add: basic configuration parsing implemented

parameters implemented:
    - input_keys
    - label_keys
    - epochs
    - labels
    - weights_path

Network weights and architecture loading is not implemented yet.

3 files changed, 85 insertions, 3 deletions

diff --git a/src/main.c b/src/main.c
index 0071426..7800495 100644
--- a/src/main.c
+++ b/src/main.c
@@ -92,9 +92,10 @@ int main(int argc, char *argv[]) {
     struct Configs ml_configs = {
         .epochs = 100,
         .alpha = 1e-5,
-        .config_filepath = "utils/config.yml",
+        .config_filepath = "utils/ml.cfg",
     };
-    util_load_config(&ml_configs);
+
+    util_load_config(&ml_configs, ml_configs.config_filepath);
     util_load_cli(&ml_configs, argc, argv);
     return 0;
 }
diff --git a/src/util.c b/src/util.c
index 9c1dba3..22c1912 100644
--- a/src/util.c
+++ b/src/util.c
@@ -5,6 +5,9 @@
 #include <getopt.h>
 
 #include "util.h"
+#define BUFFER_SIZE 1024
+
+static char ** config_read_values(size_t *n_out_keys, char *first_value, char **strtok_ptr);
 
 void die(const char *fmt, ...)
 {
@@ -33,6 +36,13 @@ void * ecalloc(size_t nmemb, size_t size)
 	return p;
 }
 
+char *e_strdup(const char *s)
+{
+    char *out = strdup(s);
+    if (out == NULL) die("strdup() Error:");
+    return out;
+}
+
 
 void version()
 {
@@ -121,3 +131,73 @@ void util_free_config(struct Configs *ml)
         free(ml->label_keys);
     }
 }
+
+void util_load_config(struct Configs *ml, char *filepath)
+{
+    int line_number = 1;
+    char line_buffer[BUFFER_SIZE], line_buffer_original[BUFFER_SIZE];
+    char token_buffer[BUFFER_SIZE];
+    FILE *fp = fopen(filepath, "r");
+    if (fp == NULL) die("util_load_config() Error:");
+
+    while (fgets(line_buffer, BUFFER_SIZE, fp)) {
+        int ret = sscanf(line_buffer, "[%[-_a-zA-Z0-9]]", token_buffer);
+        if (ret >= 1) continue;
+
+        strcpy(line_buffer_original, line_buffer);
+
+        char *line_ptr = line_buffer;
+        while (*line_ptr == ' ') line_ptr++; // delete whitespaces
+
+        /* if the line start with comments or is a blank line ignore it */
+        if (*line_ptr == ';'
+            || *line_ptr == '#'
+            || *line_ptr == '\n') continue;
+
+        /* Verify that each line starts with [a-zA-Z] */
+        if ((*line_ptr < 0x41 && *line_ptr > 0x5A)
+            || (*line_ptr < 0x61 && *line_ptr > 0x7A))
+            goto util_load_config_error;
+
+        /* Load Key Value */
+        char *key, *value;
+        char *ptr_buffer;
+        strtok_r(line_buffer, ";#", &ptr_buffer); // omit comments
+        key = strtok_r(line_buffer, " =", &ptr_buffer);
+        value = strtok_r(NULL, "= ,\n", &ptr_buffer);
+        if (value == NULL) goto util_load_config_error;
+
+        if (!strcmp(key, "weights_path"))   ml->weights_filepath = e_strdup(value);
+        else if (!strcmp(key, "loss"))      ml->loss = e_strdup(value);
+        else if (!strcmp(key, "epochs"))    ml->epochs = (size_t)atol(value);
+        else if (!strcmp(key, "alpha"))     ml->alpha = (double)atof(value);
+        else if (!strcmp(key, "inputs"))    ml->input_keys = config_read_values(&(ml->n_input_keys), value, &ptr_buffer);
+        else if (!strcmp(key, "labels"))    ml->label_keys = config_read_values(&(ml->n_label_keys), value, &ptr_buffer);
+        else die("util_load_config() Error: Unknown parameter '%s' on line '%d'", key, line_number);
+        ptr_buffer = NULL;
+        value = NULL;
+
+    }
+    fclose(fp);
+    return;
+
+util_load_config_error:
+    die("util_load_config() Error: line %d has invalid format '%s'",
+        line_number, line_buffer_original);
+}
+
+char ** config_read_values(size_t *n_out_keys, char *first_value, char **strtok_ptr)
+{
+    *n_out_keys = 1;
+    char **out_keys = ecalloc(1, sizeof(char *));
+    out_keys[0] = e_strdup(first_value);
+
+    char *value;
+    while ((value = strtok_r(NULL, ", \n", strtok_ptr)) != NULL) {
+        out_keys = realloc(out_keys, sizeof(char *) * (*n_out_keys + 1));
+        out_keys[*n_out_keys] = e_strdup(value);
+        (*n_out_keys)++;
+    }
+    return out_keys;
+}
+#undef BUFFER_SIZE
diff --git a/src/util.h b/src/util.h
index e1bcf18..980895f 100644
--- a/src/util.h
+++ b/src/util.h
@@ -8,6 +8,7 @@ struct Configs {
     double alpha;
     char **input_keys, **label_keys;
     size_t n_input_keys, n_label_keys;
+    char *loss;
     char *in_filepath;
     char *out_filepath;
     char *weights_filepath;
@@ -17,6 +18,6 @@ struct Configs {
 void die(const char *fmt, ...);
 void *ecalloc(size_t nmemb, size_t size);
 void util_load_cli(struct Configs *ml, int argc, char *argv[]);
-void util_load_config(struct Configs *ml);
+void util_load_config(struct Configs *ml, char *filepath);
 void util_free_config(struct Configs *ml);
 #endif