git.distorted.org.uk Git - u/mdw/putty/blob - charset/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     const char *errstr;
  12     int errlen;
  13     int stopped;
  14 };
  15
  16 static void charset_emit(void *ctx, long int output)
  17 {
  18     struct charset_emit_param *param = (struct charset_emit_param *)ctx;
  19     char outval;
  20     char const *p;
  21     int outlen;
  22
  23     if (output == ERROR) {
  24         p = param->errstr;
  25         outlen = param->errlen;
  26     } else {
  27         outval = output;
  28         p = &outval;
  29         outlen = 1;
  30     }
  31
  32     if (param->outlen >= outlen) {
  33         while (outlen > 0) {
  34             *param->output++ = *p++;
  35             param->outlen--;
  36             outlen--;
  37         }
  38     } else {
  39         param->stopped = 1;
  40     }
  41 }
  42
  43 int charset_from_unicode(wchar_t **input, int *inlen, char *output, int outlen,
  44                          int charset, charset_state *state,
  45                          const char *errstr, int errlen)
  46 {
  47     charset_spec const *spec = charset_find_spec(charset);
  48     charset_state localstate;
  49     struct charset_emit_param param;
  50
  51     param.output = output;
  52     param.outlen = outlen;
  53     param.stopped = 0;
  54
  55     /*
  56      * charset_emit will expect a valid errstr.
  57      */
  58     if (!errstr) {
  59         /* *shrug* this is good enough, and consistent across all SBCS... */
  60         param.errstr = ".";
  61         param.errlen = 1;
  62     }
  63     param.errstr = errstr;
  64     param.errlen = errlen;
  65
  66     if (!state) {
  67         localstate.s0 = 0;
  68     } else {
  69         localstate = *state;           /* structure copy */
  70     }
  71     state = &localstate;
  72
  73     while (*inlen > 0) {
  74         int lenbefore = param.output - output;
  75         spec->write(spec, **input, &localstate, charset_emit, &param);
  76         if (param.stopped) {
  77             /*
  78              * The emit function has _tried_ to output some
  79              * characters, but ran up against the end of the
  80              * buffer. Leave immediately, and return what happened
  81              * _before_ attempting to process this character.
  82              */
  83             return lenbefore;
  84         }
  85         if (state)
  86             *state = localstate;       /* structure copy */
  87         (*input)++;
  88         (*inlen)--;
  89     }
  90     return param.output - output;
  91 }