LOLWUT: refactoring + skeleton of LOLWUT 6.

src/Makefile

@@ -164,7 +164,7 @@ endif
 
 REDIS_SERVER_NAME=redis-server
 REDIS_SENTINEL_NAME=redis-sentinel
-REDIS_SERVER_OBJ=adlist.o quicklist.o ae.o anet.o dict.o server.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endianconv.o slowlog.o scripting.o bio.o rio.o rand.o memtest.o crc64.o bitops.o sentinel.o notify.o setproctitle.o blocked.o hyperloglog.o latency.o sparkline.o redis-check-rdb.o redis-check-aof.o geo.o lazyfree.o module.o evict.o expire.o geohash.o geohash_helper.o childinfo.o defrag.o siphash.o rax.o t_stream.o listpack.o localtime.o lolwut.o lolwut5.o acl.o gopher.o tracking.o sha256.o
+REDIS_SERVER_OBJ=adlist.o quicklist.o ae.o anet.o dict.o server.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endianconv.o slowlog.o scripting.o bio.o rio.o rand.o memtest.o crc64.o bitops.o sentinel.o notify.o setproctitle.o blocked.o hyperloglog.o latency.o sparkline.o redis-check-rdb.o redis-check-aof.o geo.o lazyfree.o module.o evict.o expire.o geohash.o geohash_helper.o childinfo.o defrag.o siphash.o rax.o t_stream.o listpack.o localtime.o lolwut.o lolwut5.o lolwut6.o acl.o gopher.o tracking.o sha256.o
 REDIS_CLI_NAME=redis-cli
 REDIS_CLI_OBJ=anet.o adlist.o dict.o redis-cli.o zmalloc.o release.o anet.o ae.o crc64.o siphash.o crc16.o
 REDIS_BENCHMARK_NAME=redis-benchmark

src/lolwut.c

@@ -34,8 +34,11 @@
  */
 
 #include "server.h"
+#include "lolwut.h"
+#include <math.h>
 
 void lolwut5Command(client *c);
+void lolwut6Command(client *c);
 
 /* The default target for LOLWUT if no matching version was found.
  * This is what unstable versions of Redis will display. */
@@ -47,11 +50,127 @@ void lolwutUnstableCommand(client *c) {
     sdsfree(rendered);
 }
 
+/* LOLWUT [<version>] */
 void lolwutCommand(client *c) {
     char *v = REDIS_VERSION;
-    if ((v[0] == '5' && v[1] == '.') ||
+    char verstr[64];
+
+    if (c->argc == 2) {
+        long ver;
+        if (getLongFromObjectOrReply(c,c->argv[1],&ver,NULL) != C_OK) return;
+        snprintf(verstr,sizeof(verstr),"%u.0.0",(unsigned int)ver);
+        v = verstr;
+    }
+
+    if ((v[0] == '5' && v[1] == '.' && v[2] != '9') ||
         (v[0] == '4' && v[1] == '.' && v[2] == '9'))
         lolwut5Command(c);
+    else if ((v[0] == '6' && v[1] == '.' && v[2] != '9') ||
+             (v[0] == '5' && v[1] == '.' && v[2] == '9'))
+        lolwut6Command(c);
     else
         lolwutUnstableCommand(c);
 }
+
+/* ========================== LOLWUT Canvase ===============================
+ * Many LOWUT versions will likely print some computer art to the screen.
+ * This is the case with LOLWUT 5 and LOLWUT 6, so here there is a generic
+ * canvas implementation that can be reused.  */
+
+/* Allocate and return a new canvas of the specified size. */
+lwCanvas *lwCreateCanvas(int width, int height) {
+    lwCanvas *canvas = zmalloc(sizeof(*canvas));
+    canvas->width = width;
+    canvas->height = height;
+    canvas->pixels = zmalloc(width*height);
+    memset(canvas->pixels,0,width*height);
+    return canvas;
+}
+
+/* Free the canvas created by lwCreateCanvas(). */
+void lwFreeCanvas(lwCanvas *canvas) {
+    zfree(canvas->pixels);
+    zfree(canvas);
+}
+
+/* Set a pixel to the specified color. Color is 0 or 1, where zero means no
+ * dot will be displyed, and 1 means dot will be displayed.
+ * Coordinates are arranged so that left-top corner is 0,0. You can write
+ * out of the size of the canvas without issues. */
+void lwDrawPixel(lwCanvas *canvas, int x, int y, int color) {
+    if (x < 0 || x >= canvas->width ||
+        y < 0 || y >= canvas->height) return;
+    canvas->pixels[x+y*canvas->width] = color;
+}
+
+/* Return the value of the specified pixel on the canvas. */
+int lwGetPixel(lwCanvas *canvas, int x, int y) {
+    if (x < 0 || x >= canvas->width ||
+        y < 0 || y >= canvas->height) return 0;
+    return canvas->pixels[x+y*canvas->width];
+}
+
+/* Draw a line from x1,y1 to x2,y2 using the Bresenham algorithm. */
+void lwDrawLine(lwCanvas *canvas, int x1, int y1, int x2, int y2, int color) {
+    int dx = abs(x2-x1);
+    int dy = abs(y2-y1);
+    int sx = (x1 < x2) ? 1 : -1;
+    int sy = (y1 < y2) ? 1 : -1;
+    int err = dx-dy, e2;
+
+    while(1) {
+        lwDrawPixel(canvas,x1,y1,color);
+        if (x1 == x2 && y1 == y2) break;
+        e2 = err*2;
+        if (e2 > -dy) {
+            err -= dy;
+            x1 += sx;
+        }
+        if (e2 < dx) {
+            err += dx;
+            y1 += sy;
+        }
+    }
+}
+
+/* Draw a square centered at the specified x,y coordinates, with the specified
+ * rotation angle and size. In order to write a rotated square, we use the
+ * trivial fact that the parametric equation:
+ *
+ *  x = sin(k)
+ *  y = cos(k)
+ *
+ * Describes a circle for values going from 0 to 2*PI. So basically if we start
+ * at 45 degrees, that is k = PI/4, with the first point, and then we find
+ * the other three points incrementing K by PI/2 (90 degrees), we'll have the
+ * points of the square. In order to rotate the square, we just start with
+ * k = PI/4 + rotation_angle, and we are done.
+ *
+ * Of course the vanilla equations above will describe the square inside a
+ * circle of radius 1, so in order to draw larger squares we'll have to
+ * multiply the obtained coordinates, and then translate them. However this
+ * is much simpler than implementing the abstract concept of 2D shape and then
+ * performing the rotation/translation transformation, so for LOLWUT it's
+ * a good approach. */
+void lwDrawSquare(lwCanvas *canvas, int x, int y, float size, float angle, int color) {
+    int px[4], py[4];
+
+    /* Adjust the desired size according to the fact that the square inscribed
+     * into a circle of radius 1 has the side of length SQRT(2). This way
+     * size becomes a simple multiplication factor we can use with our
+     * coordinates to magnify them. */
+    size /= 1.4142135623;
+    size = round(size);
+
+    /* Compute the four points. */
+    float k = M_PI/4 + angle;
+    for (int j = 0; j < 4; j++) {
+        px[j] = round(sin(k) * size + x);
+        py[j] = round(cos(k) * size + y);
+        k += M_PI/2;
+    }
+
+    /* Draw the square. */
+    for (int j = 0; j < 4; j++)
+        lwDrawLine(canvas,px[j],py[j],px[(j+1)%4],py[(j+1)%4],color);
+}

src/lolwut.h

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2018-2019, Salvatore Sanfilippo <antirez at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Redis nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/* This structure represents our canvas. Drawing functions will take a pointer
+ * to a canvas to write to it. Later the canvas can be rendered to a string
+ * suitable to be printed on the screen, using unicode Braille characters. */
+
+/* This represents a very simple generic canvas in order to draw stuff.
+ * It's up to each LOLWUT versions to translate what they draw to the
+ * screen, depending on the result to accomplish. */
+typedef struct lwCanvas {
+    int width;
+    int height;
+    char *pixels;
+} lwCanvas;
+
+/* Drawing functions implemented inside lolwut.c. */
+lwCanvas *lwCreateCanvas(int width, int height);
+void lwFreeCanvas(lwCanvas *canvas);
+void lwDrawPixel(lwCanvas *canvas, int x, int y, int color);
+int lwGetPixel(lwCanvas *canvas, int x, int y);
+void lwDrawLine(lwCanvas *canvas, int x1, int y1, int x2, int y2, int color);
+void lwDrawSquare(lwCanvas *canvas, int x, int y, float size, float angle, int color);

src/lolwut5.c

@@ -34,17 +34,9 @@
  */
 
 #include "server.h"
+#include "lolwut.h"
 #include <math.h>
 
-/* This structure represents our canvas. Drawing functions will take a pointer
- * to a canvas to write to it. Later the canvas can be rendered to a string
- * suitable to be printed on the screen, using unicode Braille characters. */
-typedef struct lwCanvas {
-    int width;
-    int height;
-    char *pixels;
-} lwCanvas;
-
 /* Translate a group of 8 pixels (2x4 vertical rectangle) to the corresponding
  * braille character. The byte should correspond to the pixels arranged as
  * follows, where 0 is the least significant bit, and 7 the most significant
@@ -69,104 +61,6 @@ void lwTranslatePixelsGroup(int byte, char *output) {
     output[2] = 0x80 | (code & 0x3F);         /* 10-xxxxxx */
 }
 
-/* Allocate and return a new canvas of the specified size. */
-lwCanvas *lwCreateCanvas(int width, int height) {
-    lwCanvas *canvas = zmalloc(sizeof(*canvas));
-    canvas->width = width;
-    canvas->height = height;
-    canvas->pixels = zmalloc(width*height);
-    memset(canvas->pixels,0,width*height);
-    return canvas;
-}
-
-/* Free the canvas created by lwCreateCanvas(). */
-void lwFreeCanvas(lwCanvas *canvas) {
-    zfree(canvas->pixels);
-    zfree(canvas);
-}
-
-/* Set a pixel to the specified color. Color is 0 or 1, where zero means no
- * dot will be displyed, and 1 means dot will be displayed.
- * Coordinates are arranged so that left-top corner is 0,0. You can write
- * out of the size of the canvas without issues. */
-void lwDrawPixel(lwCanvas *canvas, int x, int y, int color) {
-    if (x < 0 || x >= canvas->width ||
-        y < 0 || y >= canvas->height) return;
-    canvas->pixels[x+y*canvas->width] = color;
-}
-
-/* Return the value of the specified pixel on the canvas. */
-int lwGetPixel(lwCanvas *canvas, int x, int y) {
-    if (x < 0 || x >= canvas->width ||
-        y < 0 || y >= canvas->height) return 0;
-    return canvas->pixels[x+y*canvas->width];
-}
-
-/* Draw a line from x1,y1 to x2,y2 using the Bresenham algorithm. */
-void lwDrawLine(lwCanvas *canvas, int x1, int y1, int x2, int y2, int color) {
-    int dx = abs(x2-x1);
-    int dy = abs(y2-y1);
-    int sx = (x1 < x2) ? 1 : -1;
-    int sy = (y1 < y2) ? 1 : -1;
-    int err = dx-dy, e2;
-
-    while(1) {
-        lwDrawPixel(canvas,x1,y1,color);
-        if (x1 == x2 && y1 == y2) break;
-        e2 = err*2;
-        if (e2 > -dy) {
-            err -= dy;
-            x1 += sx;
-        }
-        if (e2 < dx) {
-            err += dx;
-            y1 += sy;
-        }
-    }
-}
-
-/* Draw a square centered at the specified x,y coordinates, with the specified
- * rotation angle and size. In order to write a rotated square, we use the
- * trivial fact that the parametric equation:
- *
- *  x = sin(k)
- *  y = cos(k)
- *
- * Describes a circle for values going from 0 to 2*PI. So basically if we start
- * at 45 degrees, that is k = PI/4, with the first point, and then we find
- * the other three points incrementing K by PI/2 (90 degrees), we'll have the
- * points of the square. In order to rotate the square, we just start with
- * k = PI/4 + rotation_angle, and we are done.
- *
- * Of course the vanilla equations above will describe the square inside a
- * circle of radius 1, so in order to draw larger squares we'll have to
- * multiply the obtained coordinates, and then translate them. However this
- * is much simpler than implementing the abstract concept of 2D shape and then
- * performing the rotation/translation transformation, so for LOLWUT it's
- * a good approach. */
-void lwDrawSquare(lwCanvas *canvas, int x, int y, float size, float angle) {
-    int px[4], py[4];
-
-    /* Adjust the desired size according to the fact that the square inscribed
-     * into a circle of radius 1 has the side of length SQRT(2). This way
-     * size becomes a simple multiplication factor we can use with our
-     * coordinates to magnify them. */
-    size /= 1.4142135623;
-    size = round(size);
-
-    /* Compute the four points. */
-    float k = M_PI/4 + angle;
-    for (int j = 0; j < 4; j++) {
-        px[j] = round(sin(k) * size + x);
-        py[j] = round(cos(k) * size + y);
-        k += M_PI/2;
-    }
-
-    /* Draw the square. */
-    for (int j = 0; j < 4; j++)
-        lwDrawLine(canvas,px[j],py[j],px[(j+1)%4],py[(j+1)%4],1);
-}
-
 /* Schotter, the output of LOLWUT of Redis 5, is a computer graphic art piece
  * generated by Georg Nees in the 60s. It explores the relationship between
  * caos and order.
@@ -200,7 +94,7 @@ lwCanvas *lwDrawSchotter(int console_cols, int squares_per_row, int squares_per_
                 sx += r2*square_side/3;
                 sy += r3*square_side/3;
             }
-            lwDrawSquare(canvas,sx,sy,square_side,angle);
+            lwDrawSquare(canvas,sx,sy,square_side,angle,1);
         }
     }
 

src/lolwut6.c

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2019, Salvatore Sanfilippo <antirez at gmail dot com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of Redis nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * ----------------------------------------------------------------------------
+ *
+ * This file implements the LOLWUT command. The command should do something
+ * fun and interesting, and should be replaced by a new implementation at
+ * each new version of Redis.
+ */
+
+#include "server.h"
+#include "lolwut.h"
+
+/* The LOLWUT 6 command:
+ *
+ * LOLWUT [columns] [rows]
+ *
+ * By default the command uses 80 columns, 40 squares per row
+ * per column.
+ */
+void lolwut6Command(client *c) {
+    long cols = 80;
+    long rows = 40;
+
+    /* Parse the optional arguments if any. */
+    if (c->argc > 1 &&
+        getLongFromObjectOrReply(c,c->argv[1],&cols,NULL) != C_OK)
+        return;
+
+    if (c->argc > 2 &&
+        getLongFromObjectOrReply(c,c->argv[2],&rows,NULL) != C_OK)
+        return;
+
+    /* Limits. We want LOLWUT to be always reasonably fast and cheap to execute
+     * so we have maximum number of columns, rows, and output resulution. */
+    if (cols < 1) cols = 1;
+    if (cols > 1000) cols = 1000;
+    if (rows < 1) rows = 1;
+    if (rows > 1000) rows = 1000;
+
+    /* Generate the city skyline and reply. */
+    sds rendered = sdsempty();
+    rendered = sdscat(rendered,
+        "\nDedicated to the 8 bit game developers of the past. Redis ver. ");
+    rendered = sdscat(rendered,REDIS_VERSION);
+    rendered = sdscatlen(rendered,"\n",1);
+    addReplyVerbatim(c,rendered,sdslen(rendered),"txt");
+    sdsfree(rendered);
+    // lwFreeCanvas(canvas);
+}