#include "avcodec.h"
#include "bytestream.h"
-
-#define MAXBITS 12
-#define SIZTABLE (1<<MAXBITS)
+#include "lzw.h"
#define GCE_DISPOSAL_NONE 0
#define GCE_DISPOSAL_INPLACE 1
#define GCE_DISPOSAL_RESTORE 3
typedef struct GifState {
+ AVFrame picture;
int screen_width;
int screen_height;
int bits_per_pixel;
int background_color_index;
int transparent_color_index;
int color_resolution;
- uint8_t *image_buf;
- int image_linesize;
- uint32_t image_palette[256];
- int pix_fmt;
+ uint32_t *image_palette;
/* after the frame is displayed, the disposal method is used */
int gce_disposal;
int gce_delay;
/* LZW compatible decoder */
- uint8_t *bytestream;
- int eob_reached;
- uint8_t *pbuf, *ebuf;
- int bbits;
- unsigned int bbuf;
-
- int cursize; /* The current code size */
- int curmask;
- int codesize;
- int clear_code;
- int end_code;
- int newcodes; /* First available code */
- int top_slot; /* Highest code for current size */
- int slot; /* Last read code */
- int fc, oc;
- uint8_t *sp;
- uint8_t stack[SIZTABLE];
- uint8_t suffix[SIZTABLE];
- uint16_t prefix[SIZTABLE];
+ const uint8_t *bytestream;
+ const uint8_t *bytestream_end;
+ LZWState *lzw;
/* aux buffers */
uint8_t global_palette[256 * 3];
uint8_t local_palette[256 * 3];
- uint8_t buf[256];
+
+ AVCodecContext* avctx;
} GifState;
static const uint8_t gif87a_sig[6] = "GIF87a";
static const uint8_t gif89a_sig[6] = "GIF89a";
-static const uint16_t mask[17] =
-{
- 0x0000, 0x0001, 0x0003, 0x0007,
- 0x000F, 0x001F, 0x003F, 0x007F,
- 0x00FF, 0x01FF, 0x03FF, 0x07FF,
- 0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF
-};
-
-static void GLZWDecodeInit(GifState * s, int csize)
-{
- /* read buffer */
- s->eob_reached = 0;
- s->pbuf = s->buf;
- s->ebuf = s->buf;
- s->bbuf = 0;
- s->bbits = 0;
-
- /* decoder */
- s->codesize = csize;
- s->cursize = s->codesize + 1;
- s->curmask = mask[s->cursize];
- s->top_slot = 1 << s->cursize;
- s->clear_code = 1 << s->codesize;
- s->end_code = s->clear_code + 1;
- s->slot = s->newcodes = s->clear_code + 2;
- s->oc = s->fc = 0;
- s->sp = s->stack;
-}
-
-/* XXX: optimize */
-static inline int GetCode(GifState * s)
-{
- int c, sizbuf;
- uint8_t *ptr;
-
- while (s->bbits < s->cursize) {
- ptr = s->pbuf;
- if (ptr >= s->ebuf) {
- if (!s->eob_reached) {
- sizbuf = bytestream_get_byte(&s->bytestream);
- s->ebuf = s->buf + sizbuf;
- s->pbuf = s->buf;
- if (sizbuf > 0) {
- bytestream_get_buffer(&s->bytestream, s->buf, sizbuf);
- } else {
- s->eob_reached = 1;
- }
- }
- ptr = s->pbuf;
- }
- s->bbuf |= ptr[0] << s->bbits;
- ptr++;
- s->pbuf = ptr;
- s->bbits += 8;
- }
- c = s->bbuf & s->curmask;
- s->bbuf >>= s->cursize;
- s->bbits -= s->cursize;
- return c;
-}
-
-/* NOTE: the algorithm here is inspired from the LZW GIF decoder
- written by Steven A. Bennett in 1987. */
-/* return the number of byte decoded */
-static int GLZWDecode(GifState * s, uint8_t * buf, int len)
-{
- int l, c, code, oc, fc;
- uint8_t *sp;
-
- if (s->end_code < 0)
- return 0;
-
- l = len;
- sp = s->sp;
- oc = s->oc;
- fc = s->fc;
-
- while (sp > s->stack) {
- *buf++ = *(--sp);
- if ((--l) == 0)
- goto the_end;
- }
-
- for (;;) {
- c = GetCode(s);
- if (c == s->end_code) {
- s->end_code = -1;
- break;
- } else if (c == s->clear_code) {
- s->cursize = s->codesize + 1;
- s->curmask = mask[s->cursize];
- s->slot = s->newcodes;
- s->top_slot = 1 << s->cursize;
- while ((c = GetCode(s)) == s->clear_code);
- if (c == s->end_code) {
- s->end_code = -1;
- break;
- }
- /* test error */
- if (c >= s->slot)
- c = 0;
- fc = oc = c;
- *buf++ = c;
- if ((--l) == 0)
- break;
- } else {
- code = c;
- if (code >= s->slot) {
- *sp++ = fc;
- code = oc;
- }
- while (code >= s->newcodes) {
- *sp++ = s->suffix[code];
- code = s->prefix[code];
- }
- *sp++ = code;
- if (s->slot < s->top_slot) {
- s->suffix[s->slot] = fc = code;
- s->prefix[s->slot++] = oc;
- oc = c;
- }
- if (s->slot >= s->top_slot) {
- if (s->cursize < MAXBITS) {
- s->top_slot <<= 1;
- s->curmask = mask[++s->cursize];
- }
- }
- while (sp > s->stack) {
- *buf++ = *(--sp);
- if ((--l) == 0)
- goto the_end;
- }
- }
- }
- the_end:
- s->sp = sp;
- s->oc = oc;
- s->fc = fc;
- return len - l;
-}
-
static int gif_read_image(GifState *s)
{
int left, top, width, height, bits_per_pixel, code_size, flags;
- int is_interleaved, has_local_palette, y, x, pass, y1, linesize, n, i;
- uint8_t *ptr, *line, *d, *spal, *palette, *sptr, *ptr1;
+ int is_interleaved, has_local_palette, y, pass, y1, linesize, n, i;
+ uint8_t *ptr, *spal, *palette, *ptr1;
left = bytestream_get_le16(&s->bytestream);
top = bytestream_get_le16(&s->bytestream);
has_local_palette = flags & 0x80;
bits_per_pixel = (flags & 0x07) + 1;
#ifdef DEBUG
- dprintf("gif: image x=%d y=%d w=%d h=%d\n", left, top, width, height);
+ dprintf(s->avctx, "gif: image x=%d y=%d w=%d h=%d\n", left, top, width, height);
#endif
if (has_local_palette) {
/* verify that all the image is inside the screen dimensions */
if (left + width > s->screen_width ||
top + height > s->screen_height)
- return -EINVAL;
+ return AVERROR(EINVAL);
/* build the palette */
- n = (1 << bits_per_pixel);
- spal = palette;
- for(i = 0; i < n; i++) {
- s->image_palette[i] = (0xff << 24) |
- (spal[0] << 16) | (spal[1] << 8) | (spal[2]);
- spal += 3;
- }
- for(; i < 256; i++)
- s->image_palette[i] = (0xff << 24);
- /* handle transparency */
- if (s->transparent_color_index >= 0)
- s->image_palette[s->transparent_color_index] = 0;
- line = NULL;
+ n = (1 << bits_per_pixel);
+ spal = palette;
+ for(i = 0; i < n; i++) {
+ s->image_palette[i] = (0xff << 24) | AV_RB24(spal);
+ spal += 3;
+ }
+ for(; i < 256; i++)
+ s->image_palette[i] = (0xff << 24);
+ /* handle transparency */
+ if (s->transparent_color_index >= 0)
+ s->image_palette[s->transparent_color_index] = 0;
/* now get the image data */
code_size = bytestream_get_byte(&s->bytestream);
- GLZWDecodeInit(s, code_size);
+ ff_lzw_decode_init(s->lzw, code_size, s->bytestream,
+ s->bytestream_end - s->bytestream, FF_LZW_GIF);
/* read all the image */
- linesize = s->image_linesize;
- ptr1 = s->image_buf + top * linesize + (left * 3);
+ linesize = s->picture.linesize[0];
+ ptr1 = s->picture.data[0] + top * linesize + left;
ptr = ptr1;
pass = 0;
y1 = 0;
for (y = 0; y < height; y++) {
- GLZWDecode(s, ptr, width);
+ ff_lzw_decode(s->lzw, ptr, width);
if (is_interleaved) {
switch(pass) {
default:
y1 += 8;
ptr += linesize * 8;
if (y1 >= height) {
- y1 = 4;
- if (pass == 0)
- ptr = ptr1 + linesize * 4;
- else
- ptr = ptr1 + linesize * 2;
+ y1 = pass ? 2 : 4;
+ ptr = ptr1 + linesize * y1;
pass++;
}
break;
ptr += linesize;
}
}
- av_free(line);
-
/* read the garbage data until end marker is found */
- while (!s->eob_reached)
- GetCode(s);
+ ff_lzw_decode_tail(s->lzw);
+ s->bytestream = ff_lzw_cur_ptr(s->lzw);
return 0;
}
ext_code = bytestream_get_byte(&s->bytestream);
ext_len = bytestream_get_byte(&s->bytestream);
#ifdef DEBUG
- dprintf("gif: ext_code=0x%x len=%d\n", ext_code, ext_len);
+ dprintf(s->avctx, "gif: ext_code=0x%x len=%d\n", ext_code, ext_len);
#endif
switch(ext_code) {
case 0xf9:
s->transparent_color_index = -1;
s->gce_disposal = (gce_flags >> 2) & 0x7;
#ifdef DEBUG
- dprintf("gif: gce_flags=%x delay=%d tcolor=%d disposal=%d\n",
+ dprintf(s->avctx, "gif: gce_flags=%x delay=%d tcolor=%d disposal=%d\n",
gce_flags, s->gce_delay,
s->transparent_color_index, s->gce_disposal);
#endif
bytestream_get_byte(&s->bytestream);
ext_len = bytestream_get_byte(&s->bytestream);
#ifdef DEBUG
- dprintf("gif: ext_len1=%d\n", ext_len);
+ dprintf(s->avctx, "gif: ext_len1=%d\n", ext_len);
#endif
}
return 0;
static int gif_read_header1(GifState *s)
{
uint8_t sig[6];
- int ret, v, n;
+ int v, n;
int has_global_palette;
+ if (s->bytestream_end < s->bytestream + 13)
+ return -1;
+
/* read gif signature */
bytestream_get_buffer(&s->bytestream, sig, 6);
if (memcmp(sig, gif87a_sig, 6) != 0 &&
s->background_color_index = bytestream_get_byte(&s->bytestream);
bytestream_get_byte(&s->bytestream); /* ignored */
#ifdef DEBUG
- dprintf("gif: screen_w=%d screen_h=%d bpp=%d global_palette=%d\n",
+ dprintf(s->avctx, "gif: screen_w=%d screen_h=%d bpp=%d global_palette=%d\n",
s->screen_width, s->screen_height, s->bits_per_pixel,
has_global_palette);
#endif
if (has_global_palette) {
n = 1 << s->bits_per_pixel;
+ if (s->bytestream_end < s->bytestream + n * 3)
+ return -1;
bytestream_get_buffer(&s->bytestream, s->global_palette, n * 3);
}
return 0;
static int gif_parse_next_image(GifState *s)
{
- int ret, code;
-
- for (;;) {
- code = bytestream_get_byte(&s->bytestream);
+ while (s->bytestream < s->bytestream_end) {
+ int code = bytestream_get_byte(&s->bytestream);
#ifdef DEBUG
- dprintf("gif: code=%02x '%c'\n", code, code);
+ dprintf(s->avctx, "gif: code=%02x '%c'\n", code, code);
#endif
switch (code) {
case ',':
- if (gif_read_image(s) < 0)
- return -1;
- ret = 0;
- goto the_end;
- case ';':
- /* end of image */
- ret = -1;
- goto the_end;
+ return gif_read_image(s);
case '!':
if (gif_read_extension(s) < 0)
return -1;
break;
- case EOF:
+ case ';':
+ /* end of image */
default:
- /* error or errneous EOF */
- ret = -1;
- goto the_end;
+ /* error or erroneous EOF */
+ return -1;
}
}
- the_end:
- return ret;
+ return -1;
}
-static int gif_decode_init(AVCodecContext *avctx)
+static av_cold int gif_decode_init(AVCodecContext *avctx)
{
GifState *s = avctx->priv_data;
+ s->avctx = avctx;
+
+ avcodec_get_frame_defaults(&s->picture);
+ avctx->coded_frame= &s->picture;
+ s->picture.data[0] = NULL;
+ ff_lzw_decode_open(&s->lzw);
return 0;
}
-static int gif_decode_frame(AVCodecContext *avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
+static int gif_decode_frame(AVCodecContext *avctx, void *data, int *data_size, const uint8_t *buf, int buf_size)
{
GifState *s = avctx->priv_data;
AVFrame *picture = data;
int ret;
s->bytestream = buf;
+ s->bytestream_end = buf + buf_size;
if (gif_read_header1(s) < 0)
return -1;
- /* allocate image buffer */
- s->image_linesize = s->screen_width * 3;
- s->image_buf = av_malloc(s->screen_height * s->image_linesize);
- if (!s->image_buf)
- return -ENOMEM;
- s->pix_fmt = PIX_FMT_PAL8;
- /* now we are ready: build format streams */
-
- /* XXX: check if screen size is always valid */
- avctx->width = s->screen_width;
- avctx->height = s->screen_height;
avctx->pix_fmt = PIX_FMT_PAL8;
+ if (avcodec_check_dimensions(avctx, s->screen_width, s->screen_height))
+ return -1;
+ avcodec_set_dimensions(avctx, s->screen_width, s->screen_height);
+ if (s->picture.data[0])
+ avctx->release_buffer(avctx, &s->picture);
+ if (avctx->get_buffer(avctx, &s->picture) < 0) {
+ av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+ return -1;
+ }
+ s->image_palette = (uint32_t *)s->picture.data[1];
ret = gif_parse_next_image(s);
if (ret < 0)
return ret;
- picture->data[0] = s->image_buf;
- picture->linesize[0] = s->image_linesize;
- picture->data[1] = s->image_palette;
- picture->linesize[1] = 4;
-
+ *picture = s->picture;
*data_size = sizeof(AVPicture);
+ return s->bytestream - buf;
+}
+
+static av_cold int gif_decode_close(AVCodecContext *avctx)
+{
+ GifState *s = avctx->priv_data;
+
+ ff_lzw_decode_close(&s->lzw);
+ if(s->picture.data[0])
+ avctx->release_buffer(avctx, &s->picture);
return 0;
}
sizeof(GifState),
gif_decode_init,
NULL,
- NULL,
+ gif_decode_close,
gif_decode_frame,
+ .long_name = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"),
};
projects / ffmpeg / blobdiff