X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fgifdec.c;h=386c039c9c2110f96a1b34ada7427b065077d1f4;hb=ea82552c09b5c35528d0d8d79ed6b2879e5e3299;hp=8aabe546cbeb1cb62af85ea55b0ff4b2f27264a1;hpb=a7fb3a96009c477a643de3eca82791870294e748;p=ffmpeg

diff --git a/libavcodec/gifdec.c b/libavcodec/gifdec.c
index 8aabe546cbe..386c039c9c2 100644
--- a/libavcodec/gifdec.c
+++ b/libavcodec/gifdec.c
@@ -24,9 +24,7 @@
 
 #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
@@ -34,16 +32,14 @@
 #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;
@@ -52,180 +48,24 @@ typedef struct GifState {
 
     /* 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];
+    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, 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);
@@ -236,7 +76,7 @@ static int gif_read_image(GifState *s)
     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) {
@@ -250,35 +90,35 @@ 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]);
-            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) |
+            (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;
 
     /* now get the image data */
     code_size = bytestream_get_byte(&s->bytestream);
-    GLZWDecodeInit(s, code_size);
+    //TODO: add proper data size
+    ff_lzw_decode_init(s->lzw, code_size, s->bytestream, 0, 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:
@@ -313,11 +153,9 @@ 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;
 }
 
@@ -329,7 +167,7 @@ static int gif_read_extension(GifState *s)
     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:
@@ -345,7 +183,7 @@ static int gif_read_extension(GifState *s)
             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
@@ -360,7 +198,7 @@ static int gif_read_extension(GifState *s)
             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;
@@ -372,6 +210,9 @@ 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 &&
@@ -395,12 +236,14 @@ static int gif_read_header1(GifState *s)
     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;
@@ -408,42 +251,41 @@ static int gif_read_header1(GifState *s)
 
 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;
+            return 0;
         case ';':
             /* end of image */
-            ret = -1;
-            goto the_end;
+            return -1;
         case '!':
             if (gif_read_extension(s) < 0)
                 return -1;
             break;
-        case EOF:
         default:
             /* error or errneous EOF */
-            ret = -1;
-            goto the_end;
+            return -1;
         }
     }
-  the_end:
-    return ret;
+    return -1;
 }
 
 static 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;
 }
 
@@ -454,32 +296,38 @@ static int gif_decode_frame(AVCodecContext *avctx, void *data, int *data_size, u
     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 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;
 }
 
@@ -490,6 +338,6 @@ AVCodec gif_decoder = {
     sizeof(GifState),
     gif_decode_init,
     NULL,
-    NULL,
+    gif_decode_close,
     gif_decode_frame,
 };