[Qemu-devel] [RfC PATCH] add pflib: PixelFormat conversion library.

[Gerd Hoffmann <kraxel@redhat.com>]

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 Makefile.objs |    1 +
 pflib.c       |  204 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 pflib.h       |    6 ++
 3 files changed, 211 insertions(+), 0 deletions(-)
 create mode 100644 pflib.c
 create mode 100644 pflib.h

diff --git a/Makefile.objs b/Makefile.objs
index 2dad0f9..6201675 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -83,6 +83,7 @@ common-obj-y += qemu-char.o savevm.o #aio.o
 common-obj-y += msmouse.o ps2.o
 common-obj-y += qdev.o qdev-properties.o
 common-obj-y += block-migration.o
+common-obj-y += pflib.o
 
 common-obj-$(CONFIG_BRLAPI) += baum.o
 common-obj-$(CONFIG_POSIX) += migration-exec.o migration-unix.o migration-fd.o
diff --git a/pflib.c b/pflib.c
new file mode 100644
index 0000000..1c04378
--- /dev/null
+++ b/pflib.c
@@ -0,0 +1,204 @@
+#include "qemu-common.h"
+#include "console.h"
+#include "pflib.h"
+
+typedef struct QemuPixel QemuPixel;
+
+typedef void (*pf_convert)(QemuPfConv *conv,
+                           void *dst, void *src, uint32_t cnt);
+typedef void (*pf_convert_from)(PixelFormat *pf,
+                                QemuPixel *dst, void *src, uint32_t cnt);
+typedef void (*pf_convert_to)(PixelFormat *pf,
+                              void *dst, QemuPixel *src, uint32_t cnt);
+
+struct QemuPfConv {
+    pf_convert        convert;
+    PixelFormat       src;
+    PixelFormat       dst;
+
+    /* for copy_generic() */
+    pf_convert_from   conv_from;
+    pf_convert_to     conv_to;
+    QemuPixel         *conv_buf;
+    uint32_t          conv_cnt;
+};
+
+struct QemuPixel {
+    uint8_t red;
+    uint8_t green;
+    uint8_t blue;
+    uint8_t alpha;
+};
+
+/* ----------------------------------------------------------------------- */
+/* PixelFormat -> QemuPixel conversions                                    */
+
+static void conv_16_to_pixel(PixelFormat *pf,
+                             QemuPixel *dst, void *src, uint32_t cnt)
+{
+    uint16_t *src16 = src;
+
+    while (cnt > 0) {
+        dst->red   = ((*src16 & pf->rmask) >> pf->rshift) << (8 - pf->rbits);
+        dst->green = ((*src16 & pf->gmask) >> pf->gshift) << (8 - pf->gbits);
+        dst->blue  = ((*src16 & pf->bmask) >> pf->bshift) << (8 - pf->bbits);
+        dst->alpha = ((*src16 & pf->amask) >> pf->ashift) << (8 - pf->abits);
+        dst++, src16++, cnt--;
+    }
+}
+
+/* assumes pf->{r,g,b,a}bits == 8 */
+static void conv_32_to_pixel_fast(PixelFormat *pf,
+                                  QemuPixel *dst, void *src, uint32_t cnt)
+{
+    uint32_t *src32 = src;
+
+    while (cnt > 0) {
+        dst->red   = (*src32 & pf->rmask) >> pf->rshift;
+        dst->green = (*src32 & pf->gmask) >> pf->gshift;
+        dst->blue  = (*src32 & pf->bmask) >> pf->bshift;
+        dst->alpha = (*src32 & pf->amask) >> pf->ashift;
+        dst++, src32++, cnt--;
+    }
+}
+
+static void conv_32_to_pixel_generic(PixelFormat *pf,
+                                     QemuPixel *dst, void *src, uint32_t cnt)
+{
+    uint32_t *src32 = src;
+
+    while (cnt > 0) {
+        if (pf->rbits < 8) {
+            dst->red   = ((*src32 & pf->rmask) >> pf->rshift) << (8 - pf->rbits);
+        } else {
+            dst->red   = ((*src32 & pf->rmask) >> pf->rshift) >> (pf->rbits - 8);
+        }
+        if (pf->gbits < 8) {
+            dst->green = ((*src32 & pf->gmask) >> pf->gshift) << (8 - pf->gbits);
+        } else {
+            dst->green = ((*src32 & pf->gmask) >> pf->gshift) >> (pf->gbits - 8);
+        }
+        if (pf->bbits < 8) {
+            dst->blue  = ((*src32 & pf->bmask) >> pf->bshift) << (8 - pf->bbits);
+        } else {
+            dst->blue  = ((*src32 & pf->bmask) >> pf->bshift) >> (pf->bbits - 8);
+        }
+        if (pf->abits < 8) {
+            dst->alpha = ((*src32 & pf->amask) >> pf->ashift) << (8 - pf->abits);
+        } else {
+            dst->alpha = ((*src32 & pf->amask) >> pf->ashift) >> (pf->abits - 8);
+        }
+        dst++, src32++, cnt--;
+    }
+}
+
+/* ----------------------------------------------------------------------- */
+/* QemuPixel -> PixelFormat conversions                                    */
+
+static void conv_pixel_to_16(PixelFormat *pf,
+                             void *dst, QemuPixel *src, uint32_t cnt)
+{
+    uint16_t *dst16 = dst;
+
+    while (cnt > 0) {
+        *dst16  = ((uint16_t)src->red   >> (8 - pf->rbits)) << pf->rshift;
+        *dst16 |= ((uint16_t)src->green >> (8 - pf->gbits)) << pf->gshift;
+        *dst16 |= ((uint16_t)src->blue  >> (8 - pf->bbits)) << pf->bshift;
+        *dst16 |= ((uint16_t)src->alpha >> (8 - pf->abits)) << pf->ashift;
+        dst16++, src++, cnt--;
+    }
+}
+
+static void conv_pixel_to_32(PixelFormat *pf,
+                             void *dst, QemuPixel *src, uint32_t cnt)
+{
+    uint32_t *dst32 = dst;
+
+    while (cnt > 0) {
+        *dst32  = ((uint32_t)src->red   >> (8 - pf->rbits)) << pf->rshift;
+        *dst32 |= ((uint32_t)src->green >> (8 - pf->gbits)) << pf->gshift;
+        *dst32 |= ((uint32_t)src->blue  >> (8 - pf->bbits)) << pf->bshift;
+        *dst32 |= ((uint32_t)src->alpha >> (8 - pf->abits)) << pf->ashift;
+        dst32++, src++, cnt--;
+    }
+}
+
+/* ----------------------------------------------------------------------- */
+/* PixelFormat -> PixelFormat conversions                                  */
+
+static void convert_copy(QemuPfConv *conv, void *dst, void *src, uint32_t cnt)
+{
+    uint32_t bytes = cnt * conv->src.bytes_per_pixel;
+    memcpy(dst, src, bytes);
+}
+
+static void convert_generic(QemuPfConv *conv, void *dst, void *src, uint32_t cnt)
+{
+    if (conv->conv_cnt < cnt) {
+        conv->conv_cnt = cnt;
+        conv->conv_buf = qemu_realloc(conv->conv_buf, sizeof(QemuPixel) * conv->conv_cnt);
+    }
+    conv->conv_from(&conv->src, conv->conv_buf, src, cnt);
+    conv->conv_to(&conv->dst, dst, conv->conv_buf, cnt);
+}
+
+/* ----------------------------------------------------------------------- */
+/* public interface                                                        */
+
+QemuPfConv *qemu_pf_conv_get(PixelFormat *dst, PixelFormat *src)
+{
+    QemuPfConv *conv = qemu_mallocz(sizeof(QemuPfConv));
+
+    conv->src = *src;
+    conv->dst = *dst;
+
+    if (memcmp(&conv->src, &conv->dst, sizeof(PixelFormat)) == 0) {
+        /* formats identical, can simply copy */
+        conv->convert = convert_copy;
+    } else {
+        /* generic two-step conversion: src -> QemuPixel -> dst  */
+        switch (conv->src.bytes_per_pixel) {
+        case 2:
+            conv->conv_from = conv_16_to_pixel;
+            break;
+        case 4:
+            if (conv->src.rbits == 8 && conv->src.gbits == 8 && conv->src.bbits == 8) {
+                conv->conv_from = conv_32_to_pixel_fast;
+            } else {
+                conv->conv_from = conv_32_to_pixel_generic;
+            }
+            break;
+        default:
+            goto err;
+        }
+        switch (conv->dst.bytes_per_pixel) {
+        case 2:
+            conv->conv_to = conv_pixel_to_16;
+            break;
+        case 4:
+            conv->conv_to = conv_pixel_to_32;
+            break;
+        default:
+            goto err;
+        }
+        conv->convert = convert_generic;
+    }
+    return conv;
+
+err:
+    qemu_free(conv);
+    return NULL;
+}
+
+void qemu_pf_conv_run(QemuPfConv *conv, void *dst, void *src, uint32_t cnt)
+{
+    conv->convert(conv, dst, src, cnt);
+}
+
+void qemu_pf_conv_put(QemuPfConv *conv)
+{
+    if (conv) {
+        qemu_free(conv->conv_buf);
+        qemu_free(conv);
+    }
+}
diff --git a/pflib.h b/pflib.h
new file mode 100644
index 0000000..8d73fdd
--- /dev/null
+++ b/pflib.h
@@ -0,0 +1,6 @@
+/* public */
+typedef struct QemuPfConv QemuPfConv;
+
+QemuPfConv *qemu_pf_conv_get(PixelFormat *dst, PixelFormat *src);
+void qemu_pf_conv_run(QemuPfConv *conv, void *dst, void *src, uint32_t cnt);
+void qemu_pf_conv_put(QemuPfConv *conv);
-- 
1.6.5.2