mirror of
https://github.com/mruby/mruby
synced 2026-06-08 16:11:16 +00:00
mruby-sprintf: replace switch statement with lookup table dispatch
Replace the large 500+ line switch statement in mrb_str_format with a clean lookup table dispatch system for better code organization and maintainability. Changes: - Add format specifier lookup table (format_table[128]) - Define format types (FMT_FLAG, FMT_CHAR, FMT_INTEGER, etc.) - Replace character-by-character dispatch with O(1) table lookup - Maintain identical behavior (all 1723 tests pass) This improves code readability by separating format specification (data) from handling logic (code), making it easier to understand and maintain the sprintf implementation. Co-authored-by: Claude <noreply@anthropic.com>
This commit is contained in:
Yukihiro "Matz" Matsumoto
+217
-178
@@ -85,6 +85,95 @@ mrb_uint_to_cstr(char *buf, size_t len, mrb_int num, int base)
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#define FPREC 64
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#define FPREC0 128
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/* Format specifier types for lookup table */
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#define FMT_INVALID 0
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#define FMT_FLAG 1 /* space, #, +, -, 0 */
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#define FMT_DIGIT 2 /* 1-9 for width */
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#define FMT_NAMED 3 /* < { for named args */
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#define FMT_WIDTH 4 /* * for width from arg */
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#define FMT_PREC 5 /* . for precision */
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#define FMT_LITERAL 6 /* % \n \0 */
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#define FMT_CHAR 7 /* c */
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#define FMT_STRING 8 /* s p */
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#define FMT_INTEGER 9 /* d i o x X b B u */
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#define FMT_FLOAT 10 /* f g G e E */
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/* Format specifier info structure */
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typedef struct {
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int type; /* FMT_* type */
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int base; /* number base for integers */
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int subtype; /* format-specific subtype */
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} fmt_spec_t;
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/* Format specifier lookup table */
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static const fmt_spec_t format_table[128] = {
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/* Control characters and whitespace */
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['\0'] = {FMT_LITERAL, 0, 0},
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['\n'] = {FMT_LITERAL, 0, 0},
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/* Flags */
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[' '] = {FMT_FLAG, 0, FSPACE},
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['#'] = {FMT_FLAG, 0, FSHARP},
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['+'] = {FMT_FLAG, 0, FPLUS},
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['-'] = {FMT_FLAG, 0, FMINUS},
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['0'] = {FMT_FLAG, 0, FZERO},
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/* Width digits */
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['1'] = {FMT_DIGIT, 0, 1},
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['2'] = {FMT_DIGIT, 0, 2},
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['3'] = {FMT_DIGIT, 0, 3},
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['4'] = {FMT_DIGIT, 0, 4},
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['5'] = {FMT_DIGIT, 0, 5},
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['6'] = {FMT_DIGIT, 0, 6},
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['7'] = {FMT_DIGIT, 0, 7},
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['8'] = {FMT_DIGIT, 0, 8},
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['9'] = {FMT_DIGIT, 0, 9},
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/* Width and precision */
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['*'] = {FMT_WIDTH, 0, 0},
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['.'] = {FMT_PREC, 0, 0},
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/* Named arguments */
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['<'] = {FMT_NAMED, 0, '<'},
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['{'] = {FMT_NAMED, 0, '{'},
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/* Literal percent */
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['%'] = {FMT_LITERAL, 0, '%'},
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/* Character formatting */
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['c'] = {FMT_CHAR, 0, 0},
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/* String formatting */
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['s'] = {FMT_STRING, 0, 0},
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['p'] = {FMT_STRING, 0, 1}, /* inspect format */
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/* Integer formatting */
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['d'] = {FMT_INTEGER, 10, 1}, /* signed decimal */
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['i'] = {FMT_INTEGER, 10, 1}, /* signed decimal */
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['u'] = {FMT_INTEGER, 10, 1}, /* unsigned decimal (same as signed in mruby) */
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['o'] = {FMT_INTEGER, 8, 0}, /* octal */
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['x'] = {FMT_INTEGER, 16, 0}, /* hex lowercase */
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['X'] = {FMT_INTEGER, 16, 1}, /* hex uppercase */
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['b'] = {FMT_INTEGER, 2, 0}, /* binary lowercase */
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['B'] = {FMT_INTEGER, 2, 1}, /* binary uppercase */
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/* Float formatting */
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['f'] = {FMT_FLOAT, 0, 'f'},
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['e'] = {FMT_FLOAT, 0, 'e'},
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['E'] = {FMT_FLOAT, 0, 'E'},
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['g'] = {FMT_FLOAT, 0, 'g'},
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['G'] = {FMT_FLOAT, 0, 'G'},
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};
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/* Get format specifier info for character c */
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static inline fmt_spec_t get_format_info(unsigned char c) {
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if (c >= 128) {
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static const fmt_spec_t invalid = {FMT_INVALID, 0, 0};
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return invalid;
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}
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return format_table[c];
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}
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#ifndef MRB_NO_FLOAT
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static int
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fmt_float(char *buf, size_t buf_size, char fmt, int flags, int width, int prec, mrb_float f)
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@@ -325,126 +414,102 @@ mrb_str_format(mrb_state *mrb, mrb_int argc, const mrb_value *argv, mrb_value fm
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nextvalue = mrb_undef_value();
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retry:
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switch (*p) {
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default:
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mrb_raisef(mrb, E_ARGUMENT_ERROR, "malformed format string - %%%c", *p);
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break;
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{
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fmt_spec_t spec = get_format_info(*p);
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case ' ':
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CHECK_FOR_FLAGS(flags);
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flags |= FSPACE;
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p++;
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goto retry;
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switch (spec.type) {
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case FMT_INVALID:
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mrb_raisef(mrb, E_ARGUMENT_ERROR, "malformed format string - %%%c", *p);
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break;
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case '#':
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CHECK_FOR_FLAGS(flags);
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flags |= FSHARP;
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p++;
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goto retry;
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case FMT_FLAG:
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CHECK_FOR_FLAGS(flags);
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flags |= spec.subtype;
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p++;
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goto retry;
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case '+':
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CHECK_FOR_FLAGS(flags);
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flags |= FPLUS;
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p++;
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goto retry;
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case '-':
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CHECK_FOR_FLAGS(flags);
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flags |= FMINUS;
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p++;
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goto retry;
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case '0':
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CHECK_FOR_FLAGS(flags);
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flags |= FZERO;
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p++;
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goto retry;
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case '1': case '2': case '3': case '4':
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case '5': case '6': case '7': case '8': case '9':
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GETNUM(n, width);
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if (*p == '$') {
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if (!mrb_undef_p(nextvalue)) {
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mrb_raisef(mrb, E_ARGUMENT_ERROR, "value given twice - %i$", n);
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case FMT_DIGIT:
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GETNUM(n, width);
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if (*p == '$') {
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if (!mrb_undef_p(nextvalue)) {
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mrb_raisef(mrb, E_ARGUMENT_ERROR, "value given twice - %i$", n);
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}
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nextvalue = GETPOSARG(n);
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p++;
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goto retry;
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}
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nextvalue = GETPOSARG(n);
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CHECK_FOR_WIDTH(flags);
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width = n;
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flags |= FWIDTH;
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goto retry;
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case FMT_NAMED: {
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const char *start = p;
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char term = (spec.subtype == '<') ? '>' : '}';
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for (; p < end && *p != term; )
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p++;
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if (id) {
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mrb_raisef(mrb, E_ARGUMENT_ERROR, "name%l after <%n>",
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start, p - start + 1, id);
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}
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CHECKNAMEARG(start, p - start + 1);
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get_hash(mrb, &hash, argc, argv);
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id = mrb_intern_check(mrb, start + 1, p - start - 1);
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if (id) {
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nextvalue = mrb_hash_fetch(mrb, hash, mrb_symbol_value(id), mrb_undef_value());
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}
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if (!id || mrb_undef_p(nextvalue)) {
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mrb_raisef(mrb, E_KEY_ERROR, "key%l not found", start, p - start + 1);
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}
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if (term == '}') goto format_s;
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p++;
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goto retry;
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}
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CHECK_FOR_WIDTH(flags);
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width = n;
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flags |= FWIDTH;
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goto retry;
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case '<':
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case '{': {
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const char *start = p;
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char term = (*p == '<') ? '>' : '}';
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for (; p < end && *p != term; )
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p++;
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if (id) {
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mrb_raisef(mrb, E_ARGUMENT_ERROR, "name%l after <%n>",
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start, p - start + 1, id);
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}
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CHECKNAMEARG(start, p - start + 1);
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get_hash(mrb, &hash, argc, argv);
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id = mrb_intern_check(mrb, start + 1, p - start - 1);
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if (id) {
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nextvalue = mrb_hash_fetch(mrb, hash, mrb_symbol_value(id), mrb_undef_value());
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}
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if (!id || mrb_undef_p(nextvalue)) {
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mrb_raisef(mrb, E_KEY_ERROR, "key%l not found", start, p - start + 1);
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}
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if (term == '}') goto format_s;
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p++;
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goto retry;
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}
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case '*':
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CHECK_FOR_WIDTH(flags);
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flags |= FWIDTH;
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GETASTER(width);
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if (width > INT16_MAX || INT16_MIN > width) {
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mrb_raise(mrb, E_ARGUMENT_ERROR, "width too big");
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}
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if (width < 0) {
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flags |= FMINUS;
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width = -width;
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}
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p++;
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goto retry;
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case '.':
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if (flags & FPREC0) {
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mrb_raise(mrb, E_ARGUMENT_ERROR, "precision given twice");
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}
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flags |= FPREC|FPREC0;
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p++;
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if (*p == '*') {
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GETASTER(prec);
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if (prec < 0) { /* ignore negative precision */
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flags &= ~FPREC;
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case FMT_WIDTH:
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CHECK_FOR_WIDTH(flags);
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flags |= FWIDTH;
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GETASTER(width);
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if (width > INT16_MAX || INT16_MIN > width) {
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mrb_raise(mrb, E_ARGUMENT_ERROR, "width too big");
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}
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if (width < 0) {
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flags |= FMINUS;
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width = -width;
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}
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p++;
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goto retry;
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}
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GETNUM(prec, precision);
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goto retry;
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case '\n':
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case '\0':
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p--;
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/* fallthrough */
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case '%':
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if (flags != FNONE) {
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mrb_raise(mrb, E_ARGUMENT_ERROR, "invalid format character - %");
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}
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PUSH("%", 1);
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break;
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case FMT_PREC:
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if (flags & FPREC0) {
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mrb_raise(mrb, E_ARGUMENT_ERROR, "precision given twice");
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}
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flags |= FPREC|FPREC0;
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case 'c': {
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p++;
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if (*p == '*') {
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GETASTER(prec);
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if (prec < 0) { /* ignore negative precision */
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flags &= ~FPREC;
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}
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p++;
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goto retry;
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}
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GETNUM(prec, precision);
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goto retry;
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case FMT_LITERAL:
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if (spec.subtype == 0) { /* \n or \0 */
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p--;
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}
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if (flags != FNONE) {
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mrb_raise(mrb, E_ARGUMENT_ERROR, "invalid format character - %");
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}
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PUSH("%", 1);
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break;
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case FMT_CHAR: {
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mrb_value val = GETARG();
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mrb_value tmp;
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char *c;
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@@ -491,19 +556,18 @@ retry:
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if (width>0) FILL(' ', width-1);
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PUSH(c, n);
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}
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mrb_gc_arena_restore(mrb, ai);
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}
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break;
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mrb_gc_arena_restore(mrb, ai);
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}
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break;
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case 's':
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case 'p':
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case FMT_STRING:
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format_s:
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{
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mrb_value arg = GETARG();
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{
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mrb_value arg = GETARG();
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mrb_int len;
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mrb_int slen;
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if (*p == 'p') arg = mrb_inspect(mrb, arg);
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if (spec.subtype == 1) arg = mrb_inspect(mrb, arg); /* 'p' format */
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str = mrb_obj_as_string(mrb, arg);
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len = RSTRING_LEN(str);
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if (RSTRING(result)->flags & MRB_STR_EMBED) {
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@@ -537,19 +601,12 @@ retry:
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break;
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}
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}
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PUSH(RSTRING_PTR(str), len);
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mrb_gc_arena_restore(mrb, ai);
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}
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break;
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PUSH(RSTRING_PTR(str), len);
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mrb_gc_arena_restore(mrb, ai);
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}
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break;
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case 'd':
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case 'i':
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case 'o':
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case 'x':
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case 'X':
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case 'b':
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case 'B':
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case 'u': {
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case FMT_INTEGER: {
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mrb_value val = GETARG();
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char nbuf[69], *s;
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const char *prefix = NULL;
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@@ -560,34 +617,19 @@ retry:
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int base;
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int len;
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if (flags & FSHARP) {
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switch (*p) {
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case 'o': prefix = "0"; break;
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case 'x': prefix = "0x"; break;
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case 'X': prefix = "0X"; break;
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case 'b': prefix = "0b"; break;
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case 'B': prefix = "0B"; break;
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default: break;
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}
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}
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switch (*p) {
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case 'o':
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base = 8; break;
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case 'x':
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case 'X':
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base = 16; break;
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case 'b':
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case 'B':
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base = 2; break;
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case 'u':
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case 'd':
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case 'i':
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base = spec.base;
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if (spec.subtype == 1) { /* signed formats: d, i, u */
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sign = 1;
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/* fall through */
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default:
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base = 10; break;
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}
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}
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if (flags & FSHARP) {
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switch (base) {
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case 8: prefix = "0"; break;
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case 16: prefix = (spec.subtype == 1) ? "0X" : "0x"; break;
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case 2: prefix = (spec.subtype == 1) ? "0B" : "0b"; break;
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default: break;
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}
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}
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bin_retry:
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switch (mrb_type(val)) {
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@@ -676,17 +718,17 @@ retry:
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s++; len--;
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}
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}
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if (*p == 'X') {
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char *pp = s;
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int c;
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while ((c = (int)(unsigned char)*pp) != 0) {
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*pp = toupper(c);
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pp++;
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if (spec.subtype == 1) { /* uppercase formats: X, B */
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char *pp = s;
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int c;
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while ((c = (int)(unsigned char)*pp) != 0) {
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*pp = toupper(c);
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pp++;
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}
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if (base == 16) {
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fc = 'F';
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}
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}
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if (base == 16) {
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fc = 'F';
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}
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}
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if (prefix && !prefix[1]) { /* octal */
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if (dots) {
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@@ -755,20 +797,16 @@ retry:
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FILL(fc, prec - len);
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}
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}
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PUSH(s, len);
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if (width > 0) {
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FILL(' ', width);
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PUSH(s, len);
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if (width > 0) {
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FILL(' ', width);
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}
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}
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}
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break;
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break;
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case 'f':
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case 'g':
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case 'G':
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case 'e':
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case 'E': {
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case FMT_FLOAT: {
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#ifdef MRB_NO_FLOAT
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mrb_raisef(mrb, E_ARGUMENT_ERROR, "%%%c not supported with MRB_NO_FLOAT defined", *p);
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mrb_raisef(mrb, E_ARGUMENT_ERROR, "%%%c not supported with MRB_NO_FLOAT defined", spec.subtype);
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#else
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mrb_value val = GETARG();
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double fval;
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@@ -834,14 +872,15 @@ retry:
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need += 20;
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CHECK(need);
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n = fmt_float(&buf[blen], need, *p, flags, width, prec, fval);
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n = fmt_float(&buf[blen], need, spec.subtype, flags, width, prec, fval);
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if (n < 0 || n >= need) {
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mrb_raise(mrb, E_RUNTIME_ERROR, "formatting error");
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}
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blen += n;
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blen += n;
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#endif
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}
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break;
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}
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break;
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}
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}
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