Fixed code which moved buffer around as new data comes in to work

1999-11-03  Michael Fulbright  <drmike@redhat.com>

	* src/io-jpg.c image_load_increment(): Fixed code which moved
	buffer around as new data comes in to work properly. JPEG progressive
	loading should be working now except for grayscale JPEG's, which I

1 files changed, 22 insertions, 21 deletions

diff --git a/gdk-pixbuf/io-jpeg.c b/gdk-pixbuf/io-jpeg.c
index cfd15effcc..4f913d35e4 100644
--- a/gdk-pixbuf/io-jpeg.c
+++ b/gdk-pixbuf/io-jpeg.c
@@ -45,6 +45,8 @@
 
 #include <config.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <setjmp.h>
 #include <jpeglib.h>
 #include "gdk-pixbuf.h"
@@ -53,11 +55,12 @@
 
 
 /* we are a "source manager" as far as libjpeg is concerned */
+#define JPEG_PROG_BUF_SIZE 4096
+
 typedef struct {
 	struct jpeg_source_mgr pub;   /* public fields */
 
-	JOCTET * buffer;              /* start of buffer */
-	gboolean start_of_file;       /* have we gotten any data yet? */
+	JOCTET buffer[JPEG_PROG_BUF_SIZE];              /* start of buffer */
 	long  skip_next;              /* number of bytes to skip next read */
 
 } my_source_mgr;
@@ -85,8 +88,6 @@ typedef struct {
 	struct error_handler_data     jerr;
 } JpegProgContext;
 
-#define JPEG_PROG_BUF_SIZE 4096
-
 GdkPixbuf *image_load (FILE *f);
 gpointer image_begin_load (ModulePreparedNotifyFunc func, gpointer user_data);
 void image_stop_load (gpointer context);
@@ -227,7 +228,6 @@ init_source (j_decompress_ptr cinfo)
 {
 	my_src_ptr src = (my_src_ptr) cinfo->src;
 
-	src->start_of_file = TRUE;
 	src->skip_next = 0;
 }
 
@@ -278,7 +278,7 @@ image_begin_load (ModulePreparedNotifyFunc func, gpointer user_data)
 	JpegProgContext *context;
 	my_source_mgr   *src;
 
-	context = g_new (JpegProgContext, 1);
+	context = g_new0 (JpegProgContext, 1);
 	context->notify_func = func;
 	context->notify_user_data = user_data;
 	context->pixbuf = NULL;
@@ -289,9 +289,8 @@ image_begin_load (ModulePreparedNotifyFunc func, gpointer user_data)
 	/* create libjpeg structures */
 	jpeg_create_decompress (&context->cinfo);
 
-	context->cinfo.src = (struct jpeg_source_mgr *) g_new (my_source_mgr, 1);
+	context->cinfo.src = (struct jpeg_source_mgr *) g_new0 (my_source_mgr, 1);
 	src = (my_src_ptr) context->cinfo.src;
-	src->buffer = g_malloc (JPEG_PROG_BUF_SIZE);
 
 	context->cinfo.err = jpeg_std_error (&context->jerr.pub);
 
@@ -316,6 +315,7 @@ void
 image_stop_load (gpointer data)
 {
 	JpegProgContext *context = (JpegProgContext *) data;
+
 	g_return_if_fail (context != NULL);
 
 	if (context->pixbuf)
@@ -324,8 +324,6 @@ image_stop_load (gpointer data)
 	if (context->cinfo.src) {
 		my_src_ptr src = (my_src_ptr) context->cinfo.src;
 		
-		if (src->buffer)
-			g_free (src->buffer);
 		g_free (src);
 	}
 
@@ -352,12 +350,12 @@ image_load_increment (gpointer data, guchar *buf, guint size)
 	struct jpeg_decompress_struct *cinfo;
 	my_src_ptr  src;
 	guint       num_left, num_copy;
-	guchar      *nextptr;
 
 	g_return_val_if_fail (context != NULL, FALSE);
 	g_return_val_if_fail (buf != NULL, FALSE);
 
 	src = (my_src_ptr) context->cinfo.src;
+
 	cinfo = &context->cinfo;
 
 	/* skip over data if requested, handle unsigned int sizes cleanly */
@@ -374,23 +372,24 @@ image_load_increment (gpointer data, guchar *buf, guint size)
 		num_left = size;
 	}
 
+
 	while (num_left > 0) {
 		/* copy as much data into buffer as possible */
+
+		if(src->pub.bytes_in_buffer && 
+		   src->pub.next_input_byte != src->buffer)
+			memmove(src->buffer, src->pub.next_input_byte,
+				src->pub.bytes_in_buffer);
+
 		num_copy = MIN (JPEG_PROG_BUF_SIZE - src->pub.bytes_in_buffer,
 				size);
 
 		if (num_copy == 0) 
-			g_assert ("Buffer overflow!\n");
+			g_error ("Buffer overflow!");
 
-		nextptr = src->buffer + src->pub.bytes_in_buffer;
-		memcpy (nextptr, buf, num_copy);
-		
-		if (src->pub.next_input_byte == NULL ||
-		    src->pub.bytes_in_buffer == 0)
+		memcpy(src->buffer + src->pub.bytes_in_buffer, buf, num_copy);
 		src->pub.next_input_byte = src->buffer;
-
 		src->pub.bytes_in_buffer += num_copy;
-
 		num_left -= num_copy;
 
 		/* try to load jpeg header */
@@ -399,6 +398,7 @@ image_load_increment (gpointer data, guchar *buf, guint size)
 
 			rc = jpeg_read_header (cinfo, TRUE);
 			context->src_initialized = TRUE;
+
 			if (rc == JPEG_SUSPENDED)
 				continue;
 
@@ -418,7 +418,7 @@ image_load_increment (gpointer data, guchar *buf, guint size)
 
 			if (context->pixbuf == NULL) {
 				/* Failed to allocate memory */
-				g_assert ("Couldn't allocate gdkpixbuf\n");
+				g_error ("Couldn't allocate gdkpixbuf");
 			}
 
 			/* Use pixbuf buffer to store decompressed data */
@@ -430,7 +430,6 @@ image_load_increment (gpointer data, guchar *buf, guint size)
 				(* context->notify_func) (context->pixbuf,
 							  context->notify_user_data);
 
-			src->start_of_file = FALSE;
 		} else if (!context->did_prescan) {
 			int rc;
 
@@ -461,9 +460,11 @@ image_load_increment (gpointer data, guchar *buf, guint size)
 					rowptr += context->pixbuf->art_pixbuf->rowstride;;
 				}
 
+#ifdef IO_JPEG_DEBUG_GREY
 				for (p=lines[0],i=0; i< context->pixbuf->art_pixbuf->rowstride;i++, p++)
 					*p = 0;
 				
+#endif
 				nlines = jpeg_read_scanlines (cinfo, lines,
 							      cinfo->rec_outbuf_height);
 				if (nlines == 0)