X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fgifdec.c;h=4bb77895ad1dfd609b903c17bfbbbbf61e4392e0;hb=bb6941af2afd057c3897afb78d034de2c355b8a0;hp=23d023f43247a23767dad627330035e28720af2e;hpb=47babca8396af9e765d9f29b1e8586603b0f1ebd;p=ffmpeg diff --git a/libavcodec/gifdec.c b/libavcodec/gifdec.c index 23d023f4324..4bb77895ad1 100644 --- a/libavcodec/gifdec.c +++ b/libavcodec/gifdec.c @@ -1,32 +1,31 @@ /* * GIF decoder - * Copyright (c) 2003 Fabrice Bellard. - * Copyright (c) 2006 Baptiste Coudurier. + * Copyright (c) 2003 Fabrice Bellard + * Copyright (c) 2006 Baptiste Coudurier * - * This file is part of FFmpeg. + * This file is part of Libav. * - * FFmpeg is free software; you can redistribute it and/or + * Libav 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 2.1 of the License, or (at your option) any later version. * - * FFmpeg is distributed in the hope that it will be useful, + * Libav 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 FFmpeg; if not, write to the Free Software + * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ //#define DEBUG +#include "libavutil/imgutils.h" #include "avcodec.h" #include "bytestream.h" - -#define MAXBITS 12 -#define SIZTABLE (1<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, pass, y1, linesize, n, i; - uint8_t *ptr, *line, *spal, *palette, *ptr1; + uint8_t *ptr, *spal, *palette, *ptr1; left = bytestream_get_le16(&s->bytestream); top = bytestream_get_le16(&s->bytestream); @@ -233,9 +76,8 @@ static int gif_read_image(GifState *s) is_interleaved = flags & 0x40; 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); -#endif + + av_dlog(s->avctx, "gif: image x=%d y=%d w=%d h=%d\n", left, top, width, height); if (has_local_palette) { bytestream_get_buffer(&s->bytestream, s->local_palette, 3 * (1 << bits_per_pixel)); @@ -248,35 +90,34 @@ static int gif_read_image(GifState *s) /* 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]); + s->image_palette[i] = (0xffu << 24) | AV_RB24(spal); spal += 3; } for(; i < 256; i++) - s->image_palette[i] = (0xff << 24); + s->image_palette[i] = (0xffu << 24); /* handle transparency */ if (s->transparent_color_index >= 0) s->image_palette[s->transparent_color_index] = 0; - line = NULL; /* 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->picture.linesize[0]; - ptr1 = s->picture.data[0] + top * linesize + (left * 3); + 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: @@ -285,11 +126,8 @@ static int gif_read_image(GifState *s) 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; @@ -311,11 +149,9 @@ static int gif_read_image(GifState *s) 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; } @@ -326,9 +162,9 @@ static int gif_read_extension(GifState *s) /* extension */ 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); -#endif + + av_dlog(s->avctx, "gif: ext_code=0x%x len=%d\n", ext_code, ext_len); + switch(ext_code) { case 0xf9: if (ext_len != 4) @@ -342,11 +178,11 @@ static int gif_read_extension(GifState *s) else 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", + + av_dlog(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 + ext_len = bytestream_get_byte(&s->bytestream); break; } @@ -357,9 +193,8 @@ static int gif_read_extension(GifState *s) for (i = 0; i < ext_len; i++) bytestream_get_byte(&s->bytestream); ext_len = bytestream_get_byte(&s->bytestream); -#ifdef DEBUG - dprintf("gif: ext_len1=%d\n", ext_len); -#endif + + av_dlog(s->avctx, "gif: ext_len1=%d\n", ext_len); } return 0; } @@ -370,6 +205,9 @@ static int gif_read_header1(GifState *s) 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 && @@ -392,13 +230,15 @@ static int gif_read_header1(GifState *s) s->bits_per_pixel = (v & 0x07) + 1; 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", + + av_dlog(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; @@ -406,60 +246,56 @@ static int gif_read_header1(GifState *s) static int gif_parse_next_image(GifState *s) { - int ret, code; + while (s->bytestream < s->bytestream_end) { + int code = bytestream_get_byte(&s->bytestream); + + av_dlog(s->avctx, "gif: code=%02x '%c'\n", code, code); - for (;;) { - code = bytestream_get_byte(&s->bytestream); -#ifdef DEBUG - dprintf("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, AVPacket *avpkt) { + const uint8_t *buf = avpkt->data; + int buf_size = avpkt->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; - avctx->pix_fmt = PIX_FMT_PAL8; - if (avcodec_check_dimensions(avctx, s->screen_width, s->screen_height)) + avctx->pix_fmt = AV_PIX_FMT_PAL8; + if (av_image_check_size(s->screen_width, s->screen_height, 0, avctx)) return -1; avcodec_set_dimensions(avctx, s->screen_width, s->screen_height); @@ -476,25 +312,27 @@ static int gif_decode_frame(AVCodecContext *avctx, void *data, int *data_size, u *picture = s->picture; *data_size = sizeof(AVPicture); - return 0; + return s->bytestream - buf; } -static int gif_decode_close(AVCodecContext *avctx) +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; } -AVCodec gif_decoder = { - "gif", - CODEC_TYPE_VIDEO, - CODEC_ID_GIF, - sizeof(GifState), - gif_decode_init, - NULL, - gif_decode_close, - gif_decode_frame, +AVCodec ff_gif_decoder = { + .name = "gif", + .type = AVMEDIA_TYPE_VIDEO, + .id = AV_CODEC_ID_GIF, + .priv_data_size = sizeof(GifState), + .init = gif_decode_init, + .close = gif_decode_close, + .decode = gif_decode_frame, + .capabilities = CODEC_CAP_DR1, + .long_name = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"), };