diff options
| -rw-r--r-- | src/lib/jpeg.c | 36 |
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; } |