char *databuf_export(DataBuf *db)
{
DATABUF_VALIDATE(db);
databuf_shift_data_to_beginning(db);
DATABUF_VALIDATE(db);
return db->alloc_ptr;
}
static int databuf_strcat(DataBuf *db, const char *str)
{
size_t str_len;
DATABUF_VALIDATE(db);
if (str == NULL) return 0;
// +1 so the data append also copies the NULL terminator
str_len = strlen(str) + 1;
// If there is a NULL terminator exclude it so the subsequent
// data append produces a proper string concatenation
if (db->len > 0) {
char *last_char = databuf_end(db) - 1;
if (*last_char == 0) {
db->len--; // backup over NULL terminator
}
}
// Copy string and NULL terminator
databuf_append(db, str, str_len);
DATABUF_VALIDATE(db);
return 1;
}
static int databuf_shift_data_to_beginning(DataBuf *db)
{
DATABUF_VALIDATE(db);
if (db->flags & DATABUF_FLAG_PRESERVE_HEAD) return -1;
if (databuf_beg(db) == NULL) return 1;
if (db->offset) {
memmove(db->alloc_ptr, databuf_beg(db), db->len);
db->offset = 0;
}
DATABUF_VALIDATE(db);
return 1;
}
void databuf_free(DataBuf *db)
{
DATABUF_VALIDATE(db);
if (db->alloc_ptr != NULL) {
free(db->alloc_ptr);
}
db->alloc_ptr = NULL;
db->alloc_size = 0;
db->offset = 0;
db->len = 0;
db->max_len = 0;
DATABUF_VALIDATE(db);
}
int databuf_append(DataBuf *db, const char *src, size_t src_size)
{
size_t new_size;
DATABUF_VALIDATE(db);
if (src == NULL || src_size == 0) return 0;
new_size = db->len+src_size;
#ifdef DEBUG
if (debug) databuf_print(db, 1, "databuf_append() size=%zd", src_size);
#endif
if ((new_size > db->alloc_size) ||
((db->flags & DATABUF_FLAG_PRESERVE_HEAD) && !databuf_tail_available(db, src_size))) {
/* not enough room, we must realloc */
void *new_alloc;
databuf_shift_data_to_beginning(db);
if ((new_alloc = realloc(db->alloc_ptr, new_size))) {
db->alloc_ptr = new_alloc;
db->alloc_size = new_size;
} else {
return -1; /* realloc failed */
}
} else {
/* we can fit within current allocation, but can we append? */
if (!databuf_tail_available(db, src_size)) {
/* we can't append in place, must create room at tail by shifting
data forward to the beginning of the allocation block */
databuf_shift_data_to_beginning(db);
}
}
#ifdef DEBUG
if (debug) databuf_print(db, 1, "databuf_append() about to memmove()");
#endif
/* pointers all set up and room availble, move the data and update */
memmove(databuf_end(db), src, src_size);
db->len = new_size;
db->max_len = MAX(db->max_len, new_size);
#ifdef DEBUG
if (debug) databuf_print(db, 1, "databuf_append() conclusion");
#endif
DATABUF_VALIDATE(db);
return 1;
}
int databuf_compress(DataBuf *db)
{
void *new_alloc;
DATABUF_VALIDATE(db);
if (databuf_beg(db) == NULL || db->len == 0) return 0;
databuf_shift_data_to_beginning(db);
if ((new_alloc = realloc(db->alloc_ptr, db->len))) {
db->alloc_ptr = new_alloc;
db->alloc_size = db->len;
} else {
return -1; /* realloc failed */
}
DATABUF_VALIDATE(db);
return 1;
}
int databuf_advance(DataBuf *db, size_t advance)
{
size_t actual_advance;
DATABUF_VALIDATE(db);
if (debug) databuf_print(db, 1, "databuf_advance() enter, advance=%d", advance);
actual_advance = MIN(advance, db->len);
db->offset += actual_advance;
db->len -= actual_advance;
if (debug) databuf_print(db, 1, "databuf_advance() leave, actual_advance=%d", actual_advance);
DATABUF_VALIDATE(db);
if (advance == actual_advance) {
return 1;
} else {
errno = ESPIPE; // Illegal seek
return -1;
}
}