Initial revision

1 files changed, 220 insertions, 0 deletions

diff --git a/rd/read-gif.c b/rd/read-gif.c
new file mode 100644
index 0000000..b841dc7
--- /dev/null
+++ b/rd/read-gif.c
@@ -0,0 +1,220 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <gif_lib.h>
+
+#include "readers.h"
+
+struct gif_state {
+    FILE         *infile;
+    GifFileType  *gif;
+    GifPixelType *row;
+    GifPixelType *il;
+    int w,h;
+};
+
+static GifRecordType
+gif_fileread(struct gif_state *h)
+{
+    GifRecordType RecordType;
+    GifByteType *Extension;
+    int ExtCode, rc;
+    char *type;
+
+    for (;;) {
+	if (GIF_ERROR == DGifGetRecordType(h->gif,&RecordType)) {
+	    if (debug)
+		fprintf(stderr,"gif: DGifGetRecordType failed\n");
+	    PrintGifError();
+	    return -1;
+	}
+	switch (RecordType) {
+	case IMAGE_DESC_RECORD_TYPE:
+	    if (debug)
+		fprintf(stderr,"gif: IMAGE_DESC_RECORD_TYPE found\n");
+	    return RecordType;
+	case EXTENSION_RECORD_TYPE:
+	    if (debug)
+		fprintf(stderr,"gif: EXTENSION_RECORD_TYPE found\n");
+	    for (rc = DGifGetExtension(h->gif,&ExtCode,&Extension);
+		 NULL != Extension;
+		 rc = DGifGetExtensionNext(h->gif,&Extension)) {
+		if (rc == GIF_ERROR) {
+		    if (debug)
+			fprintf(stderr,"gif: DGifGetExtension failed\n");
+		    PrintGifError();
+		    return -1;
+		}
+		if (debug) {
+		    switch (ExtCode) {
+		    case COMMENT_EXT_FUNC_CODE:     type="comment";   break;
+		    case GRAPHICS_EXT_FUNC_CODE:    type="graphics";  break;
+		    case PLAINTEXT_EXT_FUNC_CODE:   type="plaintext"; break;
+		    case APPLICATION_EXT_FUNC_CODE: type="appl";      break;
+		    default:                        type="???";       break;
+		    }
+		    fprintf(stderr,"gif: extcode=0x%x [%s]\n",ExtCode,type);
+		}
+	    }
+	    break;
+	case TERMINATE_RECORD_TYPE:
+	    if (debug)
+		fprintf(stderr,"gif: TERMINATE_RECORD_TYPE found\n");
+	    return RecordType;
+	default:
+	    if (debug)
+		fprintf(stderr,"gif: unknown record type [%d]\n",RecordType);
+	    return -1;
+	}
+    }
+}
+
+#if 0
+static void
+gif_skipimage(struct gif_state *h)
+{
+    unsigned char *line;
+    int i;
+
+    if (debug)
+	fprintf(stderr,"gif: skipping image record ...\n");
+    DGifGetImageDesc(h->gif);
+    line = malloc(h->gif->SWidth);
+    for (i = 0; i < h->gif->SHeight; i++)
+	DGifGetLine(h->gif, line, h->gif->SWidth);
+    free(line);
+}
+#endif
+
+static void*
+gif_init(FILE *fp, char *filename, unsigned int page,
+	 struct ida_image_info *info, int thumbnail)
+{
+    struct gif_state *h;
+    GifRecordType RecordType;
+    int i, image = 0;
+    
+    h = malloc(sizeof(*h));
+    memset(h,0,sizeof(*h));
+
+    h->infile = fp;
+    h->gif = DGifOpenFileHandle(fileno(fp));
+    h->row = malloc(h->gif->SWidth * sizeof(GifPixelType));
+
+    while (0 == image) {
+	RecordType = gif_fileread(h);
+	switch (RecordType) {
+	case IMAGE_DESC_RECORD_TYPE:
+	    if (GIF_ERROR == DGifGetImageDesc(h->gif)) {
+		if (debug)
+		    fprintf(stderr,"gif: DGifGetImageDesc failed\n");
+		PrintGifError();
+	    }
+	    if (NULL == h->gif->SColorMap &&
+		NULL == h->gif->Image.ColorMap) {
+		if (debug)
+		    fprintf(stderr,"gif: oops: no colormap found\n");
+		goto oops;
+	    }
+#if 0
+	    info->width  = h->w = h->gif->SWidth;
+	    info->height = h->h = h->gif->SHeight;
+#else
+	    info->width  = h->w = h->gif->Image.Width;
+	    info->height = h->h = h->gif->Image.Height;
+#endif
+            info->npages = 1;
+	    image = 1;
+	    if (debug)
+		fprintf(stderr,"gif: reading image record ...\n");
+	    if (h->gif->Image.Interlace) {
+		if (debug)
+		    fprintf(stderr,"gif: interlaced\n");
+		h->il = malloc(h->w * h->h * sizeof(GifPixelType));
+		for (i = 0; i < h->h; i += 8)
+		    DGifGetLine(h->gif, h->il + h->w*i,h->w);
+		for (i = 4; i < h->gif->SHeight; i += 8)
+		    DGifGetLine(h->gif, h->il + h->w*i,h->w);
+		for (i = 2; i < h->gif->SHeight; i += 4)
+		    DGifGetLine(h->gif, h->il + h->w*i,h->w);
+	    }
+	    break;
+	case TERMINATE_RECORD_TYPE:
+	default:
+	    goto oops;
+	}
+    }
+    if (0 == info->width || 0 == info->height)
+	goto oops;
+
+    if (debug)
+	fprintf(stderr,"gif: s=%dx%d i=%dx%d\n",
+		h->gif->SWidth,h->gif->SHeight,
+		h->gif->Image.Width,h->gif->Image.Height);
+    return h;
+
+ oops:
+    if (debug)
+	fprintf(stderr,"gif: fatal error, aborting\n");
+    DGifCloseFile(h->gif);
+    fclose(h->infile);
+    free(h->row);
+    free(h);
+    return NULL;
+}
+
+static void
+gif_read(unsigned char *dst, unsigned int line, void *data)
+{
+    struct gif_state *h = data;
+    GifColorType *cmap;
+    int x;
+    
+    if (h->gif->Image.Interlace) {
+	if (line % 2) {
+	    DGifGetLine(h->gif, h->row, h->w);
+	} else {
+	    memcpy(h->row, h->il + h->w * line, h->w);
+	}
+    } else {
+	DGifGetLine(h->gif, h->row, h->w);
+    }
+    cmap = h->gif->Image.ColorMap ?
+	h->gif->Image.ColorMap->Colors : h->gif->SColorMap->Colors;
+    for (x = 0; x < h->w; x++) {
+        dst[0] = cmap[h->row[x]].Red;
+	dst[1] = cmap[h->row[x]].Green;
+	dst[2] = cmap[h->row[x]].Blue;
+	dst += 3;
+    }
+}
+
+static void
+gif_done(void *data)
+{
+    struct gif_state *h = data;
+
+    if (debug)
+	fprintf(stderr,"gif: done, cleaning up\n");
+    DGifCloseFile(h->gif);
+    fclose(h->infile);
+    if (h->il)
+	free(h->il);
+    free(h->row);
+    free(h);
+}
+
+static struct ida_loader gif_loader = {
+    magic: "GIF",
+    moff:  0,
+    mlen:  3,
+    name:  "libungif",
+    init:  gif_init,
+    read:  gif_read,
+    done:  gif_done,
+};
+
+static void __init init_rd(void)
+{
+    load_register(&gif_loader);
+}