/[svn]/libgig/trunk/src/helper.h
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revision 803 by schoenebeck, Sat Nov 12 12:36:49 2005 UTC revision 1179 by persson, Sat May 12 11:25:04 2007 UTC
# Line 1  Line 1 
1  /***************************************************************************  /***************************************************************************
2   *                                                                         *   *                                                                         *
3   *   libgig - C++ cross-platform Gigasampler format file loader library    *   *   libgig - C++ cross-platform Gigasampler format file access library    *
4   *                                                                         *   *                                                                         *
5   *   Copyright (C) 2003-2005 by Christian Schoenebeck                      *   *   Copyright (C) 2003-2006 by Christian Schoenebeck                      *
6   *                              <cuse@users.sourceforge.net>               *   *                              <cuse@users.sourceforge.net>               *
7   *                                                                         *   *                                                                         *
8   *   This library is free software; you can redistribute it and/or modify  *   *   This library is free software; you can redistribute it and/or modify  *
# Line 24  Line 24 
24  #ifndef __LIBGIG_HELPER_H__  #ifndef __LIBGIG_HELPER_H__
25  #define __LIBGIG_HELPER_H__  #define __LIBGIG_HELPER_H__
26    
27    #include <string.h>
28  #include <string>  #include <string>
29  #include <sstream>  #include <sstream>
30    
31    #include "RIFF.h"
32    
33  // *************** Helper Functions **************  // *************** Helper Functions **************
34  // *  // *
35    
# Line 36  template<class T> inline std::string ToS Line 39  template<class T> inline std::string ToS
39      return ss.str();      return ss.str();
40  }  }
41    
42    inline long Min(long A, long B) {
43        return (A > B) ? B : A;
44    }
45    
46    inline long Abs(long val) {
47        return (val > 0) ? val : -val;
48    }
49    
50    /**
51     * Stores a 16 bit integer in memory using little-endian format.
52     *
53     * @param pData - memory pointer
54     * @param data  - integer to be stored
55     */
56    inline void store16(uint8_t* pData, uint16_t data) {
57        pData[0] = data;
58        pData[1] = data >> 8;
59    }
60    
61    /**
62     * Stores a 32 bit integer in memory using little-endian format.
63     *
64     * @param pData - memory pointer
65     * @param data  - integer to be stored
66     */
67    inline void store32(uint8_t* pData, uint32_t data) {
68        pData[0] = data;
69        pData[1] = data >> 8;
70        pData[2] = data >> 16;
71        pData[3] = data >> 24;
72    }
73    
74    /**
75     * Swaps the order of the data words in the given memory area
76     * with a granularity given by \a WordSize.
77     *
78     * @param pData    - pointer to the memory area to be swapped
79     * @param AreaSize - size of the memory area to be swapped (in bytes)
80     * @param WordSize - size of the data words (in bytes)
81     */
82    inline void SwapMemoryArea(void* pData, unsigned long AreaSize, uint WordSize) {
83        switch (WordSize) { // TODO: unefficient
84            case 1: {
85                uint8_t* pDst = (uint8_t*) pData;
86                uint8_t  cache;
87                unsigned long lo = 0, hi = AreaSize - 1;
88                for (; lo < hi; hi--, lo++) {
89                    cache    = pDst[lo];
90                    pDst[lo] = pDst[hi];
91                    pDst[hi] = cache;
92                }
93                break;
94            }
95            case 2: {
96                uint16_t* pDst = (uint16_t*) pData;
97                uint16_t  cache;
98                unsigned long lo = 0, hi = (AreaSize >> 1) - 1;
99                for (; lo < hi; hi--, lo++) {
100                    cache    = pDst[lo];
101                    pDst[lo] = pDst[hi];
102                    pDst[hi] = cache;
103                }
104                break;
105            }
106            case 4: {
107                uint32_t* pDst = (uint32_t*) pData;
108                uint32_t  cache;
109                unsigned long lo = 0, hi = (AreaSize >> 2) - 1;
110                for (; lo < hi; hi--, lo++) {
111                    cache    = pDst[lo];
112                    pDst[lo] = pDst[hi];
113                    pDst[hi] = cache;
114                }
115                break;
116            }
117            default: {
118                uint8_t* pCache = new uint8_t[WordSize]; // TODO: unefficient
119                unsigned long lo = 0, hi = AreaSize - WordSize;
120                for (; lo < hi; hi -= WordSize, lo += WordSize) {
121                    memcpy(pCache, (uint8_t*) pData + lo, WordSize);
122                    memcpy((uint8_t*) pData + lo, (uint8_t*) pData + hi, WordSize);
123                    memcpy((uint8_t*) pData + hi, pCache, WordSize);
124                }
125                delete[] pCache;
126                break;
127            }
128        }
129    }
130    
131    /** @brief Load given info field (string).
132     *
133     * Load info field string from given info chunk (\a ck) and save value to \a s.
134     */
135    inline void LoadString(RIFF::Chunk* ck, std::string& s) {
136        if (ck) {
137            const char* str = (char*)ck->LoadChunkData();
138            int size = ck->GetSize();
139            int len;
140            for (len = 0 ; len < size ; len++)
141                if (str[len] == '\0') break;
142            s.assign(str, len);
143            ck->ReleaseChunkData();
144        }
145    }
146    
147    /** @brief Apply given INFO field to the respective chunk.
148     *
149     * Apply given info value string to given info chunk, which is a
150     * subchunk of INFO list chunk \a lstINFO. If the given chunk already
151     * exists, value \a s will be applied. Otherwise if it doesn't exist yet
152     * and either \a s or \a sDefault is not an empty string, such a chunk
153     * will be created and either \a s or \a sDefault will be applied
154     * (depending on which one is not an empty string, if both are not an
155     * empty string \a s will be preferred).
156     *
157     * @param ChunkID  - 32 bit RIFF chunk ID of INFO subchunk (only used in case \a ck is NULL)
158     * @param ck       - INFO (sub)chunk where string should be stored to
159     * @param lstINFO  - parent (INFO) RIFF list chunk
160     * @param s        - current value of info field
161     * @param sDefault - default value
162     * @param bUseFixedLengthStrings - should a specific string size be forced in the chunk?
163     * @param size     - wanted size of the INFO chunk. This is ignored if bUseFixedLengthStrings is false.
164     */
165    inline void SaveString(uint32_t ChunkID, RIFF::Chunk* ck, RIFF::List* lstINFO, const std::string& s, const std::string& sDefault, bool bUseFixedLengthStrings, int size) {
166        if (ck) { // if chunk exists already, use 's' as value
167            if (!bUseFixedLengthStrings) size = s.size() + 1;
168            ck->Resize(size);
169            char* pData = (char*) ck->LoadChunkData();
170            strncpy(pData, s.c_str(), size);
171        } else if (s != "" || sDefault != "") { // create chunk
172            const std::string& sToSave = (s != "") ? s : sDefault;
173            if (!bUseFixedLengthStrings) size = sToSave.size() + 1;
174            ck = lstINFO->AddSubChunk(ChunkID, size);
175            char* pData = (char*) ck->LoadChunkData();
176            strncpy(pData, sToSave.c_str(), size);
177        }
178    }
179    
180  #endif // __LIBGIG_HELPER_H__  #endif // __LIBGIG_HELPER_H__
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