auto_decoder.c revision 207753
1207753Smm/////////////////////////////////////////////////////////////////////////////// 2207753Smm// 3207753Smm/// \file auto_decoder.c 4207753Smm/// \brief Autodetect between .xz Stream and .lzma (LZMA_Alone) formats 5207753Smm// 6207753Smm// Author: Lasse Collin 7207753Smm// 8207753Smm// This file has been put into the public domain. 9207753Smm// You can do whatever you want with this file. 10207753Smm// 11207753Smm/////////////////////////////////////////////////////////////////////////////// 12207753Smm 13207753Smm#include "stream_decoder.h" 14207753Smm#include "alone_decoder.h" 15207753Smm 16207753Smm 17207753Smmstruct lzma_coder_s { 18207753Smm /// Stream decoder or LZMA_Alone decoder 19207753Smm lzma_next_coder next; 20207753Smm 21207753Smm uint64_t memlimit; 22207753Smm uint32_t flags; 23207753Smm 24207753Smm enum { 25207753Smm SEQ_INIT, 26207753Smm SEQ_CODE, 27207753Smm SEQ_FINISH, 28207753Smm } sequence; 29207753Smm}; 30207753Smm 31207753Smm 32207753Smmstatic lzma_ret 33207753Smmauto_decode(lzma_coder *coder, lzma_allocator *allocator, 34207753Smm const uint8_t *restrict in, size_t *restrict in_pos, 35207753Smm size_t in_size, uint8_t *restrict out, 36207753Smm size_t *restrict out_pos, size_t out_size, lzma_action action) 37207753Smm{ 38207753Smm switch (coder->sequence) { 39207753Smm case SEQ_INIT: 40207753Smm if (*in_pos >= in_size) 41207753Smm return LZMA_OK; 42207753Smm 43207753Smm // Update the sequence now, because we want to continue from 44207753Smm // SEQ_CODE even if we return some LZMA_*_CHECK. 45207753Smm coder->sequence = SEQ_CODE; 46207753Smm 47207753Smm // Detect the file format. For now this is simple, since if 48207753Smm // it doesn't start with 0xFD (the first magic byte of the 49207753Smm // new format), it has to be LZMA_Alone, or something that 50207753Smm // we don't support at all. 51207753Smm if (in[*in_pos] == 0xFD) { 52207753Smm return_if_error(lzma_stream_decoder_init( 53207753Smm &coder->next, allocator, 54207753Smm coder->memlimit, coder->flags)); 55207753Smm } else { 56207753Smm return_if_error(lzma_alone_decoder_init(&coder->next, 57207753Smm allocator, coder->memlimit)); 58207753Smm 59207753Smm // If the application wants to know about missing 60207753Smm // integrity check or about the check in general, we 61207753Smm // need to handle it here, because LZMA_Alone decoder 62207753Smm // doesn't accept any flags. 63207753Smm if (coder->flags & LZMA_TELL_NO_CHECK) 64207753Smm return LZMA_NO_CHECK; 65207753Smm 66207753Smm if (coder->flags & LZMA_TELL_ANY_CHECK) 67207753Smm return LZMA_GET_CHECK; 68207753Smm } 69207753Smm 70207753Smm // Fall through 71207753Smm 72207753Smm case SEQ_CODE: { 73207753Smm const lzma_ret ret = coder->next.code( 74207753Smm coder->next.coder, allocator, 75207753Smm in, in_pos, in_size, 76207753Smm out, out_pos, out_size, action); 77207753Smm if (ret != LZMA_STREAM_END 78207753Smm || (coder->flags & LZMA_CONCATENATED) == 0) 79207753Smm return ret; 80207753Smm 81207753Smm coder->sequence = SEQ_FINISH; 82207753Smm } 83207753Smm 84207753Smm // Fall through 85207753Smm 86207753Smm case SEQ_FINISH: 87207753Smm // When LZMA_DECODE_CONCATENATED was used and we were decoding 88207753Smm // LZMA_Alone file, we need to check check that there is no 89207753Smm // trailing garbage and wait for LZMA_FINISH. 90207753Smm if (*in_pos < in_size) 91207753Smm return LZMA_DATA_ERROR; 92207753Smm 93207753Smm return action == LZMA_FINISH ? LZMA_STREAM_END : LZMA_OK; 94207753Smm 95207753Smm default: 96207753Smm assert(0); 97207753Smm return LZMA_PROG_ERROR; 98207753Smm } 99207753Smm} 100207753Smm 101207753Smm 102207753Smmstatic void 103207753Smmauto_decoder_end(lzma_coder *coder, lzma_allocator *allocator) 104207753Smm{ 105207753Smm lzma_next_end(&coder->next, allocator); 106207753Smm lzma_free(coder, allocator); 107207753Smm return; 108207753Smm} 109207753Smm 110207753Smm 111207753Smmstatic lzma_check 112207753Smmauto_decoder_get_check(const lzma_coder *coder) 113207753Smm{ 114207753Smm // It is LZMA_Alone if get_check is NULL. 115207753Smm return coder->next.get_check == NULL ? LZMA_CHECK_NONE 116207753Smm : coder->next.get_check(coder->next.coder); 117207753Smm} 118207753Smm 119207753Smm 120207753Smmstatic lzma_ret 121207753Smmauto_decoder_memconfig(lzma_coder *coder, uint64_t *memusage, 122207753Smm uint64_t *old_memlimit, uint64_t new_memlimit) 123207753Smm{ 124207753Smm lzma_ret ret; 125207753Smm 126207753Smm if (coder->next.memconfig != NULL) { 127207753Smm ret = coder->next.memconfig(coder->next.coder, 128207753Smm memusage, old_memlimit, new_memlimit); 129207753Smm assert(*old_memlimit == coder->memlimit); 130207753Smm } else { 131207753Smm // No coder is configured yet. Use the base value as 132207753Smm // the current memory usage. 133207753Smm *memusage = LZMA_MEMUSAGE_BASE; 134207753Smm *old_memlimit = coder->memlimit; 135207753Smm ret = LZMA_OK; 136207753Smm } 137207753Smm 138207753Smm if (ret == LZMA_OK && new_memlimit != 0) 139207753Smm coder->memlimit = new_memlimit; 140207753Smm 141207753Smm return ret; 142207753Smm} 143207753Smm 144207753Smm 145207753Smmstatic lzma_ret 146207753Smmauto_decoder_init(lzma_next_coder *next, lzma_allocator *allocator, 147207753Smm uint64_t memlimit, uint32_t flags) 148207753Smm{ 149207753Smm lzma_next_coder_init(&auto_decoder_init, next, allocator); 150207753Smm 151207753Smm if (memlimit == 0) 152207753Smm return LZMA_PROG_ERROR; 153207753Smm 154207753Smm if (flags & ~LZMA_SUPPORTED_FLAGS) 155207753Smm return LZMA_OPTIONS_ERROR; 156207753Smm 157207753Smm if (next->coder == NULL) { 158207753Smm next->coder = lzma_alloc(sizeof(lzma_coder), allocator); 159207753Smm if (next->coder == NULL) 160207753Smm return LZMA_MEM_ERROR; 161207753Smm 162207753Smm next->code = &auto_decode; 163207753Smm next->end = &auto_decoder_end; 164207753Smm next->get_check = &auto_decoder_get_check; 165207753Smm next->memconfig = &auto_decoder_memconfig; 166207753Smm next->coder->next = LZMA_NEXT_CODER_INIT; 167207753Smm } 168207753Smm 169207753Smm next->coder->memlimit = memlimit; 170207753Smm next->coder->flags = flags; 171207753Smm next->coder->sequence = SEQ_INIT; 172207753Smm 173207753Smm return LZMA_OK; 174207753Smm} 175207753Smm 176207753Smm 177207753Smmextern LZMA_API(lzma_ret) 178207753Smmlzma_auto_decoder(lzma_stream *strm, uint64_t memlimit, uint32_t flags) 179207753Smm{ 180207753Smm lzma_next_strm_init(auto_decoder_init, strm, memlimit, flags); 181207753Smm 182207753Smm strm->internal->supported_actions[LZMA_RUN] = true; 183207753Smm strm->internal->supported_actions[LZMA_FINISH] = true; 184207753Smm 185207753Smm return LZMA_OK; 186207753Smm} 187