stb_vorbis: logically dead code in decode_residue

[kcgen]

2126 static void decode_residue(vorb *f, float *residue_buffers[], int ch, int n, int rn, uint8 *do_not_decode)
2127{
2128   int i,j,pass;
2129   Residue *r = f->residue_config + rn;
2130   int rtype = f->residue_types[rn];
2131   int c = r->classbook;
2132   int classwords = f->codebooks[c].dimensions;
2133   unsigned int actual_size = rtype == 2 ? n*2 : n;
2134   unsigned int limit_r_begin = (r->begin < actual_size ? r->begin : actual_size);
2135   unsigned int limit_r_end   = (r->end   < actual_size ? r->end   : actual_size);
2136   int n_read = limit_r_end - limit_r_begin;
2137   int part_read = n_read / r->part_size;
2138   int temp_alloc_point = temp_alloc_save(f);
2139   #ifndef STB_VORBIS_DIVIDES_IN_RESIDUE
    	CID 24071: Wrong sizeof argument (SIZEOF_MISMATCH) [select issue]
2140   uint8 ***part_classdata = (uint8 ***) temp_block_array(f,f->channels, part_read * sizeof(**part_classdata));
2141   #else
2142   int **classifications = (int **) temp_block_array(f,f->channels, part_read * sizeof(**classifications));
2143   #endif
2144
2145   CHECK(f);
2146
    	cond_at_most: Condition i < ch, taking false branch. Now the value of ch is at most 0.
    	cond_at_least: Condition i < ch, taking true branch. Now the value of ch is at least 1.
    	cond_at_least: Condition i < ch, taking true branch. Now the value of ch is at least 2.
    	assignment: Assigning: i = 0.
    	incr: Incrementing i. The value of i is now 1.
2147   for (i=0; i < ch; ++i)
2148      if (!do_not_decode[i])
2149         memset(residue_buffers[i], 0, sizeof(float) * n);
2150
    	cond_cannot_single: Condition ch != 1, taking true branch. Now the value of ch cannot be equal to 1.
2151   if (rtype == 2 && ch != 1) {
    	cond_at_most: Condition j < ch, taking false branch. Now the value of ch is at most 0.
    	cond_at_least: Condition j < ch, taking true branch. Now the value of ch is at least 2.
    	incr: Incrementing j. The value of j is now 1.
    	cond_at_least: Condition j < ch, taking true branch. Now the value of ch is at least 3.
    	assignment: Assigning: j = 0.
    	incr: Incrementing j. The value of j is now 2.
2152      for (j=0; j < ch; ++j)
2153         if (!do_not_decode[j])
2154            break;
    	cond_cannot_set: Condition j == ch, taking false branch. Now the value of ch cannot be equal to any of {0, 1}.
2155      if (j == ch)
2156         goto done;
2157
2158      for (pass=0; pass < 8; ++pass) {
2159         int pcount = 0, class_set = 0;
    	cond_cannot_set: Condition ch == 2, taking false branch. Now the value of ch cannot be equal to any of {0, 1, 2}.
    	cond_cannot_set: Condition ch == 2, taking false branch. Now the value of ch cannot be equal to any of {1, 2}.
2160         if (ch == 2) {
2161            while (pcount < part_read) {
2162               int z = r->begin + pcount*r->part_size;
2163               int c_inter = (z & 1), p_inter = z>>1;
2164               if (pass == 0) {
2165                  Codebook *c = f->codebooks+r->classbook;
2166                  int q;
2167                  DECODE(q,f,c);
2168                  if (q == EOP) goto done;
2169                  #ifndef STB_VORBIS_DIVIDES_IN_RESIDUE
2170                  part_classdata[0][class_set] = r->classdata[q];
2171                  #else
2172                  for (i=classwords-1; i >= 0; --i) {
2173                     classifications[0][i+pcount] = q % r->classifications;
2174                     q /= r->classifications;
2175                  }
2176                  #endif
2177               }
2178               for (i=0; i < classwords && pcount < part_read; ++i, ++pcount) {
2179                  int z = r->begin + pcount*r->part_size;
2180                  #ifndef STB_VORBIS_DIVIDES_IN_RESIDUE
2181                  int c = part_classdata[0][class_set][i];
2182                  #else
2183                  int c = classifications[0][pcount];
2184                  #endif
2185                  int b = r->residue_books[c][pass];
2186                  if (b >= 0) {
2187                     Codebook *book = f->codebooks + b;
2188                     #ifdef STB_VORBIS_DIVIDES_IN_CODEBOOK
2189                     if (!codebook_decode_deinterleave_repeat(f, book, residue_buffers, ch, &c_inter, &p_inter, n, r->part_size))
2190                        goto done;
2191                     #else
2192                     // saves 1%
2193                     if (!codebook_decode_deinterleave_repeat(f, book, residue_buffers, ch, &c_inter, &p_inter, n, r->part_size))
2194                        goto done;
2195                     #endif
2196                  } else {
2197                     z += r->part_size;
2198                     c_inter = z & 1;
2199                     p_inter = z >> 1;
2200                  }
2201               }
2202               #ifndef STB_VORBIS_DIVIDES_IN_RESIDUE
2203               ++class_set;
2204               #endif
2205            }
    	intervals: At condition ch == 1, the value of ch must be in one of the following intervals: {(-inf,-1], [3,+inf)}.
    	cannot_set: At condition ch == 1, the value of ch cannot be equal to any of {1, 2}.
    	dead_error_condition: The condition ch == 1 cannot be true.
2206         } else if (ch == 1) {
    	
CID 24053 (#1 of 1): Logically dead code (DEADCODE)
dead_error_line: Execution cannot reach this statement: while (pcount < part_read) ....
2207            while (pcount < part_read) {

[nothings]

fixed by #854