png conversion is no longer done in a separate process.

Signed-off-by: Mattias Andrée <maandree@member.fsf.org>

1 files changed, 54 insertions, 52 deletions

diff --git a/src/png.c b/src/png.c
index 0944f18..b0da466 100644
--- a/src/png.c
+++ b/src/png.c
@@ -18,11 +18,7 @@
  */
 #include "common.h"
 #include "png.h"
-
-#ifdef __GNUC__
-# pragma GCC diagnostic ignored "-Wpadded"
-#endif
-#include <png.h>
+#include "kern.h"
 
 
 /*
@@ -30,50 +26,37 @@
  * 
  *   Users want their files in PNG (most often), not PNM.
  *   Calling an external program for conversion poses
- *   potential security risks, and is slower.
+ *   potential security risks, and is significantly slower.
  */
 
 
 /**
- * Convert an image from PNM to PNG.
- * 
- * This is a very limited conversion implementation.
- * It is not generally reusable. It makes assumptions
- * that are true only necessarily for this program.
+ * Create an PNG file.
  * 
- * @param   fdin   The file descriptor for the image to convert (PNM).
- * @param   fdout  The file descriptor for the output image (PNG).
- * @return         Zero on success, -1 on error.
+ * @param   fbfd    The file descriptor connected to framebuffer device.
+ * @param   width   The width of the image.
+ * @param   height  The height of the image.
+ * @param   imgfd   The file descriptor connected to conversion process's stdin.
+ * @return          Zero on success, -1 on error.
  */
 int
-convert (int fdin, int fdout)
+save_png (int fbfd, long width, long height, int imgfd)
 {
-#define SCAN(...)  do { if (fscanf(in, __VA_ARGS__) != 1)  goto fail; } while (0)
-
-  FILE *in = NULL;
-  FILE *out = NULL;
-  long height, width, width3;
-  long y, x, r, g, b;
-  png_byte   *pixbuf = 0;
+  char buf[8 << 10];
+  FILE *file = NULL;
+  ssize_t got, off;
+  size_t adjustment;
+  png_byte   *restrict pixbuf = NULL;
   png_struct *pngbuf = NULL;
   png_info   *pnginfo = NULL;
-  int saved_errno = 0, rc, c;
+  long width3, state = 0;
+  int rc, saved_errno;
   
-  /* Get a FILE * for the input, we want to use fscanf, there is no dscanf. */
-  in = fdopen (fdin, "r");
-  if (in == NULL)
-    goto fail;
   /* Get a FILE * for the output, libpng wants a FILE *, not a file descriptor. */
-  out = fdopen (fdout, "w");
-  if (out == NULL)
+  file = fdopen (imgfd, "w");
+  if (file == NULL)
     goto fail;
   
-  /* Read head. */
-  do c = fgetc(in); while ((c != '\n') && (c != EOF));
-  SCAN ("%li ", &width);
-  SCAN ("%li\n", &height);
-  do c = fgetc(in); while ((c != '\n') && (c != EOF));
-  
   /* Allocte structures for the PNG. */
   width3 = width * 3;
   pixbuf = malloc ((size_t)width3 * sizeof (png_byte));
@@ -89,28 +72,45 @@ convert (int fdin, int fdout)
   /* Initialise PNG write, and write head. */
   if (setjmp (png_jmpbuf(pngbuf))) /* Failing libpng calls jump here. */
     goto fail;
-  png_init_io (pngbuf, out);
+  png_init_io (pngbuf, file);
   png_set_IHDR (pngbuf, pnginfo, (png_uint_32)width, (png_uint_32)height,
 		8 /* bit depth */, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
 		PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
   png_write_info (pngbuf, pnginfo);
   
-  /* Read and convert body. */
-  for (y = 0; y < height; y++)
+  /* TODO (maybe) The image shall be packed. That is, if 24 bits per pixel is
+   *              unnecessary, less shall be used. 6 bits is often sufficient. */
+  
+  /* Convert raw framebuffer data into a PNG image (body). */
+  for (off = 0;;)
     {
-      for (x = 0; x < width3; x += 3)
+      /* Read data from the framebuffer, we may have up to 3 bytes buffered. */
+      got = read (fbfd, buf + off, sizeof (buf) - (size_t)off * sizeof (char));
+      if (got < 0)
+	goto fail;
+      if (got == 0)
+	break;
+      got += off;
+      
+      /* Convert read pixels. */
+      if (convert_fb_to_png (pngbuf, pixbuf, buf, (size_t)got,
+			     width3, &adjustment, &state) < 0)
+	goto fail;
+      
+      /* If we read a whole number of pixels, reset the buffer, otherwise,
+         move the unconverted bytes to the beginning of the buffer. */
+      if (adjustment)
 	{
-	  SCAN ("%li\n", &r);
-	  SCAN ("%li\n", &g);
-	  SCAN ("%li\n", &b);
-	  pixbuf[x + 0] = (png_byte)r;
-	  pixbuf[x + 1] = (png_byte)g;
-	  pixbuf[x + 2] = (png_byte)b;
+	  off -= (ssize_t)adjustment;
+	  memcpy (buf, buf + off, (size_t)(got - off) * sizeof (char));
+	  off = got - off;
 	}
-      png_write_row (pngbuf, pixbuf);
+      else
+	off = 0;
     }
-  png_write_end (pngbuf, pnginfo);
   
+  /* Done! */
+  png_write_end (pngbuf, pnginfo);
   rc = 0;
   goto cleanup;
  fail:
@@ -120,11 +120,13 @@ convert (int fdin, int fdout)
   
  cleanup: 
   png_destroy_write_struct (&pngbuf, (pnginfo ? &pnginfo : NULL));
-  if (in != NULL)
-    fclose (in);
-  if (out != NULL)
-    fclose (out);
+  if (file != NULL)
+    {
+      fflush (file);
+      fclose (file);
+    }
   free (pixbuf);
-  return errno = saved_errno, rc;
+  errno = saved_errno;
+  return rc;
 }