diff options
Diffstat (limited to 'sesman/chansrv/fifo.c')
| -rw-r--r-- | sesman/chansrv/fifo.c | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/sesman/chansrv/fifo.c b/sesman/chansrv/fifo.c new file mode 100644 index 00000000..630df3cd --- /dev/null +++ b/sesman/chansrv/fifo.c @@ -0,0 +1,255 @@ +/** + * xrdp: A Remote Desktop Protocol server. + * + * Copyright (C) Laxmikant Rashinkar 2013 LK.Rashinkar@gmail.com + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + + /* FIFO implementation to store a pointer to a user struct */ + +/* module based logging */ +#define MODULE_NAME "FIFO " +#define LOCAL_DEBUG + +#include "fifo.h" +#include "mlog.h" + +/** + * Initialize a FIFO that grows as required + * + * @param fp pointer to a FIFO + * @param num_entries initial size + * + * @return 0 on success, -1 on failure + *****************************************************************************/ +int +fifo_init(FIFO* fp, int num_entries) +{ + log_debug_high("entered"); + + /* validate params */ + if (!fp) + { + log_debug_high("invalid parameters"); + return -1; + } + + if (num_entries < 1) + num_entries = 10; + + fp->rd_ptr = 0; + fp->wr_ptr = 0; + fp->user_data = (long *) g_malloc(sizeof(long) * num_entries); + + if (fp->user_data) + { + fp->entries = num_entries; + log_debug_low("FIFO created; rd_ptr=%d wr_ptr=%d entries=%d", + fp->rd_ptr, fp->wr_ptr, fp->entries); + return 0; + } + else + { + log_error("FIFO create error; system out of memory"); + fp->entries = 0; + return -1; + } +} + +/** + * Deinit FIFO and release resources + * + * @param fp FIFO to deinit + * + * @return 0 on success, -1 on error + *****************************************************************************/ +int +fifo_deinit(FIFO* fp) +{ + log_debug_high("entered"); + + if (!fp) + { + log_debug_high("FIFO is null"); + return -1; + } + + if (fp->user_data) + { + g_free(fp->user_data); + fp->user_data = 0; + } + + fp->rd_ptr = 0; + fp->wr_ptr = 0; + fp->entries = 0; +} + +/** + * Check if FIFO is empty + * + * @param fp FIFO + * + * @return 1 if FIFO is empty, 0 otherwise + *****************************************************************************/ +int +fifo_is_empty(FIFO* fp) +{ + log_debug_high("entered"); + + if (!fp) + { + log_debug_high("FIFO is null"); + return 0; + } + + return (fp->rd_ptr == fp->wr_ptr) ? 1 : 0; +} + +/** + * Insert an item at the end + * + * @param fp FIFO + * @param data data to insert into FIFO + * + * @param 0 on success, -1 on error + *****************************************************************************/ + +int +fifo_insert(FIFO* fp, void* data) +{ + long* lp; + int next_val; /* next value for wr_ptr */ + int i; + + log_debug_high("entered"); + + if (!fp) + { + log_debug_high("FIFO is null"); + return -1; + } + + next_val = fp->wr_ptr + 1; + if (next_val >= fp->entries) + next_val = 0; + + if (next_val == fp->rd_ptr) + { + /* FIFO is full, expand it by 10 entries */ + lp = (long *) g_malloc(sizeof(long) * (fp->entries + 10)); + if (!lp) + { + log_debug_low("FIFO full; cannot expand, no memory"); + return -1; + } + + log_debug_low("FIFO full, expanding by 10 entries"); + + /* copy old data new location */ + for (i = 0; i < (fp->entries - 1); i++) + { + lp[i] = fp->user_data[fp->rd_ptr++]; + if (fp->rd_ptr >= fp->entries) + fp->rd_ptr = 0; + } + + /* update pointers */ + fp->rd_ptr = 0; + fp->wr_ptr = fp->entries - 1; + next_val = fp->entries; + fp->entries += 10; + + /* free old data */ + g_free(fp->user_data); + fp->user_data = lp; + } + + log_debug_low("inserting data at index %d", fp->wr_ptr); + + fp->user_data[fp->wr_ptr] = (long) data; + fp->wr_ptr = next_val; + + return 0; +} + +/** + * Remove an item from the head + * + * @param fp FIFO + * + * @param data on success, NULL on error + *****************************************************************************/ +void* +fifo_remove(FIFO* fp) +{ + long data; + + log_debug_high("entered"); + + if (!fp) + { + log_debug_high("FIFO is null"); + return 0; + } + + if (fp->rd_ptr == fp->wr_ptr) + { + log_debug_high("FIFO is empty"); + return 0; + } + + log_debug_low("removing data at index %d", fp->rd_ptr); + + data = fp->user_data[fp->rd_ptr++]; + + if (fp->rd_ptr >= fp->entries) + { + log_debug_high("FIFO rd_ptr wrapped around"); + fp->rd_ptr = 0; + } + + return (void *) data; +} + +/** + * Return item from head, but do not remove it + * + * @param fp FIFO + * + * @param data on success, NULL on error + *****************************************************************************/ +void* +fifo_peek(FIFO* fp) +{ + long data; + + log_debug_high("entered\n"); + + if (!fp) + { + log_debug_high("FIFO is null\n"); + return 0; + } + + if (fp->rd_ptr == fp->wr_ptr) + { + log_debug_high("FIFO is empty\n"); + return 0; + } + + log_debug_low("peeking data at index %d\n", fp->rd_ptr); + + return (void *) fp->user_data[fp->rd_ptr]; +} |