From fbb4a817018d6596e7cfed3addec3227dae398c9 Mon Sep 17 00:00:00 2001
From: Alexander Vdolainen <avdolainen@zoho.com>
Date: Fri, 25 Oct 2019 22:52:00 +0300
Subject: [PATCH] Added cstrwrap wrappers functions. it's dirty but quick
 implementation;

---
 lib/Makefile.am |   2 +-
 lib/cswrap.c    | 131 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 132 insertions(+), 1 deletion(-)
 create mode 100644 lib/cswrap.c

diff --git a/lib/Makefile.am b/lib/Makefile.am
index d15eb8b..203e320 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -14,7 +14,7 @@ lib_LTLIBRARIES = libsexpr.la
 
 
 libsexpr_la_SOURCES = \
-	cstring.c event_temp.c faststack.c io.c \
+	cstring.c event_temp.c faststack.c io.c cswrap.c \
 	parser.c sexp.c sexp_memory.c sexp_ops.c sexp_vis.c
 
 libsexpr_la_LDFLAGS = 
diff --git a/lib/cswrap.c b/lib/cswrap.c
new file mode 100644
index 0000000..aab6375
--- /dev/null
+++ b/lib/cswrap.c
@@ -0,0 +1,131 @@
+/**
+@cond IGNORE
+
+A wrapper functions to deal with a cstrings done as an io wrapper
+Copyright (C) 2018 Alexander Vdolainen <avdolainen@zoho.com>
+
+
+It is free software: you can redistribute it and/or modify it
+under the terms of the GNU Lesser General Public License as published
+by the Free Software Foundation, either version 2.1 of the License, or
+(at your option) any later version.
+
+This is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+See the GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.";
+
+@endcond
+**/
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sexpr/sexp.h>
+
+sexp_cstrwrap_t *init_cstrwrap(const char *src)
+{
+  sexp_cstrwrap_t *ow = NULL;
+
+  if(!src) {
+    sexp_errno = SEXP_ERR_NULLSTRING;
+    return NULL;
+  }
+
+  ow = (sexp_cstrwrap_t *)sexp_calloc(1, sizeof(sexp_cstrwrap_t));
+
+  if(!ow) {
+    sexp_errno = SEXP_ERR_MEMORY;
+    return NULL;
+  }
+
+  memset(ow, 0, sizeof(sexp_cstrwrap_t));
+  ow->seval = src;
+  ow->sln = strlen(src);
+
+  return ow;
+}
+
+void destroy_cstrwrap(sexp_cstrwrap_t *csw)
+{
+  if(!csw) return;
+
+  if(csw->cc) destroy_continuation(csw->cc);
+  sexp_free(csw->cc, sizeof(sexp_cstrwrap_t));
+
+  return;
+}
+
+sexp_t *get_one_sexp(sexp_cstrwrap_t *wr)
+{
+  sexp_t *sx = NULL;
+  int sbuf_size = 0;
+
+  if(!wr) return NULL;
+
+  /* check for existing leftovers in continuation */
+  if(wr->cc && wr->cc->lastPos) {
+    wr->cc = cparse_sexp(wr->buf, wr->rl, wr->cc);
+
+    if(!wr->cc) return NULL; /* check the errno: it's set here */
+    if(wr->cc->last_sexp) {
+      sx = wr->cc->last_sexp;
+      wr->cc->last_sexp = NULL;
+      return sx;
+    }
+    wr->rl = 0;
+  }
+
+  if(wr->rl == 0) {
+    /* check for EOB */
+    if(wr->sln == wr->cnt) {
+      sexp_errno = SEXP_ERR_OK;
+      return NULL; /* we're done here */
+    }
+
+    if(wr->sln - wr->cnt >= CSTRBUFSIZ) sbuf_size = CSTRBUFSIZ;
+    else sbuf_size = wr->sln - wr->cnt;
+
+    /* FIXME: it's ugly to copy TODO: optimize it there */
+    memcpy(wr->buf, wr->seval + wr->cnt, sbuf_size);
+    wr->cnt += sbuf_size;
+    wr->rl = sbuf_size;
+  }
+
+  wr->cc = cparse_sexp(wr->buf, wr->rl, wr->cc);
+
+  /* if expression more then buf size, read more */
+  while(wr->cc->last_sexp == NULL) {
+    if(wr->cc->error != SEXP_ERR_OK) {
+      sexp_errno = wr->cc->error;
+      return NULL;
+    }
+
+    /* TODO: FIXME: remove copy-n-paste */
+    /* check for EOB */
+    if(wr->sln == wr->cnt) {
+      sexp_errno = SEXP_ERR_IO_EMPTY;
+      return NULL; /* we're done here, s expression didn't finished */
+    }
+
+    if(wr->sln - wr->cnt >= CSTRBUFSIZ) sbuf_size = CSTRBUFSIZ;
+    else sbuf_size = wr->sln - wr->cnt;
+
+    /* FIXME: it's ugly to copy TODO: optimize it there */
+    memcpy(wr->buf, wr->seval + wr->cnt, sbuf_size);
+    wr->cnt += sbuf_size;
+    wr->rl = sbuf_size;
+
+    wr->cc = cparse_sexp(wr->buf, wr->rl, wr->cc);
+    wr->rl = 0;
+  }
+
+  sx = wr->cc->last_sexp;
+  wr->cc->last_sexp = NULL;
+
+  return sx;
+}