/**
* =========================================================================
* File : tex_jpg.cpp
* Project : 0 A.D.
* Description : JPEG codec using IJG jpeglib.
* =========================================================================
*/
// license: GPL; see lib/license.txt
#include "precompiled.h"
#include "lib/external_libraries/libjpeg.h"
#include "lib/res/res.h"
#include "tex_codec.h"
#include <setjmp.h>
// squelch "dtor / setjmp interaction" warnings.
// all attempts to resolve the underlying problem failed; apparently
// the warning is generated if setjmp is used at all in C++ mode.
// (jpg_*code have no code that would trigger ctors/dtors, nor are any
// called in their prolog/epilog code).
#if MSC_VERSION
#pragma warning(disable: 4611)
#endif
/* IMPORTANT: we assume that JOCTET is 8 bits. */
cassert(sizeof(JOCTET) == 1 && CHAR_BIT == 8);
//-----------------------------------------------------------------------------
// mem source manager
//-----------------------------------------------------------------------------
/* Expanded data source object for memory input */
typedef struct
{
struct jpeg_source_mgr pub; /* public fields */
DynArray* da;
}
SrcMgr;
typedef SrcMgr* SrcPtr;
/*
* Initialize source --- called by jpeg_read_header
* before any data is actually read.
*/
METHODDEF(void) src_init(j_decompress_ptr UNUSED(cinfo))
{
}
/*
* Fill the input buffer --- called whenever buffer is emptied.
*
* In typical applications, this should read fresh data into the buffer
* (ignoring the current state of next_input_byte & 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.
*
* There is no such thing as an EOF return. If the end of the file has been
* reached, the routine has a choice of ERREXIT() or inserting fake data into
* the buffer. In most cases, generating a warning message and inserting a
* fake EOI marker is the best course of action --- this will allow the
* decompressor to output however much of the image is there. However,
* the resulting error message is misleading if the real problem is an empty
* input file, so we handle that case specially.
*/
METHODDEF(boolean) src_fill_buffer(j_decompress_ptr cinfo)
{
SrcPtr src = (SrcPtr)cinfo->src;
static const JOCTET eoi[2] = { 0xFF, JPEG_EOI };
/*
* since jpeg_mem_src fills the buffer with everything we've got,
* jpeg is trying to read beyond end of buffer. return a fake EOI marker.
* note: don't modify input buffer: it might be read-only.
*/
WARNMS(cinfo, JWRN_JPEG_EOF);
src->pub.next_input_byte = eoi;
src->pub.bytes_in_buffer = 2;
return TRUE;
}
/*
* Skip data --- used to skip over a potentially large amount of
* uninteresting data (such as an APPn marker).
*/
METHODDEF(void) src_skip_data(j_decompress_ptr cinfo, long num_bytes)
{
SrcPtr src = (SrcPtr)cinfo->src;
size_t skip_count = (size_t)num_bytes;
/* docs say non-positive num_byte skips should be ignored */
if(num_bytes <= 0)
return;
/*
* just subtract bytes available in buffer,
* making sure we don't underflow the size_t.
* note: if we skip to or beyond end of buffer,
* bytes_in_buffer = 0 => fill_input_buffer called => abort.
*/
if(skip_count > src->pub.bytes_in_buffer)
skip_count = src->pub.bytes_in_buffer;
src->pub.bytes_in_buffer -= skip_count;
src->pub.next_input_byte += skip_count;
}
/*
* An additional method that can be provided by data source modules is the
* resync_to_restart method for error recovery in the presence of RST markers.
* For the moment, this source module just uses the default resync method
* provided by the JPEG library. That method assumes that no backtracking
* is possible.
*/
/*
* Terminate source --- called by jpeg_finish_decompress
* after all data has been read. Often a no-op.
*
* NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
* application must deal with any cleanup that should happen even
* for error exit.
*/
METHODDEF(void) src_term(j_decompress_ptr UNUSED(cinfo))
{
/*
* no-op (we don't own the buffer and shouldn't,
* to make possible multiple images in a source).
*/
}
/*
* Prepare for input from a buffer.
* The caller is responsible for freeing it after finishing decompression.
*/
GLOBAL(void) src_prepare(j_decompress_ptr cinfo, DynArray* da)
{
SrcPtr src;
const u8* p = da->base;
const size_t size = da->cur_size;
/* Treat 0-length buffer as fatal error */
if(size == 0)
ERREXIT(cinfo, JERR_INPUT_EMPTY);
/*
* The source object is made permanent so that
* a series of JPEG images can be read from the same file
* by calling jpeg_mem_src only before the first one.
* This makes it unsafe to use this manager and a different source
* manager serially with the same JPEG object. Caveat programmer.
*/
/* first time for this JPEG object? */
if(!cinfo->src)
cinfo->src = (struct jpeg_source_mgr*)
(*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_PERMANENT,
sizeof(SrcMgr));
/* (takes care of raising error if out of memory) */
src = (SrcPtr)cinfo->src;
src->pub.init_source = src_init;
src->pub.fill_input_buffer = src_fill_buffer;
src->pub.skip_input_data = src_skip_data;
src->pub.resync_to_restart = jpeg_resync_to_restart; /* default */
src->pub.term_source = src_term;
/*
* fill buffer with everything we have.
* if fill_input_buffer is called, the buffer was overrun.
*/
src->pub.bytes_in_buffer = size;
src->pub.next_input_byte = (JOCTET*)p;
}
//-----------------------------------------------------------------------------
// mem destination manager
//-----------------------------------------------------------------------------
/* Expanded data destination object for memory output */
typedef struct {
struct jpeg_destination_mgr pub; /* public fields */
DynArray* da;
} DstMgr;
typedef DstMgr* DstPtr;
// this affects how often dst_empty_output_buffer is called (which
// efficiently expands the DynArray) and how much tail memory we waste
// (not an issue because it is freed immediately after compression).
#define OUTPUT_BUF_SIZE 64*KiB /* choose an efficiently writeable size */
// note: can't call dst_empty_output_buffer from dst_init or vice versa
// because only the former must advance da->pos.
static void make_room_in_buffer(j_compress_ptr cinfo)
{
DstPtr dst = (DstPtr)cinfo->dest;
DynArray* da = dst->da;
void* start = da->base + da->cur_size;
if(da_set_size(da, da->cur_size+OUTPUT_BUF_SIZE) != 0)
ERREXIT(cinfo, JERR_FILE_WRITE);
dst->pub.next_output_byte = (JOCTET*)start;
dst->pub.free_in_buffer = OUTPUT_BUF_SIZE;
}
/*
* Initialize destination --- called by jpeg_start_compress
* before any data is actually written.
*/
METHODDEF(void) dst_init(j_compress_ptr cinfo)
{
make_room_in_buffer(cinfo);
}
/*
* Empty the output buffer --- called whenever buffer fills up.
*
* In typical applications, this should write the entire output buffer
* (ignoring the current state of next_output_byte & free_in_buffer),
* reset the pointer & count to the start of the buffer, and return TRUE
* indicating that the buffer has been dumped.
*
* <snip comments on suspended IO>
*/
METHODDEF(boolean) dst_empty_output_buffer(j_compress_ptr cinfo)
{
DstPtr dst = (DstPtr)cinfo->dest;
DynArray* da = dst->da;
// writing out OUTPUT_BUF_SIZE-dst->pub.free_in_buffer bytes
// sounds reasonable, but makes for broken output.
da->pos += OUTPUT_BUF_SIZE;
make_room_in_buffer(cinfo);
return TRUE; // not suspended
}
/*
* Terminate destination --- called by jpeg_finish_compress
* after all data has been written. Usually needs to flush buffer.
*
* NB: *not* called by jpeg_abort or jpeg_destroy; surrounding
* application must deal with any cleanup that should happen even
* for error exit.
*/
METHODDEF(void) dst_term(j_compress_ptr cinfo)
{
DstPtr dst = (DstPtr)cinfo->dest;
DynArray* da = dst->da;
// account for nbytes left in buffer
da->pos += OUTPUT_BUF_SIZE -dst->pub.free_in_buffer;
}
/*
* Prepare for output to a buffer.
* The caller is responsible for allocating and writing out to disk after
* compression is complete.
*/
GLOBAL(void) dst_prepare(j_compress_ptr cinfo, DynArray* da)
{
/* The destination object is made permanent so that multiple JPEG images
* can be written to the same file without re-executing dst_prepare.
* This makes it dangerous to use this manager and a different destination
* manager serially with the same JPEG object, because their private object
* sizes may be different. Caveat programmer.
*/
if (cinfo->dest == NULL) { /* first time for this JPEG object? */
cinfo->dest = (struct jpeg_destination_mgr*)(*cinfo->mem->alloc_small)
((j_common_ptr)cinfo, JPOOL_PERMANENT, sizeof(DstMgr));
}
DstPtr dst = (DstPtr)cinfo->dest;
dst->pub.init_destination = dst_init;
dst->pub.empty_output_buffer = dst_empty_output_buffer;
dst->pub.term_destination = dst_term;
dst->da = da;
}
//-----------------------------------------------------------------------------
// error handler, shared by jpg_(en|de)code
//-----------------------------------------------------------------------------
// the JPEG library's standard error handler (jerror.c) is divided into
// several "methods" which we can override individually. This allows
// adjusting the behavior without duplicating a lot of code, which may
// have to be updated with each future release.
//
// we here override error_exit to return control to the library's caller
// (i.e. jpg_(de|en)code) when a fatal error occurs, rather than calling exit.
//
// the replacement error_exit does a longjmp back to the caller's
// setjmp return point. it needs access to the jmp_buf,
// so we store it in a "subclass" of jpeg_error_mgr.
struct JpgErrorMgr
{
struct jpeg_error_mgr pub; // "public" fields
// jump here (back to JPEG lib caller) on error
jmp_buf call_site;
// description of first error encountered; must store in JPEG context
// for thread safety. initialized in setup_err_mgr.
char msg[JMSG_LENGTH_MAX];
JpgErrorMgr(j_common_ptr cinfo);
};
METHODDEF(void) err_error_exit(j_common_ptr cinfo)
{
// get subclass
JpgErrorMgr* err_mgr = (JpgErrorMgr*)cinfo->err;
// "output" error message (i.e. store in JpgErrorMgr;
// call_site is responsible for displaying it via debug_printf)
(*cinfo->err->output_message)(cinfo);
// jump back to call site, i.e. jpg_(de|en)code
longjmp(err_mgr->call_site, 1);
}
// stores message in JpgErrorMgr for later output by jpg_(de|en)code.
// note: don't display message here, so the caller can
// add some context (whether encoding or decoding, and filename).
METHODDEF(void) err_output_message(j_common_ptr cinfo)
{
// get subclass
JpgErrorMgr* err_mgr = (JpgErrorMgr*)cinfo->err;
// this context already had an error message; don't overwrite it.
// (subsequent errors probably aren't related to the real problem).
// note: was set to '\0' by ctor.
if(err_mgr->msg[0] != '\0')
return;
// generate the message and store it
(*cinfo->err->format_message)(cinfo, err_mgr->msg);
}
JpgErrorMgr::JpgErrorMgr(j_common_ptr cinfo)
{
// fill in pub fields
jpeg_std_error(&pub);
// .. and override some methods:
pub.error_exit = err_error_exit;
pub.output_message = err_output_message;
// required for "already have message" check in err_output_message
msg[0] = '\0';
// hack: register this error manager with cinfo.
// must be done before jpeg_create_* in case that fails
// (unlikely, but possible if out of memory).
cinfo->err = &pub;
}
//-----------------------------------------------------------------------------
static LibError jpg_transform(Tex* UNUSED(t), uint UNUSED(transforms))
{
return INFO::TEX_CODEC_CANNOT_HANDLE;
}
// note: jpg_encode and jpg_decode cannot be combined due to
// libjpg interface differences.
// we do split them up into interface and impl to simplify
// resource cleanup and avoid "dtor / setjmp interaction" warnings.
//
// rationale for row array: jpeg won't output more than a few
// scanlines at a time, so we need an output loop anyway. however,
// passing at least 2..4 rows is more efficient in low-quality modes
// due to less copying.
static LibError jpg_decode_impl(DynArray* da,
jpeg_decompress_struct* cinfo,
Handle& img_hm, RowArray& rows, Tex* t)
{
src_prepare(cinfo, da);
// ignore return value since:
// - suspension is not possible with the mem data source
// - we passed TRUE to raise an error if table-only JPEG file
(void)jpeg_read_header(cinfo, TRUE);
// set libjpg output format. we cannot go with the default because
// Photoshop writes non-standard CMYK files that must be converted to RGB.
uint flags = 0;
cinfo->out_color_space = JCS_RGB;
if(cinfo->num_components == 1)
{
flags |= TEX_GREY;
cinfo->out_color_space = JCS_GRAYSCALE;
}
// lower quality, but faster
cinfo->dct_method = JDCT_IFAST;
cinfo->do_fancy_upsampling = FALSE;
// ignore return value since suspension is not possible with the
// mem data source.
// note: since we've set out_color_space, JPEG will always
// return an acceptable image format; no need to check.
(void)jpeg_start_decompress(cinfo);
// scaled output image dimensions and final bpp are now available.
int w = cinfo->output_width;
int h = cinfo->output_height;
int bpp = cinfo->output_components * 8;
// alloc destination buffer
const size_t pitch = w * bpp / 8;
const size_t img_size = pitch * h; // for allow_rows
u8* img = (u8*)mem_alloc(img_size, 64*KiB, 0, &img_hm);
if(!img)
WARN_RETURN(ERR::NO_MEM);
// read rows
RETURN_ERR(tex_codec_alloc_rows(img, h, pitch, TEX_TOP_DOWN, 0, rows));
// could use cinfo->output_scanline to keep track of progress,
// but we need to count lines_left anyway (paranoia).
JSAMPARRAY row = (JSAMPARRAY)rows;
JDIMENSION lines_left = h;
while(lines_left != 0)
{
JDIMENSION lines_read = jpeg_read_scanlines(cinfo, row, lines_left);
row += lines_read;
lines_left -= lines_read;
// we've decoded in-place; no need to further process
}
// ignore return value since suspension is not possible with the
// mem data source.
(void)jpeg_finish_decompress(cinfo);
LibError ret = INFO::OK;
if(cinfo->err->num_warnings != 0)
ret = WARN::TEX_INVALID_DATA;
// store image info
// .. transparently switch handles - free the old (compressed)
// buffer and replace it with the decoded-image memory handle.
mem_free_h(t->hm); // must come after jpeg_finish_decompress
t->hm = img_hm;
t->w = w;
t->h = h;
t->bpp = bpp;
t->flags = flags;
return ret;
}
static LibError jpg_encode_impl(Tex* t,
jpeg_compress_struct* cinfo,
RowArray& rows, DynArray* da)
{
dst_prepare(cinfo, da);
// describe image format
// required:
cinfo->image_width = t->w;
cinfo->image_height = t->h;
cinfo->input_components = t->bpp / 8;
cinfo->in_color_space = (t->bpp == 8)? JCS_GRAYSCALE : JCS_RGB;
// defaults depend on cinfo->in_color_space already having been set!
jpeg_set_defaults(cinfo);
// (add optional settings, e.g. quality, here)
// TRUE ensures that we will write a complete interchange-JPEG file.
// don't change unless you are very sure of what you're doing.
jpeg_start_compress(cinfo, TRUE);
// if BGR, convert to RGB.
WARN_ERR(tex_transform_to(t, t->flags & ~TEX_BGR));
const size_t pitch = t->w * t->bpp / 8;
u8* data = tex_get_data(t);
RETURN_ERR(tex_codec_alloc_rows(data, t->h, pitch, t->flags, TEX_TOP_DOWN, rows));
// could use cinfo->output_scanline to keep track of progress,
// but we need to count lines_left anyway (paranoia).
JSAMPARRAY row = (JSAMPARRAY)rows;
JDIMENSION lines_left = t->h;
while(lines_left != 0)
{
JDIMENSION lines_read = jpeg_write_scanlines(cinfo, row, lines_left);
row += lines_read;
lines_left -= lines_read;
// we've decoded in-place; no need to further process
}
jpeg_finish_compress(cinfo);
LibError ret = INFO::OK;
if(cinfo->err->num_warnings != 0)
ret = WARN::TEX_INVALID_DATA;
return ret;
}
static bool jpg_is_hdr(const u8* file)
{
// JFIF requires SOI marker at start of stream.
// we compare single bytes to be endian-safe.
return (file[0] == 0xff && file[1] == 0xd8);
}
static bool jpg_is_ext(const char* ext)
{
return !strcasecmp(ext, "jpg") || !strcasecmp(ext, "jpeg");
}
static size_t jpg_hdr_size(const u8* UNUSED(file))
{
return 0; // libjpg returns decoded image data; no header
}
static LibError jpg_decode(DynArray* RESTRICT da, Tex* RESTRICT t)
{
LibError err;
// freed when ret is reached:
// .. contains the JPEG decompression parameters and pointers to
// working space (allocated as needed by the JPEG library).
struct jpeg_decompress_struct cinfo;
// .. array of pointers to scanlines (see rationale above)
RowArray rows = 0;
// freed when fail is reached:
Handle img_hm; // decompressed image memory
JpgErrorMgr jerr((j_common_ptr)&cinfo);
if(setjmp(jerr.call_site))
{
err = ERR::FAIL;
goto fail;
}
jpeg_create_decompress(&cinfo);
err = jpg_decode_impl(da, &cinfo, img_hm, rows, t);
if(err < 0)
goto fail;
ret:
jpeg_destroy_decompress(&cinfo); // releases a "good deal" of memory
free(rows);
return err;
fail:
mem_free_h(img_hm);
goto ret;
}
// limitation: palette images aren't supported
static LibError jpg_encode(Tex* RESTRICT t, DynArray* RESTRICT da)
{
LibError err;
// freed when ret is reached:
// .. contains the JPEG compression parameters and pointers to
// working space (allocated as needed by the JPEG library).
struct jpeg_compress_struct cinfo;
// .. array of pointers to scanlines (see rationale above)
RowArray rows = 0;
JpgErrorMgr jerr((j_common_ptr)&cinfo);
if(setjmp(jerr.call_site))
{
err = ERR::FAIL;
goto fail;
}
jpeg_create_compress(&cinfo);
err = jpg_encode_impl(t, &cinfo, rows, da);
if(err < 0)
goto fail;
ret:
jpeg_destroy_compress(&cinfo); // releases a "good deal" of memory
free(rows);
return err;
fail:
// currently no extra cleanup needed
goto ret;
}
TEX_CODEC_REGISTER(jpg);