tSaner mamory handling. Now the buffer is allocated only one time - skroll - scroll a text to stdout
(HTM) git clone git://z3bra.org/skroll
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---
(DIR) commit 7ef68be148e2096c510eabc70302341c3c6540dd
(DIR) parent 2a674f4c077001e6e73e036457eadfec23d5a8e0
(HTM) Author: z3bra <willy@mailoo.org>
Date: Mon, 3 Nov 2014 12:15:44 +0100
Saner mamory handling. Now the buffer is allocated only one time
Diffstat:
M skroll.c | 62 ++++++++++++++++----------------
1 file changed, 31 insertions(+), 31 deletions(-)
---
(DIR) diff --git a/skroll.c b/skroll.c
t@@ -31,31 +31,7 @@ static int number = 20; /* number of chars to be shown at the same time */
/* scroll <input> to stdout */
void skroll (const char *input)
{
- int offset, buflen = 0;
- char *tmp, *buf = NULL;
-
- /*
- * allocate a new buffer to hold our input PLUS number spaces at the
- * start/end of the string
- */
- buflen = strnlen(input, LINE_MAX) + (number * 2) + 1;
- if ((buf = calloc(buflen, sizeof(char))) == NULL)
- {
- return;
- }
-
- /* initialize memory with "spaces" and null-terminate the buffer */
- memset(buf, ' ', buflen - 1);
- buf[buflen - 1] = 0;
-
- /* copy input at place `number` */
- memcpy(buf + number, input, strlen(input));
-
- /* remove \n from input string to sanitize output */
- if ((tmp = strchr(buf, '\n')) != NULL)
- {
- tmp[0] = ' ';
- }
+ int offset = 0;
/* main loop. will loop forever if run with -l */
do
t@@ -66,12 +42,12 @@ void skroll (const char *input)
* leading/ending spaces are here to make sure that the text goes from
* far right, and goes all the way to far left
*/
- for (offset = 0; buf [offset + number] != 0; offset++)
+ for (offset = 0; input[offset + number] != 0; offset++)
{
/* print out `number` characters from the buffer ! */
putc('\r', stdout);
- write(1, buf + offset, number);
+ write(1, input + offset, number);
/* if we want a new line, let's do it here */
if (newline) putc('\n', stdout);
t@@ -89,20 +65,44 @@ void skroll (const char *input)
/* returns a char that contains the input bufferized */
const char *bufferize (FILE *stream)
{
- char *buf = NULL;
+ int len = 0;
+ char *eol, *buf = NULL;
/* allocate space to store the input */
if (!(buf = calloc (LINE_MAX + 1, sizeof(char)))) { return NULL; }
- /* buf[LINE_MAX] = 0; */
- memset(buf, 0, LINE_MAX + 1);
+ memset(buf, ' ', LINE_MAX);
+ buf[LINE_MAX] = 0;
/* OMG, NO MORE SPACE LEFT ON DEVICE (or no more input, in fact) */
- if (feof(stream) || !fgets(buf, LINE_MAX, stream))
+ if (feof(stream) || !fgets(buf + number, LINE_MAX, stream))
{
free (buf);
return NULL;
}
+ /*
+ * we need to remove trailings \n and \0 from input string to sanitize output.
+ * the buffer should now look like this:
+ * [ my input \0 \0]
+ * | | | | `- last \0, to prevent segfaults
+ * | | | `- remaining spaces (up to LINE_MAX)
+ * | | `- trailing spaces, to make the text croll to far left
+ * | `- the input itself, with \n and \0 removed from it
+ * `- leading spaces, to make the text scroll from far right
+ */
+
+ /* get the size of the input (and thus, the position of the \0) */
+ len = strnlen(buf, LINE_MAX);
+ buf[len] = ' ';
+
+ /* terminate the string a bit further */
+ buf[len + number] = 0;
+
+ /* remove those silly \n from the input */
+ if ((eol = strchr(buf, '\n')) != NULL) {
+ eol[0] = ' ';
+ }
+
return buf;
}