1 files changed, 91 insertions, 0 deletions
diff --git a/src/jpeg.cpp b/src/jpeg.cpp
new file mode 100644
index 0000000..ceee359
--- /dev/null
+++ b/src/jpeg.cpp
@@ -0,0 +1,91 @@
+/* Jpeg functions
+ *
+ * \copyright
+ * Copyright 2017 Red Hat Inc. All rights reserved.
+ */
+#include <config.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <ctype.h>
+#include <jpeglib.h>
+#include <setjmp.h>
+
+#include "jpeg.hpp"
+
+struct JpegBuffer: public jpeg_destination_mgr
+{
+    JpegBuffer(std::vector<uint8_t>& buffer);
+    ~JpegBuffer();
+
+    std::vector<uint8_t>& buffer;
+};
+
+static boolean buf_empty_output_buffer(j_compress_ptr cinfo)
+{
+    JpegBuffer *buf = (JpegBuffer *) cinfo->dest;
+    size_t size = buf->next_output_byte - &buf->buffer[0];
+    buf->buffer.resize(buf->buffer.capacity() * 2);
+    buf->next_output_byte = &buf->buffer[0] + size;
+    buf->free_in_buffer = buf->buffer.size() - size;
+    return TRUE;
+}
+
+static void dummy_destination(j_compress_ptr cinfo)
+{
+}
+
+JpegBuffer::JpegBuffer(std::vector<uint8_t>& buffer):
+    buffer(buffer)
+{
+    if (buffer.capacity() < 32 * 1024) {
+        buffer.resize(32 * 1024);
+    } else {
+        buffer.resize(buffer.capacity());
+    }
+    next_output_byte = &buffer[0];
+    free_in_buffer = buffer.size();
+    init_destination = dummy_destination;
+    empty_output_buffer = buf_empty_output_buffer;
+    term_destination = dummy_destination;
+}
+
+JpegBuffer::~JpegBuffer()
+{
+    buffer.resize(next_output_byte - &buffer[0]);
+}
+
+/* from https://github.com/LuaDist/libjpeg/blob/master/example.c */
+void write_JPEG_file(std::vector<uint8_t>& buffer, int quality, uint8_t *data, unsigned width, unsigned height)
+{
+    struct jpeg_compress_struct cinfo;
+    struct jpeg_error_mgr jerr;
+    JSAMPROW row_pointer[1];
+    int row_stride;
+
+    cinfo.err = jpeg_std_error(&jerr);
+    jpeg_create_compress(&cinfo);
+
+    JpegBuffer buf(buffer);
+    cinfo.dest = &buf;
+
+    cinfo.image_width = width;
+    cinfo.image_height = height;
+    cinfo.input_components = 4;
+    cinfo.in_color_space = JCS_EXT_BGRX;
+    jpeg_set_defaults(&cinfo);
+    jpeg_set_quality(&cinfo, quality, TRUE);
+
+    jpeg_start_compress(&cinfo, TRUE);
+
+    row_stride = width * 4;
+
+    while (cinfo.next_scanline < cinfo.image_height) {
+        row_pointer[0] = &data[cinfo.next_scanline * row_stride];
+        // TODO check error
+        (void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
+    }
+
+    jpeg_finish_compress(&cinfo);
+
+    jpeg_destroy_compress(&cinfo);
+}