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[linebuf] Support buffering of multiple lines

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Allow line buffer to accumulate multiple lines, with buffered_line()
returning each freshly-completed line as it is encountered.  This
allows buffered lines to be subsequently processed as a group.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2015-07-28 16:59:11 +01:00
parent 20d35b0145
commit 1e4ff872be
4 changed files with 359 additions and 46 deletions
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53
src/core/linebuf.c
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@@ -43,7 +43,18 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
* @ret line Buffered line, or NULL if no line ready to read
*/
char * buffered_line ( struct line_buffer *linebuf ) {
return ( linebuf->ready ? linebuf->data : NULL );
char *line = &linebuf->data[ linebuf->len ];
/* Fail unless we have a newly completed line to retrieve */
if ( ( linebuf->len == 0 ) || ( linebuf->consumed == 0 ) ||
( *(--line) != '\0' ) )
return NULL;
/* Identify start of line */
while ( ( line > linebuf->data ) && ( line[-1] != '\0' ) )
line--;
return line;
}
/**
@@ -52,10 +63,11 @@ char * buffered_line ( struct line_buffer *linebuf ) {
* @v linebuf Line buffer
*/
void empty_line_buffer ( struct line_buffer *linebuf ) {
free ( linebuf->data );
linebuf->data = NULL;
linebuf->len = 0;
linebuf->ready = 0;
linebuf->consumed = 0;
}
/**
@@ -76,16 +88,13 @@ void empty_line_buffer ( struct line_buffer *linebuf ) {
* should call empty_line_buffer() before freeing a @c struct @c
* line_buffer.
*/
ssize_t line_buffer ( struct line_buffer *linebuf,
const char *data, size_t len ) {
int line_buffer ( struct line_buffer *linebuf, const char *data, size_t len ) {
const char *eol;
size_t consume;
size_t new_len;
char *new_data;
/* Free any completed line from previous iteration */
if ( linebuf->ready )
empty_line_buffer ( linebuf );
char *lf;
char *cr;
/* Search for line terminator */
if ( ( eol = memchr ( data, '\n', len ) ) ) {
@@ -94,6 +103,10 @@ ssize_t line_buffer ( struct line_buffer *linebuf,
consume = len;
}
/* Reject any embedded NULs within the data to be consumed */
if ( memchr ( data, '\0', consume ) )
return -EINVAL;
/* Reallocate data buffer and copy in new data */
new_len = ( linebuf->len + consume );
new_data = realloc ( linebuf->data, ( new_len + 1 ) );
@@ -104,13 +117,27 @@ ssize_t line_buffer ( struct line_buffer *linebuf,
linebuf->data = new_data;
linebuf->len = new_len;
/* If we have reached end of line, trim the line and mark as ready */
/* If we have reached end of line, terminate the line */
if ( eol ) {
linebuf->data[--linebuf->len] = '\0'; /* trim NL */
if ( linebuf->data[linebuf->len - 1] == '\r' )
linebuf->data[--linebuf->len] = '\0'; /* trim CR */
linebuf->ready = 1;
/* Overwrite trailing LF (which must exist at this point) */
assert ( linebuf->len > 0 );
lf = &linebuf->data[ linebuf->len - 1 ];
assert ( *lf == '\n' );
*lf = '\0';
/* Trim (and overwrite) trailing CR, if present */
if ( linebuf->len > 1 ) {
cr = ( lf - 1 );
if ( *cr == '\r' ) {
linebuf->len--;
*cr = '\0';
}
}
}
/* Record consumed length */
linebuf->consumed = consume;
return consume;
}