diff options
Diffstat (limited to 'contrib/lar/lar.c')
| -rw-r--r-- | contrib/lar/lar.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/contrib/lar/lar.c b/contrib/lar/lar.c new file mode 100644 index 000000000..255bc0150 --- /dev/null +++ b/contrib/lar/lar.c @@ -0,0 +1,176 @@ +#include "lar.h" + +int lar_read32( int fd, uint32_t *val ) +{ + uint8_t buffer[5]; + + if( read(fd, buffer, 4) < 4 ) + LAR_DIE("Unexpected EOF while reading data"); + + buffer[4] = 0; + *val = ntohl(*((uint32_t *) buffer)); + + return 0; +} + +int lar_read16( int fd, uint16_t *val ) +{ + uint8_t buffer[3]; + + if( read(fd, buffer, 2) < 2 ) + LAR_DIE("Unexpected EOF while reading data"); + + buffer[2] = 0; + *val = ntohs(*((uint16_t *) buffer)); + + return 0; +} + +lar_index * lar_get_index( lar_archive *ar ) +{ + uint32_t i; + uint32_t idx_offset; + uint32_t idx_length; + lar_index *idx_map, *idx_ptr; + + if( lseek(ar->fd, -(sizeof(idx_offset)), SEEK_END) == -1 ) + LAR_DIE("Unable to seek to end of archive"); + + lar_read32(ar->fd, &idx_offset); + idx_length = ( ar->length - idx_offset - sizeof(idx_offset) ); + + if( lseek(ar->fd, idx_offset, SEEK_SET) == -1 ) + LAR_DIE("Unable to seek to archive index"); + + + idx_map = NULL; + + for( i = 0; i < idx_length; \ + i += (sizeof(lar_index) - sizeof(char)) + ) { + idx_ptr = (lar_index *)malloc(sizeof(lar_index)); + + lar_read32(ar->fd, &idx_ptr->noffset); + lar_read32(ar->fd, &idx_ptr->nlength); + lar_read32(ar->fd, &idx_ptr->foffset); + lar_read32(ar->fd, &idx_ptr->flength); + lar_read16(ar->fd, &idx_ptr->type); + lar_read16(ar->fd, &idx_ptr->flags); + + idx_ptr->next = idx_map; + idx_map = idx_ptr; + } + + return idx_map; +} + +uint32_t lar_get_filename( lar_archive *ar, + lar_index *idx_ptr, char *filename +) { + if( idx_ptr->nlength >= LAR_FNAME_BUFFER ) + LAR_DIE("Filename exceeds maximum allowed length"); + + if( lseek(ar->fd, idx_ptr->noffset, SEEK_SET) == -1 ) + LAR_DIE("Unexpected EOF while seeking filename"); + + if( read(ar->fd, filename, idx_ptr->nlength) < idx_ptr->nlength ) + LAR_DIE("Unexpected EOF while reading filename"); + + filename[idx_ptr->nlength] = 0; + + return idx_ptr->nlength; +} + +lar_member * lar_open_member( lar_archive *ar, const char *name ) +{ + lar_index *idx_ptr = ar->index; + lar_member *member; + char memberfile[LAR_FNAME_BUFFER]; + char *memberdata; + size_t pgsz = getpagesize(); + + while(idx_ptr) + { + lar_get_filename(ar, idx_ptr, memberfile); + + if( !strncmp(memberfile, name, idx_ptr->nlength) ) + { + memberdata = mmap( + 0, idx_ptr->flength + ( idx_ptr->foffset % pgsz ), + PROT_READ, MAP_PRIVATE, ar->fd, + idx_ptr->foffset - ( idx_ptr->foffset % pgsz ) + ); + + if( memberdata == MAP_FAILED ) + LAR_DIE("Failed to mmap() member data"); + + member = (lar_member *)malloc(sizeof(lar_member)); + member->type = idx_ptr->type; + member->flags = idx_ptr->flags; + member->length = idx_ptr->flength; + member->data = &memberdata[idx_ptr->foffset % pgsz]; + + member->mmap = memberdata; + member->mlen = idx_ptr->flength + ( idx_ptr->foffset % pgsz ); + + return member; + } + + idx_ptr = idx_ptr->next; + } + + return NULL; +} + +int lar_close_member( lar_member *member ) +{ + int stat = munmap(member->mmap, member->mlen); + free(member); + + return stat; +} + +lar_archive * lar_open( const char *filename ) +{ + int fd; + struct stat as; + lar_archive *ar; + + if( stat(filename, &as) == -1 ) + return NULL; + + if( !(as.st_mode & S_IFREG) ) + return NULL; + + if( (fd = open(filename, O_RDONLY)) != -1 ) + { + ar = (lar_archive *)malloc(sizeof(lar_archive)); + ar->fd = fd; + ar->length = as.st_size; + ar->index = lar_get_index(ar); + strncpy(ar->filename, filename, sizeof(ar->filename)); + + return ar; + } + + return NULL; +} + +int lar_close( lar_archive *ar ) +{ + lar_index *idx_head; + lar_index *idx_next; + + close(ar->fd); + + idx_head = ar->index; + do { + idx_next = idx_head->next; + free(idx_head); + } while( (idx_head = idx_next) != NULL ); + + free(ar); + + return 0; +} + |