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 // Note for the paranoids: Index encoder prevents the Stream from 55 // getting too big and still being accepted with LZMA_OK, and Block 56 // encoder catches if the input is too big. So we don't need to 57 // separately check if the buffers are too big. 58 59 // Use a local copy. We update *out_pos_ptr only if everything 60 // succeeds. 61 size_t out_pos = *out_pos_ptr; 62 63 // Check that there's enough space for both Stream Header and 64 // Stream Footer. 65 if (out_size - out_pos <= 2 * LZMA_STREAM_HEADER_SIZE) 66 return LZMA_BUF_ERROR; 67 68 // Reserve space for Stream Footer so we don't need to check for 69 // available space again before encoding Stream Footer. 70 out_size -= LZMA_STREAM_HEADER_SIZE; 71 72 // Encode the Stream Header. 73 lzma_stream_flags stream_flags = { 74 .version = 0, 75 .check = check, 76 }; 77 78 if (lzma_stream_header_encode(&stream_flags, out + out_pos) 79 != LZMA_OK) 80 return LZMA_PROG_ERROR; 81 82 out_pos += LZMA_STREAM_HEADER_SIZE; 83 84 // Block 85 lzma_block block = { 86 .version = 0, 87 .check = check, 88 .filters = filters, 89 }; 90 91 return_if_error(lzma_block_buffer_encode(&block, allocator, 92 in, in_size, out, &out_pos, out_size)); 93 94 // Index 95 { 96 // Create an Index with one Record. 97 lzma_index *i = lzma_index_init(allocator); 98 if (i == NULL) 99 return LZMA_MEM_ERROR; 100 101 lzma_ret ret = lzma_index_append(i, allocator, 102 lzma_block_unpadded_size(&block), 103 block.uncompressed_size); 104 105 // If adding the Record was successful, encode the Index 106 // and get its size which will be stored into Stream Footer. 107 if (ret == LZMA_OK) { 108 ret = lzma_index_buffer_encode( 109 i, out, &out_pos, out_size); 110 111 stream_flags.backward_size = lzma_index_size(i); 112 } 113 114 lzma_index_end(i, allocator); 115 116 if (ret != LZMA_OK) 117 return ret; 118 } 119 120 // Stream Footer. We have already reserved space for this. 121 if (lzma_stream_footer_encode(&stream_flags, out + out_pos) 122 != LZMA_OK) 123 return LZMA_PROG_ERROR; 124 125 out_pos += LZMA_STREAM_HEADER_SIZE; 126 127 // Everything went fine, make the new output position available 128 // to the application. 129 *out_pos_ptr = out_pos; 130 return LZMA_OK; 131 } 132