refactor helper functions out of libjpeg wrapper

git-svn-id: http://skia.googlecode.com/svn/trunk@476 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 189 insertions, 0 deletions

diff --git a/src/images/SkJpegUtility.cpp b/src/images/SkJpegUtility.cpp
new file mode 100644
index 0000000000..9c6eb047f6
--- /dev/null
+++ b/src/images/SkJpegUtility.cpp
@@ -0,0 +1,189 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "SkJpegUtility.h"
+
+/////////////////////////////////////////////////////////////////////
+static void sk_init_source(j_decompress_ptr cinfo) {
+    skjpeg_source_mgr*  src = (skjpeg_source_mgr*)cinfo->src;
+    src->next_input_byte = (const JOCTET*)src->fBuffer;
+    src->bytes_in_buffer = 0;
+}
+
+static boolean sk_fill_input_buffer(j_decompress_ptr cinfo) {
+    skjpeg_source_mgr* src = (skjpeg_source_mgr*)cinfo->src;
+    if (src->fDecoder != NULL && src->fDecoder->shouldCancelDecode()) {
+        return FALSE;
+    }
+    size_t bytes = src->fStream->read(src->fBuffer, skjpeg_source_mgr::kBufferSize);
+    // note that JPEG is happy with less than the full read,
+    // as long as the result is non-zero
+    if (bytes == 0) {
+        return FALSE;
+    }
+
+    src->next_input_byte = (const JOCTET*)src->fBuffer;
+    src->bytes_in_buffer = bytes;
+    return TRUE;
+}
+
+static void sk_skip_input_data(j_decompress_ptr cinfo, long num_bytes) {
+    SkASSERT(num_bytes > 0);
+
+    skjpeg_source_mgr*  src = (skjpeg_source_mgr*)cinfo->src;
+
+    long bytesToSkip = num_bytes - src->bytes_in_buffer;
+
+    // check if the skip amount exceeds the current buffer
+    if (bytesToSkip > 0) {
+        size_t bytes = src->fStream->skip(bytesToSkip);
+        if (bytes != (size_t)bytesToSkip) {
+//            SkDebugf("xxxxxxxxxxxxxx failure to skip request %d actual %d\n", bytesToSkip, bytes);
+            cinfo->err->error_exit((j_common_ptr)cinfo);
+        }
+        src->next_input_byte = (const JOCTET*)src->fBuffer;
+        src->bytes_in_buffer = 0;
+    } else {
+        src->next_input_byte += num_bytes;
+        src->bytes_in_buffer -= num_bytes;
+    }
+}
+
+static boolean sk_resync_to_restart(j_decompress_ptr cinfo, int desired) {
+    skjpeg_source_mgr*  src = (skjpeg_source_mgr*)cinfo->src;
+
+    // what is the desired param for???
+
+    if (!src->fStream->rewind()) {
+        SkDebugf("xxxxxxxxxxxxxx failure to rewind\n");
+        cinfo->err->error_exit((j_common_ptr)cinfo);
+        return FALSE;
+    }
+    src->next_input_byte = (const JOCTET*)src->fBuffer;
+    src->bytes_in_buffer = 0;
+    return TRUE;
+}
+
+static void sk_term_source(j_decompress_ptr /*cinfo*/) {}
+
+
+static void skmem_init_source(j_decompress_ptr cinfo) {
+    skjpeg_source_mgr*  src = (skjpeg_source_mgr*)cinfo->src;
+    src->next_input_byte = (const JOCTET*)src->fMemoryBase;
+    src->bytes_in_buffer = src->fMemoryBaseSize;
+}
+
+static boolean skmem_fill_input_buffer(j_decompress_ptr cinfo) {
+    SkDebugf("xxxxxxxxxxxxxx skmem_fill_input_buffer called\n");
+    return FALSE;
+}
+
+static void skmem_skip_input_data(j_decompress_ptr cinfo, long num_bytes) {
+    skjpeg_source_mgr*  src = (skjpeg_source_mgr*)cinfo->src;
+//    SkDebugf("xxxxxxxxxxxxxx skmem_skip_input_data called %d\n", num_bytes);
+    src->next_input_byte = (const JOCTET*)((const char*)src->next_input_byte + num_bytes);
+    src->bytes_in_buffer -= num_bytes;
+}
+
+static boolean skmem_resync_to_restart(j_decompress_ptr cinfo, int desired) {
+    SkDebugf("xxxxxxxxxxxxxx skmem_resync_to_restart called\n");
+    return TRUE;
+}
+
+static void skmem_term_source(j_decompress_ptr /*cinfo*/) {}
+
+
+///////////////////////////////////////////////////////////////////////////////
+
+skjpeg_source_mgr::skjpeg_source_mgr(SkStream* stream, SkImageDecoder* decoder) : fStream(stream) {
+    fDecoder = decoder;
+    const void* baseAddr = stream->getMemoryBase();
+    if (baseAddr && false) {
+        fMemoryBase = baseAddr;
+        fMemoryBaseSize = stream->getLength();
+
+        init_source = skmem_init_source;
+        fill_input_buffer = skmem_fill_input_buffer;
+        skip_input_data = skmem_skip_input_data;
+        resync_to_restart = skmem_resync_to_restart;
+        term_source = skmem_term_source;
+    } else {
+        fMemoryBase = NULL;
+        fMemoryBaseSize = 0;
+
+        init_source = sk_init_source;
+        fill_input_buffer = sk_fill_input_buffer;
+        skip_input_data = sk_skip_input_data;
+        resync_to_restart = sk_resync_to_restart;
+        term_source = sk_term_source;
+    }
+//    SkDebugf("**************** use memorybase %p %d\n", fMemoryBase, fMemoryBaseSize);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+static void sk_init_destination(j_compress_ptr cinfo) {
+    skjpeg_destination_mgr* dest = (skjpeg_destination_mgr*)cinfo->dest;
+
+    dest->next_output_byte = dest->fBuffer;
+    dest->free_in_buffer = skjpeg_destination_mgr::kBufferSize;
+}
+
+static boolean sk_empty_output_buffer(j_compress_ptr cinfo) {
+    skjpeg_destination_mgr* dest = (skjpeg_destination_mgr*)cinfo->dest;
+
+//  if (!dest->fStream->write(dest->fBuffer, skjpeg_destination_mgr::kBufferSize - dest->free_in_buffer))
+    if (!dest->fStream->write(dest->fBuffer,
+            skjpeg_destination_mgr::kBufferSize)) {
+        ERREXIT(cinfo, JERR_FILE_WRITE);
+        return false;
+    }
+
+    dest->next_output_byte = dest->fBuffer;
+    dest->free_in_buffer = skjpeg_destination_mgr::kBufferSize;
+    return TRUE;
+}
+
+static void sk_term_destination (j_compress_ptr cinfo) {
+    skjpeg_destination_mgr* dest = (skjpeg_destination_mgr*)cinfo->dest;
+
+    size_t size = skjpeg_destination_mgr::kBufferSize - dest->free_in_buffer;
+    if (size > 0) {
+        if (!dest->fStream->write(dest->fBuffer, size)) {
+            ERREXIT(cinfo, JERR_FILE_WRITE);
+            return;
+        }
+    }
+    dest->fStream->flush();
+}
+
+skjpeg_destination_mgr::skjpeg_destination_mgr(SkWStream* stream)
+        : fStream(stream) {
+    this->init_destination = sk_init_destination;
+    this->empty_output_buffer = sk_empty_output_buffer;
+    this->term_destination = sk_term_destination;
+}
+
+void skjpeg_error_exit(j_common_ptr cinfo) {
+    skjpeg_error_mgr* error = (skjpeg_error_mgr*)cinfo->err;
+
+    (*error->output_message) (cinfo);
+
+    /* Let the memory manager delete any temp files before we die */
+    jpeg_destroy(cinfo);
+
+    longjmp(error->fJmpBuf, -1);
+}