static int EmitRescaledRGB(const VP8Io* const io, WebPDecParams* const p) {
const int mb_h = io->mb_h;
const int uv_mb_h = (mb_h + 1) >> 1;
int j = 0, uv_j = 0;
int num_lines_out = 0;
while (j < mb_h) {
const int y_lines_in =
WebPRescalerImport(p->scaler_y, mb_h - j,
io->y + j * io->y_stride, io->y_stride);
j += y_lines_in;
if (WebPRescaleNeededLines(p->scaler_u, uv_mb_h - uv_j)) {
const int u_lines_in =
WebPRescalerImport(p->scaler_u, uv_mb_h - uv_j,
io->u + uv_j * io->uv_stride, io->uv_stride);
const int v_lines_in =
WebPRescalerImport(p->scaler_v, uv_mb_h - uv_j,
io->v + uv_j * io->uv_stride, io->uv_stride);
(void)v_lines_in; // remove a gcc warning
assert(u_lines_in == v_lines_in);
uv_j += u_lines_in;
}
num_lines_out += ExportRGB(p, p->last_y + num_lines_out);
}
return num_lines_out;
}
static int Rescale(const uint8_t* src, int src_stride,
int new_lines, WebPRescaler* const wrk) {
int num_lines_out = 0;
while (new_lines > 0) { // import new contributions of source rows.
const int lines_in = WebPRescalerImport(wrk, new_lines, src, src_stride);
src += lines_in * src_stride;
new_lines -= lines_in;
num_lines_out += WebPRescalerExport(wrk); // emit output row(s)
}
return num_lines_out;
}
static int Rescale(const uint8_t* src, int src_stride,
int new_lines, WebPRescaler* const wrk) {
int num_lines_out = 0;
while (new_lines > 0) {
const int lines_in = WebPRescalerImport(wrk, new_lines, src, src_stride);
src += lines_in * src_stride;
new_lines -= lines_in;
num_lines_out += WebPRescalerExport(wrk);
}
return num_lines_out;
}
static int EmitRescaledAlphaRGB(const VP8Io* const io, WebPDecParams* const p) {
if (io->a != NULL) {
WebPRescaler* const scaler = &p->scaler_a;
int j = 0;
int pos = 0;
while (j < io->mb_h) {
j += WebPRescalerImport(scaler, io->mb_h - j,
io->a + j * io->width, io->width);
pos += p->emit_alpha_row(p, pos);
}
}
return 0;
}
static int EmitRescaledRGB(const VP8Io* const io, WebPDecParams* const p) {
const int mb_h = io->mb_h;
const int uv_mb_h = (mb_h + 1) >> 1;
int j = 0, uv_j = 0;
int num_lines_out = 0;
while (j < mb_h) {
const int y_lines_in =
WebPRescalerImport(&p->scaler_y, mb_h - j,
io->y + j * io->y_stride, io->y_stride);
const int u_lines_in =
WebPRescalerImport(&p->scaler_u, uv_mb_h - uv_j,
io->u + uv_j * io->uv_stride, io->uv_stride);
const int v_lines_in =
WebPRescalerImport(&p->scaler_v, uv_mb_h - uv_j,
io->v + uv_j * io->uv_stride, io->uv_stride);
(void)v_lines_in;
assert(u_lines_in == v_lines_in);
j += y_lines_in;
uv_j += u_lines_in;
num_lines_out += ExportRGB(p, num_lines_out);
}
return num_lines_out;
}
static int EmitRescaledAlphaRGB(const VP8Io* const io, WebPDecParams* const p,
int expected_num_out_lines) {
if (io->a != NULL) {
WebPRescaler* const scaler = p->scaler_a;
int lines_left = expected_num_out_lines;
const int y_end = p->last_y + lines_left;
while (lines_left > 0) {
const int row_offset = scaler->src_y - io->mb_y;
WebPRescalerImport(scaler, io->mb_h + io->mb_y - scaler->src_y,
io->a + row_offset * io->width, io->width);
lines_left -= p->emit_alpha_row(p, y_end - lines_left, lines_left);
}
}
return 0;
}