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authorMattias Andrée <maandree@operamail.com>2015-09-04 15:17:05 +0200
committerMattias Andrée <maandree@operamail.com>2015-09-04 15:17:05 +0200
commit426b249855fb0b12427e0b951aef72a040504afd (patch)
tree35bae9dac557dded8c41e7e7fd90bf5a20d0266a /src/libmdsclient
parentm doc (diff)
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optimise libmds_message
Signed-off-by: Mattias Andrée <maandree@operamail.com>
Diffstat (limited to 'src/libmdsclient')
-rw-r--r--src/libmdsclient/inbound.c148
-rw-r--r--src/libmdsclient/inbound.h10
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;