FreeCalypso > hg > osmo-playpen
view smsc-sendmt/hexdecode.c @ 16:33129d7df7e4
README: update for current status
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sun, 27 Aug 2023 22:01:45 -0800 |
parents | 7543aa173634 |
children |
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/* * This library module implements decoding of long hex strings, * such as SMS PDUs. */ #include <ctype.h> #include <stdint.h> int decode_hex_line(const char *inbuf, uint8_t *outbuf, unsigned outmax) { const char *inp = inbuf; uint8_t *outp = outbuf; unsigned outcnt = 0; int c, d[2], i; while (*inp) { if (!isxdigit(inp[0]) || !isxdigit(inp[1])) return(-1); if (outcnt >= outmax) break; for (i = 0; i < 2; i++) { c = *inp++; if (isdigit(c)) d[i] = c - '0'; else if (isupper(c)) d[i] = c - 'A' + 10; else d[i] = c - 'a' + 10; } *outp++ = (d[0] << 4) | d[1]; outcnt++; } return outcnt; }