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-rw-r--r--src/lib/jpeg.c36
1 files changed, 21 insertions, 15 deletions
diff --git a/src/lib/jpeg.c b/src/lib/jpeg.c
index 242cf0ca8e..617ab0b22a 100644
--- a/src/lib/jpeg.c
+++ b/src/lib/jpeg.c
@@ -1,9 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0-only */
/*
- * Provide a simple API around the Wuffs JPEG decoder
- * Uses the heap (and lots of it) for the image-size specific
- * work buffer, so ramstage-only.
+ * Provide a simple API around the Wuffs JPEG decoder.
*/
#include <stdint.h>
@@ -85,6 +83,24 @@ int jpeg_decode(unsigned char *filedata, size_t filesize, unsigned char *pic,
return JPEG_DECODE_FAILED;
}
+ /* Opting in to lower quality means that we can pass an empty slice as the
+ * "work buffer" argument to wuffs_jpeg__decoder__decode_frame below.
+ *
+ * Decoding progressive (not sequential) JPEGs would still require dynamic
+ * memory allocation (and the amount of work buffer required depends on the
+ * image dimensions), but we choose to just reject progressive JPEGs. It is
+ * simpler than sometimes calling malloc (which can fail, especially for
+ * large allocations) and free.
+ *
+ * More commentary about these quirks is at
+ * https://github.com/google/wuffs/blob/beaf45650085a16780b5f708b72daaeb1aa865c8/std/jpeg/decode_quirks.wuffs
+ */
+ wuffs_jpeg__decoder__set_quirk(
+ &dec, WUFFS_BASE__QUIRK_QUALITY,
+ WUFFS_BASE__QUIRK_QUALITY__VALUE__LOWER_QUALITY);
+ wuffs_jpeg__decoder__set_quirk(
+ &dec, WUFFS_JPEG__QUIRK_REJECT_PROGRESSIVE_JPEGS, 1);
+
wuffs_base__image_config imgcfg;
wuffs_base__io_buffer src = wuffs_base__ptr_u8__reader(filedata, filesize, true);
status = wuffs_jpeg__decoder__decode_image_config(&dec, &imgcfg, &src);
@@ -104,19 +120,9 @@ int jpeg_decode(unsigned char *filedata, size_t filesize, unsigned char *pic,
return JPEG_DECODE_FAILED;
}
- uint64_t workbuf_len_min_incl = wuffs_jpeg__decoder__workbuf_len(&dec).min_incl;
- uint8_t *workbuf_array = malloc(workbuf_len_min_incl);
- if ((workbuf_array == NULL) && workbuf_len_min_incl) {
- return JPEG_DECODE_FAILED;
- }
-
- wuffs_base__slice_u8 workbuf =
- wuffs_base__make_slice_u8(workbuf_array, workbuf_len_min_incl);
status = wuffs_jpeg__decoder__decode_frame(&dec, &pixbuf, &src,
- WUFFS_BASE__PIXEL_BLEND__SRC, workbuf, NULL);
-
- free(workbuf_array);
-
+ WUFFS_BASE__PIXEL_BLEND__SRC,
+ wuffs_base__empty_slice_u8(), NULL);
if (status.repr) {
return JPEG_DECODE_FAILED;
}