mdw@git.distorted.org.uk Git - sgt/charset/blob - fromucs.c

   1 /*
   2  * fromucs.c - convert Unicode to other character sets.
   3  */
   4
   5 #include "charset.h"
   6 #include "internal.h"
   7
   8 struct charset_emit_param {
   9     char *output;
  10     int outlen;
  11     int stopped;
  12 };
  13
  14 static void charset_emit(void *ctx, long int output)
  15 {
  16     struct charset_emit_param *param = (struct charset_emit_param *)ctx;
  17
  18     if (param->outlen > 0) {
  19         *param->output++ = output;
  20         param->outlen--;
  21     } else {
  22         param->stopped = 1;
  23     }
  24 }
  25
  26 int charset_from_unicode(const wchar_t **input, int *inlen,
  27                          char *output, int outlen,
  28                          int charset, charset_state *state, int *error)
  29 {
  30     charset_spec const *spec = charset_find_spec(charset);
  31     charset_state localstate = CHARSET_INIT_STATE;
  32     struct charset_emit_param param;
  33     int locallen;
  34
  35     if (!input) {
  36         locallen = 1;
  37         inlen = &locallen;
  38     }
  39
  40     param.output = output;
  41     param.outlen = outlen;
  42     param.stopped = 0;
  43
  44     if (state)
  45         localstate = *state;           /* structure copy */
  46     if (error)
  47         *error = FALSE;
  48
  49     while (*inlen > 0) {
  50         int lenbefore = param.output - output;
  51         int ret;
  52
  53         if (input)
  54             ret = spec->write(spec, **input, &localstate,
  55                               charset_emit, &param);
  56         else
  57             ret = spec->write(spec, -1, &localstate, charset_emit, &param);
  58         if (error && !ret) {
  59             /*
  60              * We have hit a difficult character, which the user
  61              * wants to know about. Leave now.
  62              */
  63             *error = TRUE;
  64             return lenbefore;
  65         }
  66         if (param.stopped) {
  67             /*
  68              * The emit function has _tried_ to output some
  69              * characters, but ran up against the end of the
  70              * buffer. Leave immediately, and return what happened
  71              * _before_ attempting to process this character.
  72              */
  73             return lenbefore;
  74         }
  75         if (state)
  76             *state = localstate;       /* structure copy */
  77         if (input)
  78             (*input)++;
  79         (*inlen)--;
  80     }
  81     return param.output - output;
  82 }