puzzles: add formatting to help viewer

The help text is now processed to generate a style array to pass to the
display_text library in addition to the text itself. The help text is still
compressed using LZ4, and still fits on the c200v2.

Change-Id: I7a3a664f90f67a1a018956c72d2b62d92b8ffd17

apps/plugins/puzzles/compress.c

@@ -2,11 +2,14 @@
  * output. Do not directly compile or use this program, instead it
  * will be automatically used by genhelp.sh */
 
+#include <assert.h>
 #include <ctype.h>
 #include <lz4hc.h>
-#include <string.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
+
 #include "help.h"
 
 char *compress(const char *in, int inlen, int *rc, int *minsz, int *minlev)
@@ -18,7 +21,7 @@ char *compress(const char *in, int inlen, int *rc, int *minsz, int *minlev)
 
     for(int i = LZ4HC_CLEVEL_MIN; i < LZ4HC_CLEVEL_MAX; ++i)
     {
-        *rc = LZ4_compress_HC(help_text, outbuf, inlen, maxsz, i);
+        *rc = LZ4_compress_HC(in, outbuf, inlen, maxsz, i);
         if(!*rc)
         {
             fprintf(stderr, "compress failed\n");
@@ -30,7 +33,7 @@ char *compress(const char *in, int inlen, int *rc, int *minsz, int *minlev)
             *minlev = i;
         }
     }
-    *rc = LZ4_compress_HC(help_text, outbuf, inlen, maxsz, *minlev);
+    *rc = LZ4_compress_HC(in, outbuf, inlen, maxsz, *minlev);
     return outbuf;
 }
 
@@ -42,28 +45,121 @@ void dump_bytes(unsigned char *buf, int len)
         int stop = i + 10;
         for(;i < stop && i < len; ++i)
         {
-            printf("0x%02x, ", buf[i]);
+            unsigned char c = buf[i];
+            printf("0x%02x,", c);
+            if(i != stop - 1 && i != len - 1)
+                printf(" ");
         }
         printf("\n");
     }
 }
 
+/* Input: help text in help_text array (to be compiled against) as a
+ * standard C string
+ * Output: C source code on stdout defining the following:
+ *
+ * const char help_text_words[];
+ * const unsigned short help_text_len;
+ * const struct style_text help_text_style[];
+ *
+ * help_text_words consists of help_text_len bytes containing the
+ * words of the help text, delimited with NULs, not a standard C
+ * string. The rockbox frontend is responsible for generating an array
+ * of pointers into this array to pass to display_text. */
+
 int main()
 {
-    int inlen = strlen(help_text) + 1, len;
+    int inlen = strlen(help_text) + 1, outlen;
     int minsz, minlev;
-    unsigned char *outbuf = compress(help_text, inlen, &len, &minsz, &minlev);
 
     printf("/* auto-generated on " __DATE__ " by genhelp.sh */\n");
-    printf("/* orig %d comp %d ratio %g level %d saved %d */\n", inlen, minsz, (double)minsz / inlen, minlev, inlen - minsz);
+    printf("/* help text is compressed using LZ4; see compress.c for details */\n");
     printf("/* DO NOT EDIT! */\n\n");
+
+    printf("#include \"lib/display_text.h\"\n\n");
+
+    printf("const struct style_text help_text_style[] = {\n");
+
+    /* break up words on spaces and newline while printing indices of
+     * underlined words */
+    char *buf = strdup(help_text);
+    bool underline = false, center = false;
+    int word_idx = 0, help_text_len = inlen;
+
+    for(int i = 0; i < help_text_len; ++i)
+    {
+        switch(buf[i])
+        {
+        case '#':
+        case '_':
+            /* title or underlined portion */
+            if(buf[i] == '#')
+            {
+                center = !center;
+                if(center)
+                    printf(" { %d, TEXT_CENTER | C_RED },\n", word_idx);
+            }
+            else
+            {
+                /* underline */
+                underline = !underline;
+
+                if(underline)
+                    printf(" { %d, TEXT_UNDERLINE },\n", word_idx);
+            }
+
+            /* delete the formatting character */
+            memmove(buf + i, buf + i + 1, help_text_len - i - 1);
+            --help_text_len;
+            --i;
+            break;
+        case '$':
+            /* genhelp.sh replaces the dollar signs in URLs with
+             * dollar signs to help us out. */
+            buf[i] = '_';
+            break;
+        case '\n':
+            center = false;
+            /* fall through */
+        case ' ':
+        case '\0':
+            /* Groups of words that are centered or underlined are
+             * counted as a single "word". */
+            if(!underline && !center)
+            {
+                buf[i] = '\0';
+                ++word_idx;
+            }
+            break;
+        }
+    }
+    /* sanity check */
+    int words_check = 0;
+    for(int i = 0; i < help_text_len; ++i)
+        if(!buf[i])
+        {
+            ++words_check;
+        }
+
+    assert(words_check == word_idx);
+
+    printf(" LAST_STYLE_ITEM\n};\n\n");
+
+    /* remove trailing NULs */
+    for(int i = help_text_len - 2; i >= 0 && !buf[i]; --i, --help_text_len, --word_idx);
+
+    unsigned char *outbuf = compress(buf, help_text_len, &outlen, &minsz, &minlev);
+
+    printf("/* orig %d comp %d ratio %g level %d saved %d */\n", help_text_len, minsz, (double)minsz / help_text_len, minlev, help_text_len - minsz);
     printf("const char help_text[] = {\n");
 
-    dump_bytes(outbuf, len);
+    dump_bytes(outbuf, outlen);
     free(outbuf);
+    free(buf);
 
-    printf("};\n");
-    printf("const unsigned short help_text_len = %d;\n", inlen);
+    printf("};\n\n");
+    printf("const unsigned short help_text_len = %d;\n", help_text_len);
+    printf("const unsigned short help_text_words = %d;\n", word_idx);
 
     return 0;
 }