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Diffstat (limited to 'src/lolwut.c')
| -rw-r--r-- | src/lolwut.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/src/lolwut.c b/src/lolwut.c new file mode 100644 index 0000000..c014840 --- /dev/null +++ b/src/lolwut.c @@ -0,0 +1,188 @@ +/* + * Copyright (c) 2018, 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" +#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. */ +void lolwutUnstableCommand(client *c) { + sds rendered = sdsnew("Redis ver. "); + rendered = sdscat(rendered,REDIS_VERSION); + rendered = sdscatlen(rendered,"\n",1); + addReplyVerbatim(c,rendered,sdslen(rendered),"txt"); + sdsfree(rendered); +} + +/* LOLWUT [VERSION <version>] [... version specific arguments ...] */ +void lolwutCommand(client *c) { + char *v = REDIS_VERSION; + char verstr[64]; + + if (c->argc >= 3 && !strcasecmp(c->argv[1]->ptr,"version")) { + long ver; + if (getLongFromObjectOrReply(c,c->argv[2],&ver,NULL) != C_OK) return; + snprintf(verstr,sizeof(verstr),"%u.0.0",(unsigned int)ver); + v = verstr; + + /* Adjust argv/argc to filter the "VERSION ..." option, since the + * specific LOLWUT version implementations don't know about it + * and expect their arguments. */ + c->argv += 2; + c->argc -= 2; + } + + 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); + + /* Fix back argc/argv in case of VERSION argument. */ + if (v == verstr) { + c->argv -= 2; + c->argc += 2; + } +} + +/* ========================== LOLWUT Canvas =============================== + * Many LOLWUT 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, int bgcolor) { + lwCanvas *canvas = zmalloc(sizeof(*canvas)); + canvas->width = width; + canvas->height = height; + canvas->pixels = zmalloc((size_t)width*height); + memset(canvas->pixels,bgcolor,(size_t)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 displayed, 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); +} |