Batch and error check allocations (#3224)

* Batch PyMem_New-s in draw routines

* Batch and error check mallocs in blur routines

* Move PyErr_NoMemory out of GIL-less block

* Remove misplaced PyMem_Free

Author: Starbuck5

src_c/draw.c

@@ -279,7 +279,6 @@ aalines(PyObject *self, PyObject *arg, PyObject *kwargs)
     Uint32 color;
     float pts[4];
     float pts_prev[4];
-    float *xlist, *ylist;
     float x, y;
     int l, t;
     int extra_px;
@@ -333,16 +332,12 @@ aalines(PyObject *self, PyObject *arg, PyObject *kwargs)
                      "points argument must contain 2 or more points");
     }
 
-    xlist = PyMem_New(float, length);
-    ylist = PyMem_New(float, length);
+    // Allocate bytes for the xlist and ylist at once to reduce allocations.
+    float *points_buf = PyMem_New(float, length * 2);
+    float *xlist = points_buf;
+    float *ylist = points_buf + length;
 
-    if (NULL == xlist || NULL == ylist) {
-        if (xlist) {
-            PyMem_Free(xlist);
-        }
-        if (ylist) {
-            PyMem_Free(ylist);
-        }
+    if (points_buf == NULL) {
         return RAISE(PyExc_MemoryError,
                      "cannot allocate memory to draw aalines");
     }
@@ -357,8 +352,7 @@ aalines(PyObject *self, PyObject *arg, PyObject *kwargs)
         Py_DECREF(item);
 
         if (!result) {
-            PyMem_Free(xlist);
-            PyMem_Free(ylist);
+            PyMem_Free(points_buf);
             return RAISE(PyExc_TypeError, "points must be number pairs");
         }
 
@@ -367,8 +361,7 @@ aalines(PyObject *self, PyObject *arg, PyObject *kwargs)
     }
 
     if (!pgSurface_Lock(surfobj)) {
-        PyMem_Free(xlist);
-        PyMem_Free(ylist);
+        PyMem_Free(points_buf);
         return RAISE(PyExc_RuntimeError, "error locking surface");
     }
 
@@ -460,8 +453,7 @@ aalines(PyObject *self, PyObject *arg, PyObject *kwargs)
                     disable_endpoints, disable_endpoints, extra_px);
     }
 
-    PyMem_Free(xlist);
-    PyMem_Free(ylist);
+    PyMem_Free(points_buf);
 
     if (!pgSurface_Unlock(surfobj)) {
         return RAISE(PyExc_RuntimeError, "error unlocking surface");
@@ -970,7 +962,6 @@ polygon(PyObject *self, PyObject *arg, PyObject *kwargs)
     PyObject *colorobj, *points, *item = NULL;
     SDL_Surface *surf = NULL;
     Uint32 color;
-    int *xlist = NULL, *ylist = NULL;
     int width = 0; /* Default width. */
     int x, y, result, l, t;
     int drawn_area[4] = {INT_MAX, INT_MAX, INT_MIN,
@@ -1021,16 +1012,12 @@ polygon(PyObject *self, PyObject *arg, PyObject *kwargs)
                      "points argument must contain more than 2 points");
     }
 
-    xlist = PyMem_New(int, length);
-    ylist = PyMem_New(int, length);
+    // Allocate bytes for the xlist and ylist at once to reduce allocations.
+    int *points_buf = PyMem_New(int, length * 2);
+    int *xlist = points_buf;
+    int *ylist = points_buf + length;
 
-    if (NULL == xlist || NULL == ylist) {
-        if (xlist) {
-            PyMem_Free(xlist);
-        }
-        if (ylist) {
-            PyMem_Free(ylist);
-        }
+    if (points_buf == NULL) {
         return RAISE(PyExc_MemoryError,
                      "cannot allocate memory to draw polygon");
     }
@@ -1045,8 +1032,7 @@ polygon(PyObject *self, PyObject *arg, PyObject *kwargs)
         Py_DECREF(item);
 
         if (!result) {
-            PyMem_Free(xlist);
-            PyMem_Free(ylist);
+            PyMem_Free(points_buf);
             return RAISE(PyExc_TypeError, "points must be number pairs");
         }
 
@@ -1055,8 +1041,7 @@ polygon(PyObject *self, PyObject *arg, PyObject *kwargs)
     }
 
     if (!pgSurface_Lock(surfobj)) {
-        PyMem_Free(xlist);
-        PyMem_Free(ylist);
+        PyMem_Free(points_buf);
         return RAISE(PyExc_RuntimeError, "error locking surface");
     }
 
@@ -1066,8 +1051,7 @@ polygon(PyObject *self, PyObject *arg, PyObject *kwargs)
     else {
         draw_filltri(surf, xlist, ylist, color, drawn_area);
     }
-    PyMem_Free(xlist);
-    PyMem_Free(ylist);
+    PyMem_Free(points_buf);
 
     if (!pgSurface_Unlock(surfobj)) {
         return RAISE(PyExc_RuntimeError, "error unlocking surface");

src_c/transform.c

@@ -3562,7 +3562,7 @@ surf_average_color(PyObject *self, PyObject *args, PyObject *kwargs)
     return Py_BuildValue("(bbbb)", r, g, b, a);
 }
 
-static void
+static int
 box_blur(SDL_Surface *src, SDL_Surface *dst, int radius, SDL_bool repeat)
 {
     // Reference : https://blog.csdn.net/blogshinelee/article/details/80997324
@@ -3574,9 +3574,16 @@ box_blur(SDL_Surface *src, SDL_Surface *dst, int radius, SDL_bool repeat)
     int dst_pitch = dst->pitch;
     int src_pitch = src->pitch;
     int i, x, y, color;
-    Uint32 *buf = malloc(dst_pitch * sizeof(Uint32));
-    Uint32 *sum_v = malloc(dst_pitch * sizeof(Uint32));
-    Uint32 *sum_h = malloc(nb * sizeof(Uint32));
+
+    // Allocate bytes for buf, sum_v, and sum_h at once to reduce allocations.
+    Uint32 *overall_buf = malloc(sizeof(Uint32) * (dst_pitch * 2 + nb));
+    Uint32 *buf = overall_buf;
+    Uint32 *sum_v = overall_buf + dst_pitch;
+    Uint32 *sum_h = overall_buf + dst_pitch * 2;
+
+    if (overall_buf == NULL) {
+        return -1;
+    }
 
     memset(sum_v, 0, dst_pitch * sizeof(Uint32));
     for (y = 0; y <= radius; y++) {  // y-pre
@@ -3641,12 +3648,11 @@ box_blur(SDL_Surface *src, SDL_Surface *dst, int radius, SDL_bool repeat)
         }
     }
 
-    free(buf);
-    free(sum_v);
-    free(sum_h);
+    free(overall_buf);
+    return 0;
 }
 
-static void
+static int
 gaussian_blur(SDL_Surface *src, SDL_Surface *dst, int sigma, SDL_bool repeat)
 {
     Uint8 *srcpx = (Uint8 *)src->pixels;
@@ -3657,11 +3663,19 @@ gaussian_blur(SDL_Surface *src, SDL_Surface *dst, int sigma, SDL_bool repeat)
     int src_pitch = src->pitch;
     int i, j, x, y, color;
     int kernel_radius = sigma * 2;
-    float *buf = malloc(dst_pitch * sizeof(float));
-    float *buf2 = malloc(dst_pitch * sizeof(float));
-    float *lut = malloc((kernel_radius + 1) * sizeof(float));
     float lut_sum = 0.0;
 
+    // Allocate bytes for buf, buf2, and lut at once to reduce allocations.
+    float *overall_buf =
+        malloc(sizeof(float) * (dst_pitch * 2 + kernel_radius + 1));
+    float *buf = overall_buf;
+    float *buf2 = overall_buf + dst_pitch;
+    float *lut = overall_buf + dst_pitch * 2;
+
+    if (overall_buf == NULL) {
+        return -1;
+    }
+
     for (i = 0; i <= kernel_radius; i++) {  // init gaussian lut
         // Gaussian function
         lut[i] =
@@ -3723,9 +3737,8 @@ gaussian_blur(SDL_Surface *src, SDL_Surface *dst, int sigma, SDL_bool repeat)
         }
     }
 
-    free(buf);
-    free(buf2);
-    free(lut);
+    free(overall_buf);
+    return 0;
 }
 
 static SDL_Surface *
@@ -3734,6 +3747,7 @@ blur(pgSurfaceObject *srcobj, pgSurfaceObject *dstobj, int radius,
 {
     SDL_Surface *src = NULL;
     SDL_Surface *retsurf = NULL;
+    int result = 0;
 
     if (radius < 0) {
         return RAISE(PyExc_ValueError,
@@ -3793,17 +3807,24 @@ blur(pgSurfaceObject *srcobj, pgSurfaceObject *dstobj, int radius,
     Py_BEGIN_ALLOW_THREADS;
 
     if (algorithm == 'b') {
-        box_blur(src, retsurf, radius, repeat);
+        result = box_blur(src, retsurf, radius, repeat);
     }
     else if (algorithm == 'g') {
-        gaussian_blur(src, retsurf, radius, repeat);
+        result = gaussian_blur(src, retsurf, radius, repeat);
     }
 
     Py_END_ALLOW_THREADS;
 
     pgSurface_Unlock(srcobj);
     SDL_UnlockSurface(retsurf);
 
+    // Routines only set error flag if memory allocation failed
+    // Setting Python exception here outside of Py_ THREADS block to be safe
+    if (result) {
+        PyErr_NoMemory();
+        return NULL;
+    }
+
     return retsurf;
 }