feat: First stable release

bin.c

@@ -0,0 +1,121 @@
+/*
+ * bin.c
+ *  Pastes handling.
+ *
+ *
+ * Copyright (c) 2022
+ *     Tom MTT. <tom@heimdall.pm>
+ *
+ * This file is licensed under the 3-Clause BSD License.
+ * You should have received a copy of the 3-Clause BSD License
+ * along with this program. If not, see
+ * <https://basedwa.re/tmtt/feuille/src/branch/main/LICENSE>.
+ */
+
+#include "bin.h"
+
+#include <stdio.h>    /* for NULL, fclose, fopen, fputs, snprintf, FILE */
+#include <stdlib.h>   /* for calloc, free, malloc, rand, realloc        */
+#include <string.h>   /* for strlen                                     */
+#include <unistd.h>   /* for access, F_OK                               */
+
+#include "feuille.h"  /* for Settings, settings                         */
+
+/* symbols used to generate IDs */
+static char *id_symbols = "abcdefghijklmnopqrstuvwxyz0123456789";
+
+/**
+ * Generate a random ID, until one is available on disk.
+ *   min_length: the minimum ID length. Will be increased if a collision occurs.
+ * -> a pointer to the ID. Needs to be freed.
+ */
+char *generate_id(int min_length)
+{
+    int length = min_length;
+
+    /* allocate a buffer to store the ID */
+    char *buffer;
+    if ((buffer = calloc(length + 1, sizeof(char))) == NULL)
+        return NULL;
+
+    /* for each letter, generate a random one */
+    for (int i = 0; i < length; i++) {
+        if (i > 8 * min_length)
+            return NULL;
+
+        buffer[i]     = id_symbols[rand() % strlen(id_symbols)];
+
+        /* collision? */
+        if (i == length - 1 && paste_exists(buffer)) {
+            /* add one to the ID length and re-allocate the buffer */
+            length++;
+
+            void *tmp;
+            if ((tmp = realloc(buffer, (length + 1) * sizeof(char))) == NULL) {
+                free(buffer);
+                return NULL;
+            }
+
+            buffer = tmp;
+        }
+    }
+
+    buffer[length] = 0;
+    return buffer;
+}
+
+/**
+ * Check if an ID is already used.
+ *   id: the ID in question.
+ * -> 1 if exists, 0 if not.
+ */
+int paste_exists(char *id)
+{
+    return access(id, F_OK) == 0;
+}
+
+/**
+ * Write the paste content to disk.
+ *   paste: the string containing the paste.
+ *   id: the ID of the paste.
+ * -> 0 if done, -1 if not.
+ */
+int write_paste(char *paste, char *id)
+{
+    /* open the file with write access */
+    FILE *file;
+    if ((file = fopen(id, "w")) == NULL)
+        return -1;
+
+    /* write the content to file */
+    if (fputs(paste, file) == -1) {
+        fclose(file);
+        return -1;
+    }
+
+    /* close the file (obviously) */
+    fclose(file);
+    return 0;
+}
+
+/**
+ * Make the full URL for the paste.
+ *   id: the ID of the paste.
+ * -> a pointer to the URL. Needs to be freed.
+ */
+char *create_url(char *id)
+{
+    /* calculate the length of the URL */
+    /* the 3 characters added are the trailing slash, newline and null byte */
+    int length = strlen(id) + strlen(settings.url) + 3;
+
+    /* allocate a buffer to store the URL */
+    char *buffer;
+    if ((buffer = malloc(length * sizeof(char))) == NULL)
+        return NULL;
+
+    /* set the buffer to the actual URL */
+    snprintf(buffer, length, "%s/%s\n", settings.url, id);
+
+    return buffer;
+}