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 writtenlen;
  12     int stopped;
  13 };
  14
  15 static void charset_emit(void *ctx, long int output)
  16 {
  17     struct charset_emit_param *param = (struct charset_emit_param *)ctx;
  18
  19     if (param->outlen != 0) {
  20         if (param->output)
  21             *param->output++ = output;
  22         if (param->outlen > 0)
  23             param->outlen--;
  24         param->writtenlen++;
  25     } else {
  26         param->stopped = 1;
  27     }
  28 }
  29
  30 int charset_from_unicode(const wchar_t **input, int *inlen,
  31                          char *output, int outlen,
  32                          int charset, charset_state *state, int *error)
  33 {
  34     charset_spec const *spec = charset_find_spec(charset);
  35     charset_state localstate = CHARSET_INIT_STATE;
  36     struct charset_emit_param param;
  37     int locallen;
  38
  39     if (!input) {
  40         locallen = 1;
  41         inlen = &locallen;
  42     }
  43
  44     param.output = output;
  45     param.outlen = outlen;
  46     param.writtenlen = 0;
  47     param.stopped = 0;
  48
  49     if (state)
  50         localstate = *state;           /* structure copy */
  51     if (error)
  52         *error = FALSE;
  53
  54     while (*inlen > 0) {
  55         int lenbefore = param.writtenlen;
  56         int ret;
  57
  58         if (input)
  59             ret = spec->write(spec, **input, &localstate,
  60                               charset_emit, &param);
  61         else
  62             ret = spec->write(spec, -1, &localstate, charset_emit, &param);
  63         if (error && !ret) {
  64             /*
  65              * We have hit a difficult character, which the user
  66              * wants to know about. Leave now.
  67              */
  68             *error = TRUE;
  69             return lenbefore;
  70         }
  71         if (param.stopped) {
  72             /*
  73              * The emit function has _tried_ to output some
  74              * characters, but ran up against the end of the
  75              * buffer. Leave immediately, and return what happened
  76              * _before_ attempting to process this character.
  77              */
  78             return lenbefore;
  79         }
  80         if (state)
  81             *state = localstate;       /* structure copy */
  82         if (input)
  83             (*input)++;
  84         (*inlen)--;
  85     }
  86     return param.writtenlen;
  87 }