implement external interface to library and use it in tests. need to be

reworked a bit to use file descriptor or buffer provided to callse

src/libpst.cpp

@@ -0,0 +1,91 @@
+/*
+ * libpst.c
+ *
+ *  Created on: Feb 5, 2020
+ *      Author: nnosov
+ */
+
+#include <ucontext.h>
+#include <stdio.h>
+#include <stdint.h>
+
+#include "utils/allocator.h"
+#include "dwarf/dwarf_handler.h"
+
+// allocate and initialize libpst handler.
+pst_handler* pst_new_handler(ucontext_t* hctx)
+{
+    // global
+    pst_alloc_init(&allocator);
+    pst_log_init_console(&logger);
+
+    pst_new(pst_handler, handler, hctx);
+    return handler;
+}
+
+// deallocate libpst handler
+void pst_del_handler(pst_handler* h)
+{
+    pst_free(h);
+
+    // global
+    pst_log_fini(&logger);
+    pst_alloc_fini(&allocator);
+}
+
+// write stack trace information to provided file descriptor
+int pst_unwind_simple(pst_handler* h, FILE* fd)
+{
+    int ret = pst_handler_unwind(h);
+    if(ret) {
+        fwrite(h->ctx.buff, 1, strlen(h->ctx.buff), fd);
+        return 0;
+    }
+
+    return -1;
+}
+
+// save stack trace information to provided buffer in RAM
+int pst_unwind_simple(pst_handler* h, char* buff, uint32_t buff_size)
+{
+    int ret = pst_handler_unwind(h);
+    if(ret) {
+        uint32_t cnt = buff_size < sizeof(h->ctx.buff) ? buff_size : sizeof(h->ctx.buff);
+        memcpy(buff, h->ctx.buff, cnt - 2);
+        buff[cnt - 1] = 0;
+
+        return 0;
+    }
+
+    return -1;
+}
+
+
+// write stack trace information to provided file descriptor
+int pst_unwind_pretty(pst_handler* h, FILE* fd)
+{
+    int ret = pst_handler_handle_dwarf(h);
+    if(ret) {
+        pst_handler_print_dwarf(h);
+        fwrite(h->ctx.buff, 1, strlen(h->ctx.buff), fd);
+        return 0;
+    }
+
+    return -1;
+}
+
+// save stack trace information to provided buffer in RAM
+int pst_unwind_pretty(pst_handler* h, char* buff, uint32_t buff_size)
+{
+    int ret = pst_handler_handle_dwarf(h);
+    if(ret) {
+        pst_handler_print_dwarf(h);
+        uint32_t cnt = buff_size < sizeof(h->ctx.buff) ? buff_size : sizeof(h->ctx.buff);
+        memcpy(buff, h->ctx.buff, cnt - 2);
+        buff[cnt - 1] = 0;
+
+        return 0;
+    }
+
+    return -1;
+}