annotate libcoding/gsm7_pack.c @ 0:2d0082216916

libcoding: beginning with a subset of uptools version
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 05 Aug 2023 00:46:23 +0000
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2d0082216916 libcoding: beginning with a subset of uptools version
Mychaela Falconia <falcon@freecalypso.org>
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1 /*
2d0082216916 libcoding: beginning with a subset of uptools version
Mychaela Falconia <falcon@freecalypso.org>
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2 * This library module implements the function for packing septets into octets.
2d0082216916 libcoding: beginning with a subset of uptools version
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3 */
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4
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5 #include <sys/types.h>
2d0082216916 libcoding: beginning with a subset of uptools version
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6
2d0082216916 libcoding: beginning with a subset of uptools version
Mychaela Falconia <falcon@freecalypso.org>
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7 gsm7_pack(inbuf, outbuf, noctets)
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8 u_char *inbuf, *outbuf;
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Mychaela Falconia <falcon@freecalypso.org>
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9 unsigned noctets;
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Mychaela Falconia <falcon@freecalypso.org>
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10 {
2d0082216916 libcoding: beginning with a subset of uptools version
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11 u_char *ip = inbuf, *op = outbuf;
2d0082216916 libcoding: beginning with a subset of uptools version
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12 unsigned n, c;
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13
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14 for (n = 0; n < noctets; n++) {
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Mychaela Falconia <falcon@freecalypso.org>
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15 c = n % 7;
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16 *op++ = ((ip[1] << 7) | ip[0]) >> c;
2d0082216916 libcoding: beginning with a subset of uptools version
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17 if (c == 6)
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18 ip += 2;
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Mychaela Falconia <falcon@freecalypso.org>
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19 else
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20 ip += 1;
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21 }
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22 }