Improve TWKT performance by avoiding lots of allocations

on the heap. (Closes #3855)

git-svn-id: http://svn.osgeo.org/postgis/trunk@15780 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/liblwgeom/bytebuffer.c b/liblwgeom/bytebuffer.c
index 4428392ac4a762efa78960aa81a0f3b3b9bf8d8c..913cc96cf827969175471c5c7254900984da0adb 100644 (file)
--- a/liblwgeom/bytebuffer.c
+++ b/liblwgeom/bytebuffer.c
@@ -47,11 +47,19 @@ bytebuffer_create_with_size(size_t size)
        bytebuffer_t *s;
 
        s = lwalloc(sizeof(bytebuffer_t));
-       s->buf_start = lwalloc(size);
+       if ( size < BYTEBUFFER_STATICSIZE )
+       {
+               s->capacity = BYTEBUFFER_STATICSIZE;
+               s->buf_start = s->buf_static;
+       }
+       else
+       {
+               s->buf_start = lwalloc(size);
+               s->capacity = size;
+       }
        s->readcursor = s->writecursor = s->buf_start;
-       s->capacity = size;
-       memset(s->buf_start,0,size);
-       LWDEBUGF(4,"We create a buffer on %p of %d bytes", s->buf_start, size);
+       memset(s->buf_start,0,s->capacity);
+       LWDEBUGF(4,"We create a buffer on %p of %d bytes", s->buf_start, s->capacity);
        return s;
 }
 
@@ -60,12 +68,20 @@ bytebuffer_create_with_size(size_t size)
 * struct. Useful for allocating short-lived bytebuffers off the stack.
 */
 void
-bytebuffer_init_with_size(bytebuffer_t *b, size_t size)
+bytebuffer_init_with_size(bytebuffer_t *s, size_t size)
 {
-       b->buf_start = lwalloc(size);
-       b->readcursor = b->writecursor = b->buf_start;
-       b->capacity = size;
-       memset(b->buf_start, 0, size);
+       if ( size < BYTEBUFFER_STATICSIZE )
+       {
+               s->capacity = BYTEBUFFER_STATICSIZE;
+               s->buf_start = s->buf_static;
+       }
+       else
+       {
+               s->buf_start = lwalloc(size);
+               s->capacity = size;
+       }
+       s->readcursor = s->writecursor = s->buf_start;
+       memset(s->buf_start, 0, s->capacity);
 }
 
 /**
@@ -74,20 +90,22 @@ bytebuffer_init_with_size(bytebuffer_t *b, size_t size)
 void
 bytebuffer_destroy(bytebuffer_t *s)
 {
-       LWDEBUG(2,"Entered bytebuffer_destroy");
-       LWDEBUGF(4,"The buffer has used %d bytes",bytebuffer_getlength(s));
-
-       if ( s->buf_start )
-       {
-               LWDEBUGF(4,"let's free buf_start %p",s->buf_start);
-               lwfree(s->buf_start);
-               LWDEBUG(4,"buf_start is freed");
-       }
+       bytebuffer_destroy_buffer(s);
        if ( s )
-       {
                lwfree(s);
-               LWDEBUG(4,"bytebuffer_t is freed");
-       }
+
+       return;
+}
+
+/**
+* Free the bytebuffer_t and all memory managed within it.
+*/
+void
+bytebuffer_destroy_buffer(bytebuffer_t *s)
+{
+       if ( s->buf_start != s->buf_static )
+               lwfree(s->buf_start);
+
        return;
 }
 
@@ -120,6 +138,7 @@ bytebuffer_makeroom(bytebuffer_t *s, size_t size_to_add)
 {
        LWDEBUGF(2,"Entered bytebuffer_makeroom with space need of %d", size_to_add);
        size_t current_write_size = (s->writecursor - s->buf_start);
+       size_t current_read_size = (s->readcursor - s->buf_start);
        size_t capacity = s->capacity;
        size_t required_size = current_write_size + size_to_add;
 
@@ -130,14 +149,44 @@ bytebuffer_makeroom(bytebuffer_t *s, size_t size_to_add)
        if ( capacity > s->capacity )
        {
                LWDEBUGF(4,"We need to realloc more memory. New capacity is %d", capacity);
-               s->buf_start = lwrealloc(s->buf_start, capacity);
+               if ( s->buf_start == s->buf_static )
+               {
+                       s->buf_start = lwalloc(capacity);
+                       memcpy(s->buf_start, s->buf_static, s->capacity);
+               }
+               else
+               {
+                       s->buf_start = lwrealloc(s->buf_start, capacity);
+               }
                s->capacity = capacity;
                s->writecursor = s->buf_start + current_write_size;
-               s->readcursor = s->buf_start + (s->readcursor - s->buf_start);
+               s->readcursor = s->buf_start + current_read_size;
        }
        return;
 }
 
+/** Returns a copy of the internal buffer */
+uint8_t*
+bytebuffer_get_buffer_copy(const bytebuffer_t *s, size_t *buffer_length)
+{
+       size_t bufsz = bytebuffer_getlength(s);
+       uint8_t *buf = lwalloc(bufsz);
+       memcpy(buf, s->buf_start, bufsz);
+       if ( buffer_length )
+               *buffer_length = bufsz;
+       return buf;
+}
+
+/** Returns a read-only reference to the internal buffer */
+const uint8_t*
+bytebuffer_get_buffer(const bytebuffer_t *s, size_t *buffer_length)
+{
+       if ( buffer_length )
+               *buffer_length = bytebuffer_getlength(s);
+       return s->buf_start;
+}
+
+
 /**
 * Writes a uint8_t value to the buffer
 */
@@ -322,7 +371,7 @@ bytebuffer_read_uvarint(bytebuffer_t *b)
 * Returns the length of the current buffer
 */
 size_t
-bytebuffer_getlength(bytebuffer_t *s)
+bytebuffer_getlength(const bytebuffer_t *s)
 {
        return (size_t) (s->writecursor - s->buf_start);
 }

diff --git a/liblwgeom/bytebuffer.h b/liblwgeom/bytebuffer.h
index 645a5e28f401fa49b79bc99eb9708417a8336ff2..8a2a152417e4bad8e7da27a6c0f938d12293e700 100644 (file)
--- a/liblwgeom/bytebuffer.h
+++ b/liblwgeom/bytebuffer.h
@@ -32,7 +32,8 @@
 #include "varint.h"
 
 #include "lwgeom_log.h"
-#define BYTEBUFFER_STARTSIZE 128
+#define BYTEBUFFER_STARTSIZE 512
+#define BYTEBUFFER_STATICSIZE 1024
 
 typedef struct
 {
@@ -40,6 +41,7 @@ typedef struct
        uint8_t *buf_start;
        uint8_t *writecursor;
        uint8_t *readcursor;
+       uint8_t buf_static[BYTEBUFFER_STATICSIZE];
 }
 bytebuffer_t;
 
@@ -47,15 +49,18 @@ void bytebuffer_init_with_size(bytebuffer_t *b, size_t size);
 bytebuffer_t *bytebuffer_create_with_size(size_t size);
 bytebuffer_t *bytebuffer_create(void);
 void bytebuffer_destroy(bytebuffer_t *s);
+void bytebuffer_destroy_buffer(bytebuffer_t *s);
 void bytebuffer_clear(bytebuffer_t *s);
 void bytebuffer_append_byte(bytebuffer_t *s, const uint8_t val);
 void bytebuffer_append_varint(bytebuffer_t *s, const int64_t val);
 void bytebuffer_append_uvarint(bytebuffer_t *s, const uint64_t val);
 uint64_t bytebuffer_read_uvarint(bytebuffer_t *s);
 int64_t bytebuffer_read_varint(bytebuffer_t *s);
-size_t bytebuffer_getlength(bytebuffer_t *s);
+size_t bytebuffer_getlength(const bytebuffer_t *s);
 bytebuffer_t* bytebuffer_merge(bytebuffer_t **buff_array, int nbuffers);
 void bytebuffer_reset_reading(bytebuffer_t *s);
+uint8_t* bytebuffer_get_buffer_copy(const bytebuffer_t *s, size_t *buffer_length);
+const uint8_t* bytebuffer_get_buffer(const bytebuffer_t *s, size_t *buffer_length);
 
 void bytebuffer_append_bytebuffer(bytebuffer_t *write_to,bytebuffer_t *write_from);
 void bytebuffer_append_bulk(bytebuffer_t *s, void * start, size_t size);

diff --git a/liblwgeom/lwout_twkb.c b/liblwgeom/lwout_twkb.c
index f535b4b2771755f1663c762e1b8c90f49a22cbfa..38ca94046142f480f59f9e8e833fe96f82fe6bf5 100644 (file)
--- a/liblwgeom/lwout_twkb.c
+++ b/liblwgeom/lwout_twkb.c
@@ -409,13 +409,17 @@ static int lwgeom_write_to_buffer(const LWGEOM *geom, TWKB_GLOBALS *globals, TWK
        int i, is_empty, has_z, has_m, ndims;
        size_t bbox_size = 0, optional_precision_byte = 0;
        uint8_t flag = 0, type_prec = 0;
+       bytebuffer_t header_bytebuffer, geom_bytebuffer;
 
        TWKB_STATE child_state;
        memset(&child_state, 0, sizeof(TWKB_STATE));
-       child_state.header_buf = bytebuffer_create_with_size(16);
-       child_state.geom_buf = bytebuffer_create_with_size(64);
+       child_state.header_buf = &header_bytebuffer;
+       child_state.geom_buf = &geom_bytebuffer;
        child_state.idlist = parent_state->idlist;
 
+       bytebuffer_init_with_size(child_state.header_buf, 16);
+       bytebuffer_init_with_size(child_state.geom_buf, 64);
+
        /* Read dimensionality from input */
        has_z = lwgeom_has_z(geom);
        has_m = lwgeom_has_m(geom);
@@ -499,8 +503,8 @@ static int lwgeom_write_to_buffer(const LWGEOM *geom, TWKB_GLOBALS *globals, TWK
                        bytebuffer_append_byte(child_state.header_buf, 0);
 
                bytebuffer_append_bytebuffer(parent_state->geom_buf, child_state.header_buf);
-               bytebuffer_destroy(child_state.header_buf);
-               bytebuffer_destroy(child_state.geom_buf);
+               bytebuffer_destroy_buffer(child_state.header_buf);
+               bytebuffer_destroy_buffer(child_state.geom_buf);
                return 0;
        }
 
@@ -546,8 +550,8 @@ static int lwgeom_write_to_buffer(const LWGEOM *geom, TWKB_GLOBALS *globals, TWK
        bytebuffer_append_bytebuffer(parent_state->geom_buf,child_state.header_buf);
        bytebuffer_append_bytebuffer(parent_state->geom_buf,child_state.geom_buf);
 
-       bytebuffer_destroy(child_state.header_buf);
-       bytebuffer_destroy(child_state.geom_buf);
+       bytebuffer_destroy_buffer(child_state.header_buf);
+       bytebuffer_destroy_buffer(child_state.geom_buf);
        return 0;
 }
 
@@ -566,6 +570,7 @@ lwgeom_to_twkb_with_idlist(const LWGEOM *geom, int64_t *idlist, uint8_t variant,
 
        TWKB_GLOBALS tg;
        TWKB_STATE ts;
+       bytebuffer_t geom_bytebuffer;
 
        uint8_t *twkb;
 
@@ -592,14 +597,12 @@ lwgeom_to_twkb_with_idlist(const LWGEOM *geom, int64_t *idlist, uint8_t variant,
 
        ts.idlist = idlist;
        ts.header_buf = NULL;
-       ts.geom_buf = bytebuffer_create();
+       ts.geom_buf = &geom_bytebuffer;
+       bytebuffer_init_with_size(ts.geom_buf, 512);
        lwgeom_write_to_buffer(geom, &tg, &ts);
 
-       if ( twkb_size )
-               *twkb_size = bytebuffer_getlength(ts.geom_buf);
-
-       twkb = ts.geom_buf->buf_start;
-       lwfree(ts.geom_buf);
+       twkb = bytebuffer_get_buffer_copy(ts.geom_buf, twkb_size);
+       bytebuffer_destroy_buffer(ts.geom_buf);
        return twkb;
 }
 

diff --git a/postgis/lwgeom_inout.c b/postgis/lwgeom_inout.c
index f67903456152211b4062691e8d98fd86dfbfb7e1..5fcb3ead64e2a9ec868450090cbf6c4a5fcc3b51 100644 (file)
--- a/postgis/lwgeom_inout.c
+++ b/postgis/lwgeom_inout.c
@@ -507,15 +507,12 @@ Datum TWKBFromLWGEOM(PG_FUNCTION_ARGS)
        /* Create TWKB binary string */
        lwgeom = lwgeom_from_gserialized(geom);
        twkb = lwgeom_to_twkb(lwgeom, variant, sp.precision_xy, sp.precision_z, sp.precision_m, &twkb_size);
-       lwgeom_free(lwgeom);
 
        /* Prepare the PgSQL text return type */
        result = palloc(twkb_size + VARHDRSZ);
        memcpy(VARDATA(result), twkb, twkb_size);
        SET_VARSIZE(result, twkb_size + VARHDRSZ);
 
-       pfree(twkb);
-       PG_FREE_IF_COPY(geom, 0);
        PG_RETURN_BYTEA_P(result);
 }