yes, PNG can be simpler :-)

Originally committed as revision 1545 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/Makefile

@@ -20,7 +20,7 @@ OBJS+= asf.o
 endif
 
 # image formats
-OBJS+= pnm.o yuv.o png.o libpng/png.o libpng/pngread.o libpng/pngrutil.o libpng/pngwrite.o libpng/pngwutil.o jpeg.o gifdec.o
+OBJS+= pnm.o yuv.o png.o jpeg.o gifdec.o
 # file I/O
 OBJS+= avio.o aviobuf.o file.o 
 OBJS+= framehook.o 

libavformat/png.c

@@ -18,216 +18,462 @@
  */
 #include "avformat.h"
 
-#include "libpng/png.h"
-
-extern const uint8_t png_sig[];
+#include <zlib.h>
+
+//#define DEBUG
+
+#define PNG_COLOR_MASK_PALETTE    1
+#define PNG_COLOR_MASK_COLOR      2
+#define PNG_COLOR_MASK_ALPHA      4
+
+#define PNG_COLOR_TYPE_GRAY 0
+#define PNG_COLOR_TYPE_PALETTE  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
+#define PNG_COLOR_TYPE_RGB        (PNG_COLOR_MASK_COLOR)
+#define PNG_COLOR_TYPE_RGB_ALPHA  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
+#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
+
+#define PNG_FILTER_VALUE_NONE  0
+#define PNG_FILTER_VALUE_SUB   1
+#define PNG_FILTER_VALUE_UP    2
+#define PNG_FILTER_VALUE_AVG   3
+#define PNG_FILTER_VALUE_PAETH 4
+
+#define PNG_IHDR      0x0001
+#define PNG_IDAT      0x0002
+#define PNG_ALLIMAGE  0x0004
+
+#define IOBUF_SIZE 4096
+
+typedef struct PNGDecodeState {
+    int state;
+    int width, height;
+    int bit_depth;
+    int color_type;
+    int compression_type;
+    int interlace_type;
+    int filter_type;
+    int channels;
+    int bits_per_pixel;
+    int bpp;
+    
+    uint8_t *image_buf;
+    int image_linesize;
+    uint8_t *crow_buf;
+    uint8_t *empty_row;
+    int crow_size; /* compressed row size (include filter type) */
+    int row_size; /* decompressed row size */
+    int y;
+    z_stream zstream;
+} PNGDecodeState;
+
+const uint8_t pngsig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
 
 static int png_probe(AVProbeData *pd)
 {
     if (pd->buf_size >= 8 &&
-        memcmp(pd->buf, png_sig, 8) == 0)
+        memcmp(pd->buf, pngsig, 8) == 0)
         return AVPROBE_SCORE_MAX;
     else
         return 0;
 }
 
-png_voidp PNGAPI
-png_memset_check (png_structp png_ptr, png_voidp s1, int value,
-   png_uint_32 length)
+void *png_zalloc(void *opaque, unsigned int items, unsigned int size)
 {
-   png_size_t size;
-
-   size = (png_size_t)length;
-   if ((png_uint_32)size != length)
-      png_error(png_ptr,"Overflow in png_memset_check.");
-
-   return (png_memset (s1, value, size));
-
+    return av_malloc(items * size);
 }
 
-png_voidp PNGAPI
-png_memcpy_check (png_structp png_ptr, png_voidp s1, png_voidp s2,
-   png_uint_32 length)
+void png_zfree(void *opaque, void *ptr)
 {
-   png_size_t size;
-
-   size = (png_size_t)length;
-   if ((png_uint_32)size != length)
-      png_error(png_ptr,"Overflow in png_memcpy_check.");
-
-   return(png_memcpy (s1, s2, size));
+    av_free(ptr);
 }
 
-void png_error (png_struct *png_ptr, const char *message)
+/* XXX: optimize */
+static void png_filter_row(uint8_t *dst, int filter_type, 
+                           uint8_t *src, uint8_t *last, int size, int bpp)
 {
-    longjmp(png_ptr->jmpbuf, 0);
-}
+    int i, p;
 
-void png_warning (png_struct *png_ptr, const char *message)
-{
+    switch(filter_type) {
+    case PNG_FILTER_VALUE_NONE:
+        memcpy(dst, src, size);
+        break;
+    case PNG_FILTER_VALUE_SUB:
+        for(i = 0; i < bpp; i++) {
+            dst[i] = src[i];
+        }
+        for(i = bpp; i < size; i++) {
+            p = dst[i - bpp];
+            dst[i] = p + src[i];
+        }
+        break;
+    case PNG_FILTER_VALUE_UP:
+        for(i = 0; i < size; i++) {
+            p = last[i];
+            dst[i] = p + src[i];
+        }
+        break;
+    case PNG_FILTER_VALUE_AVG:
+        for(i = 0; i < bpp; i++) {
+            p = (last[i] >> 1);
+            dst[i] = p + src[i];
+        }
+        for(i = bpp; i < size; i++) {
+            p = ((dst[i - bpp] + last[i]) >> 1);
+            dst[i] = p + src[i];
+        }
+        break;
+    case PNG_FILTER_VALUE_PAETH:
+        for(i = 0; i < bpp; i++) {
+            p = last[i];
+            dst[i] = p + src[i];
+        }
+        for(i = bpp; i < size; i++) {
+            int a, b, c, pa, pb, pc;
+
+            a = dst[i - bpp];
+            b = last[i];
+            c = last[i - bpp];
+
+            p = b - c;
+            pc = a - c;
+
+            pa = abs(p);
+            pb = abs(pc);
+            pc = abs(p + pc);
+
+            if (pa <= pb && pa <= pc)
+                p = a;
+            else if (pb <= pc)
+                p = b;
+            else
+                p = c;
+            dst[i] = p + src[i];
+        }
+        break;
+    }
 }
 
-void PNGAPI
-png_chunk_error(png_structp png_ptr, png_const_charp error_message)
+static void png_handle_row(PNGDecodeState *s)
 {
-   char msg[18+64];
-   //   png_format_buffer(png_ptr, msg, error_message);
-   png_error(png_ptr, msg);
-}
+    uint8_t *ptr, *last_row;
+    ptr = s->image_buf + s->image_linesize * s->y;
+    if (s->y == 0)
+        last_row = s->empty_row;
+    else
+        last_row = ptr - s->image_linesize;
 
-void PNGAPI
-png_chunk_warning(png_structp png_ptr, png_const_charp warning_message)
-{
-   char msg[18+64];
-   //   png_format_buffer(png_ptr, msg, warning_message);
-   png_warning(png_ptr, msg);
+    png_filter_row(ptr, s->crow_buf[0], s->crow_buf + 1, 
+                   last_row, s->row_size, s->bpp);
 }
 
-void png_read_data (png_struct *png_ptr, png_byte *data, png_uint_32 length)
+static int png_decode_idat(PNGDecodeState *s, ByteIOContext *f, int length)
 {
+    uint8_t buf[IOBUF_SIZE];
+    int buf_size;
     int ret;
-
-    ret = get_buffer(png_ptr->io_ptr, data, length);
-    if (ret != length)
-	png_error (png_ptr, "Read Error");
-}
-
-void *png_malloc (png_struct *png_ptr, png_uint_32 size)
-{
-    return av_malloc(size);
-}
-
-void png_free (png_struct *png_ptr, void *ptr)
-{
-    return av_free(ptr);
+    while (length > 0) {
+        /* read the buffer */
+        buf_size = IOBUF_SIZE;
+        if (buf_size > length)
+            buf_size = length;
+        ret = get_buffer(f, buf, buf_size);
+        if (ret != buf_size)
+            return -1;
+        s->zstream.avail_in = buf_size;
+        s->zstream.next_in = buf;
+        /* decode one line if possible */
+        while (s->zstream.avail_in > 0) {
+            ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
+            if (ret != Z_OK && ret != Z_STREAM_END) {
+                return -1;
+            }
+            if (s->zstream.avail_out == 0) {
+                if (s->y < s->height) {
+                    png_handle_row(s);
+                    s->y++;
+                    if (s->y == s->height)
+                        s->state |= PNG_ALLIMAGE;
+                }
+                s->zstream.avail_out = s->crow_size;
+                s->zstream.next_out = s->crow_buf;
+            }
+        }
+        length -= buf_size;
+    }
+    return 0;
 }
 
 static int png_read(ByteIOContext *f, 
                     int (*alloc_cb)(void *opaque, AVImageInfo *info), void *opaque)
 {
-    png_struct png_struct1, *png_ptr;
-    png_info png_info1, png_info2, *info_ptr, *end_info;
     AVImageInfo info1, *info = &info1;
-    int y, height, ret, row_size;
-    uint8_t *ptr;
-
-    png_ptr = &png_struct1;
-    png_read_init(png_ptr);
-
-    info_ptr = &png_info1;
-    end_info = &png_info2;
-    
-    png_info_init(info_ptr);
-    png_info_init(end_info);
-    
-    png_ptr->io_ptr = f;
-
-    if (setjmp(png_jmpbuf(png_ptr))) {
-        png_read_destroy (png_ptr, info_ptr, NULL);
+    PNGDecodeState s1, *s = &s1;
+    uint32_t tag, length;
+    int ret, crc;
+    uint8_t buf[8];
+
+    /* check signature */
+    ret = get_buffer(f, buf, 8);
+    if (ret != 8)
         return -1;
-    }
-    
-    png_read_info (png_ptr, info_ptr);
-    
-    /* init image info */
-    info->width = info_ptr->width;
-    info->height = info_ptr->height;
-    
-    if (info_ptr->bit_depth == 8 && 
-        info_ptr->color_type == PNG_COLOR_TYPE_RGB) {
-        info->pix_fmt = PIX_FMT_RGB24;
-        row_size = info_ptr->width * 3;
-    } else if (info_ptr->bit_depth == 8 && 
-               info_ptr->color_type == PNG_COLOR_TYPE_GRAY) {
-        info->pix_fmt = PIX_FMT_GRAY8;
-        row_size = info_ptr->width;
-    } else if (info_ptr->bit_depth == 1 && 
-               info_ptr->color_type == PNG_COLOR_TYPE_GRAY) {
-        info->pix_fmt = PIX_FMT_MONOBLACK;
-        row_size = (info_ptr->width + 7) >> 3;
-    } else {
-        png_read_destroy (png_ptr, info_ptr, NULL);
+    if (memcmp(buf, pngsig, 8) != 0)
         return -1;
+    memset(s, 0, sizeof(PNGDecodeState));
+    /* init the zlib */
+    s->zstream.zalloc = png_zalloc;
+    s->zstream.zfree = png_zfree;
+    s->zstream.opaque = NULL;
+    ret = inflateInit(&s->zstream);
+    if (ret != Z_OK)
+        return -1;
+    for(;;) {
+        if (url_feof(f))
+            goto fail;
+        length = get_be32(f);
+        if (length > 0x7fffffff)
+            goto fail;
+        tag = get_le32(f);
+#ifdef DEBUG
+        printf("png: tag=%c%c%c%c length=%u\n", 
+               (tag & 0xff),
+               ((tag >> 8) & 0xff),
+               ((tag >> 16) & 0xff),
+               ((tag >> 24) & 0xff), length);
+#endif
+        switch(tag) {
+        case MKTAG('I', 'H', 'D', 'R'):
+            if (length != 13)
+                goto fail;
+            s->width = get_be32(f);
+            s->height = get_be32(f);
+            s->bit_depth = get_byte(f);
+            s->color_type = get_byte(f);
+            s->compression_type = get_byte(f);
+            s->filter_type = get_byte(f);
+            s->interlace_type = get_byte(f);
+            crc = get_be32(f);
+            s->state |= PNG_IHDR;
+#ifdef DEBUG
+            printf("width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n", 
+                   s->width, s->height, s->bit_depth, s->color_type, 
+                   s->compression_type, s->filter_type, s->interlace_type);
+#endif
+            break;
+        case MKTAG('I', 'D', 'A', 'T'):
+            if (!(s->state & PNG_IHDR))
+                goto fail;
+            if (!(s->state & PNG_IDAT)) {
+                /* init image info */
+                info->width = s->width;
+                info->height = s->height;
+
+                s->channels = 1;
+                if ((s->color_type & (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)) ==
+                    PNG_COLOR_MASK_COLOR)
+                    s->channels = 3;
+                if (s->color_type & PNG_COLOR_MASK_ALPHA)
+                    s->channels++;
+                s->bits_per_pixel = s->bit_depth * s->channels;
+                s->bpp = (s->bits_per_pixel + 7) >> 3;
+                if (s->bit_depth == 8 && 
+                    s->color_type == PNG_COLOR_TYPE_RGB) {
+                    info->pix_fmt = PIX_FMT_RGB24;
+                    s->row_size = s->width * 3;
+                } else if (s->bit_depth == 8 && 
+                           s->color_type == PNG_COLOR_TYPE_GRAY) {
+                    info->pix_fmt = PIX_FMT_GRAY8;
+                    s->row_size = s->width;
+                } else if (s->bit_depth == 1 && 
+                           s->color_type == PNG_COLOR_TYPE_GRAY) {
+                    info->pix_fmt = PIX_FMT_MONOBLACK;
+                    s->row_size = (s->width + 7) >> 3;
+                } else {
+                    goto fail;
+                }
+                /* compute the compressed row size */
+                if (!s->interlace_type) {
+                    s->crow_size = s->row_size + 1;
+                } else {
+                    /* XXX: handle interlacing */
+                    goto fail;
+                }
+                ret = alloc_cb(opaque, info);
+                if (ret) 
+                    goto the_end;
+#ifdef DEBUG
+                printf("row_size=%d crow_size =%d\n", 
+                       s->row_size, s->crow_size);
+#endif
+                s->image_buf = info->pict.data[0];
+                s->image_linesize = info->pict.linesize[0];
+                /* empty row is used if differencing to the first row */
+                s->empty_row = av_mallocz(s->row_size);
+                if (!s->empty_row)
+                    goto fail;
+                /* compressed row */
+                s->crow_buf = av_malloc(s->crow_size);
+                if (!s->crow_buf)
+                    goto fail;
+                s->zstream.avail_out = s->crow_size;
+                s->zstream.next_out = s->crow_buf;
+            }
+            s->state |= PNG_IDAT;
+            if (png_decode_idat(s, f, length) < 0)
+                goto fail;
+            /* skip crc */
+            crc = get_be32(f);
+            break;
+        case MKTAG('I', 'E', 'N', 'D'):
+            if (!(s->state & PNG_ALLIMAGE))
+                goto fail;
+            crc = get_be32(f);
+            goto exit_loop;
+        default:
+            /* skip tag */
+            url_fskip(f, length + 4);
+            break;
+        }
     }
-    ret = alloc_cb(opaque, info);
-    if (ret) {
-        png_read_destroy (png_ptr, info_ptr, NULL);
-        return ret;
-    }
-    
-    /* now read the whole image */
-    png_start_read_image (png_ptr);
-
-    height = info->height;
-    ptr = info->pict.data[0];
-    for (y = 0; y < height; y++) {
-        png_read_row (png_ptr, NULL, NULL);
-        memcpy(ptr, png_ptr->row_buf + 1, row_size);
-        ptr += info->pict.linesize[0];
+ exit_loop:
+    ret = 0;
+ the_end:
+    inflateEnd(&s->zstream);
+    av_free(s->crow_buf);
+    return ret;
+ fail:
+    ret = -1;
+    goto the_end;
+}
+
+static void png_write_chunk(ByteIOContext *f, uint32_t tag,
+                            const uint8_t *buf, int length)
+{
+    uint32_t crc;
+    uint8_t tagbuf[4];
+
+    put_be32(f, length);
+    crc = crc32(0, Z_NULL, 0);
+    tagbuf[0] = tag;
+    tagbuf[1] = tag >> 8;
+    tagbuf[2] = tag >> 16;
+    tagbuf[3] = tag >> 24;
+    crc = crc32(crc, tagbuf, 4);
+    put_le32(f, tag);
+    if (length > 0) {
+        crc = crc32(crc, buf, length);
+        put_buffer(f, buf, length);
     }
-    
-    png_read_destroy (png_ptr, info_ptr, NULL);
-    return 0;
+    put_be32(f, crc);
 }
 
-void
-png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
+/* XXX: use avcodec generic function ? */
+static void to_be32(uint8_t *p, uint32_t v)
 {
-    put_buffer(png_ptr->io_ptr, data, length);
+    p[0] = v >> 24;
+    p[1] = v >> 16;
+    p[2] = v >> 8;
+    p[3] = v;
 }
 
-static int png_write(ByteIOContext *pb, AVImageInfo *info)
+static int png_write(ByteIOContext *f, AVImageInfo *info)
 {
-    png_struct png_struct1, *png_ptr;
-    png_info png_info1, *info_ptr;
-    int w, h, y;
+    int bit_depth, color_type, y, len, row_size, ret;
     uint8_t *ptr;
-
-    png_ptr = &png_struct1;
-    info_ptr = &png_info1;
-
-    png_write_init(png_ptr);
-    png_info_init(info_ptr);
+    uint8_t buf[IOBUF_SIZE];
+    uint8_t *crow_buf = NULL;
+    z_stream zstream;
     
-    png_ptr->io_ptr = pb;
-
-    if (setjmp(png_ptr->jmpbuf)) {
-        png_write_destroy(png_ptr);
-        return -1;
-    }
-
-    w = info->width;
-    h = info->height;
-
-    info_ptr->width = w;
-    info_ptr->height = h;
     switch(info->pix_fmt) {
     case PIX_FMT_RGB24:
-        info_ptr->bit_depth = 8;
-        info_ptr->color_type = PNG_COLOR_TYPE_RGB;
+        bit_depth = 8;
+        color_type = PNG_COLOR_TYPE_RGB;
+        row_size = info->width * 3;
         break;
     case PIX_FMT_GRAY8:
-        info_ptr->bit_depth = 8;
-        info_ptr->color_type = PNG_COLOR_TYPE_GRAY;
+        bit_depth = 8;
+        color_type = PNG_COLOR_TYPE_GRAY;
+        row_size = info->width;
         break;
     case PIX_FMT_MONOBLACK:
-        info_ptr->bit_depth = 1;
-        info_ptr->color_type = PNG_COLOR_TYPE_GRAY;
+        bit_depth = 1;
+        color_type = PNG_COLOR_TYPE_GRAY;
+        row_size = (info->width + 7) >> 3;
         break;
     default:
         return -1;
     }
-    png_write_info(png_ptr, info_ptr);
+    zstream.zalloc = png_zalloc;
+    zstream.zfree = png_zfree;
+    zstream.opaque = NULL;
+    ret = deflateInit2(&zstream, Z_DEFAULT_COMPRESSION,
+                       Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
+    if (ret != Z_OK)
+        return -1;
+    crow_buf = av_malloc(row_size + 1);
+    if (!crow_buf)
+        goto fail;
 
-    ptr = info->pict.data[0];
-    for(y=0;y<h;y++) {
-        png_write_row(png_ptr, ptr);
-        ptr += info->pict.linesize[0];
+    /* write png header */
+    put_buffer(f, pngsig, 8);
+    
+    to_be32(buf, info->width);
+    to_be32(buf + 4, info->height);
+    buf[8] = bit_depth;
+    buf[9] = color_type;
+    buf[10] = 0; /* compression type */
+    buf[11] = 0; /* filter type */
+    buf[12] = 0; /* interlace type */
+    
+    png_write_chunk(f, MKTAG('I', 'H', 'D', 'R'), buf, 13);
+
+    /* now put each row */
+    zstream.avail_out = IOBUF_SIZE;
+    zstream.next_out = buf;
+    for(y = 0;y < info->height; y++) {
+        /* XXX: do filtering */
+        ptr = info->pict.data[0] + y * info->pict.linesize[0];
+        memcpy(crow_buf + 1, ptr, row_size);
+        crow_buf[0] = PNG_FILTER_VALUE_NONE;
+        zstream.avail_in = row_size + 1;
+        zstream.next_in = crow_buf;
+        while (zstream.avail_in > 0) {
+            ret = deflate(&zstream, Z_NO_FLUSH);
+            if (ret != Z_OK)
+                goto fail;
+            if (zstream.avail_out == 0) {
+                png_write_chunk(f, MKTAG('I', 'D', 'A', 'T'), buf, IOBUF_SIZE);
+                zstream.avail_out = IOBUF_SIZE;
+                zstream.next_out = buf;
+            }
+        }
     }
-    png_write_end(png_ptr, info_ptr);
-    png_write_destroy(png_ptr);
-    put_flush_packet(pb);
-    return 0;
+    /* compress last bytes */
+    for(;;) {
+        ret = deflate(&zstream, Z_FINISH);
+        if (ret == Z_OK || ret == Z_STREAM_END) {
+            len = IOBUF_SIZE - zstream.avail_out;
+            if (len > 0) {
+                png_write_chunk(f, MKTAG('I', 'D', 'A', 'T'), buf, len);