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Remove pointer casts as they may lead to UB and refactor code to not use union rgb565 structs

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This commit is contained in:
REDxEYE 2022-08-12 16:57:28 +03:00
parent a05be82920
commit c6c0749a16
2 changed files with 53 additions and 51 deletions
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12
src/libImaging/Bcn.h
View File

@ -28,3 +28,15 @@ typedef struct {
INT8 a0, a1;
UINT8 lut[6];
} bc5s_alpha;
#define BIT_MASK(bit_count) ((1 << (bit_count)) - 1)
#define SET_BITS(target, bit_offset, bit_count, value) \
target |= (((value)&BIT_MASK(bit_count)) << (bit_offset))
#define GET_BITS(source, bit_offset, bit_count) \
((source) & (BIT_MASK(bit_count) << (bit_offset))) >> (bit_offset)
#define SWAP(TYPE, A, B) \
do { \
TYPE TMP = A; \
(A) = B; \
(B) = TMP; \
} while (0)

92
src/libImaging/BcnEncode.c
View File

@ -16,54 +16,44 @@
#include "Bcn.h"
#include "math.h"
#define BIT_MASK(bit_count) ((1 << (bit_count)) - 1)
#define SET_BITS(target, bit_offset, bit_count, value) \
target |= (((value)&BIT_MASK(bit_count)) << (bit_offset))
#define SWAP(TYPE, A, B) \
do { \
TYPE TMP = A; \
A = B; \
B = TMP; \
} while (0)
#define PACK_SHORT_565(r, g, b) \
((((b) << 8) & 0xF800) | (((g) << 3) & 0x7E0) | ((r) >> 3))
typedef union {
struct {
UINT16 r : 5;
UINT16 g : 6;
UINT16 b : 5;
} color;
UINT16 value;
} rgb565;
#define UNPACK_SHORT_565(source, r, g, b) \
(r) = GET_BITS((source), 0, 5); \
(g) = GET_BITS((source), 5, 6); \
(b) = GET_BITS((source), 11, 5);
static UINT16
pack_565(UINT8 r, UINT8 g, UINT8 b) {
rgb565 color;
color.color.r = r / (255 / 31);
color.color.g = g / (255 / 63);
color.color.b = b / (255 / 31);
return color.value;
}
#define WRITE_SHORT(buf, value) \
*(buf++) = value & 0xFF; \
*(buf++) = value >> 8;
static UINT16
rgb565_diff(UINT16 a, UINT16 b) {
rgb565 c0;
c0.value = a;
rgb565 c1;
c1.value = b;
return ((UINT16)abs(c0.color.r - c1.color.r)) + abs(c0.color.g - c1.color.g) +
abs(c0.color.b - c1.color.b);
#define WRITE_INT(buf, value) \
WRITE_SHORT(buf, value & 0xFFFF) \
WRITE_SHORT(buf, value >> 16)
#define WRITE_BC1_BLOCK(buf, block) \
WRITE_SHORT(buf, block.c0) \
WRITE_SHORT(buf, block.c1) \
WRITE_INT(buf, block.lut)
static inline UINT16
rgb565_diff(UINT16 c0, UINT16 c1) {
UINT8 r0, g0, b0, r1, g1, b1;
UNPACK_SHORT_565(c0, r0, g0, b0)
UNPACK_SHORT_565(c1, r1, g1, b1)
return ((UINT16)abs(r0 - r1)) + abs(g0 - g1) + abs(b0 - b1);
}
static inline UINT16
rgb565_lerp(UINT16 a, UINT16 b, UINT8 a_fac, UINT8 b_fac) {
rgb565 c0;
c0.value = a;
rgb565 c1;
c1.value = b;
return pack_565(
(c0.color.r * a_fac + c1.color.r * b_fac) / (a_fac + b_fac),
(c0.color.g * a_fac + c1.color.g * b_fac) / (a_fac + b_fac),
(c0.color.b * a_fac + c1.color.b * b_fac) / (a_fac + b_fac));
rgb565_lerp(UINT16 c0, UINT16 c1, UINT8 a_fac, UINT8 b_fac) {
UINT8 r0, g0, b0, r1, g1, b1;
UNPACK_SHORT_565(c0, r0, g0, b0)
UNPACK_SHORT_565(c1, r1, g1, b1)
return PACK_SHORT_565(
(r0 * a_fac + r1 * b_fac) / (a_fac + b_fac),
(g0 * a_fac + g1 * b_fac) / (a_fac + b_fac),
(b0 * a_fac + b1 * b_fac) / (a_fac + b_fac));
}
typedef struct {
@ -131,13 +121,13 @@ get_closest_color_index(const UINT16 *colors, UINT16 color) {
int
encode_bc1(Imaging im, ImagingCodecState state, UINT8 *buf, int bytes) {
bc1_color *blocks = (bc1_color *)buf;
UINT8* dst = buf;
UINT8 no_alpha = 0;
INT32 block_index;
if (strchr(im->mode, 'A') == NULL) {
no_alpha = 1;
}
UINT32 block_count = (im->xsize * im->ysize) / 16;
INT32 block_count = (im->xsize * im->ysize) / 16;
if (block_count * sizeof(bc1_color) > bytes) {
state->errcode = IMAGING_CODEC_MEMORY;
return 0;
@ -166,7 +156,7 @@ encode_bc1(Imaging im, ImagingCodecState state, UINT8 *buf, int bytes) {
UINT8 g = im->image[y][x * im->pixelsize + 1];
UINT8 b = im->image[y][x * im->pixelsize + 0];
UINT8 a = im->image[y][x * im->pixelsize + 3];
UINT16 color = pack_565(r, g, b);
UINT16 color = PACK_SHORT_565(r, g, b);
opaque[bx + by * 4] = a >= 127;
all_colors[bx + by * 4] = color;
@ -201,10 +191,9 @@ encode_bc1(Imaging im, ImagingCodecState state, UINT8 *buf, int bytes) {
palette[2] = rgb565_lerp(c0, c1, 1, 1);
palette[3] = 0;
}
bc1_color *block = &blocks[block_index];
block->c0 = c0;
block->c1 = c1;
bc1_color block = {0};
block.c0 = c0;
block.c1 = c1;
UINT32 color_id;
for (color_id = 0; color_id < 16; ++color_id) {
UINT8 bc_color_id;
@ -213,11 +202,12 @@ encode_bc1(Imaging im, ImagingCodecState state, UINT8 *buf, int bytes) {
} else {
bc_color_id = 3;
}
SET_BITS(block->lut, color_id * 2, 2, bc_color_id);
SET_BITS(block.lut, color_id * 2, 2, bc_color_id);
}
WRITE_BC1_BLOCK(dst, block)
}
state->errcode = IMAGING_CODEC_END;
return block_count * sizeof(bc1_color);
return dst - buf;
}
int