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sniff webp from the magic number

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removes the 100 byte minimum file size

see https://github.com/lovell/sharp/issues/996
This commit is contained in:
John Cupitt 2017-10-18 09:00:34 +01:00
parent a8bbe05596
commit 6912fe91ed
1 changed files with 13 additions and 13 deletions
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26
libvips/foreign/webp2vips.c
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@ -8,6 +8,8 @@
* - add @shrink
* 7/11/16
* - support XMP/ICC/EXIF metadata
* 18/10/17
* - sniff file type from magic number
*/
/*
@ -62,13 +64,6 @@
#include "pforeign.h"
/* How many bytes do we need to read from the start of the file to be able to
* validate the header?
*
* This doesn't seem to be documented anywhere :-( guess a value.
*/
#define MINIMAL_HEADER (100)
/* What we track during a read.
*/
typedef struct {
@ -107,8 +102,11 @@ typedef struct {
int
vips__iswebp_buffer( const void *buf, size_t len )
{
if( len >= MINIMAL_HEADER &&
WebPGetInfo( buf, MINIMAL_HEADER, NULL, NULL ) )
/* WebP is "RIFF xxxx WEBP" at the start, so we need 12 bytes.
*/
if( len >= 12 &&
vips_isprefix( "RIFF", (char *) buf ) &&
vips_isprefix( "WEBP", (char *) buf + 8 ) )
return( 1 );
return( 0 );
@ -117,10 +115,12 @@ vips__iswebp_buffer( const void *buf, size_t len )
int
vips__iswebp( const char *filename )
{
unsigned char header[MINIMAL_HEADER];
/* Magic number, see above.
*/
unsigned char header[12];
if( vips__get_bytes( filename, header, MINIMAL_HEADER ) &&
vips__iswebp_buffer( header, MINIMAL_HEADER ) )
if( vips__get_bytes( filename, header, 12 ) &&
vips__iswebp_buffer( header, 12 ) )
return( 1 );
return( 0 );
@ -178,7 +178,7 @@ read_new( const char *filename, const void *data, size_t length, int shrink )
}
WebPInitDecoderConfig( &read->config );
if( WebPGetFeatures( read->data, MINIMAL_HEADER,
if( WebPGetFeatures( read->data, read->length,
&read->config.input ) != VP8_STATUS_OK ) {
read_free( read );
return( NULL );