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[trunk] support seeking in files larger than 2 GB

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This commit is contained in:
Julien Malik
2011-11-24 15:30:09 +00:00
parent 20c05a3add
commit c974cb1b8e
3 changed files with 23 additions and 1 deletions
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20
libopenjpeg/openjpeg.c
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@@ -165,7 +165,25 @@ OPJ_SIZE_T opj_skip_from_file (OPJ_SIZE_T p_nb_bytes, FILE * p_user_data)
opj_bool opj_seek_from_file (OPJ_SIZE_T p_nb_bytes, FILE * p_user_data)
{
if (fseek(p_user_data,p_nb_bytes,SEEK_SET)) {
/*
* p_nb_bytes is 'OPJ_SIZE_T' but fseek takes a 'signed long'
*
* As such, fseek can seek to a maximum of 2^31-1 bytes (2 GB)
* To support seeking in files between 2 GB and 4 GB :
* - first, do a seek with the max supported by fseek
* - secondly, seek of the remaining bytes
*/
if (p_nb_bytes > LONG_MAX) {
if (fseek(p_user_data,LONG_MAX,SEEK_SET)) {
return EXIT_FAILURE;
}
p_nb_bytes -= LONG_MAX;
if (fseek(p_user_data,p_nb_bytes,SEEK_CUR)) {
return EXIT_FAILURE;
}
}
else if (fseek(p_user_data,p_nb_bytes,SEEK_SET)) {
return EXIT_FAILURE;
}