commit 11df3aeee548b959ccd4b9a4d3c44651eab6b3ce
author K.Takata <kentkt@csc.jp> Wed Oct 19 14:02:40 2022 +0100
committer Bram Moolenaar <Bram@vim.org> Wed Oct 19 14:02:40 2022 +0100
tree 13cdeec4447038acdffe1084b3b5f91dabae038b
parent 9f62ea01a08e69f44050f59469a0e64beddefac0

patch 9.0.0795: readblob() always reads the whole file

Problem:    readblob() always reads the whole file.
Solution:   Add arguments to read part of the file. (Ken Takata,
            closes #11402)

src/filepath.c

diff --git a/src/filepath.c b/src/filepath.c
index d9fe83a..023c732 100644
--- a/src/filepath.c
+++ b/src/filepath.c
@@ -1792,16 +1792,27 @@
     long	cnt	 = 0;
     char_u	*p;			// position in buf
     char_u	*start;			// start of current line
+    off_T	offset = 0;
+    off_T	size = -1;
 
     if (argvars[1].v_type != VAR_UNKNOWN)
     {
-	if (STRCMP(tv_get_string(&argvars[1]), "b") == 0)
-	    binary = TRUE;
-	if (STRCMP(tv_get_string(&argvars[1]), "B") == 0)
-	    blob = TRUE;
+	if (always_blob)
+	{
+	    offset = (off_T)tv_get_number(&argvars[1]);
+	    if (argvars[2].v_type != VAR_UNKNOWN)
+		size = (off_T)tv_get_number(&argvars[2]);
+	}
+	else
+	{
+	    if (STRCMP(tv_get_string(&argvars[1]), "b") == 0)
+		binary = TRUE;
+	    if (STRCMP(tv_get_string(&argvars[1]), "B") == 0)
+		blob = TRUE;
 
-	if (argvars[2].v_type != VAR_UNKNOWN)
-	    maxline = (long)tv_get_number(&argvars[2]);
+	    if (argvars[2].v_type != VAR_UNKNOWN)
+		maxline = (long)tv_get_number(&argvars[2]);
+	}
     }
 
     if ((blob ? rettv_blob_alloc(rettv) : rettv_list_alloc(rettv)) == FAIL)
@@ -1818,19 +1829,15 @@
     }
     if (*fname == NUL || (fd = mch_fopen((char *)fname, READBIN)) == NULL)
     {
-	semsg(_(e_cant_open_file_str), *fname == NUL ? (char_u *)_("<empty>") : fname);
+	semsg(_(e_cant_open_file_str),
+			       *fname == NUL ? (char_u *)_("<empty>") : fname);
 	return;
     }
 
     if (blob)
     {
-	if (read_blob(fd, rettv->vval.v_blob) == FAIL)
-	{
+	if (read_blob(fd, rettv, offset, size) == FAIL)
 	    semsg(_(e_cant_read_file_str), fname);
-	    // An empty blob is returned on error.
-	    blob_free(rettv->vval.v_blob);
-	    rettv->vval.v_blob = NULL;
-	}
 	fclose(fd);
 	return;
     }
@@ -2007,7 +2014,11 @@
     void
 f_readblob(typval_T *argvars, typval_T *rettv)
 {
-    if (in_vim9script() && check_for_string_arg(argvars, 0) == FAIL)
+    if (in_vim9script()
+	    && (check_for_string_arg(argvars, 0) == FAIL
+		|| check_for_opt_number_arg(argvars, 1) == FAIL
+		|| (argvars[1].v_type != VAR_UNKNOWN
+		    && check_for_opt_number_arg(argvars, 2) == FAIL)))
 	return;
 
     read_file_or_blob(argvars, rettv, TRUE);