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make ReadPNG and ReadJPEG take a filename instead of a FILE

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-> read is a bit slower (memory allocation and such) than reading directly from disk.

-> we're not yet ready to accept stdin as input (-- -) because we still need to guess
the file type with GetImageType(). And since we can't rewind on stdin, this will need
a bit more work before being able to read from stdin.

Change-Id: I6491fac4b07d28d1854518325ead88669656ddbf
This commit is contained in:
Pascal Massimino
2015-12-06 09:23:17 +01:00
parent d478e58960
commit 4c60f63c64
5 changed files with 98 additions and 23 deletions
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65
examples/jpegdec.c
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@ -19,11 +19,13 @@
#ifdef WEBP_HAVE_JPEG
#include <jpeglib.h>
#include <jerror.h>
#include <setjmp.h>
#include <stdlib.h>
#include <string.h>
#include "webp/encode.h"
#include "./example_util.h"
#include "./metadata.h"
// -----------------------------------------------------------------------------
@ -208,13 +210,64 @@ static void my_error_exit(j_common_ptr dinfo) {
longjmp(myerr->setjmp_buffer, 1);
}
int ReadJPEG(FILE* in_file, WebPPicture* const pic, Metadata* const metadata) {
int ok = 0;
typedef struct {
struct jpeg_source_mgr pub;
const uint8_t* data;
size_t data_size;
} JPEGReadContext;
static void ContextInit(j_decompress_ptr cinfo) {
JPEGReadContext* const ctx = (JPEGReadContext*)cinfo->src;
ctx->pub.next_input_byte = ctx->data;
ctx->pub.bytes_in_buffer = ctx->data_size;
}
static int ContextFill(j_decompress_ptr cinfo) {
// we shouldn't get here.
ERREXIT(cinfo, JERR_FILE_READ);
return 0;
}
static void ContextSkip(j_decompress_ptr cinfo, long jump_size) {
JPEGReadContext* const ctx = (JPEGReadContext*)cinfo->src;
size_t jump = (size_t)jump_size;
if (jump > ctx->pub.bytes_in_buffer) { // Don't overflow the buffer.
jump = ctx->pub.bytes_in_buffer;
}
ctx->pub.bytes_in_buffer -= jump;
ctx->pub.next_input_byte += jump;
}
static void ContextTerm(j_decompress_ptr cinfo) {
(void)cinfo;
}
static void ContextSetup(volatile struct jpeg_decompress_struct* const cinfo,
JPEGReadContext* const ctx) {
cinfo->src = (struct jpeg_source_mgr*)ctx;
ctx->pub.init_source = ContextInit;
ctx->pub.fill_input_buffer = ContextFill;
ctx->pub.skip_input_data = ContextSkip;
ctx->pub.resync_to_restart = jpeg_resync_to_restart;
ctx->pub.term_source = ContextTerm;
ctx->pub.bytes_in_buffer = 0;
ctx->pub.next_input_byte = NULL;
}
int ReadJPEG(const char* const filename, WebPPicture* const pic,
Metadata* const metadata) {
volatile int ok = 0;
int stride, width, height;
volatile struct jpeg_decompress_struct dinfo;
struct my_error_mgr jerr;
uint8_t* volatile rgb = NULL;
JSAMPROW buffer[1];
JPEGReadContext ctx;
memset(&ctx, 0, sizeof(ctx));
ok = ExUtilReadFile(filename, &ctx.data, &ctx.data_size);
if (!ok) goto End;
memset((j_decompress_ptr)&dinfo, 0, sizeof(dinfo)); // for setjmp sanity
dinfo.err = jpeg_std_error(&jerr.pub);
@ -228,7 +281,7 @@ int ReadJPEG(FILE* in_file, WebPPicture* const pic, Metadata* const metadata) {
}
jpeg_create_decompress((j_decompress_ptr)&dinfo);
jpeg_stdio_src((j_decompress_ptr)&dinfo, in_file);
ContextSetup(&dinfo, &ctx);
if (metadata != NULL) SaveMetadataMarkers((j_decompress_ptr)&dinfo);
jpeg_read_header((j_decompress_ptr)&dinfo, TRUE);
@ -277,12 +330,14 @@ int ReadJPEG(FILE* in_file, WebPPicture* const pic, Metadata* const metadata) {
End:
free(rgb);
free((void*)ctx.data);
return ok;
}
#else // !WEBP_HAVE_JPEG
int ReadJPEG(FILE* in_file, struct WebPPicture* const pic,
int ReadJPEG(const char* const filename,
struct WebPPicture* const pic,
struct Metadata* const metadata) {
(void)in_file;
(void)filename;
(void)pic;
(void)metadata;
fprintf(stderr, "JPEG support not compiled. Please install the libjpeg "