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Diffstat (limited to '')
| -rw-r--r-- | src/libmdsserver/mds-message.c | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/src/libmdsserver/mds-message.c b/src/libmdsserver/mds-message.c new file mode 100644 index 0000000..94e9e63 --- /dev/null +++ b/src/libmdsserver/mds-message.c @@ -0,0 +1,219 @@ +/** + * mds — A micro-display server + * Copyright © 2014 Mattias Andrée (maandree@member.fsf.org) + * + * 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 <http://www.gnu.org/licenses/>. + */ +#include "mds-message.h" + +#include <stdlib.h> +#include <string.h> + + +/** + * Initialsie a message slot so that it can + * be used by `mds_message_read`. + * + * @param this Memory slot in which to store the new message + * @return Non-zero on error, errno will be set accordingly. + * Destroy the message on error. + */ +int mds_message_initialise(mds_message_t* this) +{ + this->headers = NULL; + this->header_count = 0; + this->payload = NULL; + this->payload_size = 0; + this->buffer = NULL; + this->buffer_size = 128; + this->buffer_ptr = 0; + this->buffer = malloc(this->buffer_size * sizeof(char)); + if (this->buffer == NULL) + return -1; + return 0; +} + + +/** + * Release all resources in a message, should + * be done even if initialisation fails + * + * @param this The message + */ +void mds_message_destroy(mds_message_t* this) +{ + if (this->headers != NULL) + { + size_t i; + for (i = 0; i < this->header_count; i++) + if (this->headers[i] != NULL) + free(this->headers[i]); + free(this->headers); + } + + if (this->payload != NULL) + free(this->payload); + + if (this->buffer != NULL) + free(this->buffer); +} + + +/** + * Read the next message from a file descriptor + * + * @param this Memory slot in which to store the new message + * @param fd The file descriptor + * @return Non-zero on error, errno will be set accordingly. + * Destroy the message on error. + */ +int mds_message_read(mds_message_t* this, int fd) +{ + return 0; +} + + +/** + * Get the required allocation size for `data` of the + * function `mds_message_marshal` + * + * @param this The message + * @param include_buffer Whether buffer should be marshalled (state serialisation, not communication) + * @return The size of the message when marshalled + */ +size_t mds_message_marshal_size(mds_message_t* this, int include_buffer) +{ + size_t rc = (include_buffer ? 3 : 2) + this->header_count + this->payload_size; + size_t i; + for (i = 0; i < this->header_count; i++) + rc += strlen(this->headers[i]); + return rc * sizeof(char); +} + + +/** + * Marshal a message, this can be used both when serialising + * the servers state or to get the byte stream to send to + * the recipient of the message + * + * @param this The message + * @param data Output buffer for the marshalled data + * @param include_buffer Whether buffer should be marshalled (state serialisation, not communication) + */ +void mds_message_marshal(mds_message_t* this, char* data, int include_buffer) +{ + size_t i, n; + + ((size_t*)data)[0] = this->header_count; + ((size_t*)data)[1] = this->payload_size; + if (include_buffer) + ((size_t*)data)[2] = this->buffer_ptr; + data += (include_buffer ? 3 : 2) * sizeof(size_t) / sizeof(char); + + for (i = 0; i < this->header_count; i++) + { + n = strlen(this->headers[i]) + 1; + memcpy(data, this->headers[i], n * sizeof(char)); + data += n; + } + + memcpy(data, this->payload, this->payload_size * sizeof(char)); + + if (include_buffer) + { + data += this->payload_size; + memcpy(data, this->buffer, this->buffer_ptr * sizeof(char)); + } +} + + +/** + * Unmarshal a message, it is assumed that the buffer is marshalled + * + * @param this Memory slot in which to store the new message + * @param data In buffer with the marshalled data + * @return Non-zero on error, errno will be set accordingly. + * Destroy the message on error. + */ +int mds_message_unmarshal(mds_message_t* this, char* data) +{ + size_t i, n, header_count; + + header_count = ((size_t*)data)[0]; + this->header_count = 0; + this->payload_size = ((size_t*)data)[1]; + this->buffer_ptr = ((size_t*)data)[2]; + this->buffer_size = this->buffer_ptr; + this->headers = NULL; + this->payload = NULL; + this->buffer = NULL; + + data += 3 * sizeof(size_t) / sizeof(char); + + /* To 2-power-multiple of 128 bytes. */ + this->buffer_size >>= 7; + if (this->buffer_size == 0) + this->buffer_size = 1; + else + { + this->buffer_size -= 1; + this->buffer_size |= this->buffer_size >> 1; + this->buffer_size |= this->buffer_size >> 2; + this->buffer_size |= this->buffer_size >> 4; + this->buffer_size |= this->buffer_size >> 8; + this->buffer_size |= this->buffer_size >> 16; +#if __WORDSIZE == 64 + this->buffer_size |= this->buffer_size >> 32; +#endif + this->buffer_size += 1; + } + this->buffer_size <<= 7; + + if (header_count > 0) + { + this->headers = malloc(header_count * sizeof(char*)); + if (this->headers == NULL) + return -1; + } + + if (this->payload_size > 0) + { + this->payload = malloc(this->payload_size * sizeof(char)); + if (this->payload == NULL) + return -1; + } + + this->buffer = malloc(this->buffer_size * sizeof(char)); + if (this->buffer == NULL) + return -1; + + for (i = 0; i < this->header_count; i++) + { + n = strlen(data) + 1; + this->headers[i] = malloc(n * sizeof(char)); + if (this->headers[i] == NULL) + return -1; + memcpy(this->headers[i], data, n * sizeof(char)); + data += n; + this->header_count++; + } + + memcpy(this->payload, data, this->payload_size * sizeof(char)); + data += this->payload_size; + + memcpy(this->buffer, data, this->buffer_ptr * sizeof(char)); + + return 0; +} + |