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| 1 | +// Copyright 2018 Google |
| 2 | +// |
| 3 | +// Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | +// you may not use this file except in compliance with the License. |
| 5 | +// You may obtain a copy of the License at |
| 6 | +// |
| 7 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | +// |
| 9 | +// Unless required by applicable law or agreed to in writing, software |
| 10 | +// distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | +// See the License for the specific language governing permissions and |
| 13 | +// limitations under the License. |
| 14 | + |
| 15 | +#import "GULNSData+zlib.h" |
| 16 | + |
| 17 | +#import <zlib.h> |
| 18 | + |
| 19 | +#define kChunkSize 1024 |
| 20 | +#define Z_DEFAULT_COMPRESSION (-1) |
| 21 | + |
| 22 | +NSString *const GULNSDataZlibErrorDomain = @"com.google.GULNSDataZlibErrorDomain"; |
| 23 | +NSString *const GULNSDataZlibErrorKey = @"GULNSDataZlibErrorKey"; |
| 24 | +NSString *const GULNSDataZlibRemainingBytesKey = @"GULNSDataZlibRemainingBytesKey"; |
| 25 | + |
| 26 | +@implementation NSData (GULGzip) |
| 27 | + |
| 28 | ++ (NSData *)gul_dataByInflatingGzippedData:(NSData *)data error:(NSError **)error { |
| 29 | + const void *bytes = [data bytes]; |
| 30 | + NSUInteger length = [data length]; |
| 31 | + if (!bytes || !length) { |
| 32 | + return nil; |
| 33 | + } |
| 34 | + |
| 35 | +#if defined(__LP64__) && __LP64__ |
| 36 | + // Don't support > 32bit length for 64 bit, see note in header. |
| 37 | + if (length > UINT_MAX) { |
| 38 | + return nil; |
| 39 | + } |
| 40 | +#endif |
| 41 | + |
| 42 | + z_stream strm; |
| 43 | + bzero(&strm, sizeof(z_stream)); |
| 44 | + |
| 45 | + // Setup the input. |
| 46 | + strm.avail_in = (unsigned int)length; |
| 47 | + strm.next_in = (unsigned char *)bytes; |
| 48 | + |
| 49 | + int windowBits = 15; // 15 to enable any window size |
| 50 | + windowBits += 32; // and +32 to enable zlib or gzip header detection. |
| 51 | + |
| 52 | + int retCode; |
| 53 | + if ((retCode = inflateInit2(&strm, windowBits)) != Z_OK) { |
| 54 | + if (error) { |
| 55 | + NSDictionary *userInfo = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:retCode] |
| 56 | + forKey:GULNSDataZlibErrorKey]; |
| 57 | + *error = [NSError errorWithDomain:GULNSDataZlibErrorDomain |
| 58 | + code:GULNSDataZlibErrorInternal |
| 59 | + userInfo:userInfo]; |
| 60 | + } |
| 61 | + return nil; |
| 62 | + } |
| 63 | + |
| 64 | + // Hint the size at 4x the input size. |
| 65 | + NSMutableData *result = [NSMutableData dataWithCapacity:(length * 4)]; |
| 66 | + unsigned char output[kChunkSize]; |
| 67 | + |
| 68 | + // Loop to collect the data. |
| 69 | + do { |
| 70 | + // Update what we're passing in. |
| 71 | + strm.avail_out = kChunkSize; |
| 72 | + strm.next_out = output; |
| 73 | + retCode = inflate(&strm, Z_NO_FLUSH); |
| 74 | + if ((retCode != Z_OK) && (retCode != Z_STREAM_END)) { |
| 75 | + if (error) { |
| 76 | + NSMutableDictionary *userInfo = |
| 77 | + [NSMutableDictionary dictionaryWithObject:[NSNumber numberWithInt:retCode] |
| 78 | + forKey:GULNSDataZlibErrorKey]; |
| 79 | + if (strm.msg) { |
| 80 | + NSString *message = [NSString stringWithUTF8String:strm.msg]; |
| 81 | + if (message) { |
| 82 | + [userInfo setObject:message forKey:NSLocalizedDescriptionKey]; |
| 83 | + } |
| 84 | + } |
| 85 | + *error = [NSError errorWithDomain:GULNSDataZlibErrorDomain |
| 86 | + code:GULNSDataZlibErrorInternal |
| 87 | + userInfo:userInfo]; |
| 88 | + } |
| 89 | + inflateEnd(&strm); |
| 90 | + return nil; |
| 91 | + } |
| 92 | + // Collect what we got. |
| 93 | + unsigned gotBack = kChunkSize - strm.avail_out; |
| 94 | + if (gotBack > 0) { |
| 95 | + [result appendBytes:output length:gotBack]; |
| 96 | + } |
| 97 | + |
| 98 | + } while (retCode == Z_OK); |
| 99 | + |
| 100 | + // Make sure there wasn't more data tacked onto the end of a valid compressed stream. |
| 101 | + if (strm.avail_in != 0) { |
| 102 | + if (error) { |
| 103 | + NSDictionary *userInfo = |
| 104 | + [NSDictionary dictionaryWithObject:[NSNumber numberWithUnsignedInt:strm.avail_in] |
| 105 | + forKey:GULNSDataZlibRemainingBytesKey]; |
| 106 | + *error = [NSError errorWithDomain:GULNSDataZlibErrorDomain |
| 107 | + code:GULNSDataZlibErrorDataRemaining |
| 108 | + userInfo:userInfo]; |
| 109 | + } |
| 110 | + result = nil; |
| 111 | + } |
| 112 | + // The only way out of the loop was by hitting the end of the stream. |
| 113 | + NSAssert(retCode == Z_STREAM_END, |
| 114 | + @"Thought we finished inflate w/o getting a result of stream end, code %d", retCode); |
| 115 | + |
| 116 | + // Clean up. |
| 117 | + inflateEnd(&strm); |
| 118 | + |
| 119 | + return result; |
| 120 | +} |
| 121 | + |
| 122 | ++ (NSData *)gul_dataByGzippingData:(NSData *)data error:(NSError **)error { |
| 123 | + const void *bytes = [data bytes]; |
| 124 | + NSUInteger length = [data length]; |
| 125 | + |
| 126 | + int level = Z_DEFAULT_COMPRESSION; |
| 127 | + if (!bytes || !length) { |
| 128 | + return nil; |
| 129 | + } |
| 130 | + |
| 131 | +#if defined(__LP64__) && __LP64__ |
| 132 | + // Don't support > 32bit length for 64 bit, see note in header. |
| 133 | + if (length > UINT_MAX) { |
| 134 | + if (error) { |
| 135 | + *error = [NSError errorWithDomain:GULNSDataZlibErrorDomain |
| 136 | + code:GULNSDataZlibErrorGreaterThan32BitsToCompress |
| 137 | + userInfo:nil]; |
| 138 | + } |
| 139 | + return nil; |
| 140 | + } |
| 141 | +#endif |
| 142 | + |
| 143 | + z_stream strm; |
| 144 | + bzero(&strm, sizeof(z_stream)); |
| 145 | + |
| 146 | + int memLevel = 8; // Default. |
| 147 | + int windowBits = 15 + 16; // Enable gzip header instead of zlib header. |
| 148 | + |
| 149 | + int retCode; |
| 150 | + if ((retCode = deflateInit2(&strm, level, Z_DEFLATED, windowBits, memLevel, |
| 151 | + Z_DEFAULT_STRATEGY)) != Z_OK) { |
| 152 | + if (error) { |
| 153 | + NSDictionary *userInfo = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:retCode] |
| 154 | + forKey:GULNSDataZlibErrorKey]; |
| 155 | + *error = [NSError errorWithDomain:GULNSDataZlibErrorDomain |
| 156 | + code:GULNSDataZlibErrorInternal |
| 157 | + userInfo:userInfo]; |
| 158 | + } |
| 159 | + return nil; |
| 160 | + } |
| 161 | + |
| 162 | + // Hint the size at 1/4 the input size. |
| 163 | + NSMutableData *result = [NSMutableData dataWithCapacity:(length / 4)]; |
| 164 | + unsigned char output[kChunkSize]; |
| 165 | + |
| 166 | + // Setup the input. |
| 167 | + strm.avail_in = (unsigned int)length; |
| 168 | + strm.next_in = (unsigned char *)bytes; |
| 169 | + |
| 170 | + // Collect the data. |
| 171 | + do { |
| 172 | + // update what we're passing in |
| 173 | + strm.avail_out = kChunkSize; |
| 174 | + strm.next_out = output; |
| 175 | + retCode = deflate(&strm, Z_FINISH); |
| 176 | + if ((retCode != Z_OK) && (retCode != Z_STREAM_END)) { |
| 177 | + if (error) { |
| 178 | + NSDictionary *userInfo = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:retCode] |
| 179 | + forKey:GULNSDataZlibErrorKey]; |
| 180 | + *error = [NSError errorWithDomain:GULNSDataZlibErrorDomain |
| 181 | + code:GULNSDataZlibErrorInternal |
| 182 | + userInfo:userInfo]; |
| 183 | + } |
| 184 | + deflateEnd(&strm); |
| 185 | + return nil; |
| 186 | + } |
| 187 | + // Collect what we got. |
| 188 | + unsigned gotBack = kChunkSize - strm.avail_out; |
| 189 | + if (gotBack > 0) { |
| 190 | + [result appendBytes:output length:gotBack]; |
| 191 | + } |
| 192 | + |
| 193 | + } while (retCode == Z_OK); |
| 194 | + |
| 195 | + // If the loop exits, it used all input and the stream ended. |
| 196 | + NSAssert(strm.avail_in == 0, |
| 197 | + @"Should have finished deflating without using all input, %u bytes left", strm.avail_in); |
| 198 | + NSAssert(retCode == Z_STREAM_END, |
| 199 | + @"thought we finished deflate w/o getting a result of stream end, code %d", retCode); |
| 200 | + |
| 201 | + // Clean up. |
| 202 | + deflateEnd(&strm); |
| 203 | + |
| 204 | + return result; |
| 205 | +} |
| 206 | + |
| 207 | +@end |
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