diff options
| -rw-r--r-- | src/libmdsclient/inbound.c | 148 | ||||
| -rw-r--r-- | src/libmdsclient/inbound.h | 10 |
2 files changed, 66 insertions, 92 deletions
diff --git a/src/libmdsclient/inbound.c b/src/libmdsclient/inbound.c index d56cf56..739cbcb 100644 --- a/src/libmdsclient/inbound.c +++ b/src/libmdsclient/inbound.c @@ -16,6 +16,8 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include "inbound.h" +/* Some optimisations have been attempted. Verify that this implementation + * works, then update the implementation in libmdsserver. */ #include <stdlib.h> #include <string.h> @@ -24,7 +26,8 @@ #include <sys/socket.h> -#define try(INSTRUCTION) if ((r = INSTRUCTION) < 0) return r +#define try(INSTRUCTION) if ((r = INSTRUCTION) < 0) return r +#define static_strlen(str) (sizeof(str) / sizeof(char) - 1) @@ -45,7 +48,6 @@ int libmds_message_initialise(libmds_message_t* restrict this) this->header_count = 0; this->payload = NULL; this->payload_size = 0; - this->payload_ptr = 0; this->buffer_size = 128; this->buffer_ptr = 0; this->stage = 0; @@ -62,13 +64,7 @@ int libmds_message_initialise(libmds_message_t* restrict this) */ void libmds_message_destroy(libmds_message_t* restrict this) { - size_t i, n = this->header_count; - if (this->headers != NULL) - for (i = 0; i < n; i++) - free(this->headers[i]); - free(this->headers), this->headers = NULL; - free(this->payload), this->payload = NULL; free(this->buffer), this->buffer = NULL; } @@ -80,7 +76,7 @@ void libmds_message_destroy(libmds_message_t* restrict this) * @param allow_modified_nul Whether Modified UTF-8 is allowed, which allows a two-byte encoding for NUL * @return Zero if good, -1 on encoding error */ -__attribute__((nonnull)) +__attribute__((nonnull, warn_unused_result)) static int verify_utf8(const char* string, int allow_modified_nul) /* Cannibalised from <libmdsserver/util.h> */ { static long BYTES_TO_MIN_BITS[] = {0, 0, 8, 12, 17, 22, 37}; @@ -161,7 +157,7 @@ static int verify_utf8(const char* string, int allow_modified_nul) /* Cannibalis * @throws ENOMEM Out of memory. Possibly, the process hit the RLIMIT_AS or * RLIMIT_DATA limit described in getrlimit(2). */ -__attribute__((nonnull)) +__attribute__((nonnull, warn_unused_result)) static int extend_headers(libmds_message_t* restrict this, size_t extent) { char** new_headers = realloc(this->headers, (this->header_count + extent) * sizeof(char*)); @@ -175,20 +171,25 @@ static int extend_headers(libmds_message_t* restrict this, size_t extent) /** * Extend the read buffer by way of doubling * - * @param this The message - * @return Zero on success, -1 on error + * @param this The message + * @param shift The number of bits to shift buffer size + * @return Zero on success, -1 on error * * @throws ENOMEM Out of memory. Possibly, the process hit the RLIMIT_AS or * RLIMIT_DATA limit described in getrlimit(2). */ -__attribute__((nonnull)) -static int extend_buffer(libmds_message_t* restrict this) +__attribute__((nonnull, warn_unused_result)) +static int extend_buffer(libmds_message_t* restrict this, int shift) { - char* new_buf = realloc(this->buffer, (this->buffer_size << 1) * sizeof(char)); + size_t i, n = this->header_count; + char* new_buf = realloc(this->buffer, (this->buffer_size << shift) * sizeof(char)); if (new_buf == NULL) return -1; + if (new_buf != this->buffer) + for (i = 0; i < n; i++) + this->headers[i] = new_buf + (size_t)(this->headers[i] - this->buffer); this->buffer = new_buf; - this->buffer_size <<= 1; + this->buffer_size <<= shift; return 0; } @@ -200,20 +201,19 @@ static int extend_buffer(libmds_message_t* restrict this) __attribute__((nonnull)) static void reset_message(libmds_message_t* restrict this) { - size_t i, n = this->header_count; - if (this->headers != NULL) - { - for (i = 0; i < n; i++) - free(this->headers[i]); - free(this->headers); - this->headers = NULL; - } + size_t overrun = this->buffer_ptr - this->buffer_off; + + if (overrun) + memmove(this->buffer, this->buffer + this->buffer_off, overrun * sizeof(char)); + this->buffer_ptr -= this->buffer_off; + this->buffer_off = 0; + + free(this->headers); + this->headers = NULL; this->header_count = 0; - free(this->payload); this->payload = NULL; this->payload_size = 0; - this->payload_ptr = 0; } @@ -223,7 +223,7 @@ static void reset_message(libmds_message_t* restrict this) * @param this The message * @return Zero on success, negative on error (malformated message: unrecoverable state) */ -__attribute__((pure, nonnull)) +__attribute__((pure, nonnull, warn_unused_result)) static int get_payload_length(libmds_message_t* restrict this) { char* header; @@ -233,7 +233,7 @@ static int get_payload_length(libmds_message_t* restrict this) if (strstr(this->headers[i], "Length: ") == this->headers[i]) { /* Store the message length. */ - header = this->headers[i] + strlen("Length: "); + header = this->headers[i] + static_strlen("Length: "); this->payload_size = (size_t)atoll(header); /* Do not except a length that is not correctly formated. */ @@ -256,7 +256,7 @@ static int get_payload_length(libmds_message_t* restrict this) * @param length The length of the header * @return Zero if valid, negative if invalid (malformated message: unrecoverable state) */ -__attribute__((pure, nonnull)) +__attribute__((pure, nonnull, warn_unused_result)) static int validate_header(const char* header, size_t length) { char* p = memchr(header, ':', length * sizeof(char)); @@ -275,22 +275,6 @@ static int validate_header(const char* header, size_t length) /** - * Remove the beginning of the read buffer - * - * @param this The message - * @param length The number of characters to remove - * @param update_ptr Whether to update the buffer pointer - */ -__attribute__((nonnull)) -static void unbuffer_beginning(libmds_message_t* restrict this, size_t length, int update_ptr) -{ - memmove(this->buffer, this->buffer + length, (this->buffer_ptr - length) * sizeof(char)); - if (update_ptr) - this->buffer_ptr -= length; -} - - -/** * Remove the header–payload delimiter from the buffer, * get the payload's size and allocate the payload * @@ -303,24 +287,30 @@ static void unbuffer_beginning(libmds_message_t* restrict this, size_t length, i __attribute__((nonnull)) static int initialise_payload(libmds_message_t* restrict this) { - /* Remove the \n (end of empty line) we found from the buffer. */ - unbuffer_beginning(this, 1, 1); + int shift = 0; + + /* Skip over the \n (end of empty line) we found from the buffer. */ + this->buffer_off++; /* Get the length of the payload. */ if (get_payload_length(this) < 0) return -2; /* Malformated value, enters unrecoverable state. */ - /* Allocate the payload buffer. */ - if (this->payload_size > 0) - if ((this->payload = malloc(this->payload_size * sizeof(char))) == NULL) - return -1; + /* Reallocate the buffer if it is too small. */ + while (this->buffer_off + this->payload_size > this->buffer_size << shift) + shift++; + if (shift ? (extend_buffer(this, shift) < 0) : 0) + return -1; + + /* Set pointer to payload. */ + this->payload = this->buffer + this->buffer_off; return 0; } /** - * Create a header from the buffer and store it + * Store a header * * @param this The message * @param length The length of the header, including LF-termination @@ -329,30 +319,23 @@ static int initialise_payload(libmds_message_t* restrict this) * @throws ENOMEM Out of memory. Possibly, the process hit the RLIMIT_AS or * RLIMIT_DATA limit described in getrlimit(2). */ -__attribute__((nonnull)) +__attribute__((nonnull, warn_unused_result)) static int store_header(libmds_message_t* restrict this, size_t length) { char* header; - /* Allocate the header. */ - header = malloc(length * sizeof(char)); /* Last char is a LF, which is substituted with NUL. */ - if (header == NULL) - return -1; - /* Copy the header data into the allocated header, */ - memcpy(header, this->buffer, length * sizeof(char)); - /* and NUL-terminate it. */ + /* Get pointer to header in buffer. */ + header = this->buffer + this->buffer_off; + /* NUL-terminate the header. */ header[length - 1] = '\0'; - /* Remove the header data from the read buffer. */ - unbuffer_beginning(this, length, 1); + /* Update read offset. */ + this->buffer += length; /* Make sure the the header syntax is correct so that the program does not need to care about it. */ if (validate_header(header, length)) - { - free(header); - return -2; - } + return -2; /* Store the header in the header list. */ this->headers[this->header_count++] = header; @@ -386,7 +369,7 @@ static int continue_read(libmds_message_t* restrict this, int fd) if (n < 128) { /* grow the buffer, */ - try (extend_buffer(this)); + try (extend_buffer(this, 1)); /* and recalculate how much space we have left. */ n = this->buffer_size - this->buffer_ptr; @@ -444,8 +427,9 @@ int libmds_message_read(libmds_message_t* restrict this, int fd) /* Stage 0: headers. */ /* Read all headers that we have stored into the read buffer. */ while ((this->stage == 0) && - ((p = memchr(this->buffer, '\n', this->buffer_ptr * sizeof(char))) != NULL)) - if ((length = (size_t)(p - this->buffer))) + ((p = memchr(this->buffer + this->buffer_off, '\n', + (this->buffer_ptr - this->buffer_off) * sizeof(char))) != NULL)) + if ((length = (size_t)(p - (this->buffer + this->buffer_off)))) { /* We have found a header. */ @@ -455,7 +439,7 @@ int libmds_message_read(libmds_message_t* restrict this, int fd) if (header_commit_buffer == 0) try (extend_headers(this, header_commit_buffer = 8)); - /* Create and store header. */ + /* Store header. */ try (store_header(this, length + 1)); header_commit_buffer -= 1; } @@ -463,8 +447,8 @@ int libmds_message_read(libmds_message_t* restrict this, int fd) { /* We have found an empty line, i.e. the end of the headers. */ - /* Remove the header–payload delimiter from the buffer, - get the payload's size and allocate the payload. */ + /* Make sure the full payload fits the buffer, and set + * the payload buffer pointer. */ try (initialise_payload(this)); /* Mark end of stage, next stage is getting the payload. */ @@ -473,26 +457,16 @@ int libmds_message_read(libmds_message_t* restrict this, int fd) /* Stage 1: payload. */ - if ((this->stage == 1) && (this->payload_size > 0)) - { - /* How much of the payload that has not yet been filled. */ - size_t need = this->payload_size - this->payload_ptr; - /* How much we have of that what is needed. */ - size_t move = this->buffer_ptr < need ? this->buffer_ptr : need; - - /* Copy what we have, and remove it from the the read buffer. */ - memcpy(this->payload + this->payload_ptr, this->buffer, move * sizeof(char)); - unbuffer_beginning(this, move, 1); - - /* Keep track of how much we have read. */ - this->payload_ptr += move; - } - if ((this->stage == 1) && (this->payload_ptr == this->payload_size)) + if ((this->stage == 1) && (this->buffer_ptr - this->buffer_off >= this->payload_size)) { /* If we have filled the payload (or there was no payload), mark the end of this stage, i.e. that the message is complete, and return with success. */ this->stage = 2; + + /* Mark the end of the message. */ + this->buffer_off += this->payload_size; + return 0; } diff --git a/src/libmdsclient/inbound.h b/src/libmdsclient/inbound.h index 158ca10..f0e3d20 100644 --- a/src/libmdsclient/inbound.h +++ b/src/libmdsclient/inbound.h @@ -56,11 +56,6 @@ typedef struct libmds_message size_t payload_size; /** - * How much of the payload that has been stored (internal data) - */ - size_t payload_ptr; - - /** * Internal buffer for the reading function (internal data) */ char* buffer; @@ -76,6 +71,11 @@ typedef struct libmds_message size_t buffer_ptr; /** + * The number of bytes read from `buffer` (internal data) + */ + size_t buffer_off; + + /** * 0 while reading headers, 1 while reading payload, and 2 when done (internal data) */ int stage; |