/* -*- c-basic-offset: 8 -*- rdesktop: A Remote Desktop Protocol client. Sound Channel Process Functions Copyright 2006-2010 Pierre Ossman for Cendio AB Copyright 2009-2011 Peter Astrand for Cendio AB Copyright (C) Matthew Chapman 2003-2008 Copyright (C) GuoJunBo 2003 This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ /* * Oracle GPL Disclaimer: For the avoidance of doubt, except that if any license choice * other than GPL or LGPL is available it will apply instead, Oracle elects to use only * the General Public License version 2 (GPLv2) at this time for any software where * a choice of GPL license versions is made available with the language indicating * that GPLv2 or any later version may be used, or where a choice of which version * of the GPL is applied is otherwise unspecified. */ #include #include "rdesktop.h" #include "rdpsnd.h" #include "rdpsnd_dsp.h" #define RDPSND_CLOSE 1 #define RDPSND_WRITE 2 #define RDPSND_SET_VOLUME 3 #define RDPSND_UNKNOWN4 4 #define RDPSND_COMPLETION 5 #define RDPSND_PING 6 #define RDPSND_NEGOTIATE 7 #define RDPSND_REC_NEGOTIATE 39 #define RDPSND_REC_START 40 #define RDPSND_REC_STOP 41 #define RDPSND_REC_DATA 42 #define RDPSND_REC_SET_VOLUME 43 /* Special flag for RDPSND recording extension, not defined in MS specs. See doc/rdpsnd-rec.txt for more information. */ #define RDPSND_FLAG_RECORD 0x00800000 #define MAX_FORMATS 10 #define MAX_QUEUE 50 extern RD_BOOL g_rdpsnd; static VCHANNEL *rdpsnd_channel; static VCHANNEL *rdpsnddbg_channel; static struct audio_driver *drivers = NULL; struct audio_driver *current_driver = NULL; static RD_BOOL rdpsnd_negotiated; static RD_BOOL rdpsnd_rec_negotiated; static RD_BOOL device_open; static RD_BOOL rec_device_open; static RD_WAVEFORMATEX formats[MAX_FORMATS]; static unsigned int format_count; static unsigned int current_format; static RD_WAVEFORMATEX rec_formats[MAX_FORMATS]; static unsigned int rec_format_count; static unsigned int rec_current_format; unsigned int queue_hi, queue_lo, queue_pending; struct audio_packet packet_queue[MAX_QUEUE]; static char record_buffer[8192]; static uint32 record_buffer_size; static uint8 packet_opcode; static struct stream packet; void (*wave_out_play) (void); static void rdpsnd_queue_write(STREAM s, uint16 tick, uint8 index); static void rdpsnd_queue_init(void); static void rdpsnd_queue_clear(void); static void rdpsnd_queue_complete_pending(void); static long rdpsnd_queue_next_completion(void); static STREAM rdpsnd_init_packet(uint16 type, uint16 size) { STREAM s; s = channel_init(rdpsnd_channel, size + 4); out_uint16_le(s, type); out_uint16_le(s, size); return s; } static void rdpsnd_send(STREAM s) { channel_send(s, rdpsnd_channel); } static void rdpsnd_send_completion(uint16 tick, uint8 packet_index) { STREAM s; s = rdpsnd_init_packet(RDPSND_COMPLETION, 4); out_uint16_le(s, tick); out_uint8(s, packet_index); out_uint8(s, 0); s_mark_end(s); rdpsnd_send(s); DEBUG_SOUND(("RDPSND: -> RDPSND_COMPLETION(tick: %u, index: %u)\n", (unsigned) tick, (unsigned) packet_index)); } static void rdpsnd_flush_record(void) { STREAM s; unsigned int chunk_size; char *data; if (record_buffer_size == 0) return; assert(record_buffer_size <= sizeof(record_buffer)); data = record_buffer; /* * Microsoft's RDP server keeps dropping chunks, so we need to * transmit everything inside one channel fragment or we risk * making the rdpsnd server go out of sync with the byte stream. */ while (record_buffer_size) { if (record_buffer_size < 1596) chunk_size = record_buffer_size; else chunk_size = 1596; s = rdpsnd_init_packet(RDPSND_REC_DATA, chunk_size); out_uint8p(s, data, chunk_size); s_mark_end(s); rdpsnd_send(s); data = data + chunk_size; record_buffer_size -= chunk_size; DEBUG_SOUND(("RDPSND: -> RDPSND_REC_DATA(length: %u)\n", (unsigned) chunk_size)); } record_buffer_size = 0; } static void rdpsnd_clear_record(void) { /* * Silently drop everything we have in the record buffer as * we've somehow gotten a reset in regard to the server. */ record_buffer_size = 0; } void rdpsnd_record(const void *data, unsigned int size) { uint32 remain, chunk; assert(rec_device_open); while (size) { remain = sizeof(record_buffer) - record_buffer_size; if (size >= remain) chunk = remain; else chunk = size; memcpy(record_buffer + record_buffer_size, data, chunk); #ifdef B_ENDIAN if (current_driver->need_byteswap_on_be) rdpsnd_dsp_swapbytes(record_buffer + record_buffer_size, chunk, &rec_formats[rec_current_format]); #endif record_buffer_size += chunk; data = (const char *) data + chunk; size -= chunk; if (record_buffer_size == sizeof(record_buffer)) rdpsnd_flush_record(); } } static RD_BOOL rdpsnd_auto_select(void) { static RD_BOOL failed = False; if (!failed) { current_driver = drivers; while (current_driver != NULL) { DEBUG(("trying %s...\n", current_driver->name)); if (current_driver->wave_out_open()) { DEBUG(("selected %s\n", current_driver->name)); current_driver->wave_out_close(); return True; } current_driver = current_driver->next; } warning("no working audio-driver found\n"); failed = True; current_driver = NULL; } return False; } static void rdpsnd_process_negotiate(STREAM in) { uint16 in_format_count, i; uint8 pad; uint16 version; RD_WAVEFORMATEX *format; STREAM out; RD_BOOL device_available = False; int readcnt; int discardcnt; in_uint8s(in, 14); /* initial bytes not valid from server */ in_uint16_le(in, in_format_count); in_uint8(in, pad); in_uint16_le(in, version); in_uint8s(in, 1); /* padding */ DEBUG_SOUND(("RDPSND: RDPSND_NEGOTIATE(formats: %d, pad: 0x%02x, version: %x)\n", (int) in_format_count, (unsigned) pad, (unsigned) version)); if (rdpsnd_negotiated) { error("RDPSND: Extra RDPSND_NEGOTIATE in the middle of a session\n"); /* Do a complete reset of the sound state */ rdpsnd_reset_state(); } if (!current_driver && g_rdpsnd) device_available = rdpsnd_auto_select(); if (current_driver && !device_available && current_driver->wave_out_open()) { current_driver->wave_out_close(); device_available = True; } format_count = 0; if (s_check_rem(in, 18 * in_format_count)) { for (i = 0; i < in_format_count; i++) { format = &formats[format_count]; in_uint16_le(in, format->wFormatTag); in_uint16_le(in, format->nChannels); in_uint32_le(in, format->nSamplesPerSec); in_uint32_le(in, format->nAvgBytesPerSec); in_uint16_le(in, format->nBlockAlign); in_uint16_le(in, format->wBitsPerSample); in_uint16_le(in, format->cbSize); /* read in the buffer of unknown use */ readcnt = format->cbSize; discardcnt = 0; if (format->cbSize > MAX_CBSIZE) { fprintf(stderr, "cbSize too large for buffer: %d\n", format->cbSize); readcnt = MAX_CBSIZE; discardcnt = format->cbSize - MAX_CBSIZE; } in_uint8a(in, format->cb, readcnt); in_uint8s(in, discardcnt); if (current_driver && current_driver->wave_out_format_supported(format)) { format_count++; if (format_count == MAX_FORMATS) break; } } } out = rdpsnd_init_packet(RDPSND_NEGOTIATE | 0x200, 20 + 18 * format_count); uint32 flags = TSSNDCAPS_VOLUME; /* if sound is enabled, set snd caps to alive to enable transmision of audio from server */ if (g_rdpsnd) { flags |= TSSNDCAPS_ALIVE; flags |= RDPSND_FLAG_RECORD; } out_uint32_le(out, flags); /* TSSNDCAPS flags */ out_uint32(out, 0xffffffff); /* volume */ out_uint32(out, 0); /* pitch */ out_uint16(out, 0); /* UDP port */ out_uint16_le(out, format_count); out_uint8(out, 0); /* padding */ out_uint16_le(out, 2); /* version */ out_uint8(out, 0); /* padding */ for (i = 0; i < format_count; i++) { format = &formats[i]; out_uint16_le(out, format->wFormatTag); out_uint16_le(out, format->nChannels); out_uint32_le(out, format->nSamplesPerSec); out_uint32_le(out, format->nAvgBytesPerSec); out_uint16_le(out, format->nBlockAlign); out_uint16_le(out, format->wBitsPerSample); out_uint16(out, 0); /* cbSize */ } s_mark_end(out); DEBUG_SOUND(("RDPSND: -> RDPSND_NEGOTIATE(formats: %d)\n", (int) format_count)); rdpsnd_send(out); rdpsnd_negotiated = True; } static void rdpsnd_process_ping(STREAM in) { uint16 tick; STREAM out; in_uint16_le(in, tick); DEBUG_SOUND(("RDPSND: RDPSND_PING(tick: 0x%04x)\n", (unsigned) tick)); out = rdpsnd_init_packet(RDPSND_PING | 0x2300, 4); out_uint16_le(out, tick); out_uint16_le(out, 0); s_mark_end(out); rdpsnd_send(out); DEBUG_SOUND(("RDPSND: -> (tick: 0x%04x)\n", (unsigned) tick)); } static void rdpsnd_process_rec_negotiate(STREAM in) { uint16 in_format_count, i; uint16 version; RD_WAVEFORMATEX *format; STREAM out; RD_BOOL device_available = False; int readcnt; int discardcnt; in_uint8s(in, 8); /* initial bytes not valid from server */ in_uint16_le(in, in_format_count); in_uint16_le(in, version); DEBUG_SOUND(("RDPSND: RDPSND_REC_NEGOTIATE(formats: %d, version: %x)\n", (int) in_format_count, (unsigned) version)); if (rdpsnd_rec_negotiated) { error("RDPSND: Extra RDPSND_REC_NEGOTIATE in the middle of a session\n"); /* Do a complete reset of the sound state */ rdpsnd_reset_state(); } if (!current_driver) device_available = rdpsnd_auto_select(); if (current_driver && !device_available && current_driver->wave_in_open && current_driver->wave_in_open()) { current_driver->wave_in_close(); device_available = True; } rec_format_count = 0; if (s_check_rem(in, 18 * in_format_count)) { for (i = 0; i < in_format_count; i++) { format = &rec_formats[rec_format_count]; in_uint16_le(in, format->wFormatTag); in_uint16_le(in, format->nChannels); in_uint32_le(in, format->nSamplesPerSec); in_uint32_le(in, format->nAvgBytesPerSec); in_uint16_le(in, format->nBlockAlign); in_uint16_le(in, format->wBitsPerSample); in_uint16_le(in, format->cbSize); /* read in the buffer of unknown use */ readcnt = format->cbSize; discardcnt = 0; if (format->cbSize > MAX_CBSIZE) { fprintf(stderr, "cbSize too large for buffer: %d\n", format->cbSize); readcnt = MAX_CBSIZE; discardcnt = format->cbSize - MAX_CBSIZE; } in_uint8a(in, format->cb, readcnt); in_uint8s(in, discardcnt); if (current_driver && current_driver->wave_in_format_supported && current_driver->wave_in_format_supported(format)) { rec_format_count++; if (rec_format_count == MAX_FORMATS) break; } } } out = rdpsnd_init_packet(RDPSND_REC_NEGOTIATE, 12 + 18 * rec_format_count); out_uint32_le(out, 0x00000000); /* flags */ out_uint32_le(out, 0xffffffff); /* volume */ out_uint16_le(out, rec_format_count); out_uint16_le(out, 1); /* version */ for (i = 0; i < rec_format_count; i++) { format = &rec_formats[i]; out_uint16_le(out, format->wFormatTag); out_uint16_le(out, format->nChannels); out_uint32_le(out, format->nSamplesPerSec); out_uint32_le(out, format->nAvgBytesPerSec); out_uint16_le(out, format->nBlockAlign); out_uint16_le(out, format->wBitsPerSample); out_uint16(out, 0); /* cbSize */ } s_mark_end(out); DEBUG_SOUND(("RDPSND: -> RDPSND_REC_NEGOTIATE(formats: %d)\n", (int) rec_format_count)); rdpsnd_send(out); rdpsnd_rec_negotiated = True; } static void rdpsnd_process_packet(uint8 opcode, STREAM s) { uint16 vol_left, vol_right; static uint16 tick, format; static uint8 packet_index; switch (opcode) { case RDPSND_WRITE: in_uint16_le(s, tick); in_uint16_le(s, format); in_uint8(s, packet_index); in_uint8s(s, 3); DEBUG_SOUND(("RDPSND: RDPSND_WRITE(tick: %u, format: %u, index: %u, data: %u bytes)\n", (unsigned) tick, (unsigned) format, (unsigned) packet_index, (unsigned) s->size - 8)); if (format >= MAX_FORMATS) { error("RDPSND: Invalid format index\n"); break; } if (!device_open || (format != current_format)) { /* * If we haven't selected a device by now, then either * we've failed to find a working device, or the server * is sending bogus RDPSND_WRITE. */ if (!current_driver) { rdpsnd_send_completion(tick, packet_index); break; } if (!device_open && !current_driver->wave_out_open()) { rdpsnd_send_completion(tick, packet_index); break; } if (!current_driver->wave_out_set_format(&formats[format])) { rdpsnd_send_completion(tick, packet_index); current_driver->wave_out_close(); device_open = False; break; } device_open = True; current_format = format; } rdpsnd_queue_write(rdpsnd_dsp_process (s->p, s->end - s->p, current_driver, &formats[current_format]), tick, packet_index); return; break; case RDPSND_CLOSE: DEBUG_SOUND(("RDPSND: RDPSND_CLOSE()\n")); if (device_open) current_driver->wave_out_close(); device_open = False; break; case RDPSND_NEGOTIATE: rdpsnd_process_negotiate(s); break; case RDPSND_PING: rdpsnd_process_ping(s); break; case RDPSND_SET_VOLUME: in_uint16_le(s, vol_left); in_uint16_le(s, vol_right); DEBUG_SOUND(("RDPSND: RDPSND_VOLUME(left: 0x%04x (%u %%), right: 0x%04x (%u %%))\n", (unsigned) vol_left, (unsigned) vol_left / 655, (unsigned) vol_right, (unsigned) vol_right / 655)); if (device_open) current_driver->wave_out_volume(vol_left, vol_right); break; case RDPSND_REC_NEGOTIATE: rdpsnd_process_rec_negotiate(s); break; case RDPSND_REC_START: in_uint16_le(s, format); DEBUG_SOUND(("RDPSND: RDPSND_REC_START(format: %u)\n", (unsigned) format)); if (format >= MAX_FORMATS) { error("RDPSND: Invalid format index\n"); break; } if (rec_device_open) { error("RDPSND: Multiple RDPSND_REC_START\n"); break; } if (!current_driver->wave_in_open()) break; if (!current_driver->wave_in_set_format(&rec_formats[format])) { error("RDPSND: Device not accepting format\n"); current_driver->wave_in_close(); break; } rec_current_format = format; rec_device_open = True; break; case RDPSND_REC_STOP: DEBUG_SOUND(("RDPSND: RDPSND_REC_STOP()\n")); rdpsnd_flush_record(); if (rec_device_open) current_driver->wave_in_close(); rec_device_open = False; break; case RDPSND_REC_SET_VOLUME: in_uint16_le(s, vol_left); in_uint16_le(s, vol_right); DEBUG_SOUND(("RDPSND: RDPSND_REC_VOLUME(left: 0x%04x (%u %%), right: 0x%04x (%u %%))\n", (unsigned) vol_left, (unsigned) vol_left / 655, (unsigned) vol_right, (unsigned) vol_right / 655)); if (rec_device_open) current_driver->wave_in_volume(vol_left, vol_right); break; default: unimpl("RDPSND packet type %x\n", opcode); break; } } static void rdpsnd_process(STREAM s) { uint16 len; while (!s_check_end(s)) { /* New packet */ if (packet.size == 0) { if ((s->end - s->p) < 4) { error("RDPSND: Split at packet header. Things will go south from here...\n"); return; } in_uint8(s, packet_opcode); in_uint8s(s, 1); /* Padding */ in_uint16_le(s, len); DEBUG_SOUND(("RDPSND: == Opcode %x Length: %d ==\n", (int) packet_opcode, (int) len)); packet.p = packet.data; packet.end = packet.data + len; packet.size = len; } else { len = MIN(s->end - s->p, packet.end - packet.p); /* Microsoft's server is so broken it's not even funny... */ if (packet_opcode == RDPSND_WRITE) { if ((packet.p - packet.data) < 12) len = MIN(len, 12 - (packet.p - packet.data)); else if ((packet.p - packet.data) == 12) { DEBUG_SOUND(("RDPSND: Eating 4 bytes of %d bytes...\n", len)); in_uint8s(s, 4); len -= 4; } } in_uint8a(s, packet.p, len); packet.p += len; } /* Packet fully assembled */ if (packet.p == packet.end) { packet.p = packet.data; rdpsnd_process_packet(packet_opcode, &packet); packet.size = 0; } } } static RD_BOOL rdpsnddbg_line_handler(const char *line, void *data) { #ifdef WITH_DEBUG_SOUND fprintf(stderr, "SNDDBG: %s\n", line); #endif return True; } static void rdpsnddbg_process(STREAM s) { unsigned int pkglen; static char *rest = NULL; char *buf; pkglen = s->end - s->p; /* str_handle_lines requires null terminated strings */ buf = (char *) xmalloc(pkglen + 1); STRNCPY(buf, (char *) s->p, pkglen + 1); str_handle_lines(buf, &rest, rdpsnddbg_line_handler, NULL); xfree(buf); } static void rdpsnd_register_drivers(char *options) { struct audio_driver **reg; /* The order of registrations define the probe-order when opening the device for the first time */ reg = &drivers; #if defined(RDPSND_ALSA) *reg = alsa_register(options); assert(*reg); reg = &((*reg)->next); #endif #if defined(RDPSND_SUN) *reg = sun_register(options); assert(*reg); reg = &((*reg)->next); #endif #if defined(RDPSND_OSS) *reg = oss_register(options); assert(*reg); reg = &((*reg)->next); #endif #if defined(RDPSND_SGI) *reg = sgi_register(options); assert(*reg); reg = &((*reg)->next); #endif #if defined(RDPSND_LIBAO) *reg = libao_register(options); assert(*reg); reg = &((*reg)->next); #endif *reg = NULL; } RD_BOOL rdpsnd_init(char *optarg) { struct audio_driver *pos; char *driver = NULL, *options = NULL; drivers = NULL; packet.data = (uint8 *) xmalloc(65536); packet.p = packet.end = packet.data; packet.size = 0; rdpsnd_channel = channel_register("rdpsnd", CHANNEL_OPTION_INITIALIZED | CHANNEL_OPTION_ENCRYPT_RDP, rdpsnd_process); rdpsnddbg_channel = channel_register("snddbg", CHANNEL_OPTION_INITIALIZED | CHANNEL_OPTION_ENCRYPT_RDP, rdpsnddbg_process); if ((rdpsnd_channel == NULL) || (rdpsnddbg_channel == NULL)) { error("channel_register\n"); return False; } rdpsnd_queue_init(); if (optarg != NULL && strlen(optarg) > 0) { driver = options = optarg; while (*options != '\0' && *options != ':') options++; if (*options == ':') { *options = '\0'; options++; } if (*options == '\0') options = NULL; } rdpsnd_register_drivers(options); if (!driver) return True; pos = drivers; while (pos != NULL) { if (!strcmp(pos->name, driver)) { DEBUG(("selected %s\n", pos->name)); current_driver = pos; return True; } pos = pos->next; } return False; } void rdpsnd_reset_state(void) { if (device_open) current_driver->wave_out_close(); device_open = False; rdpsnd_queue_clear(); rdpsnd_negotiated = False; if (rec_device_open) current_driver->wave_in_close(); rec_device_open = False; rdpsnd_clear_record(); rdpsnd_rec_negotiated = False; } void rdpsnd_show_help(void) { struct audio_driver *pos; rdpsnd_register_drivers(NULL); pos = drivers; while (pos != NULL) { fprintf(stderr, " %s:\t%s\n", pos->name, pos->description); pos = pos->next; } } void rdpsnd_add_fds(int *n, fd_set * rfds, fd_set * wfds, struct timeval *tv) { long next_pending; if (device_open || rec_device_open) current_driver->add_fds(n, rfds, wfds, tv); next_pending = rdpsnd_queue_next_completion(); if (next_pending >= 0) { long cur_timeout; cur_timeout = tv->tv_sec * 1000000 + tv->tv_usec; if (cur_timeout > next_pending) { tv->tv_sec = next_pending / 1000000; tv->tv_usec = next_pending % 1000000; } } } void rdpsnd_check_fds(fd_set * rfds, fd_set * wfds) { rdpsnd_queue_complete_pending(); if (device_open || rec_device_open) current_driver->check_fds(rfds, wfds); } static void rdpsnd_queue_write(STREAM s, uint16 tick, uint8 index) { struct audio_packet *packet = &packet_queue[queue_hi]; unsigned int next_hi = (queue_hi + 1) % MAX_QUEUE; if (next_hi == queue_pending) { error("No space to queue audio packet\n"); return; } queue_hi = next_hi; packet->s = *s; packet->tick = tick; packet->index = index; gettimeofday(&packet->arrive_tv, NULL); } struct audio_packet * rdpsnd_queue_current_packet(void) { return &packet_queue[queue_lo]; } RD_BOOL rdpsnd_queue_empty(void) { return (queue_lo == queue_hi); } static void rdpsnd_queue_init(void) { queue_pending = queue_lo = queue_hi = 0; } static void rdpsnd_queue_clear(void) { struct audio_packet *packet; /* Go through everything, not just the pending packets */ while (queue_pending != queue_hi) { packet = &packet_queue[queue_pending]; xfree(packet->s.data); queue_pending = (queue_pending + 1) % MAX_QUEUE; } /* Reset everything back to the initial state */ queue_pending = queue_lo = queue_hi = 0; } void rdpsnd_queue_next(unsigned long completed_in_us) { struct audio_packet *packet; assert(!rdpsnd_queue_empty()); packet = &packet_queue[queue_lo]; gettimeofday(&packet->completion_tv, NULL); packet->completion_tv.tv_usec += completed_in_us; packet->completion_tv.tv_sec += packet->completion_tv.tv_usec / 1000000; packet->completion_tv.tv_usec %= 1000000; queue_lo = (queue_lo + 1) % MAX_QUEUE; rdpsnd_queue_complete_pending(); } int rdpsnd_queue_next_tick(void) { if (((queue_lo + 1) % MAX_QUEUE) != queue_hi) { return packet_queue[(queue_lo + 1) % MAX_QUEUE].tick; } else { return (packet_queue[queue_lo].tick + 65535) % 65536; } } static void rdpsnd_queue_complete_pending(void) { struct timeval now; long elapsed; struct audio_packet *packet; gettimeofday(&now, NULL); while (queue_pending != queue_lo) { packet = &packet_queue[queue_pending]; if (now.tv_sec < packet->completion_tv.tv_sec) break; if ((now.tv_sec == packet->completion_tv.tv_sec) && (now.tv_usec < packet->completion_tv.tv_usec)) break; elapsed = (packet->completion_tv.tv_sec - packet->arrive_tv.tv_sec) * 1000000 + (packet->completion_tv.tv_usec - packet->arrive_tv.tv_usec); elapsed /= 1000; xfree(packet->s.data); rdpsnd_send_completion((packet->tick + elapsed) % 65536, packet->index); queue_pending = (queue_pending + 1) % MAX_QUEUE; } } static long rdpsnd_queue_next_completion(void) { struct audio_packet *packet; long remaining; struct timeval now; if (queue_pending == queue_lo) return -1; gettimeofday(&now, NULL); packet = &packet_queue[queue_pending]; remaining = (packet->completion_tv.tv_sec - now.tv_sec) * 1000000 + (packet->completion_tv.tv_usec - now.tv_usec); if (remaining < 0) return 0; return remaining; }