1 /////////////////////////////////////////////////////////////////////////////// 2 // 3 /// \file stream_buffer_encoder.c 4 /// \brief Single-call .xz Stream encoder 5 // 6 // Author: Lasse Collin 7 // 8 // This file has been put into the public domain. 9 // You can do whatever you want with this file. 10 // 11 /////////////////////////////////////////////////////////////////////////////// 12 13 #include "index.h" 14 15 16 /// Maximum size of Index that has exactly one Record. 17 /// Index Indicator + Number of Records + Record + CRC32 rounded up to 18 /// the next multiple of four. 19 #define INDEX_BOUND ((1 + 1 + 2 * LZMA_VLI_BYTES_MAX + 4 + 3) & ~3) 20 21 /// Stream Header, Stream Footer, and Index 22 #define HEADERS_BOUND (2 * LZMA_STREAM_HEADER_SIZE + INDEX_BOUND) 23 24 25 extern LZMA_API(size_t) 26 lzma_stream_buffer_bound(size_t uncompressed_size) 27 { 28 // Get the maximum possible size of a Block. 29 const size_t block_bound = lzma_block_buffer_bound(uncompressed_size); 30 if (block_bound == 0) 31 return 0; 32 33 // Catch the possible integer overflow and also prevent the size of 34 // the Stream exceeding LZMA_VLI_MAX (theoretically possible on 35 // 64-bit systems). 36 if (my_min(SIZE_MAX, LZMA_VLI_MAX) - block_bound < HEADERS_BOUND) 37 return 0; 38 39 return block_bound + HEADERS_BOUND; 40 } 41 42 43 extern LZMA_API(lzma_ret) 44 lzma_stream_buffer_encode(lzma_filter *filters, lzma_check check, 45 lzma_allocator *allocator, const uint8_t *in, size_t in_size, 46 uint8_t *out, size_t *out_pos_ptr, size_t out_size) 47 { 48 // Sanity checks 49 if (filters == NULL || (unsigned int)(check) > LZMA_CHECK_ID_MAX 50 || (in == NULL && in_size != 0) || out == NULL 51 || out_pos_ptr == NULL || *out_pos_ptr > out_size) 52 return LZMA_PROG_ERROR; 53 54 if (!lzma_check_is_supported(check)) 55 return LZMA_UNSUPPORTED_CHECK; 56 57 // Note for the paranoids: Index encoder prevents the Stream from 58 // getting too big and still being accepted with LZMA_OK, and Block 59 // encoder catches if the input is too big. So we don't need to 60 // separately check if the buffers are too big. 61 62 // Use a local copy. We update *out_pos_ptr only if everything 63 // succeeds. 64 size_t out_pos = *out_pos_ptr; 65 66 // Check that there's enough space for both Stream Header and 67 // Stream Footer. 68 if (out_size - out_pos <= 2 * LZMA_STREAM_HEADER_SIZE) 69 return LZMA_BUF_ERROR; 70 71 // Reserve space for Stream Footer so we don't need to check for 72 // available space again before encoding Stream Footer. 73 out_size -= LZMA_STREAM_HEADER_SIZE; 74 75 // Encode the Stream Header. 76 lzma_stream_flags stream_flags = { 77 .version = 0, 78 .check = check, 79 }; 80 81 if (lzma_stream_header_encode(&stream_flags, out + out_pos) 82 != LZMA_OK) 83 return LZMA_PROG_ERROR; 84 85 out_pos += LZMA_STREAM_HEADER_SIZE; 86 87 // Encode a Block but only if there is at least one byte of input. 88 lzma_block block = { 89 .version = 0, 90 .check = check, 91 .filters = filters, 92 }; 93 94 if (in_size > 0) 95 return_if_error(lzma_block_buffer_encode(&block, allocator, 96 in, in_size, out, &out_pos, out_size)); 97 98 // Index 99 { 100 // Create an Index. It will have one Record if there was 101 // at least one byte of input to encode. Otherwise the 102 // Index will be empty. 103 lzma_index *i = lzma_index_init(allocator); 104 if (i == NULL) 105 return LZMA_MEM_ERROR; 106 107 lzma_ret ret = LZMA_OK; 108 109 if (in_size > 0) 110 ret = lzma_index_append(i, allocator, 111 lzma_block_unpadded_size(&block), 112 block.uncompressed_size); 113 114 // If adding the Record was successful, encode the Index 115 // and get its size which will be stored into Stream Footer. 116 if (ret == LZMA_OK) { 117 ret = lzma_index_buffer_encode( 118 i, out, &out_pos, out_size); 119 120 stream_flags.backward_size = lzma_index_size(i); 121 } 122 123 lzma_index_end(i, allocator); 124 125 if (ret != LZMA_OK) 126 return ret; 127 } 128 129 // Stream Footer. We have already reserved space for this. 130 if (lzma_stream_footer_encode(&stream_flags, out + out_pos) 131 != LZMA_OK) 132 return LZMA_PROG_ERROR; 133 134 out_pos += LZMA_STREAM_HEADER_SIZE; 135 136 // Everything went fine, make the new output position available 137 // to the application. 138 *out_pos_ptr = out_pos; 139 return LZMA_OK; 140 } 141