1 files changed, 163 insertions, 0 deletions
diff --git a/src/config.c b/src/config.c
new file mode 100644
index 0000000..93ff673
--- /dev/null
+++ b/src/config.c
@@ -0,0 +1,163 @@
+/**
+ * @file config.c
+ */
+#include "spm.h"
+
+/**
+ * Parse a basic configuration file
+ *
+ * NOTE: All values are stored as strings. You need to convert non-string values yourself.
+ *
+ * @param filename
+ * @return success=`ConfigItem` array, failure=NULL
+ */
+ConfigItem **config_read(const char *filename) {
+    const char sep = '=';
+    char *line = (char *)calloc(CONFIG_BUFFER_SIZE, sizeof(char));
+    FILE *fp = fopen(filename, "r");
+    if (!fp) {
+        // errno will be set, so die, and let the caller handle it
+        return NULL;
+    }
+    int record_initial = 2;
+    ConfigItem **config = (ConfigItem **) calloc(record_initial, sizeof(ConfigItem *));
+    int record = 0;
+
+    while (fgets(line, CONFIG_BUFFER_SIZE, fp) != NULL) {
+        char *lptr = line;
+        // Remove trailing space and newlines
+        lptr = strip(lptr);
+
+        // Remove leading space and newlines
+        lptr = lstrip(lptr);
+
+        // Skip empty lines
+        if (isempty(lptr)) {
+            continue;
+        }
+        // Skip comment-only lines
+        if (*lptr == '#' || *lptr == ';') {
+            continue;
+        }
+
+        // Get a pointer to the key pair separator
+        char *sep_pos = strchr(lptr, sep);
+        if (!sep_pos) {
+            printf("invalid entry on line %d: missing '%c': '%s'\n", record, sep, lptr);
+            continue;
+        }
+
+        // These values are approximations.  The real length(s) are recorded using strlen below.
+        // At most we'll lose a few heap bytes to whitespace, but it's better than allocating PATH_MAX or BUFSIZ
+        // for a measly ten byte string.
+        size_t key_length = strcspn(lptr, &sep);
+        size_t value_length = strlen(sep_pos);
+
+        // Allocate a ConfigItem record
+        config[record] = (ConfigItem *)calloc(1, sizeof(ConfigItem));
+        config[record]->key = (char *)calloc(key_length + 1, sizeof(char));
+        config[record]->value = (char *)calloc(value_length + 1, sizeof(char));
+
+        // Shortcut our array at this point. Things get pretty ugly otherwise.
+        char *key = config[record]->key;
+        char *value = config[record]->value;
+
+        // Copy the array pointers (used to populate config->key/value_length
+        char *key_orig = key;
+        char *value_orig = value;
+
+        // Populate the key and remove any trailing space
+        while (lptr != sep_pos) {
+            *key++ = *lptr++;
+        }
+        key = strip(key);
+
+        // We're at the separator now, so skip over it
+        lptr++;
+        // and remove any leading space
+        lptr = lstrip(lptr);
+
+        // Determine whether the string is surrounded by quotes, if so, get rid of them
+        if (isquoted(lptr)) {
+            // Move pointer beyond quote
+            lptr = strpbrk(lptr, "'\"") + 1;
+            // Terminate on closing quote
+            char *tmp = strpbrk(lptr, "'\"");
+            *tmp = '\0';
+        }
+
+        // Populate the value, and ignore any inline comments
+        while (*lptr) {
+            if (*lptr == '#' || *lptr == ';') {
+                // strip trailing whitespace where the comment is and stop processing
+                value = strip(value);
+                break;
+            }
+            *value++ = *lptr++;
+        }
+
+        // Populate length data
+        config[record]->key_length = strlen(key_orig);
+        config[record]->value_length = strlen(value_orig);
+
+        // Destroy contents of line buffer
+        memset(line, '\0', CONFIG_BUFFER_SIZE);
+
+        // increment record count
+        record++;
+        // Expand config by another record
+        config = (ConfigItem **)reallocarray(config, record + record_initial + 1, sizeof(ConfigItem *));
+    }
+    free(line);
+    return config;
+}
+
+/**
+ * Free memory allocated by `config_read`
+ * @param item `ConfigItem` array
+ */
+void config_free(ConfigItem **item) {
+    for (int i = 0; item[i] != NULL; i++) {
+        free(item[i]);
+    }
+    free(item);
+}
+
+/**
+ * If the configuration contains `key` return a pointer to that record
+ * @param item pointer to array of config records
+ * @param key search for key in config records
+ * @return success=pointer to record, failure=NULL
+ */
+ConfigItem *config_get(ConfigItem **item, const char *key) {
+    if (!item) {
+        return NULL;
+    }
+    for (int i = 0; item[i] != NULL; i++) {
+        if (!strcmp(item[i]->key, key)) {
+            return item[i];
+        }
+    }
+    return NULL;
+}
+
+void config_test(void) {
+    ConfigItem **config = config_read("program.conf");
+    printf("Data Parsed:\n");
+    for (int i = 0; config[i] != NULL; i++) {
+        printf("key: '%s', value: '%s'\n", config[i]->key, config[i]->value);
+    }
+
+    printf("Testing config_get():\n");
+    ConfigItem *cptr = NULL;
+    if ((cptr = config_get(config, "integer_value"))) {
+        printf("%s = %d\n", cptr->key, atoi(cptr->value));
+    }
+    if ((cptr = config_get(config, "float_value"))) {
+        printf("%s = %.3f\n", cptr->key, atof(cptr->value));
+    }
+    if ((cptr = config_get(config, "string_value"))) {
+        printf("%s = %s\n", cptr->key, cptr->value);
+    }
+    config_free(config);
+}