = {};

	using namespace gb;

	Ini_Error err = ini_parse("test.ini", &test_ini_handler, &lib);
	if (err.type != INI_ERROR_NONE) {
		if (err.line_num > 0)
			printf("Line (%d): ", err.line_num);
		printf("%s\n", ini_error_string(err));

		return 1;
	}

	printf("Name    : %s\n", lib.name);    // Name    : gb_init.h
	printf("Version : %d\n", lib.version); // Version : 90
	printf("License : %s\n", lib.license); // License : Public Domain
	printf("Author  : %s\n", lib.author);  // Author  : Ginger Bill

	return 0;
}
#endif

#ifndef GB_INI_INCLUDE_GB_INI_H
#define GB_INI_INCLUDE_GB_INI_H

#ifndef GB_INI_MAX_LINE_LENGTH
#define GB_INI_MAX_LINE_LENGTH 1024
#endif

#ifndef GB_INI_MAX_SECTION_LENGTH
#define GB_INI_MAX_SECTION_LENGTH 256
#endif

#ifndef GB_INI_MAX_NAME_LENGTH
#define GB_INI_MAX_NAME_LENGTH 256
#endif

#ifndef GB_INI_CHECK_FOR_UTF8_BOM
#define GB_INI_CHECK_FOR_UTF8_BOM 1
#endif


#ifndef _MSC_VER
	#ifdef __cplusplus
	#define gbini_inline inline
	#else
	#define gbini_inline
	#endif
#else
#define gbini_inline __forceinline
#endif

#include <stdio.h>

#ifdef __cplusplus
extern "C" {
#endif

enum {
	GB_INI_ERROR_NONE = 0,

	GB_INI_ERROR_FILE_ERROR,
	GB_INI_ERROR_MISSING_SECTION_BRACKET,
	GB_INI_ERROR_ASSIGNMENT_MISSING,
	GB_INI_ERROR_HANDLER_ERROR,

	GB_INI_ERROR_COUNT
};

typedef struct gbIniError {
	int    type;
	size_t line_num;
} gbIniError;

#ifndef GB_INI_HANDLER_RETURN_TYPE
#define GB_INI_HANDLER_RETURN_TYPE
typedef int gbIniHRT;
#endif

/* This macro can be use to declare this type of function without
 * needing to define all the of the parameters
 */
#define GB_INI_HANDLER(func_name) gbIniHRT func_name(void *data, char const *section, char const *name, char const *value)
typedef GB_INI_HANDLER(gbIniHandler);

extern char const *GB_ERROR_STRINGS[GB_INI_ERROR_COUNT];

gbIniError gb_ini_parse(char const *filename, gbIniHandler* handler_func, void *data);
gbIniError gb_ini_parse_file(FILE *file, gbIniHandler* handler_func, void *data);

gbini_inline char const *gb_ini_error_string(gbIniError const err) { return GB_ERROR_STRINGS[err.type]; }

#ifdef __cplusplus
}
#endif

#ifdef GB_INI_CPP
#if !defined(__cplusplus)
#error You need to compile as C++ for the C++ version of gb_ini.h to work
#endif

namespace gb
{
typedef gbIniError   IniError;
typedef gbIniHandler IniHandler;

/* Just a copy but with the GB_ prefix stripped */
enum {
	INI_ERROR_NONE = 0,

	INI_ERROR_FILE_ERROR,
	INI_ERROR_MISSING_SECTION_BRACKET,
	INI_ERROR_ASSIGNMENT_MISSING,
	INI_ERROR_HANDLER_ERROR

	/* No need for enum count */
};

inline Ini_Error ini_parse(char const *filename, Ini_Handler *handler_func, void *data) { return gb_ini_parse(filename, handler_func, data); }
inline Ini_Error ini_parse(FILE *file, Ini_Handler *handler_func, void *data) { return gb_ini_parse_file(file, handler_func, data); }
inline char const *ini_error_string(const Ini_Error err) { return GB_ERROR_STRINGS[err.type]; }

} /* namespace gb */
#endif /* GB_INI_CPP */
#endif /* GB_INI_INCLUDE_GB_INI_H */

#ifdef GB_INI_IMPLEMENTATION
#include <ctype.h>
#include <string.h>

char const *GB_ERROR_STRINGS[GB_INI_ERROR_COUNT] = {
	"",

	"Error in opening file",
	"Missing closing section bracket ']'",
	"Missing assignment operator '='",
	"Error in handler function",
};

static gbini_inline char*
gb__left_whitespace_skip(char const *str)
{
	while (*str && isspace((unsigned char)(*str)))
		str++;
	return (char*)str;
}

static gbini_inline char*
gb__right_whitespace_strip(char* str)
{
	char* end = str + strlen(str);
	while (end > str && isspace((unsigned char)(*--end)))
		*end = '\0';
	return str;
}

static gbini_inline char*
gb__find_char_or_comment_in_string(char const *str, char c)
{
	int was_whitespace = 0;
	while (*str && *str != c && !(was_whitespace && *str == ';')) {
		was_whitespace = isspace((unsigned char)(*str));
		str++;
	}

	return (char*)str;
}

static gbini_inline char*
gb__string_copy(char* dst, char const *src, size_t size)
{
	strncpy(dst, src, size);
	dst[size - 1] = '\0';
	return dst;
}


gbIniError
gb_ini_parse(char const *filename, gbIniHandler *handler_func, void *data)
{
	gbIniError err = {GB_INI_ERROR_FILE_ERROR, 0};

	FILE *file = fopen(filename, "r");
	if (!file)
		return err;

	err = gb_ini_parse_file(file, handler_func, data);
	fclose(file);
	return err;
}

gbIniError
gb_ini_parse_file(FILE *file, gbIniHandler *handler_func, void *data)
{
	char line[GB_INI_MAX_LINE_LENGTH] = "";
	size_t line_num = 0;

	char section[GB_INI_MAX_SECTION_LENGTH] = "";
	char prev_name[GB_INI_MAX_NAME_LENGTH]  = "";

	char *start;
	char *end;

	struct gbIniError err = {GB_INI_ERROR_NONE, 0};

	while (fgets(line, GB_INI_MAX_LINE_LENGTH, file) != 0) {
		line_num++;

		start = line;

#if GB_INI_CHECK_FOR_UTF8_BOM
		/* Check for UTF-8 Byte Order Mark */
		if (line_num == 1 &&
		    (unsigned char)start[0] == 0xef &&
		    (unsigned char)start[1] == 0xbb &&
		    (unsigned char)start[2] == 0xbf) {
			start += 3;
		}
#endif

		start = gb__left_whitespace_skip(gb__right_whitespace_strip(start));

		if (start[0] == ';' || start[0] == '#')
			continue; /* Allow '#' and ';' comments at start of line */

		if (start[0] == '[') { /* [section] */
			end = gb__find_char_or_comment_in_string(start+1, ']');
			if (*end == ']') {
				char *sect = start + 1;
				*end = '\0';
				sect = gb__left_whitespace_skip(gb__right_whitespace_strip(sect));

				gb__string_copy(section, sect, sizeof(section));
				*prev_name = '\0';
			} else if (!err.type) {
				err.type = GB_INI_ERROR_MISSING_SECTION_BRACKET;
				err.line_num = line_num;
			}
		} else if (start[0] && start[0] != ';') {
			end = gb__find_char_or_comment_in_string(start, '=');
			if (*end == '=') {
				char *name, *value;
				*end = '\0';
				name = gb__right_whitespace_strip(start);
				value = gb__left_whitespace_skip(end + 1);
				end = gb__find_char_or_comment_in_string(value, '\0');
				if (*end == ';')
					*end = '\0';
				gb__right_whitespace_strip(value);

				gb__string_copy(prev_name, name, sizeof(prev_name));
				if (!handler_func(data, section, name, value) && !err.type) {
					err.type = GB_INI_ERROR_HANDLER_ERROR;
					err.line_num = line_num;
				}
			} else if (!err.type) {
				/* No '=' found on name=value line */
				err.type = GB_INI_ERROR_ASSIGNMENT_MISSING;
				err.line_num = line_num;
				continue;
			}
		}

		if (err.type)
			break;
	}

	return err;
}

#endif /* GB_INI_IMPLEMENTATION */