+/*
+ * ustream - library for stream buffer management
+ *
+ * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdarg.h>
+
+#include "ustream.h"
+
+void ustream_init_buf(struct ustream_buf *buf, int len)
+{
+ if (!len)
+ abort();
+
+ memset(buf, 0, sizeof(*buf));
+ buf->data = buf->tail = buf->head;
+ buf->end = buf->head + len;
+ *buf->head = 0;
+}
+
+static void ustream_add_buf(struct ustream_buf_list *l, struct ustream_buf *buf)
+{
+ if (!l->tail)
+ l->head = buf;
+ else
+ l->tail->next = buf;
+
+ buf->next = NULL;
+ l->tail = buf;
+ if (!l->data_tail)
+ l->data_tail = l->head;
+}
+
+static bool ustream_can_alloc(struct ustream_buf_list *l)
+{
+ if (l->max_buffers <= 0)
+ return true;
+
+ return (l->buffers < l->max_buffers);
+}
+
+static int ustream_alloc_default(struct ustream *s, struct ustream_buf_list *l)
+{
+ struct ustream_buf *buf;
+
+ if (!ustream_can_alloc(l))
+ return -1;
+
+ buf = malloc(sizeof(*buf) + l->buffer_len + s->string_data);
+ ustream_init_buf(buf, l->buffer_len);
+ ustream_add_buf(l, buf);
+
+ return 0;
+}
+
+static void ustream_free_buffers(struct ustream_buf_list *l)
+{
+ struct ustream_buf *buf = l->head;
+
+ while (buf) {
+ struct ustream_buf *next = buf->next;
+
+ free(buf);
+ buf = next;
+ }
+ l->head = NULL;
+ l->tail = NULL;
+ l->data_tail = NULL;
+}
+
+void ustream_free(struct ustream *s)
+{
+ if (s->free)
+ s->free(s);
+
+ uloop_timeout_cancel(&s->state_change);
+ ustream_free_buffers(&s->r);
+ ustream_free_buffers(&s->w);
+ s->write_error = false;
+ s->eof = false;
+ s->read_blocked = 0;
+}
+
+static void ustream_state_change_cb(struct uloop_timeout *t)
+{
+ struct ustream *s = container_of(t, struct ustream, state_change);
+
+ if (s->write_error)
+ ustream_free_buffers(&s->w);
+ s->notify_state(s);
+}
+
+void ustream_init_defaults(struct ustream *s)
+{
+#define DEFAULT_SET(_f, _default) \
+ do { \
+ if (!_f) \
+ _f = _default; \
+ } while(0)
+
+ DEFAULT_SET(s->r.alloc, ustream_alloc_default);
+ DEFAULT_SET(s->w.alloc, ustream_alloc_default);
+
+ DEFAULT_SET(s->r.min_buffers, 1);
+ DEFAULT_SET(s->r.max_buffers, 1);
+ DEFAULT_SET(s->r.buffer_len, 4096);
+
+ DEFAULT_SET(s->w.min_buffers, 2);
+ DEFAULT_SET(s->w.max_buffers, -1);
+ DEFAULT_SET(s->w.buffer_len, 256);
+
+#undef DEFAULT_SET
+
+ s->state_change.cb = ustream_state_change_cb;
+}
+
+static bool ustream_should_move(struct ustream_buf_list *l, struct ustream_buf *buf, int len)
+{
+ int maxlen;
+ int offset;
+
+ if (buf->data == buf->head)
+ return false;
+
+ maxlen = buf->end - buf->head;
+ offset = buf->data - buf->head;
+
+ if (offset > maxlen / 2)
+ return true;
+
+ if (buf->tail - buf->data < 32 && offset > maxlen / 4)
+ return true;
+
+ if (buf != l->tail || ustream_can_alloc(l))
+ return false;
+
+ return (buf->end - buf->tail < len);
+}
+
+static void ustream_free_buf(struct ustream_buf_list *l, struct ustream_buf *buf)
+{
+ if (buf == l->head)
+ l->head = buf->next;
+
+ if (buf == l->data_tail)
+ l->data_tail = buf->next;
+
+ if (buf == l->tail)
+ l->tail = NULL;
+
+ if (--l->buffers >= l->min_buffers) {
+ free(buf);
+ return;
+ }
+
+ /* recycle */
+ ustream_init_buf(buf, buf->end - buf->head);
+ ustream_add_buf(l, buf);
+}
+
+static void __ustream_set_read_blocked(struct ustream *s, unsigned char val)
+{
+ bool changed = !!s->read_blocked != !!val;
+
+ s->read_blocked = val;
+ if (changed)
+ s->set_read_blocked(s);
+}
+
+void ustream_set_read_blocked(struct ustream *s, bool set)
+{
+ unsigned char val = s->read_blocked & ~READ_BLOCKED_USER;
+
+ if (set)
+ val |= READ_BLOCKED_USER;
+
+ __ustream_set_read_blocked(s, val);
+}
+
+void ustream_consume(struct ustream *s, int len)
+{
+ struct ustream_buf *buf = s->r.head;
+
+ if (!len)
+ return;
+
+ s->r.data_bytes -= len;
+ if (s->r.data_bytes < 0)
+ abort();
+
+ do {
+ struct ustream_buf *next = buf->next;
+ int buf_len = buf->tail - buf->data;
+
+ if (len < buf_len) {
+ buf->data += len;
+ break;
+ }
+
+ len -= buf_len;
+ ustream_free_buf(&s->r, buf);
+ buf = next;
+ } while(len);
+
+ __ustream_set_read_blocked(s, s->read_blocked & ~READ_BLOCKED_FULL);
+}
+
+static void ustream_fixup_string(struct ustream *s, struct ustream_buf *buf)
+{
+ if (!s->string_data)
+ return;
+
+ *buf->tail = 0;
+}
+
+static bool ustream_prepare_buf(struct ustream *s, struct ustream_buf_list *l, int len)
+{
+ struct ustream_buf *buf;
+
+ buf = l->data_tail;
+ if (buf) {
+ if (ustream_should_move(l, buf, len)) {
+ int len = buf->tail - buf->data;
+
+ memmove(buf->head, buf->data, len);
+ buf->data = buf->head;
+ buf->tail = buf->data + len;
+
+ if (l == &s->r)
+ ustream_fixup_string(s, buf);
+ }
+ if (buf->tail != buf->end)
+ return true;
+ }
+
+ if (buf && buf->next) {
+ l->data_tail = buf->next;
+ return true;
+ }
+
+ if (!ustream_can_alloc(l))
+ return false;
+
+ if (l->alloc(s, l) < 0)
+ return false;
+
+ l->data_tail = l->tail;
+ return true;
+}
+
+char *ustream_reserve(struct ustream *s, int len, int *maxlen)
+{
+ struct ustream_buf *buf = s->r.head;
+
+ if (!ustream_prepare_buf(s, &s->r, len)) {
+ __ustream_set_read_blocked(s, s->read_blocked | READ_BLOCKED_FULL);
+ *maxlen = 0;
+ return NULL;
+ }
+
+ buf = s->r.data_tail;
+ *maxlen = buf->end - buf->tail;
+ return buf->tail;
+}
+
+void ustream_fill_read(struct ustream *s, int len)
+{
+ struct ustream_buf *buf = s->r.data_tail;
+ int n = len;
+ int maxlen;
+
+ s->r.data_bytes += len;
+ do {
+ if (!buf)
+ abort();
+
+ maxlen = buf->end - buf->tail;
+ if (len < maxlen)
+ maxlen = len;
+
+ len -= maxlen;
+ buf->tail += maxlen;
+ ustream_fixup_string(s, buf);
+
+ s->r.data_tail = buf;
+ buf = buf->next;
+ } while (len);
+
+ if (s->notify_read)
+ s->notify_read(s, n);
+}
+
+char *ustream_get_read_buf(struct ustream *s, int *buflen)
+{
+ char *data;
+ int len;
+
+ if (s->r.head) {
+ len = s->r.head->tail - s->r.head->data;
+ data = s->r.head->data;
+ } else {
+ len = 0;
+ data = NULL;
+ }
+
+ if (buflen)
+ *buflen = len;
+
+ return data;
+}
+
+static void ustream_write_error(struct ustream *s)
+{
+ s->write_error = true;
+ ustream_state_change(s);
+}
+
+bool ustream_write_pending(struct ustream *s)
+{
+ struct ustream_buf *buf = s->w.head;
+ int wr = 0, len;
+
+ if (s->write_error)
+ return false;
+
+ while (buf) {
+ struct ustream_buf *next = buf->next;
+ int maxlen = buf->tail - buf->data;
+
+ len = s->write(s, buf->data, maxlen, !!buf->next);
+ if (len < 0) {
+ ustream_write_error(s);
+ break;
+ }
+
+ if (len == 0)
+ break;
+
+ wr += len;
+ s->w.data_bytes -= len;
+ if (len < maxlen) {
+ buf->data += len;
+ break;
+ }
+
+ ustream_free_buf(&s->w, buf);
+ buf = next;
+ }
+
+ if (s->notify_write)
+ s->notify_write(s, wr);
+
+ if (s->eof && wr && !s->w.data_bytes)
+ ustream_state_change(s);
+
+ return !s->w.data_bytes;
+}
+
+static int ustream_write_buffered(struct ustream *s, const char *data, int len, int wr)
+{
+ struct ustream_buf_list *l = &s->w;
+ struct ustream_buf *buf;
+ int maxlen;
+
+ while (len) {
+ if (!ustream_prepare_buf(s, &s->w, len))
+ break;
+
+ buf = l->data_tail;
+
+ maxlen = buf->end - buf->tail;
+ if (maxlen > len)
+ maxlen = len;
+
+ memcpy(buf->tail, data, maxlen);
+ buf->tail += maxlen;
+ data += maxlen;
+ len -= maxlen;
+ wr += maxlen;
+ l->data_bytes += maxlen;
+ }
+
+ return wr;
+}
+
+int ustream_write(struct ustream *s, const char *data, int len, bool more)
+{
+ struct ustream_buf_list *l = &s->w;
+ int wr;
+
+ if (s->write_error)
+ return 0;
+
+ if (!l->data_bytes) {
+ wr = s->write(s, data, len, more);
+ if (wr == len)
+ return wr;
+
+ if (wr < 0) {
+ ustream_write_error(s);
+ return wr;
+ }
+
+ data += wr;
+ len -= wr;
+ }
+
+ return ustream_write_buffered(s, data, len, wr);
+}
+
+#define MAX_STACK_BUFLEN 256
+
+int ustream_vprintf(struct ustream *s, const char *format, va_list arg)
+{
+ struct ustream_buf_list *l = &s->w;
+ char *buf;
+ va_list arg2;
+ int wr, maxlen, buflen;
+
+ if (!l->data_bytes) {
+ buf = alloca(MAX_STACK_BUFLEN);
+ va_copy(arg2, arg);
+ maxlen = vsnprintf(buf, MAX_STACK_BUFLEN, format, arg2);
+ va_end(arg2);
+ if (maxlen < MAX_STACK_BUFLEN) {
+ wr = s->write(s, buf, maxlen, false);
+ if (wr < 0) {
+ ustream_write_error(s);
+ return wr;
+ }
+ if (wr == maxlen)
+ return wr;
+
+ buf += wr;
+ maxlen -= wr;
+ return ustream_write_buffered(s, buf, maxlen, wr);
+ } else {
+ buf = malloc(maxlen + 1);
+ wr = vsnprintf(buf, maxlen + 1, format, arg);
+ wr = ustream_write(s, buf, wr, false);
+ free(buf);
+ return wr;
+ }
+ }
+
+ if (!ustream_prepare_buf(s, l, 1))
+ return 0;
+
+ buf = l->data_tail->tail;
+ buflen = l->data_tail->end - buf;
+
+ va_copy(arg2, arg);
+ maxlen = vsnprintf(buf, buflen, format, arg2);
+ va_end(arg2);
+
+ wr = maxlen;
+ if (wr >= buflen)
+ wr = buflen - 1;
+
+ l->data_tail->tail += wr;
+ l->data_bytes += wr;
+ if (maxlen < buflen)
+ return wr;
+
+ buf = malloc(maxlen + 1);
+ maxlen = vsnprintf(buf, maxlen + 1, format, arg);
+ wr = ustream_write_buffered(s, buf + wr, maxlen - wr, wr);
+ free(buf);
+
+ return wr;
+}
+
+int ustream_printf(struct ustream *s, const char *format, ...)
+{
+ va_list arg;
+ int ret;
+
+ va_start(arg, format);
+ ret = ustream_vprintf(s, format, arg);
+ va_end(arg);
+
+ return ret;
+}
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