skroll

text scroller
git clone git://git.2f30.org/skroll.git
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commit 7ef68be148e2096c510eabc70302341c3c6540dd
parent 2a674f4c077001e6e73e036457eadfec23d5a8e0
Author: z3bra <willy@mailoo.org>
Date:   Mon Nov  3 12:15:44 +0100

Saner mamory handling. Now the buffer is allocated only one time

Diffstat:
skroll.c | 62+++++++++++++++++++++++++++++++-------------------------------
1 file changed, 31 insertions(+), 31 deletions(-)
diff --git a/skroll.c b/skroll.c @@ -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 @@ -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); @@ -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; }