1 | /* |
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2 | * Copyright (c) 2004-2005 Sergey Lyubka <valenok@gmail.com> |
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3 | * All rights reserved |
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4 | * |
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5 | * "THE BEER-WARE LICENSE" (Revision 42): |
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6 | * Sergey Lyubka wrote this file. As long as you retain this notice you |
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7 | * can do whatever you want with this stuff. If we meet some day, and you think |
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8 | * this stuff is worth it, you can buy me a beer in return. |
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9 | */ |
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10 | |
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11 | #ifndef IO_HEADER_INCLUDED |
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12 | #define IO_HEADER_INCLUDED |
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13 | |
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14 | #include <assert.h> |
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15 | #include <stddef.h> |
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16 | |
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17 | /* |
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18 | * I/O buffer descriptor |
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19 | */ |
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20 | struct io { |
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21 | char *buf; /* IO Buffer */ |
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22 | size_t size; /* IO buffer size */ |
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23 | size_t head; /* Bytes read */ |
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24 | size_t tail; /* Bytes written */ |
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25 | size_t total; /* Total bytes read */ |
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26 | }; |
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27 | |
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28 | static __inline void |
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29 | io_clear(struct io *io) |
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30 | { |
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31 | assert(io->buf != NULL); |
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32 | assert(io->size > 0); |
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33 | io->total = io->tail = io->head = 0; |
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34 | } |
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35 | |
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36 | static __inline char * |
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37 | io_space(struct io *io) |
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38 | { |
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39 | assert(io->buf != NULL); |
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40 | assert(io->size > 0); |
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41 | assert(io->head <= io->size); |
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42 | return (io->buf + io->head); |
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43 | } |
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44 | |
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45 | static __inline char * |
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46 | io_data(struct io *io) |
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47 | { |
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48 | assert(io->buf != NULL); |
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49 | assert(io->size > 0); |
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50 | assert(io->tail <= io->size); |
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51 | return (io->buf + io->tail); |
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52 | } |
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53 | |
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54 | static __inline size_t |
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55 | io_space_len(const struct io *io) |
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56 | { |
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57 | assert(io->buf != NULL); |
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58 | assert(io->size > 0); |
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59 | assert(io->head <= io->size); |
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60 | return (io->size - io->head); |
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61 | } |
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62 | |
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63 | static __inline size_t |
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64 | io_data_len(const struct io *io) |
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65 | { |
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66 | assert(io->buf != NULL); |
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67 | assert(io->size > 0); |
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68 | assert(io->head <= io->size); |
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69 | assert(io->tail <= io->head); |
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70 | return (io->head - io->tail); |
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71 | } |
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72 | |
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73 | static __inline void |
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74 | io_inc_tail(struct io *io, size_t n) |
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75 | { |
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76 | assert(io->buf != NULL); |
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77 | assert(io->size > 0); |
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78 | assert(io->tail <= io->head); |
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79 | assert(io->head <= io->size); |
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80 | io->tail += n; |
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81 | assert(io->tail <= io->head); |
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82 | if (io->tail == io->head) |
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83 | io->head = io->tail = 0; |
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84 | } |
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85 | |
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86 | static __inline void |
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87 | io_inc_head(struct io *io, size_t n) |
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88 | { |
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89 | assert(io->buf != NULL); |
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90 | assert(io->size > 0); |
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91 | assert(io->tail <= io->head); |
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92 | io->head += n; |
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93 | io->total += n; |
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94 | assert(io->head <= io->size); |
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95 | } |
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96 | |
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97 | #endif /* IO_HEADER_INCLUDED */ |
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