+++ /dev/null
-/*
- * GIF decoder
- * Copyright (c) 2003 Fabrice Bellard.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-#include "avformat.h"
-
-int gif_write(ByteIOContext *pb, AVImageInfo *info);
-
-//#define DEBUG
-
-#define MAXBITS 12
-#define SIZTABLE (1<<MAXBITS)
-
-#define GCE_DISPOSAL_NONE 0
-#define GCE_DISPOSAL_INPLACE 1
-#define GCE_DISPOSAL_BACKGROUND 2
-#define GCE_DISPOSAL_RESTORE 3
-
-typedef struct GifState {
- 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;
- int pix_fmt;
-
- /* after the frame is displayed, the disposal method is used */
- int gce_disposal;
- /* delay during which the frame is shown */
- int gce_delay;
-
- /* LZW compatible decoder */
- ByteIOContext *f;
- 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];
-
- /* aux buffers */
- uint8_t global_palette[256 * 3];
- uint8_t local_palette[256 * 3];
- uint8_t buf[256];
-} 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
-};
-
-/* Probe gif video format or gif image format. The current heuristic
- supposes the gif87a is always a single image. For gif89a, we
- consider it as a video only if a GCE extension is present in the
- first kilobyte. */
-static int gif_video_probe(AVProbeData * pd)
-{
- const uint8_t *p, *p_end;
- int bits_per_pixel, has_global_palette, ext_code, ext_len;
- int gce_flags, gce_disposal;
-
- if (pd->buf_size < 24 ||
- memcmp(pd->buf, gif89a_sig, 6) != 0)
- return 0;
- p_end = pd->buf + pd->buf_size;
- p = pd->buf + 6;
- bits_per_pixel = (p[4] & 0x07) + 1;
- has_global_palette = (p[4] & 0x80);
- p += 7;
- if (has_global_palette)
- p += (1 << bits_per_pixel) * 3;
- for(;;) {
- if (p >= p_end)
- return 0;
- if (*p != '!')
- break;
- p++;
- if (p >= p_end)
- return 0;
- ext_code = *p++;
- if (p >= p_end)
- return 0;
- ext_len = *p++;
- if (ext_code == 0xf9) {
- if (p >= p_end)
- return 0;
- /* if GCE extension found with gce_disposal != 0: it is
- likely to be an animation */
- gce_flags = *p++;
- gce_disposal = (gce_flags >> 2) & 0x7;
- if (gce_disposal != 0)
- return AVPROBE_SCORE_MAX;
- else
- return 0;
- }
- for(;;) {
- if (ext_len == 0)
- break;
- p += ext_len;
- if (p >= p_end)
- return 0;
- ext_len = *p++;
- }
- }
- return 0;
-}
-
-static int gif_image_probe(AVProbeData * pd)
-{
- if (pd->buf_size >= 24 &&
- (memcmp(pd->buf, gif87a_sig, 6) == 0 ||
- memcmp(pd->buf, gif89a_sig, 6) == 0))
- return AVPROBE_SCORE_MAX - 1;
- else
- return 0;
-}
-
-
-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 = get_byte(s->f);
- s->ebuf = s->buf + sizbuf;
- s->pbuf = s->buf;
- if (sizbuf > 0) {
- get_buffer(s->f, 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)
-{
- ByteIOContext *f = s->f;
- 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;
-
- left = get_le16(f);
- top = get_le16(f);
- width = get_le16(f);
- height = get_le16(f);
- flags = get_byte(f);
- is_interleaved = flags & 0x40;
- has_local_palette = flags & 0x80;
- bits_per_pixel = (flags & 0x07) + 1;
-#ifdef DEBUG
- printf("gif: image x=%d y=%d w=%d h=%d\n", left, top, width, height);
-#endif
-
- if (has_local_palette) {
- get_buffer(f, s->local_palette, 3 * (1 << bits_per_pixel));
- palette = s->local_palette;
- } else {
- palette = s->global_palette;
- bits_per_pixel = s->bits_per_pixel;
- }
-
- /* verify that all the image is inside the screen dimensions */
- if (left + width > s->screen_width ||
- top + height > s->screen_height)
- return -EINVAL;
-
- /* build the palette */
- if (s->pix_fmt == PIX_FMT_RGB24) {
- line = av_malloc(width);
- if (!line)
- return -ENOMEM;
- } else {
- 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;
- }
-
- /* now get the image data */
- s->f = f;
- code_size = get_byte(f);
- GLZWDecodeInit(s, code_size);
-
- /* read all the image */
- linesize = s->image_linesize;
- ptr1 = s->image_buf + top * linesize + (left * 3);
- ptr = ptr1;
- pass = 0;
- y1 = 0;
- for (y = 0; y < height; y++) {
- if (s->pix_fmt == PIX_FMT_RGB24) {
- /* transcode to RGB24 */
- GLZWDecode(s, line, width);
- d = ptr;
- sptr = line;
- for(x = 0; x < width; x++) {
- spal = palette + sptr[0] * 3;
- d[0] = spal[0];
- d[1] = spal[1];
- d[2] = spal[2];
- d += 3;
- sptr++;
- }
- } else {
- GLZWDecode(s, ptr, width);
- }
- if (is_interleaved) {
- switch(pass) {
- default:
- case 0:
- case 1:
- y1 += 8;
- ptr += linesize * 8;
- if (y1 >= height) {
- y1 = 4;
- if (pass == 0)
- ptr = ptr1 + linesize * 4;
- else
- ptr = ptr1 + linesize * 2;
- pass++;
- }
- break;
- case 2:
- y1 += 4;
- ptr += linesize * 4;
- if (y1 >= height) {
- y1 = 1;
- ptr = ptr1 + linesize;
- pass++;
- }
- break;
- case 3:
- y1 += 2;
- ptr += linesize * 2;
- break;
- }
- } else {
- ptr += linesize;
- }
- }
- av_free(line);
-
- /* read the garbage data until end marker is found */
- while (!s->eob_reached)
- GetCode(s);
- return 0;
-}
-
-static int gif_read_extension(GifState *s)
-{
- ByteIOContext *f = s->f;
- int ext_code, ext_len, i, gce_flags, gce_transparent_index;
-
- /* extension */
- ext_code = get_byte(f);
- ext_len = get_byte(f);
-#ifdef DEBUG
- printf("gif: ext_code=0x%x len=%d\n", ext_code, ext_len);
-#endif
- switch(ext_code) {
- case 0xf9:
- if (ext_len != 4)
- goto discard_ext;
- s->transparent_color_index = -1;
- gce_flags = get_byte(f);
- s->gce_delay = get_le16(f);
- gce_transparent_index = get_byte(f);
- if (gce_flags & 0x01)
- s->transparent_color_index = gce_transparent_index;
- else
- s->transparent_color_index = -1;
- s->gce_disposal = (gce_flags >> 2) & 0x7;
-#ifdef DEBUG
- printf("gif: gce_flags=%x delay=%d tcolor=%d disposal=%d\n",
- gce_flags, s->gce_delay,
- s->transparent_color_index, s->gce_disposal);
-#endif
- ext_len = get_byte(f);
- break;
- }
-
- /* NOTE: many extension blocks can come after */
- discard_ext:
- while (ext_len != 0) {
- for (i = 0; i < ext_len; i++)
- get_byte(f);
- ext_len = get_byte(f);
-#ifdef DEBUG
- printf("gif: ext_len1=%d\n", ext_len);
-#endif
- }
- return 0;
-}
-
-static int gif_read_header1(GifState *s)
-{
- ByteIOContext *f = s->f;
- uint8_t sig[6];
- int ret, v, n;
- int has_global_palette;
-
- /* read gif signature */
- ret = get_buffer(f, sig, 6);
- if (ret != 6)
- return -1;
- if (memcmp(sig, gif87a_sig, 6) != 0 &&
- memcmp(sig, gif89a_sig, 6) != 0)
- return -1;
-
- /* read screen header */
- s->transparent_color_index = -1;
- s->screen_width = get_le16(f);
- s->screen_height = get_le16(f);
- v = get_byte(f);
- s->color_resolution = ((v & 0x70) >> 4) + 1;
- has_global_palette = (v & 0x80);
- s->bits_per_pixel = (v & 0x07) + 1;
- s->background_color_index = get_byte(f);
- get_byte(f); /* ignored */
-#ifdef DEBUG
- printf("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;
- get_buffer(f, s->global_palette, n * 3);
- }
- return 0;
-}
-
-static int gif_parse_next_image(GifState *s)
-{
- ByteIOContext *f = s->f;
- int ret, code;
-
- for (;;) {
- code = url_fgetc(f);
-#ifdef DEBUG
- printf("gif: code=%02x '%c'\n", code, code);
-#endif
- switch (code) {
- case ',':
- if (gif_read_image(s) < 0)
- return -EIO;
- ret = 0;
- goto the_end;
- case ';':
- /* end of image */
- ret = -EIO;
- goto the_end;
- case '!':
- if (gif_read_extension(s) < 0)
- return -EIO;
- break;
- case EOF:
- default:
- /* error or errneous EOF */
- ret = -EIO;
- goto the_end;
- }
- }
- the_end:
- return ret;
-}
-
-static int gif_read_header(AVFormatContext * s1,
- AVFormatParameters * ap)
-{
- GifState *s = s1->priv_data;
- ByteIOContext *f = &s1->pb;
- AVStream *st;
-
- s->f = f;
- 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_RGB24;
- /* now we are ready: build format streams */
- st = av_new_stream(s1, 0);
- if (!st)
- return -1;
-
- st->codec.codec_type = CODEC_TYPE_VIDEO;
- st->codec.codec_id = CODEC_ID_RAWVIDEO;
- st->codec.frame_rate = 5;
- st->codec.frame_rate_base = 1;
- /* XXX: check if screen size is always valid */
- st->codec.width = s->screen_width;
- st->codec.height = s->screen_height;
- st->codec.pix_fmt = PIX_FMT_RGB24;
- return 0;
-}
-
-static int gif_read_packet(AVFormatContext * s1,
- AVPacket * pkt)
-{
- GifState *s = s1->priv_data;
- int ret;
-
- ret = gif_parse_next_image(s);
- if (ret < 0)
- return ret;
-
- /* XXX: avoid copying */
- if (av_new_packet(pkt, s->screen_width * s->screen_height * 3)) {
- return -EIO;
- }
- pkt->stream_index = 0;
- memcpy(pkt->data, s->image_buf, s->screen_width * s->screen_height * 3);
- return 0;
-}
-
-static int gif_read_close(AVFormatContext *s1)
-{
- GifState *s = s1->priv_data;
- av_free(s->image_buf);
- return 0;
-}
-
-/* read gif as image */
-static int gif_read(ByteIOContext *f,
- int (*alloc_cb)(void *opaque, AVImageInfo *info), void *opaque)
-{
- GifState s1, *s = &s1;
- AVImageInfo info1, *info = &info1;
- int ret;
-
- memset(s, 0, sizeof(GifState));
- s->f = f;
- if (gif_read_header1(s) < 0)
- return -1;
- info->width = s->screen_width;
- info->height = s->screen_height;
- info->pix_fmt = PIX_FMT_PAL8;
- ret = alloc_cb(opaque, info);
- if (ret)
- return ret;
- s->image_buf = info->pict.data[0];
- s->image_linesize = info->pict.linesize[0];
- s->image_palette = (uint32_t *)info->pict.data[1];
-
- if (gif_parse_next_image(s) < 0)
- return -1;
- return 0;
-}
-
-AVInputFormat gif_iformat =
-{
- "gif",
- "gif format",
- sizeof(GifState),
- gif_video_probe,
- gif_read_header,
- gif_read_packet,
- gif_read_close,
-};
-
-AVImageFormat gif_image_format = {
- "gif",
- "gif",
- gif_image_probe,
- gif_read,
- (1 << PIX_FMT_PAL8),
- gif_write,
-};
projects / synfig.git / blobdiff