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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 647 | andrew_pro | 1 | #include |
| 7184 | siemargl | 2 | #include |
| 3 | #include |
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| 647 | andrew_pro | 4 | #include |
| 5 | |||
| 6 | int fread(void *buffer,int size,int count,FILE* file) |
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| 7 | { |
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| 7184 | siemargl | 8 | dword res, readbytes; |
| 9 | dword fullsize, read4cache, toread, readcount; |
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| 647 | andrew_pro | 10 | |
| 6433 | siemargl | 11 | if(!file || !buffer) |
| 12 | { |
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| 13 | errno = E_INVALIDPTR; |
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| 14 | return 0; |
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| 15 | } |
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| 647 | andrew_pro | 16 | |
| 7172 | siemargl | 17 | if ((file->mode &3)!=FILE_OPEN_READ && (file->mode & FILE_OPEN_PLUS)==0) |
| 6433 | siemargl | 18 | { |
| 19 | errno = E_ACCESS; |
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| 20 | return 0; |
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| 21 | } |
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| 22 | |||
| 647 | andrew_pro | 23 | fullsize=count*size; |
| 7184 | siemargl | 24 | if (fullsize + file->filepos >= file->filesize) |
| 647 | andrew_pro | 25 | { |
| 7184 | siemargl | 26 | fullsize=file->filesize - file->filepos; |
| 27 | if (fullsize <= 0) return 0; |
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| 647 | andrew_pro | 28 | } |
| 29 | |||
| 7184 | siemargl | 30 | /***** file buffering strategy, just read forward ***** |
| 31 | if we read small part - read full buffer, but if buffer have this data - dont read again nothing (or partial read forward 4k pages) |
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| 32 | any writes drops buffers as ungetc_buf */ |
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| 33 | read4cache = 0; |
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| 34 | readcount = 0; |
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| 35 | if (file->filepos >= file->buffer_start && file->filepos < file->buffer_end) |
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| 6433 | siemargl | 36 | { |
| 7184 | siemargl | 37 | read4cache = min(file->buffer_end - file->filepos, fullsize); |
| 38 | memcpy(buffer, file->buffer + file->filepos - file->buffer_start, read4cache); |
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| 39 | file->filepos += read4cache; |
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| 40 | if (file->ungetc_buf != EOF) // subst ungetc byte |
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| 41 | { |
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| 42 | *((char*)buffer) = (char)file->ungetc_buf; |
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| 43 | file->ungetc_buf = EOF; |
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| 44 | } |
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| 45 | buffer += read4cache; // ! advance |
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| 46 | fullsize -= read4cache; |
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| 47 | readcount = read4cache / size; |
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| 647 | andrew_pro | 48 | } |
| 7184 | siemargl | 49 | |
| 50 | toread = max(fullsize, file->buffersize); |
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| 51 | if (toread + file->filepos >= file->filesize) |
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| 52 | { |
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| 53 | toread = file->filesize - file->filepos; |
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| 54 | } |
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| 55 | |||
| 56 | if (fullsize <= 0 || toread <= 0) |
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| 57 | res = 0; // already read or file end |
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| 6433 | siemargl | 58 | else |
| 7184 | siemargl | 59 | { |
| 60 | file->buffer_start = file->filepos; |
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| 61 | if (toread <= fullsize) // read to bigger buffer |
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| 62 | { |
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| 63 | res = _ksys_readfile(file->filename, file->filepos, toread, buffer, &readbytes); |
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| 64 | read4cache = min(readbytes, file->buffersize); |
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| 65 | memcpy(file->buffer, buffer, read4cache); |
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| 66 | file->filepos += readbytes; |
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| 67 | } else |
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| 68 | { |
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| 69 | res = _ksys_readfile(file->filename, file->filepos, toread, file->buffer, &readbytes); |
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| 70 | read4cache = readbytes; |
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| 71 | memcpy(buffer, file->buffer, min(fullsize, read4cache)); |
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| 72 | file->filepos += min(fullsize, read4cache); |
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| 73 | } |
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| 74 | file->buffer_end = file->buffer_start + read4cache; |
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| 75 | if (readbytes >= fullsize) |
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| 76 | readcount += fullsize / size; |
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| 77 | else |
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| 78 | readcount += readbytes / size; |
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| 79 | } |
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| 80 | |||
| 81 | if (file->ungetc_buf != EOF) // subst ungetc byte |
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| 82 | { |
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| 83 | *((char*)buffer) = (char)file->ungetc_buf; |
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| 84 | file->ungetc_buf = EOF; |
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| 85 | } |
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| 86 | |||
| 87 | if (res != 0) |
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| 6433 | siemargl | 88 | { |
| 7184 | siemargl | 89 | file->ungetc_buf = EOF; |
| 6433 | siemargl | 90 | errno = -res; |
| 91 | } |
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| 7184 | siemargl | 92 | |
| 93 | return readcount; // really full readed plus cached items |
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| 6433 | siemargl | 94 | } |