1 files changed, 522 insertions, 0 deletions
diff --git a/base/gfx/jpeg_codec.cc b/base/gfx/jpeg_codec.cc
new file mode 100644
index 0000000..f78d5af
--- /dev/null
+++ b/base/gfx/jpeg_codec.cc
@@ -0,0 +1,522 @@
+// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/gfx/jpeg_codec.h"
+
+#include <setjmp.h>
+
+#include "base/logging.h"
+#include "base/scoped_ptr.h"
+#include "skia/include/SkBitmap.h"
+
+extern "C" {
+#include "jpeglib.h"
+}
+
+// Encoder/decoder shared stuff ------------------------------------------------
+
+namespace {
+
+// used to pass error info through the JPEG library
+struct CoderErrorMgr {
+  jpeg_error_mgr pub;
+  jmp_buf setjmp_buffer;
+};
+
+void ErrorExit(jpeg_common_struct* cinfo) {
+  CoderErrorMgr *err = reinterpret_cast<CoderErrorMgr*>(cinfo->err);
+
+  // Return control to the setjmp point.
+  longjmp(err->setjmp_buffer, false);
+}
+
+}  // namespace
+
+// Encoder ---------------------------------------------------------------------
+//
+// This code is based on nsJPEGEncoder from Mozilla.
+// Copyright 2005 Google Inc. (Brett Wilson, contributor)
+
+namespace {
+
+// Initial size for the output buffer in the JpegEncoderState below.
+const static int initial_output_buffer_size = 8192;
+
+struct JpegEncoderState {
+  JpegEncoderState(std::vector<unsigned char>* o) : out(o), image_buffer_used(0) {
+  }
+
+  // Output buffer, of which 'image_buffer_used' bytes are actually used (this
+  // will often be less than the actual size of the vector because we size it
+  // so that libjpeg can write directly into it.
+  std::vector<unsigned char>* out;
+
+  // Number of bytes in the 'out' buffer that are actually used (see above).
+  size_t image_buffer_used;
+};
+
+// Initializes the JpegEncoderState for encoding, and tells libjpeg about where
+// the output buffer is.
+//
+// From the JPEG library:
+//  "Initialize destination. This is called by jpeg_start_compress() before
+//   any data is actually written. It must initialize next_output_byte and
+//   free_in_buffer. free_in_buffer must be initialized to a positive value."
+void InitDestination(jpeg_compress_struct* cinfo) {
+  JpegEncoderState* state = static_cast<JpegEncoderState*>(cinfo->client_data);
+  DCHECK(state->image_buffer_used == 0) << "initializing after use";
+
+  state->out->resize(initial_output_buffer_size);
+  state->image_buffer_used = 0;
+
+  cinfo->dest->next_output_byte = &(*state->out)[0];
+  cinfo->dest->free_in_buffer = initial_output_buffer_size;
+}
+
+// Resize the buffer that we give to libjpeg and update our and its state.
+//
+// From the JPEG library:
+//  "Callback used by libjpeg whenever the buffer has filled (free_in_buffer
+//   reaches zero). In typical applications, it should write out the *entire*
+//   buffer (use the saved start address and buffer length; ignore the current
+//   state of next_output_byte and free_in_buffer). Then reset the pointer &
+//   count to the start of the buffer, and return TRUE indicating that the
+//   buffer has been dumped. free_in_buffer must be set to a positive value
+//   when TRUE is returned. A FALSE return should only be used when I/O
+//   suspension is desired (this operating mode is discussed in the next
+//   section)."
+boolean EmptyOutputBuffer(jpeg_compress_struct* cinfo) {
+  JpegEncoderState* state = static_cast<JpegEncoderState*>(cinfo->client_data);
+
+  // note the new size, the buffer is full
+  state->image_buffer_used = state->out->size();
+
+  // expand buffer, just double size each time
+  state->out->resize(state->out->size() * 2);
+
+  // tell libjpeg where to write the next data
+  cinfo->dest->next_output_byte = &(*state->out)[state->image_buffer_used];
+  cinfo->dest->free_in_buffer = state->out->size() - state->image_buffer_used;
+  return 1;
+}
+
+// Cleans up the JpegEncoderState to prepare for returning in the final form.
+//
+// From the JPEG library:
+//  "Terminate destination --- called by jpeg_finish_compress() after all data
+//   has been written. In most applications, this must flush any data
+//   remaining in the buffer. Use either next_output_byte or free_in_buffer to
+//   determine how much data is in the buffer."
+void TermDestination(jpeg_compress_struct* cinfo) {
+  JpegEncoderState* state = static_cast<JpegEncoderState*>(cinfo->client_data);
+  DCHECK(state->out->size() >= state->image_buffer_used);
+
+  // update the used byte based on the next byte libjpeg would write to
+  state->image_buffer_used = cinfo->dest->next_output_byte - &(*state->out)[0];
+  DCHECK(state->image_buffer_used < state->out->size()) <<
+    "JPEG library busted, got a bad image buffer size";
+
+  // update our buffer so that it exactly encompases the desired data
+  state->out->resize(state->image_buffer_used);
+}
+
+// Converts RGBA to RGB (removing the alpha values) to prepare to send data to
+// libjpeg. This converts one row of data in rgba with the given width in
+// pixels the the given rgb destination buffer (which should have enough space
+// reserved for the final data).
+void StripAlpha(const unsigned char* rgba, int pixel_width, unsigned char* rgb)
+{
+  for (int x = 0; x < pixel_width; x++) {
+    const unsigned char* pixel_in = &rgba[x * 4];
+    unsigned char* pixel_out = &rgb[x * 3];
+    pixel_out[0] = pixel_in[0];
+    pixel_out[1] = pixel_in[1];
+    pixel_out[2] = pixel_in[2];
+  }
+}
+
+// Converts BGRA to RGB by reordering the color components and dropping the
+// alpha. This converts  one row of data in rgba with the given width in
+// pixels the the given rgb destination buffer (which should have enough space
+// reserved for the final data).
+void BGRAtoRGB(const unsigned char* bgra, int pixel_width, unsigned char* rgb)
+{
+  for (int x = 0; x < pixel_width; x++) {
+    const unsigned char* pixel_in = &bgra[x * 4];
+    unsigned char* pixel_out = &rgb[x * 3];
+    pixel_out[0] = pixel_in[2];
+    pixel_out[1] = pixel_in[1];
+    pixel_out[2] = pixel_in[0];
+  }
+}
+
+// This class destroys the given jpeg_compress object when it goes out of
+// scope. It simplifies the error handling in Encode (and even applies to the
+// success case).
+class CompressDestroyer {
+ public:
+  CompressDestroyer() : cinfo_(NULL) {
+  }
+  ~CompressDestroyer() {
+    DestroyManagedObject();
+  }
+  void SetManagedObject(jpeg_compress_struct* ci) {
+    DestroyManagedObject();
+    cinfo_ = ci;
+  }
+  void DestroyManagedObject() {
+    if (cinfo_) {
+      jpeg_destroy_compress(cinfo_);
+      cinfo_ = NULL;
+    }
+  }
+ private:
+  jpeg_compress_struct* cinfo_;
+};
+
+}  // namespace
+
+bool JPEGCodec::Encode(const unsigned char* input, ColorFormat format,
+                       int w, int h, int row_byte_width,
+                       int quality, std::vector<unsigned char>* output) {
+  jpeg_compress_struct cinfo;
+  CompressDestroyer destroyer;
+  output->clear();
+
+  // We set up the normal JPEG error routines, then override error_exit.
+  // This must be done before the call to create_compress.
+  CoderErrorMgr errmgr;
+  cinfo.err = jpeg_std_error(&errmgr.pub);
+  errmgr.pub.error_exit = ErrorExit;
+  // Establish the setjmp return context for ErrorExit to use.
+  if (setjmp(errmgr.setjmp_buffer)) {
+    // If we get here, the JPEG code has signaled an error.
+    // MSDN notes: "if you intend your code to be portable, do not rely on
+    // correct destruction of frame-based objects when executing a nonlocal
+    // goto using a call to longjmp."  So we delete the CompressDestroyer's
+    // object manually instead.
+    destroyer.DestroyManagedObject();
+    return false;
+  }
+
+  // The destroyer will destroy() cinfo on exit.
+  jpeg_create_compress(&cinfo);
+  destroyer.SetManagedObject(&cinfo);
+
+  cinfo.image_width = w;
+  cinfo.image_height = h;
+  cinfo.input_components = 3;
+  cinfo.in_color_space = JCS_RGB;
+  cinfo.data_precision = 8;
+
+  jpeg_set_defaults(&cinfo);
+  jpeg_set_quality(&cinfo, quality, 1);  // quality here is 0-100
+
+  // set up the destination manager
+  jpeg_destination_mgr destmgr;
+  destmgr.init_destination = InitDestination;
+  destmgr.empty_output_buffer = EmptyOutputBuffer;
+  destmgr.term_destination = TermDestination;
+  cinfo.dest = &destmgr;
+
+  JpegEncoderState state(output);
+  cinfo.client_data = &state;
+
+  jpeg_start_compress(&cinfo, 1);
+
+  // feed it the rows, doing necessary conversions for the color format
+  if (format == FORMAT_RGB) {
+    // no conversion necessary
+    while (cinfo.next_scanline < cinfo.image_height) {
+      const unsigned char* row = &input[cinfo.next_scanline * row_byte_width];
+      jpeg_write_scanlines(&cinfo, const_cast<unsigned char**>(&row), 1);
+    }
+  } else {
+    // get the correct format converter
+    void (*converter)(const unsigned char* in, int w, unsigned char* rgb);
+    if (format == FORMAT_RGBA) {
+      converter = StripAlpha;
+    } else if (format == FORMAT_BGRA) {
+      converter = BGRAtoRGB;
+    } else {
+      NOTREACHED() << "Invalid pixel format";
+      return false;
+    }
+
+    // output row after converting
+    unsigned char* row = new unsigned char[w * 3];
+
+    while (cinfo.next_scanline < cinfo.image_height) {
+      converter(&input[cinfo.next_scanline * row_byte_width], w, row);
+      jpeg_write_scanlines(&cinfo, &row, 1);
+    }
+    delete[] row;
+  }
+
+  jpeg_finish_compress(&cinfo);
+  return true;
+}
+
+// Decoder --------------------------------------------------------------------
+
+namespace {
+
+struct JpegDecoderState {
+  JpegDecoderState(const unsigned char* in, size_t len)
+      : input_buffer(in), input_buffer_length(len) {
+  }
+
+  const unsigned char* input_buffer;
+  size_t input_buffer_length;
+};
+
+// Callback to initialize the source.
+//
+// From the JPEG library:
+//  "Initialize source. This is called by jpeg_read_header() before any data is
+//   actually read. May leave bytes_in_buffer set to 0 (in which case a
+//   fill_input_buffer() call will occur immediately)."
+void InitSource(j_decompress_ptr cinfo) {
+  JpegDecoderState* state = static_cast<JpegDecoderState*>(cinfo->client_data);
+  cinfo->src->next_input_byte = state->input_buffer;
+  cinfo->src->bytes_in_buffer = state->input_buffer_length;
+}
+
+// Callback to fill the buffer. Since our buffer already contains all the data,
+// we should never need to provide more data. If libjpeg thinks it needs more
+// data, our input is probably corrupt.
+//
+// From the JPEG library:
+//  "This is called whenever bytes_in_buffer has reached zero and more data is
+//   wanted. In typical applications, it should read fresh data into the buffer
+//   (ignoring the current state of next_input_byte and bytes_in_buffer), reset
+//   the pointer & count to the start of the buffer, and return TRUE indicating
+//   that the buffer has been reloaded. It is not necessary to fill the buffer
+//   entirely, only to obtain at least one more byte. bytes_in_buffer MUST be
+//   set to a positive value if TRUE is returned. A FALSE return should only
+//   be used when I/O suspension is desired."
+boolean FillInputBuffer(j_decompress_ptr cinfo) {
+  return false;
+}
+
+// Skip data in the buffer. Since we have all the data at once, this operation
+// is easy. It is not clear if this ever gets called because the JPEG library
+// should be able to do the skip itself (it has all the data).
+//
+// From the JPEG library:
+//  "Skip num_bytes worth of data. The buffer pointer and count should be
+//   advanced over num_bytes input bytes, refilling the buffer as needed. This
+//   is used to skip over a potentially large amount of uninteresting data
+//   (such as an APPn marker). In some applications it may be possible to
+//   optimize away the reading of the skipped data, but it's not clear that
+//   being smart is worth much trouble; large skips are uncommon.
+//   bytes_in_buffer may be zero on return. A zero or negative skip count
+//   should be treated as a no-op."
+void SkipInputData(j_decompress_ptr cinfo, long num_bytes) {
+  if (num_bytes > static_cast<long>(cinfo->src->bytes_in_buffer)) {
+    // Since all our data should be in the buffer, trying to skip beyond it
+    // means that there is some kind of error or corrupt input data. A 0 for
+    // bytes left means it will call FillInputBuffer which will then fail.
+    cinfo->src->next_input_byte += cinfo->src->bytes_in_buffer;
+    cinfo->src->bytes_in_buffer = 0;
+  } else if (num_bytes > 0) {
+    cinfo->src->bytes_in_buffer -= static_cast<size_t>(num_bytes);
+    cinfo->src->next_input_byte += num_bytes;
+  }
+}
+
+// Our source doesn't need any cleanup, so this is a NOP.
+//
+// From the JPEG library:
+//  "Terminate source --- called by jpeg_finish_decompress() after all data has
+//   been read to clean up JPEG source manager. NOT called by jpeg_abort() or
+//   jpeg_destroy()."
+void TermSource(j_decompress_ptr cinfo) {
+}
+
+// Converts one row of rgb data to rgba data by adding a fully-opaque alpha
+// value.
+void AddAlpha(const unsigned char* rgb, int pixel_width, unsigned char* rgba) {
+  for (int x = 0; x < pixel_width; x++) {
+    const unsigned char* pixel_in = &rgb[x * 3];
+    unsigned char* pixel_out = &rgba[x * 4];
+    pixel_out[0] = pixel_in[0];
+    pixel_out[1] = pixel_in[1];
+    pixel_out[2] = pixel_in[2];
+    pixel_out[3] = 0xff;
+  }
+}
+
+// Converts one row of RGB data to BGRA by reordering the color components and
+// adding alpha values of 0xff.
+void RGBtoBGRA(const unsigned char* bgra, int pixel_width, unsigned char* rgb)
+{
+  for (int x = 0; x < pixel_width; x++) {
+    const unsigned char* pixel_in = &bgra[x * 3];
+    unsigned char* pixel_out = &rgb[x * 4];
+    pixel_out[0] = pixel_in[2];
+    pixel_out[1] = pixel_in[1];
+    pixel_out[2] = pixel_in[0];
+    pixel_out[3] = 0xff;
+  }
+}
+
+// This class destroys the given jpeg_decompress object when it goes out of
+// scope. It simplifies the error handling in Decode (and even applies to the
+// success case).
+class DecompressDestroyer {
+ public:
+  DecompressDestroyer() : cinfo_(NULL) {
+  }
+  ~DecompressDestroyer() {
+    DestroyManagedObject();
+  }
+  void SetManagedObject(jpeg_decompress_struct* ci) {
+    DestroyManagedObject();
+    cinfo_ = ci;
+  }
+  void DestroyManagedObject() {
+    if (cinfo_) {
+      jpeg_destroy_decompress(cinfo_);
+      cinfo_ = NULL;
+    }
+  }
+ private:
+  jpeg_decompress_struct* cinfo_;
+};
+
+}  // namespace
+
+bool JPEGCodec::Decode(const unsigned char* input, size_t input_size,
+                       ColorFormat format, std::vector<unsigned char>* output,
+                       int* w, int* h) {
+  jpeg_decompress_struct cinfo;
+  DecompressDestroyer destroyer;
+  output->clear();
+
+  // We set up the normal JPEG error routines, then override error_exit.
+  // This must be done before the call to create_decompress.
+  CoderErrorMgr errmgr;
+  cinfo.err = jpeg_std_error(&errmgr.pub);
+  errmgr.pub.error_exit = ErrorExit;
+  // Establish the setjmp return context for ErrorExit to use.
+  if (setjmp(errmgr.setjmp_buffer)) {
+    // If we get here, the JPEG code has signaled an error.
+    // See note in JPEGCodec::Encode() for why we need to destroy the cinfo
+    // manually here.
+    destroyer.DestroyManagedObject();
+    return false;
+  }
+
+  // The destroyer will destroy() cinfo on exit.  We don't want to set the
+  // destroyer's object until cinfo is initialized.
+  jpeg_create_decompress(&cinfo);
+  destroyer.SetManagedObject(&cinfo);
+
+  // set up the source manager
+  jpeg_source_mgr srcmgr;
+  srcmgr.init_source = InitSource;
+  srcmgr.fill_input_buffer = FillInputBuffer;
+  srcmgr.skip_input_data = SkipInputData;
+  srcmgr.resync_to_restart = jpeg_resync_to_restart;  // use default routine
+  srcmgr.term_source = TermSource;
+  cinfo.src = &srcmgr;
+
+  JpegDecoderState state(input, input_size);
+  cinfo.client_data = &state;
+
+  // fill the file metadata into our buffer
+  if (jpeg_read_header(&cinfo, true) != JPEG_HEADER_OK)
+    return false;
+
+  // we want to always get RGB data out
+  switch (cinfo.jpeg_color_space) {
+    case JCS_GRAYSCALE:
+    case JCS_RGB:
+    case JCS_YCbCr:
+      cinfo.out_color_space = JCS_RGB;
+      break;
+    case JCS_CMYK:
+    case JCS_YCCK:
+    default:
+      // Mozilla errors out on these color spaces, so I presume that the jpeg
+      // library can't do automatic color space conversion for them. We don't
+      // care about these anyway.
+      return false;
+  }
+  cinfo.output_components = 3;
+
+  jpeg_calc_output_dimensions(&cinfo);
+  *w = cinfo.output_width;
+  *h = cinfo.output_height;
+
+  jpeg_start_decompress(&cinfo);
+
+  // FIXME(brettw) we may want to allow the capability for callers to request
+  // how to align row lengths as we do for the compressor.
+  int row_read_stride = cinfo.output_width * cinfo.output_components;
+
+  if (format == FORMAT_RGB) {
+    // easy case, row needs no conversion
+    int row_write_stride = row_read_stride;
+    output->resize(row_write_stride * cinfo.output_height);
+
+    for (int row = 0; row < static_cast<int>(cinfo.output_height); row++) {
+      unsigned char* rowptr = &(*output)[row * row_write_stride];
+      if (!jpeg_read_scanlines(&cinfo, &rowptr, 1))
+        return false;
+    }
+  } else {
+    // Rows need conversion to output format: read into a temporary buffer and
+    // expand to the final one. Performance: we could avoid the extra
+    // allocation by doing the expansion in-place.
+    int row_write_stride;
+    void (*converter)(const unsigned char* rgb, int w, unsigned char* out);
+    if (format == FORMAT_RGBA) {
+      row_write_stride = cinfo.output_width * 4;
+      converter = AddAlpha;
+    } else if (format == FORMAT_BGRA) {
+      row_write_stride = cinfo.output_width * 4;
+      converter = RGBtoBGRA;
+    } else {
+      NOTREACHED() << "Invalid pixel format";
+      jpeg_destroy_decompress(&cinfo);
+      return false;
+    }
+
+    output->resize(row_write_stride * cinfo.output_height);
+
+    scoped_array<unsigned char> row_data(new unsigned char[row_read_stride]);
+    unsigned char* rowptr = row_data.get();
+    for (int row = 0; row < static_cast<int>(cinfo.output_height); row++) {
+      if (!jpeg_read_scanlines(&cinfo, &rowptr, 1))
+        return false;
+      converter(rowptr, *w, &(*output)[row * row_write_stride]);
+    }
+  }
+
+  jpeg_finish_decompress(&cinfo);
+  jpeg_destroy_decompress(&cinfo);
+  return true;
+}
+
+// static
+SkBitmap* JPEGCodec::Decode(const unsigned char* input, size_t input_size) {
+  int w, h;
+  std::vector<unsigned char> data_vector;
+  // Use FORMAT_BGRA as that maps to Skia's 32 bit (kARGB_8888_Config) format.
+  if (!Decode(input, input_size, FORMAT_BGRA, &data_vector, &w, &h))
+    return NULL;
+
+  // Skia only handles 32 bit images.
+  int data_length = w * h * 4;
+
+  SkBitmap* bitmap = new SkBitmap();
+  bitmap->setConfig(SkBitmap::kARGB_8888_Config, w, h);
+  bitmap->allocPixels();
+  memcpy(bitmap->getAddr32(0, 0), &data_vector[0], data_length);
+
+  return bitmap;
+}
+