void png_read_push_finish_row(png_structp png_ptr) { png_ptr->row_number++; if (png_ptr->row_number < png_ptr->num_rows) return; if (png_ptr->interlaced) { png_ptr->row_number = 0; png_memset_check(png_ptr, png_ptr->prev_row, 0, png_ptr->rowbytes + 1); do { png_ptr->pass++; if (png_ptr->pass >= 7) break; png_ptr->iwidth = (png_ptr->width + png_pass_inc[png_ptr->pass] - 1 - png_pass_start[png_ptr->pass]) / png_pass_inc[png_ptr->pass]; png_ptr->irowbytes = ((png_ptr->iwidth * png_ptr->pixel_depth + 7) >> 3) + 1; if (!(png_ptr->transformations & PNG_INTERLACE)) { png_ptr->num_rows = (png_ptr->height + png_pass_yinc[png_ptr->pass] - 1 - png_pass_ystart[png_ptr->pass]) / png_pass_yinc[png_ptr->pass]; if (!(png_ptr->num_rows)) continue; } if (png_ptr->transformations & PNG_INTERLACE) break; } while (png_ptr->iwidth == 0); }
void /* PRIVATE */ png_read_push_finish_row(png_structp png_ptr) { #ifdef PNG_USE_LOCAL_ARRAYS /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */ /* start of interlace block */ PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; /* offset to next interlace block */ PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; /* start of interlace block in the y direction */ PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1}; /* offset to next interlace block in the y direction */ PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2}; /* Height of interlace block. This is not currently used - if you need * it, uncomment it here and in png.h PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1}; */ #endif png_ptr->row_number++; if (png_ptr->row_number < png_ptr->num_rows) return; if (png_ptr->interlaced) { png_ptr->row_number = 0; png_memset_check(png_ptr, png_ptr->prev_row, 0, png_ptr->rowbytes + 1); do { png_ptr->pass++; if ((png_ptr->pass == 1 && png_ptr->width < 5) || (png_ptr->pass == 3 && png_ptr->width < 3) || (png_ptr->pass == 5 && png_ptr->width < 2)) png_ptr->pass++; if (png_ptr->pass > 7) png_ptr->pass--; if (png_ptr->pass >= 7) break; png_ptr->iwidth = (png_ptr->width + png_pass_inc[png_ptr->pass] - 1 - png_pass_start[png_ptr->pass]) / png_pass_inc[png_ptr->pass]; png_ptr->irowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, png_ptr->iwidth) + 1; if (png_ptr->transformations & PNG_INTERLACE) break; png_ptr->num_rows = (png_ptr->height + png_pass_yinc[png_ptr->pass] - 1 - png_pass_ystart[png_ptr->pass]) / png_pass_yinc[png_ptr->pass]; } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0); } }