1 /* rio.c is a simple stream-oriented I/O abstraction that provides an interface 2 * to write code that can consume/produce data using different concrete input 3 * and output devices. For instance the same rdb.c code using the rio 4 * abstraction can be used to read and write the RDB format using in-memory 5 * buffers or files. 6 * 7 * A rio object provides the following methods: 8 * read: read from stream. 9 * write: write to stream. 10 * tell: get the current offset. 11 * 12 * It is also possible to set a 'checksum' method that is used by rio.c in order 13 * to compute a checksum of the data written or read, or to query the rio object 14 * for the current checksum. 15 * 16 * ---------------------------------------------------------------------------- 17 * 18 * Copyright (c) 2009-2012, Pieter Noordhuis <pcnoordhuis at gmail dot com> 19 * Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com> 20 * All rights reserved. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions are met: 24 * 25 * * Redistributions of source code must retain the above copyright notice, 26 * this list of conditions and the following disclaimer. 27 * * Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * * Neither the name of Redis nor the names of its contributors may be used 31 * to endorse or promote products derived from this software without 32 * specific prior written permission. 33 * 34 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 35 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 36 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 37 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 38 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 39 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 40 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 41 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 42 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 43 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 44 * POSSIBILITY OF SUCH DAMAGE. 45 */ 46 47 48 #include "fmacros.h" 49 #include <string.h> 50 #include <stdio.h> 51 #include "rio.h" 52 #include "util.h" 53 #include "crc64.h" 54 55 /* Returns 1 or 0 for success/failure. */ 56 static size_t rioBufferWrite(rio *r, const void *buf, size_t len) { 57 r->io.buffer.ptr = sdscatlen(r->io.buffer.ptr,(char*)buf,len); 58 r->io.buffer.pos += len; 59 return 1; 60 } 61 62 /* Returns 1 or 0 for success/failure. */ 63 static size_t rioBufferRead(rio *r, void *buf, size_t len) { 64 if (sdslen(r->io.buffer.ptr)-r->io.buffer.pos < len) 65 return 0; /* not enough buffer to return len bytes. */ 66 memcpy(buf,r->io.buffer.ptr+r->io.buffer.pos,len); 67 r->io.buffer.pos += len; 68 return 1; 69 } 70 71 /* Returns read/write position in buffer. */ 72 static off_t rioBufferTell(rio *r) { 73 return r->io.buffer.pos; 74 } 75 76 /* Returns 1 or 0 for success/failure. */ 77 static size_t rioFileWrite(rio *r, const void *buf, size_t len) { 78 return fwrite(buf,len,1,r->io.file.fp); 79 } 80 81 /* Returns 1 or 0 for success/failure. */ 82 static size_t rioFileRead(rio *r, void *buf, size_t len) { 83 return fread(buf,len,1,r->io.file.fp); 84 } 85 86 /* Returns read/write position in file. */ 87 static off_t rioFileTell(rio *r) { 88 return ftello(r->io.file.fp); 89 } 90 91 static const rio rioBufferIO = { 92 rioBufferRead, 93 rioBufferWrite, 94 rioBufferTell, 95 NULL, /* update_checksum */ 96 0, /* current checksum */ 97 { { NULL, 0 } } /* union for io-specific vars */ 98 }; 99 100 static const rio rioFileIO = { 101 rioFileRead, 102 rioFileWrite, 103 rioFileTell, 104 NULL, /* update_checksum */ 105 0, /* current checksum */ 106 { { NULL, 0 } } /* union for io-specific vars */ 107 }; 108 109 void rioInitWithFile(rio *r, FILE *fp) { 110 *r = rioFileIO; 111 r->io.file.fp = fp; 112 } 113 114 void rioInitWithBuffer(rio *r, sds s) { 115 *r = rioBufferIO; 116 r->io.buffer.ptr = s; 117 r->io.buffer.pos = 0; 118 } 119 120 /* This function can be installed both in memory and file streams when checksum 121 * computation is needed. */ 122 void rioGenericUpdateChecksum(rio *r, const void *buf, size_t len) { 123 r->cksum = crc64(r->cksum,buf,len); 124 } 125 126 /* ------------------------------ Higher level interface --------------------------- 127 * The following higher level functions use lower level rio.c functions to help 128 * generating the Redis protocol for the Append Only File. */ 129 130 /* Write multi bulk count in the format: "*<count>\r\n". */ 131 size_t rioWriteBulkCount(rio *r, char prefix, int count) { 132 char cbuf[128]; 133 int clen; 134 135 cbuf[0] = prefix; 136 clen = 1+ll2string(cbuf+1,sizeof(cbuf)-1,count); 137 cbuf[clen++] = '\r'; 138 cbuf[clen++] = '\n'; 139 if (rioWrite(r,cbuf,clen) == 0) return 0; 140 return clen; 141 } 142 143 /* Write binary-safe string in the format: "$<count>\r\n<payload>\r\n". */ 144 size_t rioWriteBulkString(rio *r, const char *buf, size_t len) { 145 size_t nwritten; 146 147 if ((nwritten = rioWriteBulkCount(r,'$',len)) == 0) return 0; 148 if (len > 0 && rioWrite(r,buf,len) == 0) return 0; 149 if (rioWrite(r,"\r\n",2) == 0) return 0; 150 return nwritten+len+2; 151 } 152 153 /* Write a long long value in format: "$<count>\r\n<payload>\r\n". */ 154 size_t rioWriteBulkLongLong(rio *r, long long l) { 155 char lbuf[32]; 156 unsigned int llen; 157 158 llen = ll2string(lbuf,sizeof(lbuf),l); 159 return rioWriteBulkString(r,lbuf,llen); 160 } 161 162 /* Write a double value in the format: "$<count>\r\n<payload>\r\n" */ 163 size_t rioWriteBulkDouble(rio *r, double d) { 164 char dbuf[128]; 165 unsigned int dlen; 166 167 dlen = snprintf(dbuf,sizeof(dbuf),"%.17g",d); 168 return rioWriteBulkString(r,dbuf,dlen); 169 } 170