img2twit: store w+1,h+1 instead of w,h since neither width nor height can

be zero.

git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/libpipi/trunk@3531 92316355-f0b4-4df1-b90c-862c8a59935f

examples/img2twit.cpp

@@ -62,8 +62,8 @@ static const uint32_t unichars_symbols[] = { RANGE_SYMBOLS, RANGE_END };
 static const uint32_t *unichars;
 
 /* The maximum image size we want to support */
-#define MAX_W 4000
-#define MAX_H 4000
+#define RANGE_W 4000
+#define RANGE_H 4000
 
 /* How does the algorithm work: one point per cell, or two */
 #define POINTS_PER_CELL 2
@@ -442,11 +442,22 @@ static inline float int2fullrange(int val, int range)
     return range > 1 ? (float)val / (float)(range - 1) : 0.0;
 }
 
+static inline void index2cell(int index, int *dx, int *dy)
+{
+    // This check will be used once we add points to our list
+    //if(index < dw * dh * POINTS_PER_CELL)
+    {
+        *dx = (index / POINTS_PER_CELL) % dw;
+        *dy = (index / POINTS_PER_CELL) / dw;
+    }
+}
+
 static inline void set_point(int index, float x, float y, float r,
                              float g, float b, float s)
 {
-    int dx = (index / POINTS_PER_CELL) % dw;
-    int dy = (index / POINTS_PER_CELL) / dw;
+    int dx, dy;
+
+    index2cell(index, &dx, &dy);
 
     float fx = (x - dx * RANGE_X) / RANGE_X;
     float fy = (y - dy * RANGE_Y) / RANGE_Y;
@@ -468,9 +479,9 @@ static inline void get_point(int index, float *x, float *y, float *r,
                              float *g, float *b, float *s, bool final = false)
 {
     uint32_t pt = points[index];
+    int dx, dy;
 
-    unsigned int dx = (index / POINTS_PER_CELL) % dw;
-    unsigned int dy = (index / POINTS_PER_CELL) / dw;
+    index2cell(index, &dx, &dy);
 
     *s = int2fullrange(pt % RANGE_S, RANGE_S); pt /= RANGE_S;
 
@@ -936,6 +947,9 @@ int main(int argc, char *argv[])
         return EXIT_FAILURE;
     }
 
+    bitstack b(MAX_MSG_LEN); /* We cannot declare this before, because
+                              * MAX_MSG_LEN wouldn't be defined. */
+
     /* Autodetect charset if decoding, otherwise switch to CJK. */
     if(dstname)
     {
@@ -972,23 +986,6 @@ int main(int argc, char *argv[])
 
     /* Precompute bit allocation */
     NUM_CHARACTERS = count_unichars();
-    TOTAL_BITS = MAX_MSG_LEN * logf(NUM_CHARACTERS) / logf(2);
-    HEADER_BITS = logf(MAX_W * MAX_H) / logf(2);
-    DATA_BITS = TOTAL_BITS - HEADER_BITS;
-#if POINTS_PER_CELL == 1
-    CELL_BITS = logf(RANGE_SYXRGB) / logf(2);
-#else
-    // TODO: implement the following shit
-    //float coord_bits = logf((RANGE_Y * RANGE_X) * (RANGE_Y * RANGE_X + 1) / 2);
-    //float other_bits = logf(RANGE_R * RANGE_G * RANGE_B * RANGE_S);
-    //CELL_BITS = (coord_bits + 2 * other_bits) / logf(2);
-    CELL_BITS = 2 * logf(RANGE_SYXRGB) / logf(2);
-#endif
-    TOTAL_CELLS = (int)(DATA_BITS / CELL_BITS);
-    MAX_ITERATIONS = ITERATIONS_PER_POINT * POINTS_PER_CELL * TOTAL_CELLS;
-
-    bitstack b(MAX_MSG_LEN); /* We cannot declare this before, because
-                              * MAX_MSG_LEN wouldn't be defined. */
 
     if(dstname)
     {
@@ -999,8 +996,8 @@ int main(int argc, char *argv[])
 
         /* Read width and height from bitstream */
         src = NULL;
-        width = b.pop(MAX_W);
-        height = b.pop(MAX_H);
+        width = b.pop(RANGE_W) + 1;
+        height = b.pop(RANGE_H) + 1;
     }
     else
     {
@@ -1017,6 +1014,28 @@ int main(int argc, char *argv[])
         height = pipi_get_image_height(src);
     }
 
+    if(width <= 0 || height <= 0 || width > RANGE_W || height > RANGE_H)
+    {
+        fprintf(stderr, "Error: image size %ix%i is out of bounds\n",
+                width, height);
+        return EXIT_FAILURE;
+    }
+
+    TOTAL_BITS = MAX_MSG_LEN * logf(NUM_CHARACTERS) / logf(2);
+    HEADER_BITS = logf(RANGE_W * RANGE_H) / logf(2);
+    DATA_BITS = TOTAL_BITS - HEADER_BITS;
+#if POINTS_PER_CELL == 1
+    CELL_BITS = logf(RANGE_SYXRGB) / logf(2);
+#else
+    // TODO: implement the following shit
+    //float coord_bits = logf((RANGE_Y * RANGE_X) * (RANGE_Y * RANGE_X + 1) / 2);
+    //float other_bits = logf(RANGE_R * RANGE_G * RANGE_B * RANGE_S);
+    //CELL_BITS = (coord_bits + 2 * other_bits) / logf(2);
+    CELL_BITS = 2 * logf(RANGE_SYXRGB) / logf(2);
+#endif
+    TOTAL_CELLS = (int)(DATA_BITS / CELL_BITS);
+    MAX_ITERATIONS = ITERATIONS_PER_POINT * POINTS_PER_CELL * TOTAL_CELLS;
+
     /* Compute "best" w/h ratio */
     dw = 1; dh = TOTAL_CELLS;
     for(unsigned int i = 1; i <= TOTAL_CELLS; i++)
@@ -1042,10 +1061,12 @@ int main(int argc, char *argv[])
         fprintf(stderr, "Message size: %i\n", MAX_MSG_LEN);
         fprintf(stderr, "Available characters: %i\n", NUM_CHARACTERS);
         fprintf(stderr, "Available bits: %f\n", TOTAL_BITS);
-        fprintf(stderr, "Maximum image resolution: %ix%i\n", MAX_W, MAX_H);
+        fprintf(stderr, "Width/Height ranges: %ix%i\n", RANGE_W, RANGE_H);
         fprintf(stderr, "Image resolution: %ix%i\n", width, height);
         fprintf(stderr, "Header bits: %f\n", HEADER_BITS);
         fprintf(stderr, "Bits available for data: %f\n", DATA_BITS);
+        fprintf(stderr, "X/Y/Red/Green/Blue/Extra ranges: %i %i %i %i %i %i\n",
+                RANGE_X, RANGE_Y, RANGE_R, RANGE_G, RANGE_B, RANGE_S);
         fprintf(stderr, "Cell bits: %f\n", CELL_BITS);
         fprintf(stderr, "Available cells: %i\n", TOTAL_CELLS);
         fprintf(stderr, "Wasted bits: %f\n",
@@ -1210,8 +1231,8 @@ int main(int argc, char *argv[])
         /* Push our points to the bitstream */
         for(int i = 0; i < npoints; i++)
             b.push(points[i], RANGE_SYXRGB);
-        b.push(height, MAX_H);
-        b.push(width, MAX_W);
+        b.push(height - 1, RANGE_H);
+        b.push(width - 1, RANGE_W);
 
         /* Pop Unicode characters from the bitstream and print them */
         for(int i = 0; i < MAX_MSG_LEN; i++)