at work

clib/rcache.c

@@ -0,0 +1,65 @@
+/*
+ *
+ * Copyright 2023 Oleg Borodin  <borodin@unix7.org>
+ *
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <fcntl.h>
+
+#include <rcache.h>
+
+
+#define CACHE_INITCAPA 512
+
+rcache_t* rcache_init(rcache_t * cache, int fd) {
+    cache->data = malloc(CACHE_INITCAPA);
+    if (cache->data == NULL) {
+        return NULL;
+    }
+    cache->wpos = 0;
+    cache->rpos = 0;
+    cache->capa = CACHE_INITCAPA;
+    cache->fd = fd;
+    return cache;
+}
+
+#define BUFFER_SIZE 1024
+
+char rcache_getc(rcache_t * cache) {
+    size_t unread = cache->wpos - cache->rpos;
+
+    if (unread == 0) {
+        char* buffer[BUFFER_SIZE];
+        ssize_t rsize = read(cache->fd, buffer, sizeof(buffer));
+        if (rsize < 0) {
+            return EOF;
+        }
+        if (rsize == 0) {
+            return EOF;
+        }
+        if ((cache->wpos + rsize) > cache->capa) {
+            size_t newcapa = cache->capa * 2 + rsize;
+            uint8_t* newdata = realloc(cache->data, (size_t)newcapa);
+
+            if (newdata == NULL) {
+                return (ssize_t) - 1;
+            }
+            cache->data = newdata;
+            cache->capa = newcapa;
+        }
+        memcpy(&(cache->data[cache->wpos]), buffer, (size_t)rsize);
+        cache->wpos += rsize;
+    }
+    //printf("[%c]", (char)cache->data[cache->rpos]);
+    return (char)cache->data[cache->rpos++];
+}
+
+
+void rcache_destroy(rcache_t * cache) {
+    if (cache != NULL) {
+        free(cache->data);
+    }
+}