1 files changed, 150 insertions, 0 deletions
diff --git a/jxl.c b/jxl.c
new file mode 100644
index 0000000..a06f299
--- /dev/null
+++ b/jxl.c
@@ -0,0 +1,150 @@
+#include "jxl.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <jxl/decode.h>
+#include <jxl/codestream_header.h>
+#if defined(WBG_HAVE_JXL_THREADS)
+ #include <jxl/resizable_parallel_runner.h>
+#endif
+
+#define LOG_MODULE "jxl"
+#define LOG_ENABLE_DBG 0
+#include "log.h"
+#include "stride.h"
+
+pixman_image_t *
+jxl_load(FILE *fp, const char *path)
+{
+    pixman_image_t *pix = NULL;
+    pixman_format_code_t format = PIXMAN_x8b8g8r8;
+    bool ok = false;
+    uint8_t *file_data = NULL;
+    uint8_t *image = NULL;
+    size_t file_size, image_size;
+    int width, height, stride;
+
+#if defined(WBG_HAVE_JXL_THREADS)
+    JxlParallelRunner *runner = NULL;
+#endif
+    JxlDecoder *decoder = NULL;
+    JxlBasicInfo info = {0};
+    JxlPixelFormat jxl_format = {
+        .num_channels = 4,
+        .data_type = JXL_TYPE_UINT8,
+        .endianness = JXL_LITTLE_ENDIAN,
+        .align = 0
+    };
+
+    if (fseek(fp, 0, SEEK_END) < 0) {
+        LOG_ERRNO("%s: failed to seek to end of file", path);
+        return NULL;
+    }
+    file_size = ftell(fp);
+    if (fseek(fp, 0, SEEK_SET) < 0) {
+        LOG_ERRNO("%s: failed to seek to beginning of file", path);
+        return NULL;
+    }
+
+    if (!(file_data = malloc(file_size)))
+        goto err;
+    clearerr(fp);
+    if (fread(file_data, sizeof(*file_data), file_size, fp) != file_size
+            && ferror(fp)) {
+        LOG_ERRNO("%s: failed to read", path);
+        goto err;
+    }
+
+    if (JxlSignatureCheck(file_data, file_size) == JXL_SIG_INVALID) {
+        LOG_DBG("%s: not a jpegxl image", path);
+        goto err;
+    }
+
+    if (!(decoder = JxlDecoderCreate(NULL)))
+        goto err;
+#if defined(WBG_HAVE_JXL_THREADS)
+    if (!(runner = JxlResizableParallelRunnerCreate(NULL)))
+        goto err;
+    JxlDecoderSetParallelRunner(decoder, JxlResizableParallelRunner, runner);
+#endif
+
+    /* pixman expects premultiplied alpha */
+    JxlDecoderSetUnpremultiplyAlpha(decoder, JXL_FALSE);
+
+    JxlDecoderSubscribeEvents(decoder, JXL_DEC_BASIC_INFO | JXL_DEC_FULL_IMAGE);
+
+    JxlDecoderSetInput(decoder, file_data, file_size);
+    JxlDecoderCloseInput(decoder);
+
+    while (1) {
+        JxlDecoderStatus status = JxlDecoderProcessInput(decoder);
+
+        if (status == JXL_DEC_ERROR) {
+            LOG_ERR("%s: decoder error", path);
+            goto err;
+        } else if (status == JXL_DEC_NEED_MORE_INPUT) {
+            LOG_ERR("%s: decoder requires more input but already provided all input", path);
+            goto err;
+        } else if (status == JXL_DEC_BASIC_INFO) {
+            if (JxlDecoderGetBasicInfo(decoder, &info)
+                    != JXL_DEC_SUCCESS) {
+                LOG_ERR("%s: failed to get basic info", path);
+            }
+
+            width = info.xsize;
+            height = info.ysize;
+            stride = stride_for_format_and_width(format, width);
+            image_size = height * stride;
+
+            LOG_DBG("%s: %dx%d@%hhubpp, %d channels, %d alpha bits", path, width, height,
+                    info.bits_per_sample, info.num_color_channels, info.alpha_bits);
+
+            if (!(image = malloc(image_size)))
+                goto err;
+
+#if defined(WBG_HAVE_JXL_THREADS)
+            JxlResizableParallelRunnerSetThreads(runner,
+                    JxlResizableParallelRunnerSuggestThreads(width, height));
+#endif
+        } else if (status == JXL_DEC_NEED_IMAGE_OUT_BUFFER) {
+            size_t min_size;
+            if (JxlDecoderImageOutBufferSize(decoder, &jxl_format, &min_size)
+                    != JXL_DEC_SUCCESS) {
+                LOG_ERR("%s: failed to get the minimum size of the output buffer", path);
+                goto err;
+            }
+
+            if (min_size > image_size) {
+                LOG_ERR("minimum size [%zu] is greater than the expected size [%zu]",
+                        min_size, image_size);
+                goto err;
+            } else if (min_size < image_size) {
+                LOG_WARN("minimum size [%zu] is less than the expected size [%zu]",
+                        min_size, image_size);
+            }
+
+            if (JxlDecoderSetImageOutBuffer(decoder, &jxl_format, image,
+                    image_size) != JXL_DEC_SUCCESS) {
+                LOG_ERR("%s: failed to set output buffer", path);
+                goto err;
+            }
+        } else {
+            break;
+        }
+    }
+
+    pix = pixman_image_create_bits_no_clear(format, width, height,
+            (uint32_t *)image, stride);
+    ok = pix != NULL;
+
+err:
+    if (!ok)
+        free(image);
+    free(file_data);
+#if defined(WBG_HAVE_JXL_THREADS)
+    JxlResizableParallelRunnerDestroy(runner);
+#endif
+    JxlDecoderDestroy(decoder);
+
+    return pix;
+}