clean up bilinear filter

make reference version of bilinear_filters short.
use reference versions of bilinear_filters and sub_pel_filters when
possible.

recognize that Width was being passed into
filter_block2d_bil_first_pass multiple times. ARM version had already
fixed this. propegate to C.

change references to src_pixels_per_line to src_pitch and standardize on
src/dst (instead of input/output).

recognize that first_pass is only run in the verticle and second_pass
only horizontal. ARM version had already fixed this. propegate to C

Change-Id: I292d376d239a9a7ca37ec2bf03cc0720606983e2
diff --git a/vp8/common/filter.c b/vp8/common/filter.c
new file mode 100644
index 0000000..6e364a9
--- /dev/null
+++ b/vp8/common/filter.c
@@ -0,0 +1,520 @@
+/*
+ *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+
+#include <stdlib.h>
+#include "filter.h"
+#include "vpx_ports/mem.h"
+
+DECLARE_ALIGNED(16, const short, vp8_bilinear_filters[8][2]) =
+{
+    { 128,   0 },
+    { 112,  16 },
+    {  96,  32 },
+    {  80,  48 },
+    {  64,  64 },
+    {  48,  80 },
+    {  32,  96 },
+    {  16, 112 }
+};
+
+DECLARE_ALIGNED(16, const short, vp8_sub_pel_filters[8][6]) =
+{
+
+    { 0,  0,  128,    0,   0,  0 },         /* note that 1/8 pel positions are just as per alpha -0.5 bicubic */
+    { 0, -6,  123,   12,  -1,  0 },
+    { 2, -11, 108,   36,  -8,  1 },         /* New 1/4 pel 6 tap filter */
+    { 0, -9,   93,   50,  -6,  0 },
+    { 3, -16,  77,   77, -16,  3 },         /* New 1/2 pel 6 tap filter */
+    { 0, -6,   50,   93,  -9,  0 },
+    { 1, -8,   36,  108, -11,  2 },         /* New 1/4 pel 6 tap filter */
+    { 0, -1,   12,  123,  -6,  0 },
+};
+
+void vp8_filter_block2d_first_pass
+(
+    unsigned char *src_ptr,
+    int *output_ptr,
+    unsigned int src_pixels_per_line,
+    unsigned int pixel_step,
+    unsigned int output_height,
+    unsigned int output_width,
+    const short *vp8_filter
+)
+{
+    unsigned int i, j;
+    int  Temp;
+
+    for (i = 0; i < output_height; i++)
+    {
+        for (j = 0; j < output_width; j++)
+        {
+            Temp = ((int)src_ptr[-2 * (int)pixel_step] * vp8_filter[0]) +
+                   ((int)src_ptr[-1 * (int)pixel_step] * vp8_filter[1]) +
+                   ((int)src_ptr[0]                 * vp8_filter[2]) +
+                   ((int)src_ptr[pixel_step]         * vp8_filter[3]) +
+                   ((int)src_ptr[2*pixel_step]       * vp8_filter[4]) +
+                   ((int)src_ptr[3*pixel_step]       * vp8_filter[5]) +
+                   (VP8_FILTER_WEIGHT >> 1);      /* Rounding */
+
+            /* Normalize back to 0-255 */
+            Temp = Temp >> VP8_FILTER_SHIFT;
+
+            if (Temp < 0)
+                Temp = 0;
+            else if (Temp > 255)
+                Temp = 255;
+
+            output_ptr[j] = Temp;
+            src_ptr++;
+        }
+
+        /* Next row... */
+        src_ptr    += src_pixels_per_line - output_width;
+        output_ptr += output_width;
+    }
+}
+
+void vp8_filter_block2d_second_pass
+(
+    int *src_ptr,
+    unsigned char *output_ptr,
+    int output_pitch,
+    unsigned int src_pixels_per_line,
+    unsigned int pixel_step,
+    unsigned int output_height,
+    unsigned int output_width,
+    const short *vp8_filter
+)
+{
+    unsigned int i, j;
+    int  Temp;
+
+    for (i = 0; i < output_height; i++)
+    {
+        for (j = 0; j < output_width; j++)
+        {
+            /* Apply filter */
+            Temp = ((int)src_ptr[-2 * (int)pixel_step] * vp8_filter[0]) +
+                   ((int)src_ptr[-1 * (int)pixel_step] * vp8_filter[1]) +
+                   ((int)src_ptr[0]                 * vp8_filter[2]) +
+                   ((int)src_ptr[pixel_step]         * vp8_filter[3]) +
+                   ((int)src_ptr[2*pixel_step]       * vp8_filter[4]) +
+                   ((int)src_ptr[3*pixel_step]       * vp8_filter[5]) +
+                   (VP8_FILTER_WEIGHT >> 1);   /* Rounding */
+
+            /* Normalize back to 0-255 */
+            Temp = Temp >> VP8_FILTER_SHIFT;
+
+            if (Temp < 0)
+                Temp = 0;
+            else if (Temp > 255)
+                Temp = 255;
+
+            output_ptr[j] = (unsigned char)Temp;
+            src_ptr++;
+        }
+
+        /* Start next row */
+        src_ptr    += src_pixels_per_line - output_width;
+        output_ptr += output_pitch;
+    }
+}
+
+
+void vp8_filter_block2d
+(
+    unsigned char  *src_ptr,
+    unsigned char  *output_ptr,
+    unsigned int src_pixels_per_line,
+    int output_pitch,
+    const short  *HFilter,
+    const short  *VFilter
+)
+{
+    int FData[9*4]; /* Temp data buffer used in filtering */
+
+    /* First filter 1-D horizontally... */
+    vp8_filter_block2d_first_pass(src_ptr - (2 * src_pixels_per_line), FData, src_pixels_per_line, 1, 9, 4, HFilter);
+
+    /* then filter verticaly... */
+    vp8_filter_block2d_second_pass(FData + 8, output_ptr, output_pitch, 4, 4, 4, 4, VFilter);
+}
+
+
+void vp8_block_variation_c
+(
+    unsigned char  *src_ptr,
+    int   src_pixels_per_line,
+    int *HVar,
+    int *VVar
+)
+{
+    int i, j;
+    unsigned char *Ptr = src_ptr;
+
+    for (i = 0; i < 4; i++)
+    {
+        for (j = 0; j < 4; j++)
+        {
+            *HVar += abs((int)Ptr[j] - (int)Ptr[j+1]);
+            *VVar += abs((int)Ptr[j] - (int)Ptr[j+src_pixels_per_line]);
+        }
+
+        Ptr += src_pixels_per_line;
+    }
+}
+
+
+
+
+void vp8_sixtap_predict_c
+(
+    unsigned char  *src_ptr,
+    int   src_pixels_per_line,
+    int  xoffset,
+    int  yoffset,
+    unsigned char *dst_ptr,
+    int dst_pitch
+)
+{
+    const short  *HFilter;
+    const short  *VFilter;
+
+    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
+    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */
+
+    vp8_filter_block2d(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter);
+}
+void vp8_sixtap_predict8x8_c
+(
+    unsigned char  *src_ptr,
+    int  src_pixels_per_line,
+    int  xoffset,
+    int  yoffset,
+    unsigned char *dst_ptr,
+    int  dst_pitch
+)
+{
+    const short  *HFilter;
+    const short  *VFilter;
+    int FData[13*16];   /* Temp data buffer used in filtering */
+
+    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
+    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */
+
+    /* First filter 1-D horizontally... */
+    vp8_filter_block2d_first_pass(src_ptr - (2 * src_pixels_per_line), FData, src_pixels_per_line, 1, 13, 8, HFilter);
+
+
+    /* then filter verticaly... */
+    vp8_filter_block2d_second_pass(FData + 16, dst_ptr, dst_pitch, 8, 8, 8, 8, VFilter);
+
+}
+
+void vp8_sixtap_predict8x4_c
+(
+    unsigned char  *src_ptr,
+    int  src_pixels_per_line,
+    int  xoffset,
+    int  yoffset,
+    unsigned char *dst_ptr,
+    int  dst_pitch
+)
+{
+    const short  *HFilter;
+    const short  *VFilter;
+    int FData[13*16];   /* Temp data buffer used in filtering */
+
+    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
+    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */
+
+    /* First filter 1-D horizontally... */
+    vp8_filter_block2d_first_pass(src_ptr - (2 * src_pixels_per_line), FData, src_pixels_per_line, 1, 9, 8, HFilter);
+
+
+    /* then filter verticaly... */
+    vp8_filter_block2d_second_pass(FData + 16, dst_ptr, dst_pitch, 8, 8, 4, 8, VFilter);
+
+}
+
+void vp8_sixtap_predict16x16_c
+(
+    unsigned char  *src_ptr,
+    int  src_pixels_per_line,
+    int  xoffset,
+    int  yoffset,
+    unsigned char *dst_ptr,
+    int  dst_pitch
+)
+{
+    const short  *HFilter;
+    const short  *VFilter;
+    int FData[21*24];   /* Temp data buffer used in filtering */
+
+
+    HFilter = vp8_sub_pel_filters[xoffset];   /* 6 tap */
+    VFilter = vp8_sub_pel_filters[yoffset];   /* 6 tap */
+
+    /* First filter 1-D horizontally... */
+    vp8_filter_block2d_first_pass(src_ptr - (2 * src_pixels_per_line), FData, src_pixels_per_line, 1, 21, 16, HFilter);
+
+    /* then filter verticaly... */
+    vp8_filter_block2d_second_pass(FData + 32, dst_ptr, dst_pitch, 16, 16, 16, 16, VFilter);
+
+}
+
+
+/****************************************************************************
+ *
+ *  ROUTINE       : filter_block2d_bil_first_pass
+ *
+ *  INPUTS        : UINT8  *src_ptr    : Pointer to source block.
+ *                  UINT32  src_stride : Stride of source block.
+ *                  UINT32  height     : Block height.
+ *                  UINT32  width      : Block width.
+ *                  INT32  *vp8_filter : Array of 2 bi-linear filter taps.
+ *
+ *  OUTPUTS       : INT32  *dst_ptr    : Pointer to filtered block.
+ *
+ *  RETURNS       : void
+ *
+ *  FUNCTION      : Applies a 1-D 2-tap bi-linear filter to the source block
+ *                  in the horizontal direction to produce the filtered output
+ *                  block. Used to implement first-pass of 2-D separable filter.
+ *
+ *  SPECIAL NOTES : Produces INT32 output to retain precision for next pass.
+ *                  Two filter taps should sum to VP8_FILTER_WEIGHT.
+ *
+ ****************************************************************************/
+void vp8_filter_block2d_bil_first_pass
+(
+    unsigned char  *src_ptr,
+    unsigned short *dst_ptr,
+    unsigned int    src_stride,
+    unsigned int    height,
+    unsigned int    width,
+    const short    *vp8_filter
+)
+{
+    unsigned int i, j;
+
+    for (i = 0; i < height; i++)
+    {
+        for (j = 0; j < width; j++)
+        {
+            /* Apply bilinear filter */
+            dst_ptr[j] = (((int)src_ptr[0] * vp8_filter[0]) +
+                          ((int)src_ptr[1] * vp8_filter[1]) +
+                          (VP8_FILTER_WEIGHT / 2)) >> VP8_FILTER_SHIFT;
+            src_ptr++;
+        }
+
+        /* Next row... */
+        src_ptr += src_stride - width;
+        dst_ptr += width;
+    }
+}
+
+/****************************************************************************
+ *
+ *  ROUTINE       : filter_block2d_bil_second_pass
+ *
+ *  INPUTS        : INT32  *src_ptr    : Pointer to source block.
+ *                  UINT32  dst_pitch  : Destination block pitch.
+ *                  UINT32  height     : Block height.
+ *                  UINT32  width      : Block width.
+ *                  INT32  *vp8_filter : Array of 2 bi-linear filter taps.
+ *
+ *  OUTPUTS       : UINT16 *dst_ptr    : Pointer to filtered block.
+ *
+ *  RETURNS       : void
+ *
+ *  FUNCTION      : Applies a 1-D 2-tap bi-linear filter to the source block
+ *                  in the vertical direction to produce the filtered output
+ *                  block. Used to implement second-pass of 2-D separable filter.
+ *
+ *  SPECIAL NOTES : Requires 32-bit input as produced by filter_block2d_bil_first_pass.
+ *                  Two filter taps should sum to VP8_FILTER_WEIGHT.
+ *
+ ****************************************************************************/
+void vp8_filter_block2d_bil_second_pass
+(
+    unsigned short *src_ptr,
+    unsigned char  *dst_ptr,
+    int             dst_pitch,
+    unsigned int    height,
+    unsigned int    width,
+    const short    *vp8_filter
+)
+{
+    unsigned int  i, j;
+    int  Temp;
+
+    for (i = 0; i < height; i++)
+    {
+        for (j = 0; j < width; j++)
+        {
+            /* Apply filter */
+            Temp = ((int)src_ptr[0]     * vp8_filter[0]) +
+                   ((int)src_ptr[width] * vp8_filter[1]) +
+                   (VP8_FILTER_WEIGHT / 2);
+            dst_ptr[j] = (unsigned int)(Temp >> VP8_FILTER_SHIFT);
+            src_ptr++;
+        }
+
+        /* Next row... */
+        dst_ptr += dst_pitch;
+    }
+}
+
+
+/****************************************************************************
+ *
+ *  ROUTINE       : filter_block2d_bil
+ *
+ *  INPUTS        : UINT8  *src_ptr          : Pointer to source block.
+ *                  UINT32  src_pitch        : Stride of source block.
+ *                  UINT32  dst_pitch        : Stride of destination block.
+ *                  INT32  *HFilter          : Array of 2 horizontal filter taps.
+ *                  INT32  *VFilter          : Array of 2 vertical filter taps.
+ *                  INT32  Width             : Block width
+ *                  INT32  Height            : Block height
+ *
+ *  OUTPUTS       : UINT16 *dst_ptr       : Pointer to filtered block.
+ *
+ *  RETURNS       : void
+ *
+ *  FUNCTION      : 2-D filters an input block by applying a 2-tap
+ *                  bi-linear filter horizontally followed by a 2-tap
+ *                  bi-linear filter vertically on the result.
+ *
+ *  SPECIAL NOTES : The largest block size can be handled here is 16x16
+ *
+ ****************************************************************************/
+void vp8_filter_block2d_bil
+(
+    unsigned char *src_ptr,
+    unsigned char *dst_ptr,
+    unsigned int   src_pitch,
+    unsigned int   dst_pitch,
+    const short   *HFilter,
+    const short   *VFilter,
+    int            Width,
+    int            Height
+)
+{
+
+    unsigned short FData[17*16];    /* Temp data buffer used in filtering */
+
+    /* First filter 1-D horizontally... */
+    vp8_filter_block2d_bil_first_pass(src_ptr, FData, src_pitch, Height + 1, Width, HFilter);
+
+    /* then 1-D vertically... */
+    vp8_filter_block2d_bil_second_pass(FData, dst_ptr, dst_pitch, Height, Width, VFilter);
+}
+
+
+void vp8_bilinear_predict4x4_c
+(
+    unsigned char  *src_ptr,
+    int   src_pixels_per_line,
+    int  xoffset,
+    int  yoffset,
+    unsigned char *dst_ptr,
+    int dst_pitch
+)
+{
+    const short *HFilter;
+    const short *VFilter;
+
+    HFilter = vp8_bilinear_filters[xoffset];
+    VFilter = vp8_bilinear_filters[yoffset];
+#if 0
+    {
+        int i;
+        unsigned char temp1[16];
+        unsigned char temp2[16];
+
+        bilinear_predict4x4_mmx(src_ptr, src_pixels_per_line, xoffset, yoffset, temp1, 4);
+        vp8_filter_block2d_bil(src_ptr, temp2, src_pixels_per_line, 4, HFilter, VFilter, 4, 4);
+
+        for (i = 0; i < 16; i++)
+        {
+            if (temp1[i] != temp2[i])
+            {
+                bilinear_predict4x4_mmx(src_ptr, src_pixels_per_line, xoffset, yoffset, temp1, 4);
+                vp8_filter_block2d_bil(src_ptr, temp2, src_pixels_per_line, 4, HFilter, VFilter, 4, 4);
+            }
+        }
+    }
+#endif
+    vp8_filter_block2d_bil(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 4, 4);
+
+}
+
+void vp8_bilinear_predict8x8_c
+(
+    unsigned char  *src_ptr,
+    int  src_pixels_per_line,
+    int  xoffset,
+    int  yoffset,
+    unsigned char *dst_ptr,
+    int  dst_pitch
+)
+{
+    const short *HFilter;
+    const short *VFilter;
+
+    HFilter = vp8_bilinear_filters[xoffset];
+    VFilter = vp8_bilinear_filters[yoffset];
+
+    vp8_filter_block2d_bil(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 8, 8);
+
+}
+
+void vp8_bilinear_predict8x4_c
+(
+    unsigned char  *src_ptr,
+    int  src_pixels_per_line,
+    int  xoffset,
+    int  yoffset,
+    unsigned char *dst_ptr,
+    int  dst_pitch
+)
+{
+    const short *HFilter;
+    const short *VFilter;
+
+    HFilter = vp8_bilinear_filters[xoffset];
+    VFilter = vp8_bilinear_filters[yoffset];
+
+    vp8_filter_block2d_bil(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 8, 4);
+
+}
+
+void vp8_bilinear_predict16x16_c
+(
+    unsigned char  *src_ptr,
+    int  src_pixels_per_line,
+    int  xoffset,
+    int  yoffset,
+    unsigned char *dst_ptr,
+    int  dst_pitch
+)
+{
+    const short *HFilter;
+    const short *VFilter;
+
+    HFilter = vp8_bilinear_filters[xoffset];
+    VFilter = vp8_bilinear_filters[yoffset];
+
+    vp8_filter_block2d_bil(src_ptr, dst_ptr, src_pixels_per_line, dst_pitch, HFilter, VFilter, 16, 16);
+}