From 336a336e45c90851dcc8430f7f8eeabc9f3399e1 Mon Sep 17 00:00:00 2001
From: cbdev <cb@cbcdn.com>
Date: Sat, 17 Jun 2023 18:54:44 +0200
Subject: Implement configuration parser

---
 config.c | 193 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 185 insertions(+), 8 deletions(-)

(limited to 'config.c')

diff --git a/config.c b/config.c
index f11bbb6..306e578 100644
--- a/config.c
+++ b/config.c
@@ -1,29 +1,206 @@
 #include <stdio.h>
 #include <string.h>
+#include <ctype.h>
 
 #include "nfcommander.h"
 #include "config.h"
 
+typedef struct /*_config_section*/ {
+	char* name;
+	size_t entries;
+	char** keys;
+	char** values;
+} config_section_t;
+
+size_t nsections = 0, current_section = 0;
+config_section_t* sections = NULL;
+
+static int config_section(char* section){
+	size_t n = 0;
+
+	//check if section already exists
+	for(n = 0; n < nsections; n++){
+		if(!strcmp(sections[n].name, section)){
+			current_section = n;
+			return 0;
+		}
+	}
+
+	//create new section
+	sections = realloc(sections, (nsections + 1) * sizeof(config_section_t));
+	if(!sections){
+		nsections = 0;
+		printf("Failed to allocate memory\n");
+		return -1;
+	}
+
+	memset(sections + nsections, 0, sizeof(config_section_t));
+	sections[nsections].name = strdup(section);
+	if(!sections[nsections].name){
+		printf("Failed to allocate memory\n");
+		return -1;
+	}
+
+	current_section = nsections;
+	nsections++;
+	return 0;
+}
+
+static int config_set(char* key, char* value){
+	size_t n = 0;
+	if(!sections || !nsections){
+		printf("Assignment outside of section\n");
+		return 1;
+	}
+
+	//check if property already present
+	for(n = 0; n < sections[current_section].entries; n++){
+		if(!strcmp(sections[current_section].keys[n], key)){
+			printf("Overriding previous value of %s.%s with %s\n",
+					sections[current_section].name,
+					key, value);
+			free(sections[current_section].values[n]);
+			sections[current_section].values[n] = strdup(value);
+			return 0;
+		}
+	}
+
+	//add property
+	sections[current_section].keys = realloc(sections[current_section].keys, (sections[current_section].entries + 1) * sizeof(char*));
+	sections[current_section].values = realloc(sections[current_section].values, (sections[current_section].entries + 1) * sizeof(char*));
+
+	if(!sections[current_section].keys || !sections[current_section].values){
+		printf("Filed to allocate memory\n");
+		sections[current_section].entries = 0;
+		return 1;
+	}
+
+	sections[current_section].keys[sections[current_section].entries] = strdup(key);
+	sections[current_section].values[sections[current_section].entries] = strdup(value);
+	sections[current_section].entries++;
+	return 0;
+}
+
+static int config_handle_line(char* line){
+	char* next_token = NULL;
+	size_t len = 0;
+
+	//ignore comments
+	if(line[0] == ';'){
+		return 0;
+	}
+
+	//select or create section
+	if(line[0] == '['){
+		next_token = strchr(line, ']');
+		if(!next_token){
+			printf("Unterminated start of section\n");
+			return 1;
+		}
+
+		*next_token = 0;
+		return config_section(line + 1);
+	}
+
+	next_token = strchr(line, '=');
+	if(!next_token){
+		printf("Not an assignment: %s\n", line);
+		return 1;
+	}
+
+	*next_token = 0;
+	next_token++;
+
+	//rtrim line
+	len = strlen(line);
+	for(; len && !isgraph(line[len]); len--){
+		line[len] = 0;
+	}
+
+	//ltrim value
+	for(; *next_token && !isgraph(*next_token); next_token++){
+	}
+
+	if(len && strlen(next_token)){
+		return config_set(line, next_token);
+	}
+	printf("Invalid assignment\n");
+	return 1;
+}
+
 int config_read(char* path){
-	//TODO
+	ssize_t line_len = 0;
+	size_t line_alloc = 0, line_number = 1;
+	char* line = NULL;
+	FILE* input = fopen(path, "r");
+	if(!input){
+		printf("Failed to open %s as configuration file\n", path);
+		return 1;
+	}
+
 	printf("Reading config file %s\n", path);
+	for(line_len = getline(&line, &line_alloc, input); line_len >= 0; line_len = getline(&line, &line_alloc, input)){
+		//right-trim
+		for(; line_len && !isgraph(line[line_len]); line_len--){
+			line[line_len] = 0;
+		}
+
+		if(!line_len){
+			continue;
+		}
 
+		if(config_handle_line(line)){
+			printf("Failed parsing %s at line %lu\n", path, line_number);
+			return 1;
+		}
+		line_number++;
+	}
+
+	free(line);
+	fclose(input);
 	return 0;
 }
 
 char* config_get(char* section, char* property){
-	//TODO
-	printf("Querying for config property %s->%s\n", section, property);
+	size_t n = 0, p = 0;
+
+	//find section
+	for(n = 0; n < nsections; n++){
+		if(!strcmp(section, sections[n].name)){
+			break;
+		}
+	}
+
+	if(n == nsections){
+		printf("Requested config section %s not found\n", section);
+		return NULL;
+	}
 
-	//TEMP
-	if(!strcmp(property, "reader")){
-		return "yhy";
+	//find key
+	for(p = 0; p < sections[n].entries; p++){
+		if(!strcmp(sections[n].keys[p], property)){
+			return sections[n].values[p];
+		}
 	}
 
+	printf("Requested property %s.%s not configured\n", section, property);
 	return NULL;
 }
 
 void config_free(){
-	//TODO
-	printf("Cleaning up config data\n");
+	size_t n = 0, p = 0;
+
+	for(n = 0; n < nsections; n++){
+		free(sections[n].name);
+		for(p = 0; p < sections[n].entries; p++){
+			free(sections[n].keys[p]);
+			free(sections[n].values[p]);
+		}
+		free(sections[n].keys);
+		free(sections[n].values);
+	}
+
+	free(sections);
+	sections = NULL;
+	nsections = 0;
 }
-- 
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