SkJpegUtility.cpp File Reference

#include "src/codec/SkJpegUtility.h"
#include "include/core/SkStream.h"
#include "include/core/SkTypes.h"
#include "src/codec/SkCodecPriv.h"
#include "src/codec/SkJpegPriv.h"
#include <csetjmp>
#include <cstddef>
#include "jpeglib.h"

Go to the source code of this file.

Functions
void	skjpeg_err_exit (j_common_ptr dinfo)
static void	sk_init_buffered_source (j_decompress_ptr dinfo)
static boolean	sk_fill_buffered_input_buffer (j_decompress_ptr dinfo)
static void	sk_skip_buffered_input_data (j_decompress_ptr dinfo, long numBytes)
static void	sk_term_source (j_decompress_ptr dinfo)
static void	sk_init_mem_source (j_decompress_ptr dinfo)
static void	sk_skip_mem_input_data (j_decompress_ptr cinfo, long num_bytes)
static boolean	sk_fill_mem_input_buffer (j_decompress_ptr cinfo)

Function Documentation

sk_fill_buffered_input_buffer()

static boolean sk_fill_buffered_input_buffer ( j_decompress_ptr  dinfo )

static

Definition at line 50 of file SkJpegUtility.cpp.

                                                                     {
    skjpeg_source_mgr* src = (skjpeg_source_mgr*) dinfo->src;
    size_t bytes = src->fStream->read(src->fBuffer, skjpeg_source_mgr::kBufferSize);
 
    // libjpeg is still happy with a less than full read, as long as the result is non-zero
    if (bytes == 0) {
        // Let libjpeg know that the buffer needs to be refilled
        src->next_input_byte = nullptr;
        src->bytes_in_buffer = 0;
        return false;
    }
 
    src->next_input_byte = (const JOCTET*) src->fBuffer;
    src->bytes_in_buffer = bytes;
    return true;
}

sk_fill_mem_input_buffer()

static boolean sk_fill_mem_input_buffer ( j_decompress_ptr  cinfo )

static

Definition at line 122 of file SkJpegUtility.cpp.

                                                                 {
    /* The whole JPEG data is expected to reside in the supplied memory,
     * buffer, so any request for more data beyond the given buffer size
     * is treated as an error.
     */
    return false;
}

sk_init_buffered_source()

static void sk_init_buffered_source ( j_decompress_ptr  dinfo )

static

Definition at line 41 of file SkJpegUtility.cpp.

                                                            {
    skjpeg_source_mgr* src = (skjpeg_source_mgr*) dinfo->src;
    src->next_input_byte = (const JOCTET*) src->fBuffer;
    src->bytes_in_buffer = 0;
}

sk_init_mem_source()

static void sk_init_mem_source ( j_decompress_ptr  dinfo )

static

Definition at line 106 of file SkJpegUtility.cpp.

                                                       {
    /* no work necessary here, all things are done in constructor */
}

sk_skip_buffered_input_data()

static void sk_skip_buffered_input_data ( j_decompress_ptr  dinfo, long  numBytes  )

static

Definition at line 70 of file SkJpegUtility.cpp.

                                                                               {
    skjpeg_source_mgr* src = (skjpeg_source_mgr*) dinfo->src;
    size_t bytes = (size_t) numBytes;
 
    if (bytes > src->bytes_in_buffer) {
        size_t bytesToSkip = bytes - src->bytes_in_buffer;
        if (bytesToSkip != src->fStream->skip(bytesToSkip)) {
            SkCodecPrintf("Failure to skip.\n");
            dinfo->err->error_exit((j_common_ptr) dinfo);
            return;
        }
 
        src->next_input_byte = (const JOCTET*) src->fBuffer;
        src->bytes_in_buffer = 0;
    } else {
        src->next_input_byte += numBytes;
        src->bytes_in_buffer -= numBytes;
    }
}

sk_skip_mem_input_data()

static void sk_skip_mem_input_data ( j_decompress_ptr  cinfo, long  num_bytes  )

static

Definition at line 110 of file SkJpegUtility.cpp.

                                                                            {
    jpeg_source_mgr* src = cinfo->src;
    size_t bytes = static_cast<size_t>(num_bytes);
    if(bytes > src->bytes_in_buffer) {
        src->next_input_byte = nullptr;
        src->bytes_in_buffer = 0;
    } else {
        src->next_input_byte += bytes;
        src->bytes_in_buffer -= bytes;
    }
}

sk_term_source()

static void sk_term_source ( j_decompress_ptr  dinfo )

static

Definition at line 93 of file SkJpegUtility.cpp.

{
    // The current implementation of SkJpegCodec does not call
    // jpeg_finish_decompress(), so this function is never called.
    // If we want to modify this function to do something, we also
    // need to modify SkJpegCodec to call jpeg_finish_decompress().
}

skjpeg_err_exit()

void skjpeg_err_exit

(

j_common_ptr

dinfo

)

Definition at line 25 of file SkJpegUtility.cpp.

                                         {
    // Simply return to Skia client code
    // JpegDecoderMgr will take care of freeing memory
    skjpeg_error_mgr* error = (skjpeg_error_mgr*) dinfo->err;
    (*error->output_message) (dinfo);
    if (error->fStack[0] == nullptr) {
        SK_ABORT("JPEG error with no jmp_buf set.");
    }
    longjmp(*error->fStack[0], 1);
}