/* * Animated GIF encoder * Copyright (c) 2000 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 *//* * First version by Francois Revol revol@free.fr * * Features and limitations: * - currently no compression is performed, *   in fact the size of the data is 9/8 the size of the image in 8bpp * - uses only a global standard palette * - tested with IE 5.0, Opera for BeOS, NetPositive (BeOS), and Mozilla (BeOS). * * Reference documents: * http://www.goice.co.jp/member/mo/formats/gif.html * http://astronomy.swin.edu.au/pbourke/dataformats/gif/ * http://www.dcs.ed.ac.uk/home/mxr/gfx/2d/GIF89a.txt * * this url claims to have an LZW algorithm not covered by Unisys patent: * http://www.msg.net/utility/whirlgif/gifencod.html * could help reduce the size of the files _a lot_... * some sites mentions an RLE type compression also. */#include "avformat.h"/* bitstream minipacket size */#define GIF_CHUNKS 100/* slows down the decoding (and some browsers doesn't like it) *//* #define GIF_ADD_APP_HEADER */typedef struct {    unsigned char r;    unsigned char g;    unsigned char b;} rgb_triplet;/* we use the standard 216 color palette *//* this script was used to create the palette: * for r in 00 33 66 99 cc ff; do for g in 00 33 66 99 cc ff; do echo -n "    "; for b in 00 33 66 99 cc ff; do  *   echo -n "{ 0x$r, 0x$g, 0x$b }, "; done; echo ""; done; done */static const rgb_triplet gif_clut[216] = {    { 0x00, 0x00, 0x00 }, { 0x00, 0x00, 0x33 }, { 0x00, 0x00, 0x66 }, { 0x00, 0x00, 0x99 }, { 0x00, 0x00, 0xcc }, { 0x00, 0x00, 0xff },    { 0x00, 0x33, 0x00 }, { 0x00, 0x33, 0x33 }, { 0x00, 0x33, 0x66 }, { 0x00, 0x33, 0x99 }, { 0x00, 0x33, 0xcc }, { 0x00, 0x33, 0xff },    { 0x00, 0x66, 0x00 }, { 0x00, 0x66, 0x33 }, { 0x00, 0x66, 0x66 }, { 0x00, 0x66, 0x99 }, { 0x00, 0x66, 0xcc }, { 0x00, 0x66, 0xff },    { 0x00, 0x99, 0x00 }, { 0x00, 0x99, 0x33 }, { 0x00, 0x99, 0x66 }, { 0x00, 0x99, 0x99 }, { 0x00, 0x99, 0xcc }, { 0x00, 0x99, 0xff },    { 0x00, 0xcc, 0x00 }, { 0x00, 0xcc, 0x33 }, { 0x00, 0xcc, 0x66 }, { 0x00, 0xcc, 0x99 }, { 0x00, 0xcc, 0xcc }, { 0x00, 0xcc, 0xff },    { 0x00, 0xff, 0x00 }, { 0x00, 0xff, 0x33 }, { 0x00, 0xff, 0x66 }, { 0x00, 0xff, 0x99 }, { 0x00, 0xff, 0xcc }, { 0x00, 0xff, 0xff },    { 0x33, 0x00, 0x00 }, { 0x33, 0x00, 0x33 }, { 0x33, 0x00, 0x66 }, { 0x33, 0x00, 0x99 }, { 0x33, 0x00, 0xcc }, { 0x33, 0x00, 0xff },    { 0x33, 0x33, 0x00 }, { 0x33, 0x33, 0x33 }, { 0x33, 0x33, 0x66 }, { 0x33, 0x33, 0x99 }, { 0x33, 0x33, 0xcc }, { 0x33, 0x33, 0xff },    { 0x33, 0x66, 0x00 }, { 0x33, 0x66, 0x33 }, { 0x33, 0x66, 0x66 }, { 0x33, 0x66, 0x99 }, { 0x33, 0x66, 0xcc }, { 0x33, 0x66, 0xff },    { 0x33, 0x99, 0x00 }, { 0x33, 0x99, 0x33 }, { 0x33, 0x99, 0x66 }, { 0x33, 0x99, 0x99 }, { 0x33, 0x99, 0xcc }, { 0x33, 0x99, 0xff },    { 0x33, 0xcc, 0x00 }, { 0x33, 0xcc, 0x33 }, { 0x33, 0xcc, 0x66 }, { 0x33, 0xcc, 0x99 }, { 0x33, 0xcc, 0xcc }, { 0x33, 0xcc, 0xff },    { 0x33, 0xff, 0x00 }, { 0x33, 0xff, 0x33 }, { 0x33, 0xff, 0x66 }, { 0x33, 0xff, 0x99 }, { 0x33, 0xff, 0xcc }, { 0x33, 0xff, 0xff },    { 0x66, 0x00, 0x00 }, { 0x66, 0x00, 0x33 }, { 0x66, 0x00, 0x66 }, { 0x66, 0x00, 0x99 }, { 0x66, 0x00, 0xcc }, { 0x66, 0x00, 0xff },    { 0x66, 0x33, 0x00 }, { 0x66, 0x33, 0x33 }, { 0x66, 0x33, 0x66 }, { 0x66, 0x33, 0x99 }, { 0x66, 0x33, 0xcc }, { 0x66, 0x33, 0xff },    { 0x66, 0x66, 0x00 }, { 0x66, 0x66, 0x33 }, { 0x66, 0x66, 0x66 }, { 0x66, 0x66, 0x99 }, { 0x66, 0x66, 0xcc }, { 0x66, 0x66, 0xff },    { 0x66, 0x99, 0x00 }, { 0x66, 0x99, 0x33 }, { 0x66, 0x99, 0x66 }, { 0x66, 0x99, 0x99 }, { 0x66, 0x99, 0xcc }, { 0x66, 0x99, 0xff },    { 0x66, 0xcc, 0x00 }, { 0x66, 0xcc, 0x33 }, { 0x66, 0xcc, 0x66 }, { 0x66, 0xcc, 0x99 }, { 0x66, 0xcc, 0xcc }, { 0x66, 0xcc, 0xff },    { 0x66, 0xff, 0x00 }, { 0x66, 0xff, 0x33 }, { 0x66, 0xff, 0x66 }, { 0x66, 0xff, 0x99 }, { 0x66, 0xff, 0xcc }, { 0x66, 0xff, 0xff },    { 0x99, 0x00, 0x00 }, { 0x99, 0x00, 0x33 }, { 0x99, 0x00, 0x66 }, { 0x99, 0x00, 0x99 }, { 0x99, 0x00, 0xcc }, { 0x99, 0x00, 0xff },    { 0x99, 0x33, 0x00 }, { 0x99, 0x33, 0x33 }, { 0x99, 0x33, 0x66 }, { 0x99, 0x33, 0x99 }, { 0x99, 0x33, 0xcc }, { 0x99, 0x33, 0xff },    { 0x99, 0x66, 0x00 }, { 0x99, 0x66, 0x33 }, { 0x99, 0x66, 0x66 }, { 0x99, 0x66, 0x99 }, { 0x99, 0x66, 0xcc }, { 0x99, 0x66, 0xff },    { 0x99, 0x99, 0x00 }, { 0x99, 0x99, 0x33 }, { 0x99, 0x99, 0x66 }, { 0x99, 0x99, 0x99 }, { 0x99, 0x99, 0xcc }, { 0x99, 0x99, 0xff },    { 0x99, 0xcc, 0x00 }, { 0x99, 0xcc, 0x33 }, { 0x99, 0xcc, 0x66 }, { 0x99, 0xcc, 0x99 }, { 0x99, 0xcc, 0xcc }, { 0x99, 0xcc, 0xff },    { 0x99, 0xff, 0x00 }, { 0x99, 0xff, 0x33 }, { 0x99, 0xff, 0x66 }, { 0x99, 0xff, 0x99 }, { 0x99, 0xff, 0xcc }, { 0x99, 0xff, 0xff },    { 0xcc, 0x00, 0x00 }, { 0xcc, 0x00, 0x33 }, { 0xcc, 0x00, 0x66 }, { 0xcc, 0x00, 0x99 }, { 0xcc, 0x00, 0xcc }, { 0xcc, 0x00, 0xff },    { 0xcc, 0x33, 0x00 }, { 0xcc, 0x33, 0x33 }, { 0xcc, 0x33, 0x66 }, { 0xcc, 0x33, 0x99 }, { 0xcc, 0x33, 0xcc }, { 0xcc, 0x33, 0xff },    { 0xcc, 0x66, 0x00 }, { 0xcc, 0x66, 0x33 }, { 0xcc, 0x66, 0x66 }, { 0xcc, 0x66, 0x99 }, { 0xcc, 0x66, 0xcc }, { 0xcc, 0x66, 0xff },    { 0xcc, 0x99, 0x00 }, { 0xcc, 0x99, 0x33 }, { 0xcc, 0x99, 0x66 }, { 0xcc, 0x99, 0x99 }, { 0xcc, 0x99, 0xcc }, { 0xcc, 0x99, 0xff },    { 0xcc, 0xcc, 0x00 }, { 0xcc, 0xcc, 0x33 }, { 0xcc, 0xcc, 0x66 }, { 0xcc, 0xcc, 0x99 }, { 0xcc, 0xcc, 0xcc }, { 0xcc, 0xcc, 0xff },    { 0xcc, 0xff, 0x00 }, { 0xcc, 0xff, 0x33 }, { 0xcc, 0xff, 0x66 }, { 0xcc, 0xff, 0x99 }, { 0xcc, 0xff, 0xcc }, { 0xcc, 0xff, 0xff },    { 0xff, 0x00, 0x00 }, { 0xff, 0x00, 0x33 }, { 0xff, 0x00, 0x66 }, { 0xff, 0x00, 0x99 }, { 0xff, 0x00, 0xcc }, { 0xff, 0x00, 0xff },    { 0xff, 0x33, 0x00 }, { 0xff, 0x33, 0x33 }, { 0xff, 0x33, 0x66 }, { 0xff, 0x33, 0x99 }, { 0xff, 0x33, 0xcc }, { 0xff, 0x33, 0xff },    { 0xff, 0x66, 0x00 }, { 0xff, 0x66, 0x33 }, { 0xff, 0x66, 0x66 }, { 0xff, 0x66, 0x99 }, { 0xff, 0x66, 0xcc }, { 0xff, 0x66, 0xff },    { 0xff, 0x99, 0x00 }, { 0xff, 0x99, 0x33 }, { 0xff, 0x99, 0x66 }, { 0xff, 0x99, 0x99 }, { 0xff, 0x99, 0xcc }, { 0xff, 0x99, 0xff },    { 0xff, 0xcc, 0x00 }, { 0xff, 0xcc, 0x33 }, { 0xff, 0xcc, 0x66 }, { 0xff, 0xcc, 0x99 }, { 0xff, 0xcc, 0xcc }, { 0xff, 0xcc, 0xff },    { 0xff, 0xff, 0x00 }, { 0xff, 0xff, 0x33 }, { 0xff, 0xff, 0x66 }, { 0xff, 0xff, 0x99 }, { 0xff, 0xff, 0xcc }, { 0xff, 0xff, 0xff },};/* The GIF format uses reversed order for bitstreams... *//* at least they don't use PDP_ENDIAN :) *//* so we 'extend' PutBitContext. hmmm, OOP :) *//* seems this thing changed slightly since I wrote it... */#ifdef ALT_BITSTREAM_WRITER# error no ALT_BITSTREAM_WRITER support for now#endifstatic void gif_put_bits_rev(PutBitContext *s, int n, unsigned int value){    unsigned int bit_buf;    int bit_cnt;#ifdef STATS    st_out_bit_counts[st_current_index] += n;#endif    //    printf("put_bits=%d %x\n", n, value);    assert(n == 32 || value < (1U << n));    bit_buf = s->bit_buf;    bit_cnt = 32 - s->bit_left; /* XXX:lazyness... was = s->bit_cnt; */    //    printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);    /* XXX: optimize */    if (n < (32-bit_cnt)) {        bit_buf |= value << (bit_cnt);        bit_cnt+=n;    } else {        bit_buf |= value << (bit_cnt);                *s->buf_ptr = bit_buf & 0xff;        s->buf_ptr[1] = (bit_buf >> 8) & 0xff;        s->buf_ptr[2] = (bit_buf >> 16) & 0xff;        s->buf_ptr[3] = (bit_buf >> 24) & 0xff;                //printf("bitbuf = %08x\n", bit_buf);        s->buf_ptr+=4;        if (s->buf_ptr >= s->buf_end)            puts("bit buffer overflow !!"); // should never happen ! who got rid of the callback ???//            flush_buffer_rev(s);        bit_cnt=bit_cnt + n - 32;        if (bit_cnt == 0) {            bit_buf = 0;        } else {            bit_buf = value >> (n - bit_cnt);        }    }    s->bit_buf = bit_buf;    s->bit_left = 32 - bit_cnt;}/* pad the end of the output stream with zeros */static void gif_flush_put_bits_rev(PutBitContext *s){    while (s->bit_left < 32) {        /* XXX: should test end of buffer */        *s->buf_ptr++=s->bit_buf & 0xff;        s->bit_buf>>=8;        s->bit_left+=8;    }//    flush_buffer_rev(s);    s->bit_left=32;    s->bit_buf=0;}/* !RevPutBitContext *//* GIF header */static int gif_image_write_header(ByteIOContext *pb,                                   int width, int height, uint32_t *palette){    int i;    unsigned int v;    put_tag(pb, "GIF");    put_tag(pb, "89a");    put_le16(pb, width);    put_le16(pb, height);    put_byte(pb, 0xf7); /* flags: global clut, 256 entries */    put_byte(pb, 0x1f); /* background color index */    put_byte(pb, 0); /* aspect ratio */    /* the global palette */    if (!palette) {        put_buffer(pb, (unsigned char *)gif_clut, 216*3);        for(i=0;i<((256-216)*3);i++)            put_byte(pb, 0);    } else {        for(i=0;i<256;i++) {            v = palette[i];            put_byte(pb, (v >> 16) & 0xff);            put_byte(pb, (v >> 8) & 0xff);            put_byte(pb, (v) & 0xff);        }    }    /* application extension header */    /* XXX: not really sure what to put in here... */#ifdef GIF_ADD_APP_HEADER    put_byte(pb, 0x21);    put_byte(pb, 0xff);    put_byte(pb, 0x0b);    put_tag(pb, "NETSCAPE2.0");    put_byte(pb, 0x03);    put_byte(pb, 0x01);    put_byte(pb, 0x00);    put_byte(pb, 0x00);#endif